How To Fix Boat Gelcoat Spider Cracks, Hairline Cracks, and Crazing [MATERIALS LIST👇] | BoatUS

[@1StudMuff1n]

Very informative, right to the point without annoying music intro and extensive blah, blah, blah! I always appreciate videos like this, especially by those with a British accent.

[@boatus]

Thanks, Keith. Glad you found it helpful! We try to keep them to the point. And, yes, Mark's British accent apparently does make the info in the videos even more useful if the number of comments we get about it are any indication 😂

[@chunkyfather29]

This guy takes the title of ( Quick, knowledgeable, constructive, helpful) outstanding work 👏

[@boatus]

Thanks so much, Chunky! Glad you found it helpful!

[@kaneaikua955]

It’s apparent Mark knows his craft just his prep work alone show he has learned how to handle material and finishes with amazing results.Thanks for the video.

[@boatus]

Thanks so much, Kane! Yes, Mark is extremely thorough with his prep, which is 3/4 of the project.

[@andrewernst3884]

This video helped me alot, im a young guy in my early 20s and its hard to find knowledgeable people. Thanks to you I was able to restore my 1975 motorhome to a like new finish and your video helped with the cracking thank you for the demonstration and knowledge!

[@boatus]

We're so thrilled to hear that, Andrew! Good for you for tackling that job, and we're glad you were able to apply the info we used on a boat to a motor home. Here's to many happy, safe miles (and adventures) ahead!

[@Fireship1]

I worked with resins, gel coats, micro bubbles (silica) and fiberglass mat in FAA aircraft mechanic school years ago. So I had an idea on how to mix gelcoat and apply. However, it’s been years since I’ve done it. This video was just what I needed to make an almost perfect repair in my transom. (Log bumped it last year and put a bunch of radial cracks as big as my hand.) I followed this video to the letter and got results I’m proud of. Best advice I could give is don’t be afraid to grind those cracks wide. I ground next to one and not directly in it as I was being gun shy. I could see the crack when I look for it, but from a few feet away it’s invisible. I figure if it opens up again next year I’ll just give it a do over. Thanks Mark for making this video and passing on all your professional knowledge!

[@boatus]

Thanks so much for your wonderful feedback, Fireship! We're thrilled you found this so helpful, particularly with your skill level. We also appreciate you sharing your advice and experience with those looking to tackle this project. There are a lot of steps, but it's not nearly as difficult or scary as we fear. Here's hoping the repair lasts for years to come.

[@moejrbig]

Excellent Video. I have ordered all my supplies from Jamestown. I just paid $2,900.00 to have a bunch repaired on my 2009 Beneteau. It is time I learned and your video was very informative.

[@boatus]

Thanks for watching, moe! We're glad you found it useful. Let us know how your project goes. It's not hard to do this yourself--you just have to follow the steps. You might want to watch some of our other gelcoat repair videos, too, because we discuss slightly different techniques you might find helpful depending on location and depth: kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq

[@ibcrypto6139]

Clearly knows what he is doing and does an exceptions job of transferring knowledge for DIY'er with no extra distractions.... Much thanks!

[@boatus]

Thanks, crypto!

[@bwvideo0905]

I have a very challenging project ahead with an almost 50 year old 14 foot open cockpit fiberglass sailboat. Exterior of hull had been refinished before i purchased and structurally all is fine but cockpit probably has 50+ spots that need gelcoat repair nevermind a lot of spider cracks. I have watched at least a dozen instructional videos so far and this is by far the best. Extremely well done sir. I'll take all the advice I can get! Sincere thanks from Upstate SC in the US!!!

[@boatus]

Thanks so much, and we're thrilled to hear you found it helpful. Be sure to watch our other gelcoat repair videos. They have some additional techniques that you might find helpful depending on the location and depth of the repairs. kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq Good luck with your project, and be sure to document it -- or parts of it -- to share with BoatUS Magazine for consideration as part of a future Makeover article. Before/during/after pics are always great!

[@bwvideo0905]

@@boatus Will do! Thanks again!

[@bryanst.martin7134]

Pay attention to whether it is Gelcoat crazing or laminate fractures. Laminate fractures are from a strike to the hull. Gelcoat cracking is Solar induced shrinkage.

[@bwvideo0905]

Thanks much but mine is all age/exposure. No impacts. But good advice. ​@bryanst.martin7134

[@UncleScratchnSniff]

@@bryanst.martin7134 would these be different repairs? Also, how do you identify which is which?

[@tonywulk2710]

Thanks for this Mark. There are so many videos on KZbin with some many different ways to do things. As a new to me first time boat owner, I want to do it right. But, you don’t know who to trust. However, you know you can trust advise from BoatUS.

[@boatus]

BoatUS Thank you so much for your trust, Tony! That means a lot! Do check out some of our other gelcoat repair vids for additional tips and techniques you might find useful: kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq

[@BellavistaPEI]

Probably the BEST information video for this type of repair! Excellent job Mark...THANKS!

[@boatus]

Thanks for watching, Tom!

[@garyhsk8]

agreed, simple and straight to the point with good tips

[@boatus]

@@garyhsk8 Thanks for watching, Gary!

[@sg15]

Just did the same process to repair scratches on my black gel coat hull, minus the dremel tool grinding. For anyone wondering if you need a polisher, I learned that you really do in order to get the shine back. Great simply stated video. Thanks BoatUS

[@boatus]

Thanks for watching, and thanks for your helpful advice!

[@Dragon-Slay3r]

This the automatic car?

[@pwelch5944]

Thanks for the detailed instruction ... took the fear out of repairing spider cracks.

[@boatus]

Thanks for watching, pwelch! It's really not that difficult. Yes, there are a lot of steps, but if you follow the process, you'll have a great result for a lot less money than paying a pro -- or the annoyance of looking at them all the time! Good luck with the project and let us know how it goes.

[@pierredecotret481]

Great video with a wealth of information! Challenge is finding the matching grade of white for the boat. Will definitely try this !

[@boatus]

Thanks, Pierre. Yes, color matching is probably the hardest part if you don't have gelcoat that matches your boat. Thankfully several companies make premixed gelcoat to match most standard boat colors. If necessary, you can also try matching it yourself using white gelcoat and a tinting kit, though that takes a bit more finesse and practice. And some companies can create a custom match if you can bring something to match from. Good luck with your repair.

[@JohnDurden-c1y]

Good demo! And just what I needed to make a old boat look a lot better.

[@boatus]

Thanks for watching, and glad you found it helpful! You may want to check out our playlist of gelcoat repair videos because there are some other techniques that might be better depending on where the repairs are. And there are some additional tips. kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq

[@lakepowellfishing]

Excellent and thank you.

[@boatus]

You're welcome and thank you for watching!

[@judeshriner1132]

Very clear an concise demonstration and procedural explanation of the process and materials needed. One of the very best videos which is why I always subscribe to BoatUS for all my HOW-TOs!

[@boatus]

Thank you so much, Judith! We're thrilled you found the video helpful, and we hope to keep the good content coming--both in video and print.

[@olegnovikov8885]

Thank you for your great video!!! I'm doing repar on Lotus Elise front end gel coat spder cracks. Would you recommend to follow your procedure or use different techniques as it will be painted anyway.

[@joezappo7626]

Thanks a lot I now have confidence to tackle some problem areas.

[@boatus]

Thanks for watching, Joe. Glad you found this helpful. Good luck with your repair(s), and let us know how it goes!

[@harveyhauschildt1152]

Excellent video. I am going to try this on some small cracks and see if I have the confidence to take on larger cracks.

[@boatus]

Love to hear that, Harvey! Glad this gave you confidence to give it a go. Let us know how it turns out! (It's truly not difficult to do for the basic to average DIYer.)

[@nateriordan2677]

Great explanations. Lots of steps, but quality repair always has that.

[@boatus]

Thanks for watching, Nate!

[@stevemeleleu926]

Great instructions and the key seems to be take your time and have the right tools ready to make this look like a professional job.

[@boatus]

Thanks so much for watching, Steve! Glad it was helpful. Yup, you've got it! Lots of steps, but the results (and the savings) are worth it.

[@waterboy8999]

Thanks for posting your videos, I've got quite a few of these little blighters on my Sigma, now I know what to do.

[@boatus]

Glad we could help you out, Waterboy. There are a lot of steps, but it's not difficult, and the results are worth it. Once you get into the swing of it, you should be able to knock a bunch out quickly. Thanks for watching! (And let us know how it goes)

[@waterboy8999]

@@boatus thank you.

[@sibylle_]

Very helpful tutorial, I‘ll be doing this on our boat in a couple of weeks. May I ask which tip/attachment you are using on your Dremel?

[@boatus]

Great question, Sibylle. Looks like our original recommendation in the description is no longer active. We suggest using a silicon carbide or tungsten carbide bit, in a bullet or cone shape. Good luck with the repair, and let us know how it goes! It's not hard -- Just important to follow all the steps and not take shortcuts.

[@MurphysLemonadeStand]

This was a GREAT tutorial! I have (under a Shipwright) restored two boats. At the same time Gel coat was never really a issue I worked on personally. Now that I am restoring my 3rd and my hopefully last live aboard. I really love the close up. The detail and the detail list. When I do get off to actually posting our renovations I will make sure to credit your video for the help I got.

[@boatus]

Aw, shucks! Thanks so much for watching, and we're glad you found this video useful. Be sure to check out our two other gelcoat videos, which include repairing gelcoat on flat and vertical surfaces. You'll find a couple different techniques that you may find useful depending on the application. Wishing you all the best with your restoration. If you take photos during the process, feel free to send them to us at BoatUS Magazine ([e-mail]) to consider for our occasional makeover articles.

[@amandashaughness2180]

Hello Mark - Thanks for your instruction. I'm new to this process. Wondering what you can use in lieu of silica to create the paste? or would you have filled the spider crack with 3M platinum filler? If silica is the best way to go, then great; I just want to make sure I know the options. Thank you for your knowledge and instruction!

[@boatus]

Thanks for the question, Amanda. There are likely other acceptable ways to repair spider cracks in boat gelcoat, however, this is the method that Mark prefers. The silica is necessary to thicken the gelcoat enough that it fills the repair and doesn't run out. Depending on the size and location, you might be able to use mylar plastic instead. You can learn more here: kzbin.info/www/bejne/a3bEoYagr890r7Msi=bpGHmhU0RQEd8v5g

[@petersmaling2989]

Thanks for the advice and video. Following your instructions, my repairs worked a treat

[@boatus]

Thanks for the update, Peter! We're so thrilled it worked well for you. Not too difficult, right?

[@bobdidymus5769]

Great stuff! Step by step guide for everybody to easily understand. Many thanks.

[@boatus]

Thanks for watching, Bob! Glad you found it helpful.

[@garyhsk8]

amazing tutorial, it reduced my fear of messing around with Gelcoat, now I can finally make some repairs on my boats!! I would LOVe if you did a video on how to color match your own custom gel coat to match the aging and possible discoloration of an older boat. Cheers!

[@boatus]

Thanks for watching and thanks for your suggestion! A color-match/tinting vid is on our list. Gelcoat repair really isn't that difficult. It's all about taking the time and following the steps. Good luck with your project!

[@TTURocketDoc]

Could you please explain the causes of hairline cracks? Are they common? Should I be concerned about the integrity of my boat? Is a single discrete crack usually a cosmetic issue and not a sign of structural issue? Thanks so much in advance. {Edit: i just noticed a previous response to a comment that answered most of my questions. Perhaps it would be best to add this info in the description}

[@boatus]

Thanks, HG. Glad you got an answer to your question. I have now added that info to the description.

[@ibrhm_ackgz]

Mark, it was a very useful content, you are great.

[@boatus]

Thanks for watching and glad you found it helpful. Be sure to check out our gelcoat repair playlist for additional tips and techniques!

[@homeycheese1]

Nice video! The issue I find is the that cracks generally form in not so easy locations such as the one in the video. I have some repairs needed on inside corners/edges

[@boatus]

Thanks for the question, David. You're right -- cracks do not always happen to be in the most accessible/convenient places. However, if you are careful when filling the crack, it is usually possible to sand down the repaired gelcoat so that it is flush with its surroundings by wrapping the paper around a shaped block of wood. Alternatively, I suggest checking out another video we have done on repairing vertical surfaces where we discuss a technique that requires using a sheet of mylar - something that might work well for your situation: kzbin.info/www/bejne/a3bEoYagr890r7M

[@joelaszlo4725]

great video and great job sir! I learned a lot and please keep these very informative videos coming. much appreciated all your expert advice.thank you

[@boatus]

Thanks so much for watching, Joe! We will certainly keep the videos coming.

[@legaseasportfishing5372]

Wow, perfect timing for sharing this video and I've been searching for quite a while and this is, by far, the best video for small stress crack repair!!

[@boatus]

Thanks for watching, and glad we could help! Good luck with your project and let us know how it goes.

[@BrettHoustonTube]

Exceptional attention to detail! Great clip, thanks!

[@boatus]

Thanks for watching, Brett!

[@valeriewilliams5165]

Wow that was a great video. I have some bothersome cracks I may try to repair. Thanks!

[@boatus]

Thanks so much for watching, Valerie! Good luck with your project, and let us know how it goes.

[@kerny7678]

Thanks Mark. Needed this video. Was recently looking at some cracks and did not know how to fix them.

[@boatus]

Thanks for watching! Glad you found it helpful. Good luck with your project, and make sure to check out our other gelcoat repair videos for additional tips and techniques depending on the type and location of the repairs. kzbin.info/www/bejne/inurnGtnlNN-iKs

[@stephendudka6192]

Excellent video...I have spider cracks around snap holes and other places. Is the same technique used around the snap hole or should I fill the hole completely,fix the spider cracks and re drill?

[@boatus]

Hi, Steve, and thanks for the great question! You need to remove the snaps, repair the cracks as shown, and then screw the snaps back on. You should not have to fill and redrill the holes, but do put a little mastic polysulphide sealant, such as the Boatlife products available at West Marine and other retailers (www.westmarine.com/buy/boatlife--life-calk-sealant--P004_127_003_003?recordNum=2), on the threads of the screws before you reattach them.

[@DGSenergydevelopment]

Thanks Mark I just purchased a 1994 and it has some top cabin cracks. perfect training.

[@boatus]

Congrats on the new boat, David! Thanks for watching and good luck with the projects.

[@robertcain3426]

Mark. There are two reasons for getting spider cracks (three, if you include a collision). One, is the gelcoat has been incorrectly applied too thick. Two, the laminate is too thin and flexing. Or a combination of both. Gelcoat doesn't like to flex, so the thicker it is applied the less it will flex and if there is movement in the laminate, spider cracks will appear again. Cheers

[@julianr1862]

Wow! An excellent tutorial. Well done BoatUS. Subscribed.

[@boatus]

Thanks, Julian! Glad you found it helpful, and welcome aboard!

[@burtwest2424]

Thank you so much, your videos are very well done. And gives me the confidence to tackle a scrap from a dock screw we encountered. Thanks again.

[@boatus]

Thanks for watching, Burt! Hope your project goes smoothly, and let us know how it goes.

[@timgorton7353]

Great informative video, thank you!

[@boatus]

Glad you found it helpful, Tim! Thanks for watching. If you haven't done so already, you might want to watch out other gelcoat repair vids that have slightly different techniques depending on the location and depth of the repair. There are also some additional handy hints and common questions answered. kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq

[@zacharynicholas4569]

Very informative video, didn't know you were able to repair spider cracks, here goes another boating project!

[@boatus]

Thanks for watching, Zachary, and good luck tackling the project! We just added a list of products and tools used to the description with links for convenience. Let us know how it goes!

[@tristanschaper281]

Great video! I'm doing some repairs on my 2006 Boston Whaler, and all of the spots are not on flat areas. They are on the inside and outside of curves, and a couple spots are overlapping nonskid. I guess I picked a real challenge for my first time! Question: Do you recommend wax paper, thin plastic or saran wrap, for placing over the top to get it flat? And how long should I leave the wax paper/plastic on?

[@boatus]

Thanks for watching, Tristan! We like using Mylar film, often sold at stationery stores. Sometimes called acetate, I believe. It's clear, flexible, and helps smooth out the repair as well as keeping it in place. I recommend viewing our other gelcoat repair videos, especially the one on repairing vertical surfaces, for additional tips and techniques you might find helpful for your specific repair. You'll leave the sheet in place for the recommended drying time -- usually 8-12 hours ("overnight"). kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq Good luck with your project and let us know how it goes!

[@NeverBeenThereBefore]

Excellent video. It would help if you listed with links all the products that you used, would that be possible?

[@boatus]

Thanks for the suggestion, Matt. We'll look at adding that to the description shortly.

[@debianlinux9448]

BoatUS still waiting lol please

[@boatus]

Info is now in the description box! Appreciate the idea, and we'll be doing the same for our other gelcoat repair videos later today.

[@boatus]

@@debianlinux9448 OK, OK! :-) Product list and links are now in the description. Missed the mixing stick, but we'll add that when I get the info.

[@makingcookingfixing]

Thanks for this video. I have a question: my dad has a wooden boat and like on this same exact spot and others around the boat, last summer we repaired cracks with body filler and repainted with marine top gloss paint, but months later, everywhere where we repaired, around he filler it's all cracked again. We basically have to do everything over again. What would you suggest to use this time over? Many were holes under the surface from regular rusted screws that we removed and filled it. We did a great finishing job, but heartbreaking to see the cracks again.

[@boatus]

Thanks for your question, MCF. I don't have a definite answer for you, especially since we can't see the boat in person, but you probably need to start by figuring out the cause of the cracks before you can decide the best way to fix them. I came across this really useful PDF from West Systems, which may have the answers you're looking for. I believe epoxy is a better choice than body filler, which is typically a polyester or vinyl resin. A quick search turns up that epoxy actually binds to the wood and creates a much longer-lasting bond. Here's a link to the West document. Hope you find it helpful. If not, let us know, and I can reach out to some of our experts to ask. Mark, who was our resident boat repair expert, has since retired. www.westsystem.com/wp-content/uploads/0617-Wooden-Boat-Manual.pdf

[@jdlexpress7548]

Hello, nice Repaire video, is it normal for one year old boat to have bunch of gelcoat crack? Should this be fixed by the warranty? Thank you.

[@boatus]

Thanks for the question, JDL. We're assuming you are referring to superficial cracks and not structural. If they're structural (beyond just the gelcoat) -- they're DEFINITELY not normal. I consulted a couple folks around the office, and we agree spider cracks are likely not normal for a new boat either. We recommend first contacting the dealer you purchased the boat from. If necessary, reach out to the manufacturer. Good luck!

[@davidmartins6566]

That was very well done, very informative! Thank you! Great help!

[@boatus]

Thanks for watching, David!

[@markfennah4322]

Nice work and exposition - thanks you !

[@boatus]

Thanks for watching, Mark!

[@greggkathy1892]

Nice, clear demonstration! Thank you!

[@boatus]

Thanks for watching, Gregg! Glad you found it helpful. If you haven't done so already, be sure to watch all of our other gelcoat repair and maintenance videos for additional tips and techniques depending on where the repairs are located: kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq

[@Burritosarebetterthantacos]

when he pulled out that AARP card I almost died.

[@boatus]

You gotta do what you gotta do! Thanks for watching, Skip

[@edwardmcmanus1265]

Great informational vid. Not sure how to match exact color on my Pursuit.

[@boatus]

Thanks for watching, Edward. There are two ways to get the correct color: You can buy pretinted color for nearly any boat (see the description for a link) or have it matched similar to buying paint at a store. Or you can buy tints and tint it yourself, which is a much trickier job. We are looking into doing a gelcoat tinting video sometime in the future.

[@greenskynz]

thanks for the video. has Gel Coat multiple uses or mostly in marine? i am thinking to use to repair hairline cracks in an old spa.

[@boatus]

Thanks for the question, greenskynz. Unfortunately I can't speak to spa repair. Your best option would be to contact the manufacturer and ask what it recommends. Good luck with your project!

[@johncardow2493]

great vid. informative! the interior of my center consol head area has unfished fiberglass, kind of rough, can these procedures be used on the rough fiberglass to seal it over and make it smoother???

[@boatus]

Thanks for the question, John. What you’re likely seeing is fiberglass mat. This is common, generally due to cost-saving measures. It isn’t finished like the “outside” surfaces that you see, leaving the surface very rough. If you’re merely trying to smooth it, adding a layer of gelcoat isn’t going to give you the finish you’re hoping for. To do that, you’d need to sand and finish the fiberglass work before adding the gelcoat. A lot of work! If there are really rough, raised areas that are catching clothing or even drawing blood, you can try sanding them down a bit. Some boat owners have painted on an epoxy finish and report that it helps, though you may want to test a small hidden area first before you commit to the entire thing. Alternatively, many folks simply add snaps to the corners of flat unfinished areas and then snap on a canvas cover to hide it - probably the quickest, easiest fix.

[@johncardow2493]

@@boatus thank you for reply againg great information. i like the light expoxy coating idea. might try that. ty

[@boatus]

@@johncardow2493 Good luck and let us know how it goes!

[@chroniclesofstuntbucket3522]

Very cool share, thanks. Getting the color match seems pretty tricky. Also, over time, does the gel coat fix fade/discolor differently than surrounding areas?

[@boatus]

That's a really awesome question. Yes, color matching can be tough, even if you buy color-matched gelcoat. Depending on age and oxidation, it may not be exact. You can always buy a tint kit if you need to adjust a bit. Generally the area tends to blend in more with time though. And remember that even if it's slightly off, only can you see the repairs when you're close up. If the color match is critical or over a very large area, you might want to consult a pro.

[@docemeveritatum8550]

@@boatus Thanks for the speedy reply - a slight blemish should add to the pedigree of a fine boat (!)

[@boatus]

@@docemeveritatum8550 Indeed!! The stories it could tell ...

[@mikebacevich6665]

Great video! Thank you. How much Colloidal Silica should be added? Can you use too much or too little? Also, for non waxed, what is best to use to once the gel coat is applied, PVA or something else? Thanks

[@boatus]

Awesome questions, Mike. I'd call it about a tablespoon per syringeful of gelcoat. You can always start with a little and add more if needed until you get it to the consistency you want. (Don't forget to wear a respirator while handling the silica!) Too little, and the gelcoat will run out of the repair. Too much and it will become super thick. For nonwaxed gelcoat, you can use PVA or cover it with something like a mylar sheet. We talk about that a bit in this video, more so to keep the gelcoat from running, but it can also be used for nonwaxed gelcoat: kzbin.info/www/bejne/a3bEoYagr890r7M (You might find some other useful gelcoat repair tips depending on where the repair is and how deep.) Thanks for watching!

[@mikebacevich6665]

@@boatus Great info! Thank you!

[@RichardHall-rj5rw]

Thanks for the vedio its a great start to my repair.

[@boatus]

Glad you found it helpful, Richard! Be sure to check out our playlist of more gelcoat-repair vids because there are several different techniques shown depending on where the repair is located. There are also extra tips, tricks, and explanations you might find helpful. Bottom line: Repairing gelcoat is not difficult, but you do need to follow the steps for a good result. Good luck with your repair, and let us know how it goes!

[@dirkvanulden2329]

Thank you Mark, very well explained and good references to required materials.

[@boatus]

Thanks, Dirk!

[@kerryknight900]

Good job simple to follow instructions

[@boatus]

Thanks for watching, Kerry. Glad you found it helpful

[@lucianmarius2003]

Thanks for the tutorials you posted. Please explain to me why in one case you used colloidal silica as a thickening agent for gelcoat, and in another you used only simple gelcoat. For me, the depth of the gelcoat's defects was similar.

[@boatus]

That's a great question, Lucian! If you're working on a flat/horizontal surface, there's no problem using straight gelcoat for the repair. You're not fighting gravity, and it's going to stay where you put it. If, on the other hand, you are working on a vertical surface, you've got to have a way to keep the gelcoat where you put it. And it also depends on depth of the repair. If you go to our vertical gelcoat repair video (kzbin.info/www/bejne/a3bEoYagr890r7M), we had some deep holes that needed filling, which we used filler to do, essentially bringing the surface flush with the surrounding gelcoat. We just needed to brush on some gelcoat, like you would paint, to cover those repairs, and the mylar plastic gives you a smoother finish (not as much sanding required) and keeps the gelcoat from running. In the case of repairing spider cracks, you're grinding out the cracks somewhat, so there's a bit more area to fill, hence the use of the colloidal silica for thickening. Hope this helps, and thanks for watching!

[@Cdelosreyes12]

Thank you for the video. Great info! What type of bit is best to open up the cracks?

[@boatus]

Thanks for watching, Luis! This is similar to the one I use (which is currently unavailable): www.amazon.com/HOMEIDOL-Tungsten-Wood-working-Polishing-Engraving/dp/B076D4Z8LX?ref_=fsclp_pl_dp_9

[@bevspencer8583]

Great information...love you videos....but can you give me an idea where to purchase the gelcoat with wax please? I’m in the uk!

[@boatus]

Thanks for watching, Bev, and we're glad we can be of assistance! Unfortunately, we aren't able to offer any recommendations there in the UK, and our resident Brit, Mark, who was featured in the video, is now retired and enjoying his boat. However, a simple Google search might turn up some options for you. (I did a search for "color-matched waxed gelcoat.") In our experience here in the U.S., the customer service folks at the manufacturers or distributors tend to be super helpful if you have any questions or concerns. Good luck and let us know how your project turns out!

[@bevspencer8583]

Good for Mark......Googled this morning and managed to get a gelcoat kit from a supplier an hour’s drive away, so all sorted now, but thank you!

[@boatus]

@@bevspencer8583 Fantastic news! Glad you found one close by. Let us know how it goes.

[@billcook6886]

Thanks for the great series of gelcoat repair videos! Do you see any benefit to using a flexible epoxy after grinding out gelcoat stress cracks, followed by the gelcoat per your instructions? I've heard that a gelcoat-only repair may crack after a couple of years.

[@boatus]

Thanks for the question, Bill. I would caution against using any sort of flexible substrate under the gelcoat. The gelcoat is essentially a stiff coating and anything underlying gelcoat that is flexible will definitely lead to cracking. Providing the gelcoat repair is done in the way that I show in the video, all will be well. The only time that I would not use my method would be when there is extensive cracking covering the entire deck, which I have seen on some boats. In this case the only sure-fire remedy is to fill and fair the cracks with an epoxy filler and then paint the surface.

[@johnlynch7655]

good simple repair . Well presented

[@boatus]

Thanks for watching! 👍

[@ThatGuy-dj3qr]

Are the cracks not likely to reappear? I have to to assume that there are some flexion or torsion forces that caused the cracks in the first place. Is there a material that allows for some flexion in areas such as this?

[@boatus]

To answer your question, it's important to differentiate between stress cracks and spider cracks (though the terms are often used interchangeably). Stress cracks are generally deeper, involve more than just the gelcoat, have an underlying cause (structural or impact), and are likely to come back if the underlying cause isn't addressed first. Spider cracks are less likely to come back as they're superficial and often caused by age, UV, weather, or dings.

[@jeffs9530]

I like to tape much closer to the repair and when I spread with the card it leaves a tape thin layer over the repair. I like the puffing products you used and will be adding to my favorites on Amazon. Thanks!

[@boatus]

Thanks for sharing, Jeff! Glad you found it helpful.

[@michaelhines6561]

New boat owner- THANK YOU!!

[@boatus]

You are welcome, Michael! Congrats on the new boat. Here's to much fun and great memories ahead.

[@williamhallman2101]

Excellent info on repair to fiberglass.

[@boatus]

Glad it was helpful! Thanks for watching.

[@vonkelly2436]

Excellent demo from Mark!

[@boatus]

Thanks so much for watching, Von!

[@davidtunnicliff5442]

nice video..........thanks. will certainly help me to do some of my own repairs.

[@boatus]

Thanks for watching, David. It's not difficult--you just need to follow the steps. Let us know how your repairs go!

[@davidtunnicliff5442]

@@boatus will do.

[@grahamatsea3575]

Some great tips in this video, thanks

[@boatus]

Thanks for watching Graham! Glad you found it helpful. If you haven't already seen them, check out our other gelcoat repair vids for additional tips and techniques: kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq

[@Cruisingthesouth]

Awesome video! I have to do some repairs my self I’ll be making videos about the out come. Thanks for the info

[@boatus]

Thanks for watching!

[@Goinin]

WOW this guy is very good 👍👍👍 Thank you for your professional help !!!

[@boatus]

Thanks for watching, Douglas! We're glad you found it helpful. Depending on your gelcoat repair needs, we have a couple other videos you may want to watch. Each one has a little different technique that you might find helpful.

[@tamaravolovik9423]

Good job Richard

[@boatus]

I think you mean Mark? Thanks for watching, Tamara! Glad you found it useful.

[@tomhood4872]

Fantastic guidance. I have several invisible hairline cracks in the gelcoat on the hull of my kevlar kayak which are allowing water to slowly seep into the rear compartment. The gelcoat is very thin, and I would prefer not to use a Dremel on it for fear of damaging the kevlar fabric underneath. Can I seal the boat by simply painting gelcoat over the entire area? If so, how should I prep it, and should I cover the wet gelcoat with release film, such as mylar, and sand and buff after it sets?

[@boatus]

Thanks for your patience while we got you an answer, Tom. The first question I'd ask is just how sure you are that the cracks you're referring to are the source of the leak. Hairline cracks are generally in the exterior (gelcoat) only, and water shouldn't leak in through them. Of course, everyone's definition of "hairline" could vary, and maybe these are larger than what I'd call hairline. That said, any crack significant enough to leak will require the dremel and filling. Painting over it with gelcoat isn't likely to do the trick, and the cracks will almost certainly reappear in short order. Hope this helps!

[@tomhood4872]

@@boatus I filled the rear hatch with water, let it sit for several hours and found water slowly seeping from nearly invisible lines on the outside of the hull. There's a repair on the opposite side from a previous owner, and these cracks were probably sustained in the same mishap. The epoxy on the interior is obviously cracked too, or else the water wouldn't penetrate. Since posting this question I've seen a video about repairing gelcoat on a kevlar canoe. I'll have to pick the gelcoat from the crack and replace it, which will be difficult since it's not loose, and I'll have to be careful not to fray the kevlar. Very different from a cosmetic repair to a fiberglass motor boat.

[@jillkreutzer1701]

GOOD DEMO. should work for cracks on my camper, I hope. Bill K. South Dakota

[@boatus]

Thanks for watching, Bill. Yes, the process should be similar. Good luck, and let us know how it goes!

[@ronwright4684]

Is it necessary to thicken the gel coat when the cracks are in a flat horizontal area like a cabin top or a small sailboat hull turned upside down where there is no chance of running?

[@boatus]

Great question, Ron. The thickening is mainly used to keep the gelcoat in place on a vertical surface. Have a look at this other gelcoat repair video for additional tips on flat surfaces: kzbin.info/www/bejne/inurnGtnlNN-iKssi=3dvuWOsrnGRvgH-v If your gelcoat is unwaxed, you will still need to cover the repair with a mylar sheet or similar to get it to cure. If you're interested in our other gelcoat repair videos for additional tips. techniques, and explanations, see our playlist: kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq Hope this helps!

[@henrybochicchio4012]

What's the best way to match the color on a older boat?

[@boatus]

Awesome question, Henry. There are a couple ways you can go about this. Easiest way is to purchase pretinted gelcoat to match your specific hull color. Many gelcoat manufacturers offer a very wide range of premixed colors. If your hull color isn't one that's already in stock, most manufacturers can color match for you like when you go to the paint store. The second way to do this is to buy a base gelcoat along with tints and mix it yourself. This is definitely trickier and requires some patience and trial and error. It's easiest if you are just trying to lighten up a color slightly. You decant your gelcoat and add a little tint at a time until you get the right shade. Use a gloved finger to swipe it on near your repair to check for matching. It will likely lighten up a smidge once dried, and will further lighten due to UV exposure over time. Keep in mind that your hull color may have lightened slightly in the sun, so even a premixed color may not match exactly. Chances are, though, that you'll only see the repair if you're up close to it, and it will blend in over time. We are looking at doing a gelcoat tinting video at some point in the future, but everything is on hold right now. Make sure to subscribe to our channel and hit that notification bell to receive updates when we post new videos about every other week.

[@markrobbins9552]

Might try this. Lot easier than I thought it would be. I've just been filling them in with F/G resin to keep them from spreading. My boat is so ugly it really doesn't matter but I have a mental illness about perfection so it will at least help me to feel better.

[@boatus]

Thanks for watching, Mark. It is a lot of steps but totally doable for the average boat owner. And as a perfectionist, you are more likely to not shortcut anything, which will give you the best possible outcome. Do check out our other gelcoat repair videos as they each contain a little bit different method that you may find helpful depending on where the repair is, how deep it is, etc. Good luck, and let us know how it goes! If nothing else, you will feel accomplished afterward.

[@markrobbins9552]

@@boatus I do watch a lot of your videos. I've been around boats for most of my life but firmly believe you should never pass on an opportunity to learn. I seldom comment but you guys have helped me out a kazillion times and I appreciate it. It doesn't seem like a lot of steps compared to some of the other things you need to do. Boats are kinda like horses, if you don't love them stay away from them. If I do a boat video I'm going to start it with that.

[@boatus]

@@markrobbins9552 As someone who has been deeply rooted in the horse industry for the last 40-something years, I hear you! My mother always says horses and boats have a lot in common: there's a pointy end and a flat end, both need regular care and maintenance, and you have to feed them. And, yes, you certainly have to commit to either one to fully appreciate it. Thanks for being a regular viewer, and stay tuned for more videos coming up soon!

[@markrobbins9552]

@@boatus exactly, but I would add it'll make scary noises and act like it's going to try to kill you but you have to stand your ground and remind it who the boss is.

[@boatus]

@@markrobbins9552 100% true! 😂

[@TheWhiteboyjohnny]

Lovely job , I have a small hairline crack on my motorhome which I live in now . Unfortunately this repair although perfect would be far to expensive with all the products , even as far as an electric buffer.

[@boatus]

Thanks for watching, John. You can purchase smaller quantities of gelcoat, though you would need to tint it yourself to match. For one crack, it might be just as easy (and maybe less expensive) to have someone repair it for you.

[@domenicvenuto6618]

Good summary of the steps and process. Thanks!

[@boatus]

Thanks so much, Domenic!

[@grimreaper4751]

Hi, informative video, but I have to ask what type of gloves you are wearing while using the acetone? I'm guessing nitrile (blue)? I would strongly advise against using nitrile with acetone... it will burn right through. Only use latex. Nitrile is fine for resin etc.

[@boatus]

Thanks for the concern, grim. I believe they were Latex. No issues with it burning through.

[@bertherta494]

Hi, after watching this I might give a few repairs ago over commissioning the work out, so thank you for the video. My query is whether the same process is used where the topsides may have been resprayed. Small areas of spider cracking can be seen below, not under the toe-rail to one side and a slightly larger area on the other. I only believe that my boat has been resprayed as the surveyors report read "there is evidence that the vessel has been resprayed since she was built" many thanks.

[@boatus]

Thanks for the question, Bert. If I understand your question correctly, the boat was painted over the gelcoat at some point (not uncommon for older boats)? To repair the gelcoat damage, you can absolutely use the technique I described in the video if the boat has been sprayed. However, the hard part is going to be matching the color to blend with the surrounding painted area. Although you do not say what paint has been used, I do know that matching Awlgrip and similar two-part paints is very difficult. Although you may make a perfect gelcoat repair, if the paint does not match then the repair will be visible. I might suggest that you entrust the paint patchwork to a professional yard, especially if the repair is anything more than very minor.

[@krussell2713]

Do you rinse the buffer out when your done with just water for reuse?

[@boatus]

Thanks for the question, krussell. Do you mean the buffer pad or the buffer itself? Some buffer pads are generally disposed of after use. However, if you do a search, there are a bunch of videos on how to clean some buffer pads. You just want to be sure you don't introduce any grit or it can leave scratches in your finish.

[@stevenvachon9745]

Thank you for this. What product/technique would I use to build up the worn through bottom ridges on my Hobie cat? It's just the gelcoat in small areas that's worn through from dragging on the sand. Thanks

[@boatus]

Thanks for your question, Steven. Repairing the gelcoat on the bottom of the Hobie is certainly possible and you can find out more about the recommended technique for this at kzbin.info/www/bejne/inurnGtnlNN-iKs. To be successful, you really need to flip the boat over, which means removing the rig, but the results will be worth it. Trying to work upside down is difficult as you will be fighting gravity and working in awkward positions. Best of luck, and we would love to know how this turns out!

[@mariuzangoncalves6138]

Congratulations, very well explained!

[@boatus]

Thanks for watching, Mariuzan!

[@ezakoske]

If you have extensive spider cracking, is there another way to repair it? Thanks for the video - very informative!

[@boatus]

Sorry to hear about all the cracks you're dealing with, Erik. I’ve seen boats where there is spider cracking over the entire deck, and although you could repair them using the method I describe, it would be time consuming in the extreme. In this case a better option is to fill the cracks with an epoxy filler and then paint. But even if you paint you will still need to open up the cracks before filling, or the cracks will eventually show through the paint.

[@onetime7539]

Would this be an acceptable repair method for some trailer rash along the keel? Or should I use a fairing compound first?

[@boatus]

Thanks for the question, Onetime. Depending on how deep the rash is, you may want to use this technique instead: kzbin.info/www/bejne/a3bEoYagr890r7M If you have a light colored hull and use the filler method, we do recommend you use a light colored filler rather than the darker we used in our video. Or expect to need a couple coats of gelcoat to cover it fully.

[@pashkoskoda3862]

Nice video and thanks for sharing. I have a question regarding gelcoat paste. I purchased two oz of boat/color specific gelcoat and I think may have waited too long to do repairs. The consistency of the paste is like peanut butter when you first open the jar. Is this how it should be? This is my first time ever trying it and was not sure.

[@boatus]

Thanks for your question, Pashko. The gelcoat we used is the consistency of a paint, but that's not to say that all brands are the same. Did you try mixing it well? I would reach out to the manufacturer to ask whether that's normal for that brand. And if not, see if there are any recommendations for thinning it, like adding some styrene. I'm hesitant to make any specific recommendations though without being there in person. The gelcoat companies usually offer good customer service and can give you the best information based on your particular situation. Let us know what you find out!

[@pashkoskoda3862]

@@boatus I spoke with SPECTRUM COLOR REP today and was told that the paste should be peanut butter like when you open the jar (lol) which it is.

[@boatus]

@@pashkoskoda3862 (mmmmm ... peanut butter!) Perfect! Glad it's ready for your repair.

[@ralphslade9558]

Very informative and to the point. Thanks!

[@boatus]

Thanks for watching, Ralph. Glad you found it helpful.

[@obiwanfisher537]

With the left over materials I could open my own chandlery

[@boatus]

Thanks for watching, obiwanfisher. You're correct that there are quite a few materials needed for this, but the savings of doing gelcoat repairs yourself can be substantial. Hopefully you never need to do any repairs, but the investment is worthwhile if you do.

[@lornejanes6001]

Mark , excellent video , conscise, to the point. Clean and clear.. well done !! Thank you

[@markrobbins9552]

Been getting a lot of useful information from you on a number of things so I'm wondering... I'm in the process of restoring a 40yr old Wellcraft (solid hull, strong motor ) at 1st I was just going to stick to if it helps it float or find fish great but don't waste time or money on "beauty". Tired of people saying "you came out here in that? (can't wait until one of them has to ask for a tow) anyway, it has this horrible bottom paint I want to get it off. Is there a paint stripper that won't damage the gel coat underneath? Kept on a trailer, don't need it and damn is it ugly. Thanks in advance and keep up the good work. I'm subscribed to your channel if you have a magazine where can I subscribe to that?

[@boatus]

Wow, Mark! Thanks for watching and being inspired. First, the answer to your question about stripping bottom paint: There are plenty of paint strippers on the market designed for marine antifouling paints, however, be forewarned that this is a really difficult job. Some strippers create hazardous fumes, others require neutralizing after the process, and they all make a rather huge mess that has to be contained and cleaned up. Some are safe for epoxy barrier coats, and others aren't. Some require plenty of scraping along with a soak-time that can hit 24 hours to reach maximum effectiveness. Often multiple applications (and multiple gallons) are necessary. Just about everyone we know who has tackled this job has said afterward that if they had to do it all over again, they'd pay to have the paint soda-blasted off, instead. In regard to your boat: Good for you! If you love her and she makes you happy, don't listen to anyone else. You might enjoy reading this story from our contributing editor Lenny Rudow about the lessons he learned from refitting his older boat. Why he chose to do that instead of buying something newer. The things that were worth it, the things he should have done, and things he did that weren't worth it. It's a great story, and it might help you prioritize where you put your time and money: www.boatus.com/expert-advice/expert-advice-archive/2020/february/lessons-learned-from-refitting-an-old-boat Finally, we're so thrilled that you are interested in our BoatUS Magazine! The good news: We have one, and it comes out 5 times a year. Plus we have a monthly newsletter with additional stories you won't read in the magazine. It is available with a $25/year membership to BoatUS. The membership is worth it just for the magazine, but you get so much more including exclusive member discounts with manufacturers, car rentals, charters/cruises, and much more. Plus, we have a huge network of marinas, tackle shops, fuel docks, local charter companies, restaurants, and much more that offer our members special discounts on equipment, fuel, supplies, transient slips, and many others. Get rewards from our partner West Marine. Membership also includes free MMSI number registration, local and federal government representation on issues that affect boaters, discounts on online boating courses through our BoatUS Foundation, a free BoatUS App, insurance products through GEICO, discounts on boat graphics, hurricane tracking, and so much more. Or upgrade to a towing membership and get all those membership benefits PLUS on-water towing for breakdowns, dead batteries, soft ungroundings, or running out of fuel through our network of more than 300 TowBoatUS ports across the US. PHEW! To learn more or sign up, visit www.boatus.com/products-and-services/membership and www.boatus.com/products-and-services/boat-towing Especially with an older boat, the towing can offer you confidence that you'll always have an affordable way to get home at the touch of a button, a VHF call, or a phone call to dispatch.

[@pashkoskoda3862]

Excellent video! Thank you for sharing.

[@boatus]

You are quite welcome Pashko! Do check out our other two gelcoat repair videos for additional repair tips and techniques for different applications.

[@Devast8r34]

Thank you

[@boatus]

You're welcome! Be sure to check out our library of gelcoat repair videos. There are some other techniques you might find useful depending on where the repairs are located and what types of repairs they are: kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq

[@SoundzAlive1]

You certainly scared those spiders off. André

[@boatus]

🤣

[@richardolson8120]

Great job. Now to go and do it!

[@boatus]

You got this! Thanks for watching and good luck. Let us know how it goes.

[@joegreco8599]

Thank you for the tutorial!!

[@boatus]

Thanks for watching, Joe! If you haven't done so already, check out our other gelcoat repair videos. There are some additional techniques and info that you might find useful depending on the location, size, and severity of the repair. kzbin.info/aero/PLSrVa8gUFaPwF4oz5H4JmSEkdlTwkCrYq

[@fintryendrickwildlife1619]

Many thanks Easy to watch and understand …

[@boatus]

Thanks so much for watching, Allan! Glad you found it helpful.

[@jeffh5388]

Thank you so much.

[@boatus]

You are very welcome! Thanks for watching.

[@pooreyorkie4478]

Hi Mark, can you tell me what you would do if you had a jet ski that had many of these spider hairline cracks on nose of the PWC?

[@boatus]

Hi Poore. Mark has since retired to spend more time doing projects on his boat. But I have a feeling he'd send you a link to this video. Good luck with your project. It's not difficult; just takes time, good prep, and following the steps.

[@tsmith9825]

very good information. Thanks

[@boatus]

Thank you for watching! Glad you found it helpful.