Gelcoat Repair : How to repair cracks and chips in damaged gelcoat

This video is a step by step on how to properly repair your cracked gelcoat. Justin at The Skiff Shop shows us his process of grinding out the old gel coat, filling these cracks with resin paste, applying the new gelcoat and buffing it out! Hope this video is helpful with your project. Please subscribe to our channel for upcoming how to videos!
PRODUCTS
MEKP : fiberglassflorida.com/catalys...
AEROSIL : fiberglassflorida.com/aerosil...
ADTECH : fiberglassflorida.com/adtech-...
CARBON GUIDE : fiberglassflorida.com/fibergl...
GEL COAT : fiberglassflorida.com/gel-coa...

[@mekine-4606]

It is always in the prep. 98% prep, 1% hose time, and 1% buff time. If there is a "How-to video on gelcoat repair out there. This is definitely one of the VERY BEST!!! Justin rocked it, and his teaching was extremely clear and to the point, especially "rolling the tape edge for a soft line for buffing. Excellent video!! Thank you.

[@rimaggio]

I'm impressed with Justin's attention to detail and his search for perfection. Congratulations!

[@jzl300z]

Man so much work! Respect to everybody who does good work in the industry.

[@russellhughes2903]

This is the best video I've found yet explaining spider cracks and repair. I'm currently doing my Moomba but it's on the actual hull. I'm not finding much in videos for doing ski boat hulls specifically, but thanks so far.

[@seadriftcharters0624]

When I watch these videos and read the comments, the majority of them are negative in one way or another. It's great to see a young man of his age to be passionate about his work and go the extra mile to make sure it looks perfect. Keep up the good work and if I didn't live three states away, I would have you fix all the scratches and dings in my boat! BTW, I do agree that you need a mask or respirator and safety glasses. MEK is some rough stuff.

[@FiberglassFlorida]

Couldn't agree more! Justin does an awesome job and you can tell he enjoys what he does! We take the time to put these videos up to try to share some insight and best practices for people that are either new to the industry or working on a DIY. I guess people just love being negative over the Internet. lol

[@leesire]

Seadrift Creations, ditto!

[@robertjackson7590]

@@FiberglassFlorida Everyone on the internet has a PHD in whatever you're doing. Funny how that is.

[@randomschittz9461]

There were ZERO negative comments on this video. 👍🏽

[@greggkathy1892]

As is colloidal silica (aerosil, I believe is what you were using).I’m a dentist who recently started “always” wearing gloves when I wiped down dirty operatories with cavicide. I noticed I was having a lot of headaches. Now they are gone. We only get one body and we gotta take care of it. You’d have made a great dentist! I’ll be using your technique, Justin, on my SeaRay, in this upcoming Indiana offseason.

[@JChen-vs7mm]

Agree with earlier comment, so nice to see a young fellow demonstrating so much patience and attention to detail. Admirable qualities Justin! Great video...

[@MrA1582000]

You, young man, are an artist with this fiberglass repair. It was very educational and really showed how to approach such a repair.

[@FiberglassFlorida]

Justin does an awesome job, The Skiff Shop is definitely the place to get repairs done right!

[@mikelightbourn1348]

Awesome video! So much information I had to save to watch a couple more times. I can only imagine the skills 2 years later🤯🤯

[@punziracing]

By far the best video on you tube showing the right steps to correctly repair small dings in gel coat, great job!

[@FiberglassFlorida]

Thanks for watching!

[@cjharrin]

Excellent job. Takes pride in his work. Well done

[@rstyll]

Like a dentist for boats. I appreciate the detail and time it takes to make these kind of repairs. Thank you for sharing your techniques.

[@FiberglassFlorida]

you got it! make sure to subscribe for more videos like this in the future!

[@alanherrett7602]

Dang. When can you come over to my house and buff out my boat? Wow, your attention to detail is impressive.

[@billl7551]

No nonsense commentary. Perfect and focused on the job at hand. A person who knows his craft. Lots of other vids about cracks but Justin gets to the heart of the matter, routing to the glass or the crack returns!! Well done! I am doing the same for my airplane tips that have cracks but no structural damage. But - - how do you find all the hairlines? Is there a dye method? Thanks

[@cliveradvan3414]

Good presentation and dialogue. Came away with a lot of useful tips. Thanks

[@FiberglassFlorida]

you got it!

[@lilhasselhoffer]

So, a few tip to add from someone who does this a frighteningly large amount of the time. If you've got a large crack or scratch that penetrates to the chop layer, then you should not rebuild the entire thing with the Gel Coat. As stated, the shrink is actually much higher on it, and leftover internal stresses from a large blob will cause issues. Use Bondo and some chopped fiberglass to rebuild the structure. The bondo is filler, while the fiberglass fragments are where your strength comes from. Aim for about a 10-12% per weight ratio of Bondo to fiberglass. Once hardened sand and make sure the surface is rough but not jagged (100-200 grit sandpaper). Whenever you mix gel you should pay attention to a lot of things. You're looking for 80 degrees ambient minimum (usually 90 is target), with about 20-40% humidity. This is hugely important for not retarding the cure time. 10 degrees isn't a lot, but it can double cure times. You're aiming for about 1.5% catalyst (MEKP) to 98.5% gel by weight. You can eyeball it, but it's a potential failure mode. This mix will give you a pliable but thick coverage for deep damages. If you're using a wren gun, or other air tool, aim for 1.5% catalyst, 70% gel, 28.5% acetone mix. The acetone will retard the cure time, but it will allow the material to flow through most gun tips without too much issue. Flush the tip with pure acetone afterwards, or the gel can gum up in the tip. Once you apply the gel with either the air gun or as a paste allow to cure until tacky. The next bit is a huge time saver, so take it for what you will. Once the outside edge of the patch dries fully, but the inside is barely cured, gently wipe the surrounding area with an acetone laced paper or fiber towel. You'll thank me because a lot of your overspray and debris from around the patch will quickly be cleaned off with only a gentle rub. Allow the rest of the patch to cure fully, then begin the evening process with your sandpaper. For sandpaper, you've got a lot of choice. I'd recommend 3 different grits. 400, 600, and 1000 work best in my experience. 400 will allow you a shape, but not aggressively. 600 removes the remaining bits, but is fast enough to not take all day. Finally, 1000 gets you to a place where the buffing compound will absolutely shine it up, and again will allow for this to happen quickly. Finally, buffing. Your two friends here are either a red rouge stone, or polarshine. I know the later is a product, but the other stuff I've used is aquaglass...and I wouldn't recommend. Apply the rouge stone to the buffer, or the abrasive to the surface. Buff in tight circles, oscillating the head so that no one spot on the buffer head makes contact for more than 10-20 seconds. I see that using the edge is done in the video...but when you're looking for more control you should use the buffer face. An edge can easily grab onto features and wind up causing issues. Not to say it's not valid, just a lot more prone to failure. I personally would recommend red rouge for most people. The stick is stable, it'll last months or years for the average person, and it doesn't dry out into a flaky lump if left unattended. Now...why should you listen to anybody in the comments? Well, the simple answer is that I make Bathtubs. I've been white head to toe more than once, and I've repaired everything from a surface crack to a gigantic missing chunk because somebody decided to jump around in a bathtub and put their foot through a seat. You're welcome to discount the advice...but it's hard to consider it trivial when you've got 300+ units to finish in a day and about 5 minutes a unit of repair within cycle time. I could be lying...I could be pulling ratios out of thin air. Believe me if you're willing, but I can attest that boating and bathtubs are functionally the same process...and those with experience might know the MVP of guns in more Venusian than you'd think....

[@harveykellywillis8353]

Could marinetex be used for these small dings? Dents? Then spray gel over? Thnx

[@lilhasselhoffer]

@@harveykellywillis8353 I would not. The acrylic has some issues bonding to the surface in my experience. It can be done...but isn't advised for ease or repair lifetime.

[@StewartGartland]

Tremendous skills, I'm very envious!

[@gamachoduck]

felt like I was at the dentist for a minute there, gotta love air tools!. Nice work.

[@FiberglassFlorida]

we realized after we could have taken some of that audio out lol

[@Antipodean33]

Great info thanks mate. Looking at the boat you're working on makes my job on a small tender look easy and I thought I had a ton of spider cracks to fill

[@stevestaff5240]

Thank you for these videos..It helps others trying to learn .the right way! .

[@FiberglassFlorida]

Absolutely, we make sure to find the right people to get on camera! too many wrong ways on KZbin.

[@FattyMateo]

Impressive attention to detail. I would wear a respiratory though. I meet so many patients who sanded things for a living. We don't know what that stuff is going to do to your lungs in 20 years.

[@EaglefordDriller]

this guy has great work ethic.

[@erniedg]

Wow! Much more involved than I thought. Know anyone in Broward that does similar quality work??

[@madokatondo360]

Best video clear and very clear explanation with patience step by step 👌 thank you for sharing

[@markprice3909]

What’s the benefit of using the adtec after the resin? Just to get it smoother? Also do you make is slightly below level so that the gelcoat is even with the other ?

[@markciminelli5457]

That was a fantastic video, thanks for putting together such a detailed explanation of the required steps. Very helpful.

[@dwayneroberts6616]

Hey if you're getting ready to attempt this. Check out total boat gelcoat paste it has everything he just mixed up in it. You can get it from spectrum to if you give them the HIN they can match the factory color with it so filling and finish come out easier and without trying to use pigments to match the hull color.

[@dontall71]

Thanks for all the great tips and technics

[@FiberglassFlorida]

no problem at all.

[@catherineromeo4891]

Justin does a nice job explaining & pointing out the small details I’m in the process of my1st restoration project I’ve been repairing small gel cracks etc. & was looking for a touch up spray gun like he used what make , model & where to purchase , the nozl. size can it spray gel. Thank you & keep videos coming great job

[@Ranger830]

Beautiful work! I repair a lot of fiberglass and epoxy surfboards! It is def an art. Well done 😎🤙

[@KensGarage1]

Great video. I have some MC fiberglass parts to repair and this was very helpful.

[@deraeler]

Missing some key points from this video: 1) For larger holes I can mix resin and fiberglass cloth fiber...and add the aerosil to make it thicker? I've had problems adding resin to the bottom of a hull (working upside down necessarily, I cant invert the boat) and having it drip. The aerosil will help with this? 2) Once the resin mixture is dry, then I use the P-77 filler? Can I use the aerosil with this also to prevent sagging? Gravity is my enemy here. 3) The p-77 dried and sanded... I presume what you're spraying on after this at the end is the polynt 944 GelCoat paint - can I color match this to a kawasaki jet ski hull white?? I dont have a spray gun kit, can I just brush apply this and sand it?

[@fireyourrocketts]

I have a Swift Canoe with spider cracks that just appeared on the side of the hull, they are sending me (buying it for $90.00 total with shipping from Canada after I paid almost $3000 for the boat new and used only once!) It is said that the repair can be done if I have a good hand to follow the channels with the dremel tool which I think I am good enough to do those but I can see of all the work involved for a small area wonder how long will take me to do a job that would really blend and erase the cracks on the hull they are sending me the material they use so the color is White Champagne; they are including the hardener; but here you are working with far more materials; will my repair be an amateur one after done because of those differences? I am confident and have a good eye for blending and working with the tools needed but I only have the dremer tool and the rest would be using sand paper and sanding blocks; suddenly I wonder if it would not be best to just prep and work in the whole area of the cracks which is about 20inch long by 7 inch high rather than follow all the crack in channels???

[@mattlittler2588]

Good video what was the compound you used to buff with I hate having compound all over the boat when it's a small spot

[@buyamerican3191]

Excellent video, great presentation showing how it's done without too much talk! I would like to know how you color match gel coat when you're not working with plain white.

[@FiberglassFlorida]

we sell pigments on our site that people will use to help get closer to the boat color but we also sell color match gel coat by the gallon.

[@ElismyJudge]

Great video, thanks for posting. Justin, your attention to detail is first rate and a credit to your workmanship. The finish looked perfect.

[@88krazie]

Hello nice work, you skipped over mentioning what compound your brushing on, can you share?

[@trippvogel1781]

Nice professional work!

[@joeross952]

As a paint and body man by trade I have to say this is interesting. Can you not smoke gel coat in like we do clear?

[@zippythechicken]

i really liked this and you can tell justin knows what hes doing... the only thing I left wanting to know is ... he did this like a spot repair on a well maintained boat but the boat he is working on has a lot of damage ... I would have liked to have known how he would have done the whole boat I am guessing he would have done all the grinding for the whole boat and then the filler and then sprayed the whole boat with gel coat and sanded and buffed the entire boat at once

[@FiberglassFlorida]

Zippy TheChicken yes he did this small spot for the video, in the video you can see us film different spots. Justin did about 4-5 spots at a time. This boat had all the cracks repaired along with many other upgrades and repairs

[@tonyburry9036]

Now people understand why fiberglass repairs cost more money then you think, this is not a DIY lol great job keep them coming I love this!!

[@jonpalmpalm]

my man crushed it, top quality

[@zw5509]

Nicely done!

[@D_U_O]

Great video, bro !

[@agentbey]

Very awesome professional work.

[@THEtimguitartaylor]

Really useful info. Many thanks!!!

[@newbiefishing7775]

Great video and great patch job!!!

[@dawnosborn8817]

Kudos young man. mad skilz.. much respect from an OG

[@allenletizia321]

I hit tree backing up crack 4 to 5 inches long . Chip under rubber bumper . Would Marine -Tex be ok to use after get down to the fibber glass ?

[@brettlanglois8769]

Quite the process but great job young man!

[@timconrad63]

did a very good job enjoying the non-fiberglass people how to do it one more tip I would add to you is that the end of every crack drill a very fine hole that way you'll stop the fiberglass from continuing its crack

[@fishyhobby3697]

Impressive, thanks for sharing..

[@edknowles8004]

Great job thanks

[@maxpower2280]

Bloody nice work mate

[@tonyb.1994]

Good vidéo, nice job. Thank you

[@toddszymanski3907]

Excellent video.....well done sir.

[@FiberglassFlorida]

Thank you kindly!

[@yeoldepirate783]

great video,, thanks

[@FiberglassFlorida]

you are welcome!

[@catherineharris4746]

Outstanding!👍👍👍

[@markpalmer9254]

Just wanted to echo seadrifts comments. Refreshing to see a young man with such detailed knowledge and a passion for his work. But the amount of labor that goes into those repairs , I guessing that is now an 80k boat from 1980s after all that work lol.

[@1951Roy]

Nice job on the light repair.

[@MrTrker1]

How do I fix a burn from someone buffing a boat that did not know what they were doing?

[@trescocos]

Nice work! viewers need to realize this was a demo for diy people. If he were doing that boat he would be doing all 15 nick repairs at the same time! I am not sure if you need to add cf to the mix but I am sure they do it for a reason or they wouldnt be doing it!

[@FiberglassFlorida]

Chris Berlin that’s exactly right! Thanks for your comment

[@sv-macgyversridewjackbabbj6739]

i would say an excellent job . hat off to you .

[@justinmartin7723]

Hi guys quick one for you. what tool did you use on the Dremel great vid. thanks

[@ramonvenegas8535]

Exelent video 👍

[@FiberglassFlorida]

Ramon Venegas thank you!

[@dudeleboski2692]

Sorry to ask, but how much an hour would you charge for your excelente,super detailed work?

[@FiberglassFlorida]

Dude Leboski we only sell the local shops their materials. If you want any work done by them the business is called The Skiff Shop. They do awesome work. Should be easy to find it on google, Facebook and Instagram

[@rafaelreyes4251]

Hi, I really liked your video, you could make a video how to mix the gel coat to use in a spray gun, and which gel coat to use, there are two, one that has wax and the other that does not have wax. I want to do some repairs in a small boat. thanks...

[@cspray5386]

Use wax for repairs 10%

[@sq7wojwojtek314]

Perfect 👌

[@mycofairbanks3321]

Thank you my friend

[@FiberglassFlorida]

Always welcome

[@murphmurph2124]

No cutting corners here. Fine job!

[@roceksklepserwisrowerowona9773]

Hi ! Good job ! Please tell me what is the name of the paste from 11 minutes 6 seconds ?

[@redcliffebeachhire9214]

TOP CLASS GLASS WORK

[@sl5311]

Could you post a materials list and links where to buy them, Adtec, Aerosil(?), MEK and a link to buy carbon fiber? Thank you!

[@FiberglassFlorida]

ADTECH fiberglassflorida.com/adtech-filler.html AEROSIL fiberglassflorida.com/aerosil-cabosil.html MEKP fiberglassflorida.com/catalyst-mekp.html

[@FiberglassFlorida]

check out our site, we have everything you will need and more!

[@sl5311]

@@FiberglassFlorida Thank you so much. I am rehabbing my first 13 foot sailboat and you are saying these products and they aren't sounding like they are at Home Depot( ha ha)

[@fishyhobby3697]

What dremel tool is that youre using?

[@chrischudkosky5784]

I have a 23.6 ft sailfish center console, what would cost me to do a complete gel job top to bottom???

[@cspray5386]

Just paint it

[@itsjavaman]

First, thank you for the video. I appreciate the opportunity to learn from you but please answer me this. It seems like you taped off an area to repair and there are 2 or 3 more scratches or indents in the gelcoat that are inches away from the repair that your working on. At what point do you say to hell with it and sand blast the entire hull down to glass and just re-prime and paint? How many of these small dings and cracks can you repair in a day? Also does the color or age of the of the gelcoat ever become an issue?

[@FiberglassFlorida]

This a great question, when he does these repairs he usually works in much bigger areas knocking out multiple repairs at once, for the sake of the video we focused on a single spot to help show each step of the process.

[@johncasor9698]

This is a learning Video on how to do a repair... Hello... Another Great Video...

[@richardwinger6390]

what is your sprayer setup?

[@omerbbM5]

Nice work thank you

[@FiberglassFlorida]

No problem 👍

[@silvanomoreira5407]

Hello, I am thinking to have a small sauna in the after kabin of my glass fiber sailboat? May this project go well if I investering in a proper isolation? Or it that just an insane idea?

[@michaelronquillo3842]

It is doable if you can afford it.

[@nickbruton8508]

If your doing these DIY can you add color to the gel to avoid having to spray for the color match?

[@FiberglassFlorida]

Yes, if you color match the gel previous to doing the repair you can wet sand and buff the area after repairing it to avoid respraying the entire boat.

[@jasonkeith674]

Holy s#%^+, such attention to detail 👍. Thank you sir 🙏

[@FiberglassFlorida]

he kills it! planing another video with him soon

[@jasonkeith674]

@Fiberglass Florida , I have a have a ‘72 SCHUSTER I got last summer. I’m replacing the floors and now I see the exterior needs chip and crack work where the previous owner docked it a lil too hard apparently. I’m looking forward to learning from you guy’s. Keep it up 🙏

[@SCCIT-jq6jh]

What's the difference between mek and acetone?

[@Tylerdesignforcomposites]

Nice work dude

[@FiberglassFlorida]

Thanks!

[@andreaslyng]

Hello Justin! Great work with the Gelcoat! What chemical do you use to clean your paint gun after spraying the Gelcoat? Thanks

[@FiberglassFlorida]

Most likely Justin used acetone. Acetone is a great clean up solvent for any polyester products.

[@patcarr8678]

Thanks for the tutorial. It would be helpful to show the products you used. How is the color matched?

[@FiberglassFlorida]

Justin used a couple products here including Adtech P14 putty, Aerosil, polyester resin, and our white gel coat. In order color match you will have to add pigment to the gel, all of the products used in the video and the pigments can be found on our website @ Fiberglassflorida.com.

[@darrellbrown8547]

Great vid. Thanks!

[@lucianosantucci108]

Brilliant 👍

[@Xorblex]

What is the white powder ?

[@primemover1937]

Wow great job brotha! coming from an aviation background and learning how stringent the methods must be for aircraft, I recognize this guys skill and dedication to this craft. He really cares and has pride in his work. But agree on the safety gear. at lease a good dust mask a glasses

[@makingcookingfixing]

I got this job to do on my boat, I thought to dremel the cracks, then use gelcoat putty only, here I am seeing he is first closing it up with polyester resin and cabosil, then after he is using gelcoat. is the gelcoat alone not good enough?

[@makingcookingfixing]

the problem cracks I have tix : kzbin.infoCKJepBazYvs?feature=share

[@markprice3909]

How long does it take for the resin paste to cure before gelcoat? He seemed to do the whole repair in few hours.

[@FiberglassFlorida]

It sets up fairly quickly, It really depends on what percentage you shoot it at. This full video was filmed in one day about 4-5 hours total.

[@henryviljanen8341]

Whats tthe carbon "paste" before wet sanding for?

[@FiberglassFlorida]

Henry Viljanen to help you see where it’s bumpy. Helps with seeing where you’ve sanded and where you haven’t.

[@jonnywow2585]

nice video , what is the purpose of the black powder?

[@FiberglassFlorida]

The black powder is actually extremely fine strands of carbon chopped up. This gives the repair more strength.

[@geoffstein3896]

Mate awesome video thanks for sharing. I'm in Australia and I'm trying to diy a few little scratches and one half decent gauge where I missed the first keel roller. Hi did you spray a thin layer of gelcoat on the area and not wear it away sanding? I painted mine on and as I sand I keep coming back to see the fibreglass underneath and have to redo it over again. I've had to reapply the gelcoat heaps and it keeps happening. Any advice really appreciated mate. Thanks again for sharing and helping us 👍

[@FiberglassFlorida]

So what he did here was after he got the surface prepped and smooth he applied the gelcoat. You can apply it kinda thick (more to sand) and then when you get it polished out you should be good. Basically you need it thick enough to polish without going through.

[@geoffstein3896]

@@FiberglassFlorida thanks mate. I've tried it thick but somehow keep coming through it. Maybe I need to use a finer sandpaper.

[@WereAllThatBored]

What was the black stuff he put on the repair right before he hit it with 800?

[@FiberglassFlorida]

We’re All That Bored it’s a carbon powder, it’s let’s you see where it’s bumpy. It’s a good way to see where you have sanded and where isn’t finished yet

[@WereAllThatBored]

@@FiberglassFlorida Thanks. Found it. 3M dry guide coat. Had no idea that was a thing, I knew folks did guide coats but I didnt know there was a dry option.

[@dkrol997]

What was the carbon stuff you were putting on before sanding? Also what was that white polishing compound

[@FiberglassFlorida]

Its a product made by 3M know as a dry guide and it can be found on our website.

[@andrea19parme44]

Very good

[@carterlonsberry2185]

What kind of spray gun was that?

[@billysmith401]

Where do you get that carbon stuff? It's new to me

[@stonybrookmarineservice8907]

what size tip on the spray gun

[@FiberglassFlorida]

So I'm not 100% sure what he used in this video but 2.2 - 2.5mm is rated for Gel Coats and Resins

[@sandravalentini9389]

Hi, what brand of pneumatic polisher you use? Best regards

[@robormiston2841]

I find cracks using guide coat. It will show all the tiny cracks easy.

[@FiberglassFlorida]

nice! that's a good idea