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!
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MEKP : fiberglassflor...
AEROSIL : fiberglassflor...
ADTECH : fiberglassflor...
CARBON GUIDE : fiberglassflor...
GEL COAT : fiberglassflor...

[@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...

[@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.

[@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.

[@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!

[@robertpeters9587]

Great video. But now i want nothing to do with my repair!! Save it for the professionals

[@rimaggio]

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

[@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.

[@jzl300z]

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

[@RLHFreeeee]

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.

[@gorchcleave5393]

He does really good work, that came out perfect. but man.. thats time consuming.

[@lesafox4134]

and why they get the big bucks!

[@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.

[@wynnyoder5605]

dude, good instruction, but you really need some lights.

[@cliveradvan3414]

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

[@FiberglassFlorida]

you got it!

[@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

[@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.

[@blaster-zy7xx]

Great, now after a half a day of work we now have about 4 square inches of gelcoat that looks 10X better than the rest of the boat. If we multiply that out, it should only take about four to six months to complete the rest of the boat.

[@justtisha]

Did not know about the rolling tape to get the edge soft!!

[@sq7wojwojtek314]

Perfect 👌

[@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

[@Dennis_J._Aitken]

Seeing that this boat needed extensive work what would all this work cost? I am in Wisconsin. I have a 1978 Crestliner with a new 50hp Mercury motor and I have rebuilt the entire inside of the boat including the upholstery. So I am just wondering what a shop would charge. Next question is how do I find a reliable shop that does quality work?

[@jaylancaster5419]

Wear a mask when handling that silica, brother.

[@michaelhopkins4922]

and hearing protection.

[@thomastirolflorida5363]

blablablablabla

[@thomastirolflorida5363]

@@michaelhopkins4922 lol

[@jaylancaster5419]

@@thomastirolflorida5363 Seriously. Silica is some bad stuff. If you care about your own health, protective measures should be taken.

[@forrest8507]

@@jaylancaster5419 silicosis is one of the worst ways to die.

[@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)

[@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

[@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

[@KensGarage1]

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

[@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 ?

[@alanherrett7602]

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

[@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...

[@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.

[@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

[@jonpalmpalm]

my man crushed it, top quality

[@erniedg]

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

[@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?

[@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.

[@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?

[@alhwetyalhwety352]

Hello how are you I am a marine equipment technician in Abu Dhabi specialising in viberglass and boat dyeing if you have a job

[@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🤯🤯

[@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 🙏

[@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.

[@sandravalentini9389]

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

[@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!

[@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.

[@88krazie]

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

[@paulbriggs3072]

Adding MEK reduced the strength. Instead of mixing your own, use a flexible epoxy gel gunned right into the joint. It will NOT shrink.

[@markromsey4790]

You seem to be confused about the purpose of MEK. Mekp (Methyl Ethyl Ketone Peroxide) is the catalyst added to polyester resins and vinyl ester resins. As the catalyst mixes with the resin, a chemical reaction occurs, creating heat which cures (hardens) the resin. Also, epoxy will not work with this type of repair because Gel Coating is polyester based and will not bond properly to a epoxy resin.

[@StewartGartland]

Tremendous skills, I'm very envious!

[@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

[@chunkyfather29]

If you want to make it to old age I highly suggest you wear protective mask

[@stephenwhite5444]

What compound are you using to buff out 800-1000 sanding marks?

[@greggkathy1892]

Subscribe and watch Lee from Localboydidgood. He will teach you EVERYTHING you need to know about compounding and polishing gel coat. He and Justin are the best!

[@FiberglassFlorida]

It looks like Justin is using a product known as Aquabuff. You can find this product on our website.

[@brettlanglois8769]

Quite the process but great job young man!

[@larsrosing5033]

Yeah, great skills! But you must take care of your self. M-E-K, brains away! No gloves, no ventilation suction, no mask! Lot of toxic chemicals! You should last many years! ;)

[@texasfish9437]

Lars Rosing will not wearing it one time harm you that day? Or does it take many times over a certain period

[@tonyb.1994]

Good vidéo, nice job. Thank you

[@fishyhobby3697]

Impressive, thanks for sharing..

[@cjharrin]

Excellent job. Takes pride in his work. Well done

[@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

[@edknowles8004]

Great job thanks

[@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%

[@EaglefordDriller]

this guy has great work ethic.

[@robormiston2841]

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

[@FiberglassFlorida]

nice! that's a good idea

[@dannywilliams8057]

Just when I thought I could buy a cheap gelcoat repair kit lol

[@Jeff-kw8jj]

Mylar film over smaller repairs can eliminate or reduce need to sand , smooth and polish.

[@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.

[@imarginacionmxd]

like si me lees

[@maxpower2280]

Bloody nice work mate

[@noone-t8y]

Really useful info. Many thanks!!!

[@newbiefishing7775]

Great video and great patch job!!!

[@gregorywolters1064]

Where are u located

[@FiberglassFlorida]

We have two locations, one is 270 Paint street, Rockledge FL. The other is 4440 Southeast Commerce Ave, Stuart FL.

[@sv-macgyversridewjackbabbj6739]

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

[@trippvogel1781]

Nice professional work!

[@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.

[@mikejustice1196]

At 3:43, and 6:07 why would one use a filler that shrinks?

[@laxmannate07]

2 down, 10,000 to go

[@agentbey]

Very awesome professional work.

[@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

[@dawnosborn8817]

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

[@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.

[@dontall71]

Thanks for all the great tips and technics

[@FiberglassFlorida]

no problem at all.

[@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.

[@Ranger830]

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

[@madokatondo360]

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

[@timmunneke8036]

Artist

[@MrTrker1]

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

[@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 ?

[@darrellbrown8547]

Great vid. Thanks!

[@johngroen3018]

What are the names of the products that you used to fill in the damage..

[@FiberglassFlorida]

he uses general purpose. poly resin mixed with chopped up carbon fiber and some Aerosil to thicken it up a bit. We have noticed that Aerosil wasn't available on the website but we are updating that now! thanks

[@alimoghnieh1621]

بالسلامة يا أبا نضال.

[@dkell1597]

Fiberglasser here and all these videos I've seen there is a better method that's flawless and quicker and just better. I'm surprised no one does it...

[@georgelayton1862]

Great video, great talent. Hope you use PPE when NOT videoing !!

[@FiberglassFlorida]

You better beleive it! He took it off to talk but usually always has it on.

[@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

[@roceksklepserwisrowerowona9773]

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

[@zw5509]

Nicely done!

[@ericlogan6159]

I'd love to see before and after both surface and zoomed in.

[@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.

[@justinmartin7723]

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

[@davidryder3374]

8 different chemicals and a lot of skill and attention to detail. In other words, don't try this at home.

[@omerbbM5]

Nice work thank you

[@FiberglassFlorida]

No problem 👍

[@Burritosarebetterthantacos]

Meh, Ill just leave mine cracked. 😂

[@billysmith401]

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

[@mehagel65]

You could double for George from the KZbin Channel Fasterproms.

[@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???