Spraying Gelcoat Like a Pro
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- เผยแพร่เมื่อ 23 ม.ค. 2020
- In this video, you'll learn how to spray gelcoat perfectly every time. I go over some of the standard practices that pros use to get excellent results with ease. Check out my other videos on how to fiberglass like a pro, how to clean a gelcoat gun like a pro and how to make fiberglass molds. Even if you're a beginner you'll find that it's just as easy as it looks. (Note: If you have questions, feel free to ask and I'll answer them as quick as I can. TH-cam finally fixed the comments section!!!)
Thanks for watching!
POMF!!
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![Re-gelcoating your hull - PART 2 - fairing and spraying- [restoration of a sunfish sailboat]](http://i.ytimg.com/vi/bjbAjSxvE5Q/mqdefault.jpg)
![Re-gelcoating your hull - PART 2 - fairing and spraying- [restoration of a sunfish sailboat]](/img/tr.png)
This has to be one of the best how-to videos I have ever seen. Step by Step and to the point.
Thanks 😊
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@@Mofiac you can be
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@@Mofiac you can can stop 🛑 to drop iuthe the kids
Awesome info. Thank u
I have white waxed gelcoat and I want to spray my 26ft boat. Should I spray one side at a time to build layers or try to go around the boat a few times?
Excelente explicación. Muchas gracias
De nada
awsome video thanks for sharing this detailed video
Thanks for watching!
Really useful vid and loads of good answers in your comments. Just wondering how many gallons and CFM your compressor has? I've got an 8 gallon and the manufacturer says it will push 4.5 cfm @ 100psi. I know that limits me to small projects but it would be good to know yours as a comparison to what I might expect to see. Thanks
I use a large system with dual 60 gal tanks but I spray @ 60PSI from the reg on the line. I've used ad small as a 10.2SCFM @ 90PSI output compressor with the reg @ 60PSI and never run out even with long lines but I think you're going to need a larger output to keep up if you spray large parts though.
Im surprised that 60 psi can push un-thinned gelcoat thru a 1.8 nozzle at all. Much less as nicely as this shows. Can't wait to try.
Do you need to use the wax?
Nice. I’ve sprayed some of my boats with base coat clearcoat and really like the look, as I’m familiar with automotive products. You sound exactly like the rep from mimaki printers..lol , great vid
Thanks. 👍
Sorry to hijack but Shaun mcinnins do you mean automotive 2pack epoxy clearcoat? How long do you get in the sun/water? I have a dull finish on an old fibreglass dinghy and the clear would weigh less that gelcoat I’m thinking
Bc CC are not really great for boats. they look really good for a short while, not the solution. big boys like cigarette etc. used to use epoxy paint, IMRON. cant do that anymore. point here is that CAR paint is not BOAT paint. Basecoat, clearcoat on boats.... NO. The substrate is not the same, the flex is not the same. Car paint on boats...NO.
easy money thanks man
Awesome 👌
Thanks a lot
Glad it helped you out.
Do you think I can use a airless sprayer to do the job? Also should I use thinner?
No. You'd have to thin the gelcoat so much it wouldn't cure properly. There may be a model out there that can handle thicker paints that might work, though. Sorry, I couldn't be more help.
did you warm your gelcoat to get that level of viscosity? I have a PTM&W gelcoat and its way thicker then that at room temperature before mixing.
No, I never warm gelcoat. If you agitate the gelciat for 60 seconds you'll find its a lot more fluid-like and easier to spray.
I’m spraying my grandfathers old fiberglass canoe with gelcoat with wax since the old gel coat is pretty beat up. I was just wondering if I can keep layering the gelcoat with wax, or do I have to buy gelcoat without wax to get it built up?
If your gelcoat has wax in it and you let it cure you can't regelcoat unless you sand it first. If you don't sand it, it will flake off due to the wax surfacing during the cure. If you want to gelcoat successive layers and allow a cure between layers, use unwaxed gelcoat for all the layers except the last one. However, successive layers of gelcoat will craze as the boat gets used and flexes. One properly applied 18-24 mils application with waxed gelcoat will perform the best. Hope that helps. Ps mils=thousands of an inch, not millimeters.
Hey must you wax it first or can you add wax ? spraying a console for boat
I waxed the board so that the gelcoat won't stick to it. If you want gelcoat to stick to your boat console, then sand the console first and don't wax it.
Not sure if it was mentioned, if so I missed it. What size nozzle are you using on the sprayer?
In the video I'm using an hvlp spraygun with a 1.8mm needle and aircap. If you can find one that has a 2.2mm, you'll find it does the job quicker. I'm using the 1.8 so I don't have to switch back and forth from gelcoat to high gloss additive on some of the work I do.
What size spray tip on your gun?
Great video. THANKS
I'm using a 1.8mm needle and aircap. If you can find a 2.2mm you'll have an easier time. I use the 1.8 instead of a 2.2 because I use the gun for high gloss additive as well as gelcoat and its a pain to always have to switch needle and aircap.
Why do you you want to achieve orange peal ,when i was always told that it is someting to avoid because then , you have to sand ? thank you for your answer..
Gelcoat isn't like paint. It has to go on thick enough, or it won't cure. For those that don't have a thickness gauge, the orange peel finish let's you know that you're thick enough for a proper cure.
Is there a way to get a better finish after spraying or do i just have to wet sand it after? Thinking of spraying a whole 23 ft boat from the waterline up and seems like tons of work to wet sand with that much orange peel
You can add a high-gloss additive which will give you a much better finish. However, your best option for recovering a complete boat would be to do all the glass repair work then prep it for a high grade marine paint such as Imron or PPG. They make 3-component paints that give excellent results. If you were to re-gelcoat the entire boat then wetsand, you'd most likely end up with burn-through areas that you'd have to re-spray then wetsand again. Hope that helps.
@@Mofiac thanks :)
I'm wanting to try to dry flake my boat and use clear gel coat to hold the metal flakes . From what I have watched what you do is spray a layer of gel coat and blow on the dry metal flake with a flake gun like flake kings guns then let it dry sand it and spray gel coat over it . If You do it that way would I do the same thing your doing in this video with metal flake under it ?
You could, but you'll need to add a couple of things to the clear gelcoat. 1)You'll need a wax additive added to the clear gelcoat to get it to fully cure. 2) You'll need to add a high gloss additive to get the gelcoat to flow smoother. 3) Finally, you'll need to wetsand the final coat, then polish it.
Ok, so I’m embarking on my first refinish on a 17’ Whaler. Sanding the whole hull, some glass work on the dents and cracks etc... So starting fresh, do I use the Honey wax, then spray? Or do I use another product without the wax step?
Any and all suggestions and help is welcome.
If you're redoing the gelcoat on a boat do NOT apply wax on the boat before gelcoating. If you do, the gelcoat will flake off. You need to sand the boat until there's no shine left. 80-120 grit works good. Then use gelcoat that has a wax additive in it. The wax will rise to the surface when your gelcoat cures which allows the surface to achieve a full cure. Now you can sand and wetsand your gelcoat smooth then polish it. If you've never done this before, I suggest you test it on a scrap piece of fiberglass first. You'll save yourself alot of heartache by making and correcting your mistakes on the test piece. Hope that helps.
Talk to the experts.. Do not wax ahead of spray. your gel will peel off. sand 180 grit and get gelcoat with S2 added, its a wax that will surface as the gelcoat cures. you will have orange peel. you have to wet sand that off and compound the shit out of the job. I would suggest that you really talk to a good supplier. not just buying the shit online. Best knowledge I could find is Express Composites, Free knowledge and the right products. I have learned a lot by asking the questions, I have done gelcoat over a hull, bottom repairs, floor replacements. transom replacement, stringers. All as a hobby, could not have been done without the help from the people who know the products.
@@Mofiac i'm experimenting with sanding at 320 before spraying. This is suposed to allow me to spray thinner when fixing stress cracks wich should require less sanding. I noticed at 180 grit the gel absorbed by the cracks and end up thinner than wanted.
Any advice? I learn from 2 differents styles at work and i'm trying to make the best of all.
Why don't you just buy a 2 pack epoxy paint?
I gelcoat regularly over 80 grit sand marks with no print-through. Gelcoat need to be 18-24 mils thick to cure properly. Paint, on the other hand, will show through on 180 grit so I prefer spraying that over something sanded to 220-320 finish.
When shooting large areas of gelcoat, do you have to clean the gun out after each pot? Say a pint, clean, clean, pint, clean etc??
Once you have catalyzed your gelcoat, you have 10-12 minutes to get your gun cleaned at room temp; 5-10 minutes longer if your gelcoat is refrigerated and the room is at room temp. Only catalyze a pint at a time so the next pint hasn't sat catalyzed while you spray your first pint. I've used this technique to spray without cleaning the gun for about a half hour before absolutely needing to clean it. I then clean it more thoroughly because the nozzle will have clumps of gelcoat that started forming.
If you have a large project you should look into getting a pressure pot spray gun, but to get by on just one very large project, just remember that if you have to stop, clean, continue spraying, you can keep adding gelcoat for hours until the final thickness is reached and your part will come out fine.
Hope that helps!
Did you go through all that Gelcoat on those passes? That looked to be about 16oz, correct? How much (quantity) are you able to run through that 1.8mm tip and at what temps? I am going to be spraying a console soon and want to use Duratec but my thought as not to waste it is to only use it on the final pass. I also thought about spraying PVA before final pass so I don’t involve wax risking a weak mechanical bond. Thoughts?
A little less than 12oz. The gel time for that color is about 16 minutes so I had lots of time. Some colors have longer gel times. White is about 12 min. gel time and black is about 8 min. All are at temp of 72 F. If using Duratec, add it to your gelcoat first....makes spraying alot easier as it thins it a bit and you can spray a larger qty in less time. Also it flows better on flatter surfaces so the finish is smoother. Do not use a wax additive in the gelcost nor PVA film as a final coat....if you do you'll have to sand it before the fiberglass layup. Once you've completed the final layup you can spray some PVA as a barrier coat or let your layup cure and paint a final coat of resin that has some wax additive in it. Hope that helps!
@@Mofiac Duratec is the route I am planning to take. Can duratec be sprayed without sanding in between?
Yes, just add the Duratec Hi-Gloss to your gelcoat, catalyze normally, spray and let cure, then proceed with the layup as normal.
Sorry thanks for the explanation
Amazing video, breaks everything down perfectly!!
Just two things that I don't understand, Do I need to sand it down after drying?
And what is the total thickness of three coats? Is it 18 mm? Like 2 cms? It's too thick IMO
No need to sand the gelciat after cure...just layup over it and it'll bond. The thickness of each pass is 6-8mils thick...total thickness 18-24 mils. 1 mil = 1/1000 of an inch
@@Mofiac just a heads up.. you sprayed gelcoat on wax , to be covered by glass. That dont work for the viewers who think they will be spraying gelcoat on a surface, for a finish. If you are making a video for the ignorant masses, Please explain a few hard facts. unwaxed into or on a mold.. waxed for an external surface. or your gelcoat is stickey forever.
@@jameswalsh2433 well if the masses are trying to understand something they are not ignorant. I take offense and at the same time thank you for binging this point up james.
Shouldn’t it be smooth if it’s a boat hull?
Or do you sand it when finished?
In the video I'm spraying gelcoat that I will later layup over with fiberglass. That's why I waxed the board first, so the part will come off. On a boat, never wax before you spray the gelcoat or it will just flake off. You can add high gloss additive to the gel coat to get a smoother finish but you'll still have to wet sand and buff if you want a polished finish.
Hello, can you explain how you make gel coat collor ? please . Thank you
I buy it already colored, but you can order a neutral or white base and add coloring agent to it
Will it dry good since you used a wax free gel coat?
The surface won't completely cure when using wax-free gelcoat thus allowing the subsequent laminate to chemically bond with the gelcoat. If I was repairing or replacing the gelcoat on an existing part, I would use waxed gelcoat or coat the wax-free gelcoat with a barrier to allow a full cure on the surface. If you use waxed gelcoat to make parts that are to be laminated, the gelcoat will flake off. Hope that helps!
Hi , am restoring a corvette and planning to use gelcoat after repairing fiberglass , what do you recommend ? thanks for your video !!
I wouldn't use gelcoat as the finish. I would do all the glass work then use a polyester high build primer dry sanded to 320 grit, then a 2 part acrylic urethane automotive paint. Gelcoat as a final layer will craze over time, not to mention you'd have to wetsand it to 2500 grit then polish. That's a lot of work. You'll find that all the corners will end up being see-through after wetsanding, too.
@@Mofiac ok thanks for your quick answer , but maybe i didnt explain well . Was thinking to gelcoat after fiberglass work only , not as a finish . Was asking for the steps to follow for that , or what product to use ? thanks again !!!
I Have painted cars all my life and wax was the worst thing to have on the surface before painting. Does the was do something for the gel coat?
Wax in the gelcoat will surface when the gelcoat cures, allowing it to fully cure. Without wax, the surface of the gelcoat exposed to air will remain tacky and uncured. You'll only used waxed gelcoat as a last layer, otherwise successive layers won't bond.
Isnt flow coat the one with wax or both have wax can you explain the difference please🙏
unwaxed gelcoat is in a waxed mold, on a surface.. gelcoat with an additive, If they call it flowcoat or whatever? it needs to be a wax additive in the gelcoat, if sprayed on an external surface. Express Composites in MPLS. will tell you what you need. I am not a paid advertiser, just a customer who talked to the smartest people on the planet , about my projects.
Thanks for these excellent instructions. One QUESTION: Is it possible to get a deeper Orange Peel texture on the Gelcoat? I am patching a bathtub floor that has an orange peel texture on the floor for a semi-nonslip feature. But the orange peel is about 4 or 5 times deeper than the one shown in your video. So for that section of the patch I need to have a deep orange peel texture. I thought you might have some ideas on how to do this (HVLP gun with 2.0mm nozzle - but I also have smaller nozzles)? Thanks again for this excellent video !!
Take a look at this video. th-cam.com/video/3i0EkkAfFHI/w-d-xo.htmlsi=kNWBKhRRU9agVTLO
If you gelcoat the bathtub floor then let it cure for a half hour or so, you can drop the pressure on your paintgun and open the paint valve fully it might be enough texture to match what you're after. Probably best to test it on a scrap piece of plastic or painted wood first.
@@Mofiac Yes, that looks like it will work. I'll be trying it out on a test piece in about a week or two. Thanks for getting back to me.
Nice quick and simple. Tell me, what brand of gel coat did you use?
The brand name is CCP (Cook Composites and Polymers). It's an unwaxed isopthalic gelcoat. Hope that helps.
wana ask what brand your spray gun, thanks alot
It's a Star HVLP with a 1.8 mm needle and aircap
ok was it a waxed gelcoat or not? did you add s2? I ask because a surface gelcoat will never work without an addative... or I am wrong. In a mold ,there is wax . on a surface ..no. nobody except my locals at express composites explained that to me. since then , I have sprayed and rolled gel on a few projects. gelcoat without a wax modifier will always be stickey. love the video , thanks.. please address the science, and the application.
No wax was used in the gelcoat. I was making a flat board so there is a layup that goes on top of the gelcoat once it cures. The only wax I used was on the board before I sprayed the gelcoat; I want the gelcoat to come off the board after the subsequent fiberglass layup. Think of the board as if it was a mold....I used it to make a purple colored flat square panel in fiberglass. If you make a fiberglass part and the gelcoat is the last thing to go on, then yes, add a wax additive or high gloss additive so it won't remain tacky. You could also cover it with a layer of pva or peel ply.
Got a question, if i gelcoated to thick and it, like peel, is it fixable?
The gelcoat application, if done correctly will have an orange peel finish. This is normal and the subsequent layup over it will bond properly and give good results. If the orange peel finish is on the gelcoat that you sprayed as a final coat on a fiberglass piece, then you'll need to sand it down, wetsand, and polish for a smooth and shiny finish. If so, you'll need to add a wax surfacing agent to the gelcoat before spraying so you get a full cure on the surface. It'll make sanding and polishing much easier. The video shows only how to apply gelcoat to a surface that it will be removed from once the layup over the gelcoat has cured.
Hope that helps!
Was that a regular gun for spraying paint ?
Yes, but with the 1.8mm needle and air cap instead of 1.1mm.
Do you wait to it becomes tacky to start glassing or do you let the gel coat dry all the way? I have heard people say they use both techniques which is the more common way or idiot proof way?
Always wait for the gelcoat to cure before you start glossing. Textbook guides will say 2-8 hrs after application at room temp. If you do it earlier, you risk the gelcoat bleeding and having 'print through' marks from the fabric curing before the gelcoat has fully hardened. If you wait too long, you risk pre-release. In practice, I've never tried layup before the 2hrs. I have done many layups days after the gelcoat had cured with no problem. If you stick to the 2-8 hour window at room temp, you'll always get good results. 👍 Good luck with your project!
@@Mofiac thank you if it dries all they do you have to sand before glass? Or not
Is it ok to spray the gel coat all at once or wait before each coat to reach the 20 mil thickness?
Do you think you can spray a fiberglass pool the same way?
You would have to clean the gun every 10 minutes and catalyze a new batch, spray, clean, mix, repeat until the whole pool is covered. Doable- yes, but not practical. They sell specialized gelcoat guns that have automatic catalyzers and connect to 5 gallon pails to do big jobs like that. Hope that helps.
What was that in the right bottom corner?
Overfilled garbage can. Mostly filled with cured fiberglass cuttings.
Does the orange peel effect go away? How to have a smooth surface?
No, you'd have to sand and polish to get it smooth. You can add high gloss additive to make it much smoother but you'd still have to sand and polish for a bright smooth finish.
How are you shooting with a 1.8mm? Are you thinning with Gelcoat? Duratec? Thank you!
I open the paint nozzle as far as it'll go and set the pattern to wide cone shape. Straight from the 5 gallon...no thinning needed. Some colors like yellow are thicker but I can still spray it straight. If you mix the gelcoat for 60 seconds when catalyzing it'll naturally thin it a little. I use iso- NPG unwaxed spraying gelcoat but I've sprayed waxed ortho brushable gwlcoat and it comes out the gun fine. If you can find a 2.2mm needle and aircap it's even easier.
You can thin the gelcoat with acetone if needed.
@@doncunningham3124 Gelcoat should not be thinned with acetone. Breaks down the Gelcoat and not recommended by the manufacturer of the Gelcoat as listed on the can of that says anything.
@@bizzybone485 our company has been doing it successfully for over 50 years. We're fully aware of what the manufacturers say but this practice has proven to be very reliable for us.
Thin with styrene not acetone...
What did you use for tip size?
I used a 1.8mm but I recommend a 2.2mm. I use the gun for spraying high gloss additive as well as gelcoats. As such, I use the 1.8 so I don't have to change the needle and aircap when I switch which fluid I'm spraying.
What air pressure settings? What tip orifice size?
I use a Star HVLP with a 1.8mm needle and aircap at 60psi. I open the air intake wide open and the paint wide open and I set a cone spray pattern.
@@Mofiac Isn't it too small? Maybe with 2.5mm nozzle you can go lower with air pressure?
Le gelcoat est il dilué ? A combien de de % ?
La buse est de combien de diamètre ?
Merci
No, the gel coat is not diluted. The aircap, nozzle and needle are 1.8mm. If you can find a 2.2mm, go with that as it's much faster to spray with.
What size tip is in that gun?
Hi, tip/aircap size I'm using is 1.8mm. Ultimately, a 2.2mm works best, but you can get away with using a 1.1mm, albeit only on smaller parts.
What sort of gun do you use and what size cap?
It's a generic hvlp spraygun. Tip size is 1.8mm. I use it for both paint and gelcoat. If you're just going to use it for gelcoat or if you want best results, order in a 2.2mm needle, nozzle, and aircap.
@@Mofiac Thanks I'm doing a few boats here and I've been spraying cars for 47 years so I think I know what I'm doing I just needed that bit of advice cheers
Good to know. Just remember, gelcoat needs to be at least 18mils thick in order to cure properly. That's like 3 times as thick as car paint. If you're spraying the gelcoat as the final step, make sure to add a wax additive or the surface won't cure properly. If you're going to layup over the gelcoat after spraying, or you want to respray over the gelcoat, do NOT put wax additive in the gelcoat. Good luck.
What nozzle size are you using ?
1.8mm aircap and needle. If you can find a 2.2mm, you'll find it easier to spray.
How do you add color to gellcoat
just like paint.. you buy it with color added. you send or spec your color, and the supplier mixes it. you probably cannot buy the color pigments. They are specific to the brand of gelcoat, they have a color match system, and sample chips. just like a paint store.
Pardon my ignorance - I was of the impression you don't want orange peeling. How would you go about getting a uniformly smooth surface?
This application was for a subsequent fiberglass layup. If you're spraying gelcoat as a final coat and you want it smooth, you'll need to add high gloss additive. You'll still have to wetsand and polish if you're looking for the ultimate finish though. Hope that helps.
@@Mofiac yes, very helpful. Thank you. I’ve always applied gel coat with a silicone trowel with subsequent sanding for repairs on my boat. I want to learn how to spay it because it seems way less time consuming. Any recommendations for an additive?
Yes,.....use the industry standard...
Duratec High Gloss Additive 904-001
You can read their application procedures on their website. Just search for Hawkeye Industries Duratec High Gloss. Good luck!
@@Mofiac thanks again. Your videos are awesome
What does it mean when the gel coat craze?
Means it's too thick.
It should be 18-24 mils thick. Thinner than 18mils and the gelcoat will alligate. Thicker than 24mils and it will craze or spider -crack when flexed.
How do I avoid this orange peel effect?
You can add Hi-Gloss Additive to achieve a smoother finish.
I still got an orange peel even with a hi-gloss additive by prestec. Not sure what I did wrong but I’ve been sanding for weeks lol
The high gloss additive I use if from Hawkeye Industries. You could sand down what you've done and regelcoat with the Hawkeye additive.
Its that peelable?
It still needs a laminate after it cures, but yes, once the laminate is layed-up and cured, you just peel it off the board.
sorry, did you say it was 18-20mm thick? thats like 2 centimetres.
No not 18-20mm.....18-24 mils (thousandths of an inch) so that's about 0.6mm.
@@Mofiac haha yeah just checking. thanks for the reply. I have an old canal cruiser which had been painted on the hull and i am thinking about sanding down and gelcoating again
Don’t you mean .6 mm per spray?Surely you couldn’t layer 20 mm of gel oat.
Yes and no, let me explain.
NO: The thickness I mention is 6 mils not 6mm. Mils are standard measurements for thickness in manufacturing. It stands for thousandths of an inch. 3 passes of gelcoat result in a thickness of 18-24 mils. YES: 18-24 mils is approximately 0.6mm. Hope that helps!
Point of the video is missing, it feel contradictory if you have zero or minimum knowledge aout gelcoating
The point of the video is how to gelcoat with a regular spraygun.
@@Mofiac my bad i had a rough day i guess . I missed you saying that you were demoulding it. I though waxing could mix up someone with little knowledge. Great video! You definatly know what you're doing.
After that you have to buy a new paint sprayer ...
Not so, I've been using the same sprayer for over 15 years and I use it daily. I have a video showing how to clean the spraygun after each use.