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  1. #1
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    Gel Coat application?


    Well i shot some gel on Sunday and as the picture hopefully shows it didn't turn out the best in a few spots. I know i got it too thick the minute it happened. But what im wondering is what pressure should we be spraying it on at? And about how much volume leaving the gun. Im using a 1.8 tip and pressure was around 25-30 psi and i believe i had the knob almost wide open, i did thin it a very little prior to spraying and maybe i shouldn't have done that. I dont know the exact mixture of glitter i added to the clear but it didn't sag on my mixing stick where i could see the wood so i figured i was ok. The spots where i sprayed to heavy is where i had filled in the deep gouges and cracks with filler and the glitter wasn't covering very good so i sprayed until it was covering and this is what happened.

    Any advise for the future? Im going to sand it down tonight and touch up the area, but i have alot more spraying to do and i want to understand the best setting i should have for my gun to spray as even as possible.

  2. Member
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    #2
    This is the gun I use. Thin your first coats with MEK then switch to Duratec High Gloss Additive. Follow Duratec directions. Allow gelcoat to flash off well between coats. Its not paint, don't apply like paint. Gelcoat must be cut & polished so try not to orange peel it, you just have to sand it back off. Thinner and more coats works better than trying to cover in a few coats. Your spraying plastic not paint. Final 2 coat 1/2 & 1/2 mix gel with Duratec. No wax. Watch your gun, if you pull the trigger and no gel comes out clean your gun before it hardens internally. I hope this helps.

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  3. Member
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    #3
    Appreciate that rojoguio, i found a local supplier for gel and the duratech, he recommended it like you did. Question for you or Crank. Ive completed most of the repairs for the scratches and dings and its looking good. But im having a issue with trash or bugs attaching to my clear before its hard. I know its not going to be real hard right away. but what do i do to get rid of the bumps/trash off the fresh gelcoat? I tried wiping with acetone but that makes it worse by making it stickier and then smears. Lastly, i bought some black base coat gel from my local supplier for my fenders. It sets up hard alot faster than the ranger gelcoat (which doesnt seam to set up at all even after 3 days in the sun) and im thinking of using his brand in clear instead of the ranger clear. Is there any issues on doing this? I already have 2 coats of ranger clear on it now. Thoughts?

  4. Member
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    #4
    It's been a long time sense I sprayed gel. We had to spray a liquid mask over it to get it to cure. It would not dry if left exposed to the air.

  5. Member crank68's Avatar
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    #5
    Prolly hit with PVA to kick it up a bit. I hate giving gel advice....a lot has to do with the person working with it. I wouldn’t worry bout trash in it. When it sets up sand it a little to remove what ever you need to.
    BULLET 20 XRD/250 Merc Sport XS
    www.ncboatguy.com

  6. Member
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    #6
    Bud, first thing is no Gelcoat will fully cure in air. It is designed that way for a reason. You need a chemical bond as well as mechanical bond. The uncured Gel allows you to continue to work it getting chemical bonds between coats. The purpose for the Duratec is it is a patch additive, it will make your Gelcoat fully cure on the surface in minutes when very hot. It is important to build some Gelcoat to waterproof your fiberglass work. Fiberglass is not waterproof by itself. Don't laugh but I have sprayed Gelcoat and get bugs in the top coats, I just sand them out after it is cured and before polishing. You never know it was even there. With flake it is very important to build Gel clear on top with enough millage to allow cut & polish without getting into underlying flake. Applying the reduced Gel with MEK so it will spray thru HVLP gun allows you to build millage getting a chemical bond on every coat, assuming you have downloaded a catalyst chart, are weighing your initial amount of Gel before mixing, 1/2%-1-1/2% catalyst by ambient temperature, then your Gel will cure completely but not without the Duratec High Gloss Additive or a PBA type spray. But you want Gloss right? I have found no Gel by itself that will out shine Gel mixed with Duratec's High Gloss Additive. I swear by Duratec's products, they make a fantastic product if your repairing Gelcoated fiberglass. I put my materials in the coldest part of my shop overnight before spraying. I still mix my Gelcoat to ambient air temps but the 70 degree materials allows a longer window to spray before it kicks. All of your last 2 coats of clear must be mixed 1/2 & 1/2 with the Duratec. If your catalyzing properly your clear will set on less than 30 minutes. Hard in a couple of hours. TIP - un-tape your masking tape before the Gelcoat cures or it is a pain to get off cleanly. There is a proper technique to un-masking to get a clean job.

  7. Member
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    #7
    One more thing, to remove a very fresh bug an old painter taught me when I was 13 to take a piece of masking tape, fold it in half adhesive to the outside, hold it over the bug, and gently stick the bug with the tape and lift it out. If your spray is very fresh the bug will lift out. trash usually sticks too well for this to work but I use very fine, long, tweezers. Use both hands like holding a airbrush when using the tweezers. I hope this helps you.

  8. Member
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    #8


    Hopefully the pics come through. But i ran into an issue need some advise on. Trailer fenders as pics show are going to have 3 different colors. I taped off the radius around the fenders and then taped off the area i didnt want coated with the really thin paper that comes in rolls. Problem is this paper stuck to the dark gel during the application of the white in these pictures. Again i understand that it wont sure without PVA or wax or duratec. I cant find PVA, I have was that i bought for this and i dont want to add the duratec at this point. So what are my options? I have another pin stripe to apply between the white and the dark color and i know its going to be worse than the last coat. Should i apply a clear with wax added over the whole fender then tape off and mask then clean the area where the pin stripe is going to go then spray the pin stripe color with wax?

    How hard is it to clean the wax off after it dries? What exactly is a PVA and where might i find it without having to special order it?

  9. Member
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    #9
    uploading pictures

    The good news though is the scratches and gouges are all gone. Im going to have ALOT of sanding i know but it will be worth it in the end

  10. Member
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    #10
    should have sprayed pin first, taped it off and done dark color and immediately cleared them both with duratec in last coat. Then when cured, sanded it down some before spraying white up to the pin so as not to have hard lines after sanding and buffing. Need to use plastic sheeting the way you did it. Masking paper sticks to uncured gel as you found out. If you mix wax or duratec in gel you'll have to sand before spraying anything over it.

  11. Member
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    #11
    APS, how hard is it to sand the wax away? That worries me because i want to make sure i have good adhesion on the next coat

  12. Member
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    #12
    will plastic wrap like you use in the kitchen work to mask it off? Learning alot, i was ready for the learning curve im on though luckily i have all winter to work on it.

  13. Member
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    #13
    wax is mixed in with the gel and allows it to air cure. Gel once cured is pretty tough to sand smooth. You can buy the plastic with built in blue painters tape at home depot and lowes in the paint dept. It folds out and covers a couple of feet from overspray. I don't use wax or pva on my work personally. I only add duratec on last coat only and don't thin the gel.

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    #14
    I'm Busted! All my gelcoat jobs are mask with the plastic mask with the blue tape from Lowes. We have one in Bay St Louis. The plastic will wrinkle up from the gel solvents if allowed to get too much over-spray. Also the blue tape adhesive turns loose from the solvents so I go over it with green lacquer masking tape from a Auto Refinish Supply House. So again, un-mask Gelcoat jobs ASAP before things start going South. If you sand the green masking tape with red scotch brite it will give you a very sharp line, no bleeding.

  15. Member
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    #15
    Rojo when are you sanding the green masking tape with the red scotchbrite pad? Thank you for your advice and sharing your knowledge also.

  16. Member
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    #16
    I sand the tape lightly before spraying. If you don't you risk bleeding past the tape line. Pain to fix. After you have your hardline mask off take red scotchbrite and sand the tape edge in to about 1/4in from the edge. When you unmask you will have a very sharp line. Now your not trying to sand the tape off, lightly sand to seal the edge. Be sure to use a Wax and grease remover before and after masking, this is important too. A good tack rag, preferably not a brand new one, is used after to pickup up any lint or grit left. I use a blowgun while tacking off. If you only have a new tack rag unfold it completely, loosely fold back to about 4-5 times original size and let it sit out overnight to cure off excess resins. It's very easy to press too hard and deposit a impurity on the substrate causing a blemish when you spray.

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    #17
    Thank You very much.

  18. Member
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    #18
    Do not do anything other than a rolled tape edge on gel, use duratec and first coat is at 25% and run it up to 50% and your blend tape line should be 2 times if not larger than the repair. As for the gun you have to use it as directed as per the manf. you'll need a 2.3mm tip in my opinion. With the duratec you won't have the thin and blends well. Use Acetone to clean the area that has been sanded with a 220 grit and do not use a tack cloth or cotton rag to wipe, after you clean on with the acetone just blow it off with compressed air.