Procedure for gelcoating

[fmjnax]

What is the procedure for prepping a boat for fresh gelcoat? Do you have to sand down to the fiberglass or can it be sprayed over the top?

Also, how much would you typically need to spray the bottom hull of a 16' boat?

I'm currently working on restoring my 1984 16' Skeeter and there are some chips in the existing gelcoat and one area of moderate fiberglass repair needed at the bow. The color scheme is a brown with flake on the cap and a cream/brown/tan sort of color on the hull. I could color match the brown and the flake on the cap, but I'm not so certain I could match the hull color. The brown flake has a few scratches, but nothing major so I will probably leave it be and just buff it out as well as I can. Since there are so many chips and I have a significant repair to do on the bottom, I'm thinking I may as well shoot the entire bottom hull.

[fmjnax]

Just to note, I DID read the gelcoating thread pinned at the top. ;) I'm more-or-less looking for the intricate details (prep, in-between procedure, how many coats, finishing, etc) as well as a general amount needed.

[dan-k]

Prep by sanding all the gloss out of it, 120g-240g, then wash with acetone. As far as coats, from my research, it seems that you don't want it too thick or it will crack over time. When applying over existing gelcoat with a solid color, I would suggest two coats. Spray all of your coats within the same day, the sooner the better so you get a good chemical bond between coats.

[fmjnax]

Thanks dan-k. Any idea on general coverage when thinned 10%?

[dan-k]

When applying on a bare surface they say 25-30 mils, so maybe 15 mils on existing gelcoat.

[dan-k]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by fmjnax &raquo;</td></tr><tr><td class="quote">Thanks dan-k. Any idea on general coverage when thinned 10%?</td></tr></table>

Sorry, I re-read your post and I think I misunderstood the first time. A quart covered the splash well and transom of my Champion just fine. I would start with 4 gallons or so for an entire hull. User "totalbeverage" did an entire basscat, he would have a better idea of quantity than I would.

[omcforever]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by dan-k &raquo;</td></tr><tr><td class="quote"> As far as coats, from my research, it seems that you don't want it too thick or it will crack over time. When applying over existing gelcoat with a solid color, I would suggest two coats. Spray all of your coats within the same day, the sooner the better so you get a good chemical bond between coats. </td></tr></table> Gel coat is ok shot thick/need it for color sanding. Shoot it the thickness of a dime and your ok.

[fmjnax]

Thanks guys. After much debate and looking over the boat, the wife gave the go-ahead on an entire repaint. That means I'm going to end up ditching the ugly brown/tan color scheme! It also means I have new questions...

I'm switching to a white/maroon scheme (the existing tan will be white and the existing brown flake will be maroon flake).

- Is there a primer, of sorts, for covering up the color or should I just plan on sanding down closer to the fiberglass?
- For shooting the new flake, will I have to sand off all of the existing flake before laying down the maroon base color?
-Is automotive flake the same as marine flake?
-What size flake is normally put on a boat?

I'm still researching on how to shoot the new flake, but so far it seems like it is a fairly daunting task. If so, I may end up foregoing the flake and just go with solid white/maroon color. I would really love to flake it, though!

[radracer]

No primer is needed. You need to sand with 60 or 80 grit sand paper and clean real good with acetone. You really just need to remove the shine from the old gelcoat. Clear gelcoat, primarly used as a clear surface coating over polyester resin. Provides a hard, durable clear finish. Contains UV inhibitors for outdoor and marine use. The clear gelcoat can also be mixed with an automotive glitter/metal flake for a metallic finish. House of kolors has a great choose of colors. A neutral base color gelcoat should be tinted with one compatible colored pigments. In order to achieve the desired color you should add 1oz of pigment to one quart, 4oz pigment will tint one gallon .
http://www.uscomposites.com has great gelcoat.
http://www.minicraft.com you can order factory matched colors this guys are great when it comes to info and service.
http://bertram31.com/proj/tips/re-gelcoating.htm this web site will give you a crash course on gelcoating.
http://www.tcpglobal.com/kustomshop/ksflake.aspx great place for flake
this guy has some good tips.
Last but not lest.. youtube can be very helpfull on gelcoating also.
Hope this helps.


Modified by radracer at 7:58 PM 8/19/2011

[radracer]

Allmost forgot. Get you a good spray gun to shot the gel. i bought a gun off ebay that has a 2.5mm spray tip. This tip will be large to shoot flake and gel out of.
http://cgi.ebay.com/ebaymotors...Q3aIT