New Gel- Should i Wet Sand...

[cturboaddict]

Okay, Ive been restoring my boat, and ive had my fair share of fiberglass and gelcoat experience, but ive never had to make a new gelcoat surface shine on a larger scale.

So here i am... Ive finally completed the repairs on my hull and gotten my gelcoat back on. Im a normal guy in the backyard, so i did apply it with roller and brush, and i think i might put one more coat on it-depending on your suggestions.

Im going to let it cure completely over the next couple days, but i know that i have some stipple from the roller, and its no "mirror glass" finish. Whats your suggestion to getting there.
Suggestions on sanding it down then regelling again another coat~
and or, wetsanding/polishing it to get it to shine a bit before i flip the boat back over?

Here is what it looks like at the moment.....

 

[shackmaninc]

Re: New Gel- Should i Wet Sand...

hey there i am wondering the same thing i am about to embark on my own fiberglass motor housing build. is the only thing to get the gel coat that shine a sanding and buffing?

 

[BWT]

Re: New Gel- Should i Wet Sand...

The gel looks like it's pretty thin towards the edges; is the rest of the hull roughly the same thickness? If you're rolling and tipping I would guess that you'll want to have at least 4-5 layups before sanding. If you sand now and roll on another layer, you'll have stipple from that coat and have to re-sand. So, I guess the big question is how thick is the gel? Given that you're going to have to knock quite a bit of it off to get everything smooth enough for a mirror finish, before sanding you'll want to have roughly 1/8" thickness. By the time you're done sanding it will probably be closer to 1/16" thick. Of course the easy route would be to sand it smooth now and apply a bottom paint or barrier coat.

 

[ondarvr]

Re: New Gel- Should i Wet Sand...

Trying to sand down rolled on gel coat can be a difficult job on that much surface area. One thing you can try, is after a couple of rolled on coats use a squeegee (a plastic Bondo type spreader will work) to apply the last coat, this fills the low spots and adds nothing the high spots.

Don't wait long periods of time between layers, it's best to apply the next coat as soon as the current one is hard enough.

 

[tim09]

Re: New Gel- Should i Wet Sand...

hey mate, with your gel coat to get mirror finish you need to sand down all the high spots first then go down through the grades of sand paper and then buff up. so put the gel on thick cause you dont want to rub through and as smooth as possible, recoat straight after it has gone off any longer than 30 hours and you will have to scuff up the surface again to apply. if using straight gel coat the surface stays sticky designed to hold the fibreglass that goes on next in a boat mould so for the last coat you will need to add a patch aid or wax in styrene etc depending on the gel coat being used (guys at shop where you bought it can help with this). finally when time to sand use a guide coat or shadow coat this is a product you put on and when you sand off it shows the low spots so you know when you have sanded the entire surface. (if guide coat is costly then you can get away with cheap black spray paint and just put on a mist layer) with sandpaper start with 400 grit then 800 grit then 1200 grit then 1500 grit then buff with a polish designed for 1500 grit scratches and it will be the mirror finish your after. apply the guide coat everytime you change grade of sandpaper. it is a long process so stay paitient.

 

[cturboaddict]

Re: New Gel- Should i Wet Sand...

Gelcoat is on pretty thick. I think it could possibly use another coat, and that would put me close to 1/8". (more like 3/16) But i dont know if i have enough gel left to put that much on without reordering.

The gel does have wax in it already, and it has two layers basically on it now.

Anyone against leaving it the way it is? Ill get a better picture of a close up to show what it looks like today.

 

[cturboaddict]

Re: New Gel- Should i Wet Sand...

Here is a closer shot (my camera isnt the greatest)....

 

[ondarvr]

Re: New Gel- Should i Wet Sand...

Too late now, but for future reference and for others reading this, never buy gel coat or resin with wax in it, add it yourself if it's needed.

The reason behind this is the first coat(s) shouldn't have wax in it because if you let it cure even a little too long, possibly an hour or less, the entire surface needs to be sanded and cleaned before another coat can be applied. If you don't do this there is a very good chance the top layers will peel or flake off.

You can only get about 10 mils per coat when rolling gel coat, so two layers will give someplace around 20 mils, which is OK if you don't plan on sanding it, but you need much more gel coat on the surface if you plan to have a nice smooth surface and not sand through. The surface needs to sanded down until the lowest spot is reached, otherwise this spot will be a pit, so with two rolled coats you will need to remove at least 50% of the gel coat you applied to reach the bottom of the lowest areas. When spraying gel coat the surface profile is a bit more uniform and will normally require less sanding (still a lot though).

 

[Piece715]

Re: New Gel- Should i Wet Sand...

There is a thread by Dzrtcj7 called VIP Vindicator Restoration. Now granted he started with an oxidized gel coat not applying a new coat but... He graded his wet sanding up to 1000 and then went on to finish with compounds. It was meticulous work but the result was amazing. Check out his thread it may give ya some ideas... just a thought

 

[bluefishing]

Re: New Gel- Should i Wet Sand...

Not meaning to thread jack, but I have a question that goes with your post...

In general, what is the thickest gel should be? Would a good application method if your are not going to spray it be:

1. Roll on a coat, wait for it to harden
2. Squeegee to fill in low spots, wait for that to harden
3. Repeat this process till desired thickness is reached?

 

[tim09]

Re: New Gel- Should i Wet Sand...

its hard to tell from the photo the thickness, but when sanding it down the first time, you take off all the high points so at the end of your first sand you are down to the lowest point vissible, then as you go through the different grits you are taking out the depth of scratches left by the previous grade sandpaper, so you have to have a thick enough coat on so that once all the sanding is done you still have about 1.5 mm thickness of gel left (i am not sure what that is in imperial about 1 / 16 maybe. ). if there is wax in your gelcoat make sure you just scuff it up by hand with a 240 grit paper before re applying. on the other hand your talking about the bottom of the boat so its going to be in the water or on the trailer so wont really be seen, and the rough finish wont affect performance so you could just leave it and when doing the parts you see make them smooth. when bigger boats get antifoal put on its just left as a rough finish. The only thing you might find is that it will be harder to get clean with the rougher finish.

 

[Ithica DB]

Re: New Gel- Should i Wet Sand...

To the post at this point I would run it the way it is unless you want a show boat. In the future I would buy a cup gun and have a friend mixing for you, use a mil gauge, instead of wax in gel use liquid mast to cover area at the end. Bonding is very important so prep is the name of the game.
I did this on a large boat it turned out great with no sanding but by no means was it a show boat. I could keep it clean after that and looking white.

 

[cturboaddict]

Re: New Gel- Should i Wet Sand...

I think that at this point im going to just go ahead clean/scuff/ and recoat again. I want a slightly better consistency, and no regrets to flip it back over and do it again. Im going to order more gel this week. But im going to use the transom as practice to see if i can get it shiny. I planed on using some brightside for the side and top, but i might have a bunch of gel left to use up?

Well see and ill keep you updated on the progress.