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lancelot9898 06-23-2013 09:41 AM

Using brush instead of spray for gel
 
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For covering up some flaws in the hull, has anyone used a brush rather than a spray for applying gelkote? More sanding would be needed, but it should sand down rather easy would be my guess? A picture of the hull that needs work is attached.

overbored 06-23-2013 01:24 PM

Re: Using brush instead of spray for gel
 
you can use a brush for small touch up and on horizontal surface but on vertical surface no way, it just does noes not work well. if you want to spray on a small area it is best to use a Preval sprayer.
Preval ? Preval Sprayer Products.
these work great for gelcoat and you don't need a compressor

PorFin 06-23-2013 03:09 PM

Re: Using brush instead of spray for gel
 
Yes, you can use a brush.

The challenge on vertical surfaces is keeping the gel from running/sagging. If you use a piece of acetate over the top of the repair, you can keep it in check. Tape all the way across the bottom first, apply the gel, then roll the acetate up over the repair. Use a plastic squeegee or body filler spreader to work it relatively flat. Tape the top, then tape the sides. The good thing about the acetate is that it will leave you with a pretty fair surface. The bad thing is that with the molded planking, you're gonna have to reestablish all those grooves.

I've tried to get a Preval sprayer to work with gel, but have had little success. The problem is that the you need to thin the gelcoat considerably to get it to spray well. A couple of suggestions if you decide to go this route:
- Pull the strainer off of the pick-up tube on the sprayer.
- Thin the gel with Styrene only. Acetone will work, but it flashes really quickly.
- Adjust your mix before you add any catalyst. Spray onto a piece of glass, and add styrene until you get a coat that covers smoothly but doesn't sag/run.
- Add the amount of catalyst needed for the volume of the total gel & added styrene in the bottle. If you only add enough catalyst for the gel you started with, then the gel won't dry fast enough.

Good luck which ever method you choose.

lancelot9898 06-23-2013 05:32 PM

Re: Using brush instead of spray for gel
 
There is a youtube presentation by TAP Plastics that shows what looks like a disposable glue brush being used to apply gel to a vertical surface. I thought that it would remove a couple of steps from going the preval sprayer route. Plus I would not have to thin with the styrene if I go that route. A small foam brush might also be an option. Apparently the demonstration used a non wax gel in that it showed three ways to get it to cure. One being applying heat via either a hair dryer or sun, two via the standard PVA? spray and thee via a celephane sheet to block the air so that it fully cures. It does not mention the wax gel which does not require any of those steps, but someone suggested that the wax gel is a pain to work with. Also I really don't want to fill in those grouves and I'm just trying to cover the small pimples thinking that a thin coat of gel will hide those flaws.

PorFin 06-23-2013 07:03 PM

Re: Using brush instead of spray for gel
 
Just be careful with the glue/acid brush -- they shed bristles very, very easily. Nothing worse than trying to dig bristles out of wet paint/gelcoat.

A foam brush will work, but I really prefer the control you get with a real bristled brush. If you're willing to part with a couple of bucks, grab an artist's brush at Michael's or some other hobby store.

I never found waxed gelcoat a problem on it's own, but given a choice I'd go with unwaxed. You can air inhibit it with PVA or plastic, or if you know you're going to be building up a couple of coats you can just let it set and apply your second coat without having to scrub and sand.


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