Polyester Resin dye

[Hermit Scott]

Ross,

Paint store "universal colorant" should not be used with polyester resin or gelcoat. You will ruin the batch if you try and use pigment / tint made for paint.

Gelcoat & resin pigments are made specifically for use with resins or gelcoats and are usually made from a raw polyester resin base but lack the promoter agent , normally cobalt, which reacts with the MEKP. They need to be chemically compatible with the resin or gelcoat so that cross-linking occurs, paint pigments are not.

As for tinting the resin I would not bother. You can not add enough pigment, by volume, without inhibiting the cured structure of the resin to make it completely opaque. Yes, tinting can minimize bleed through on a thin coat of paint or gelcoat but properly applied gelcoat or paint will not have any problem hiding the substrate.

Rolling on gelcoat with a West Systems foam roller is easy. It will not lay down perfectly flat but can then easily be wet sanded and buffed to a factory looking finish.

I would roll two coats of un-waxed gelcoat then follow it up with a waxed layer. Let kick off in-between coats about 20-30 minutes depending upon temp then apply the next coat. The final coat that contains the wax will allow a full cure.

You could also use a product like System Three WR LPU which is a water based LPU paint, Interlux Perfection, or a single pack paint if durability is not your main concern.

I am set on spraying the deck. I don't want to roll it. I was really impressed with Tim's hull after so many years. I should probably read up on the paint he used and just make sure whatever I use is compatible with that. It was Emron right?

 

[Ross]

Maine s'l , My only experience in this is with small batches of filled resin for the purpose of fairing and not for color matching. As you know having the substrate somewhere near the color of the top coat makes life easier. I have had no trouble with a bit of tint but adding enough to actually serve as a pigment would probably be a different story.

 

[RichH]

Hermit ..... let me talk you out of painting a deck.

There is NO paint on the planet that can withstand the abrasion that happens on a deck as can gelcoat. If you can spray paint, then you most certainly can spray gelcoat. Once you paint you will be forced to continually re-paint and re-paint ad nauseum.

There are many websites that fully explain 'shooting gelcoat' .... and unlike paint, gelcoat can easily be sanded and flat sanded down if you do make 'mistreaks'. IMHO - a boat that has paint applied (topsides/deck, etc.) immediately has a severely decreased resale value and an enhanced 'maintenance' load.

For spraying 'small jobs': http://www.jamestowndistributors.co...t.do?pid=2155&familyName=Preval+Spray+Gun+Kit