Dye quantity to use for epoxy

[Lycosaurus]

Mixing up a batch of epoxy tonight, and wanting to dye the epoxy black for lower windscreen fairing. I bought a small tube of dye from the local boat supply place (and I though aviation was expensive!), and only indications on the tube is to follow instructions given by epoxy manufacturer. Don't have any such instructions for my West System.

For those who have used a dye in their epoxy, what mix ratio (e.g. drops per pump of epoxy) did you use? Just increase dosage until dark enough?

The person at the counter did not know how much to use, but said if you use too much, it may weaken the epoxy. When I asked what 'too much' is, he did not know.

[Guy Prevost]

West systems recommends 1 teaspoon per 8 fluid oz. of epoxy. You can take a look at their pigment instructions here: http://http://www.westsystem.com/web...m#publications

[Transporter]

I've used West System 503 (Gray) with good results. Info from the West Systems site (www.westsystem.com):

" WEST SYSTEM pigments are epoxy-based liquid colorants used to tint the epoxy mixture to provide an even color base for the final finish system. The colored surfaces also tend to highlight flaws and imperfections. Cured, pigmented epoxy surfaces are not a final finish surface, but require an additional opaque or UV filter coating for ultraviolet protection. Add to the mixed resin/hardener at a rate of approximately one teaspoon of pigment to 8 fl oz of epoxy. More pigment will increase opaqueness and mixture viscosity. One 4 fl oz bottle will tint approximately 2/3 gal of epoxy."

Not sure what brand you're using but the mix should be similar.

I've also used West Systems 420 Aluminum Powder instead of dye to add some UV protection and still give a gray tint:
"420 Aluminum Powder provides limited protection from ultraviolet light in areas that will not be protected with other coatings. Can be used as a base for subsequent painting. 420 will increase the hardness and abrasion resistance of the coated surface and improve its moisture resistance. Cures to a metallic gray color. Add to mixed resin/hardener at the rate of 5 to 10% by volume (approximately 6 oz. per B group). "

Good luck,
Mike

[Lycosaurus]

I'm using West Systems epoxy, and the dye is from Evercoat.

It's a 1 oz. tube, so that's 6 teaspoons-full, therefore it should dye 48 fl oz. of epoxy ... more than enough.

Thanks for the info guys .... and quick at that too.

[frazitl]

I just added a few drops of black to each 4 pump batch. Looked pretty black in the mixing cup. After sanding it looked sort of transparent with any light shining thru it. I'm still convinced that it will be OK after painting, but my advice is to add more than you think you need based on just eyeballing it...

[Lycosaurus]

Originally Posted by frazitl

I just added a few drops of black to each 4 pump batch. Looked pretty black in the mixing cup. After sanding it looked sort of transparent with any light shining thru it. I'm still convinced that it will be OK after painting, but my advice is to add more than you think you need based on just eyeballing it...

That's what I ended up doing, Terry. Just a few drops on my double pump ration of epoxy, and it was quite dark.

Right now, I'm just using a slurry of microballoons to fill in the gaps from windshield to top skin. Next step is to prepare for the fairing (tape up the whole area with electrical tape or packing tape) and use mold release wax or whatever. Several people here have had good success with doing the fairing, releasing it from the windscreen, trim / sand / paint, then apply fairing back to windscreen with epoxy. I'll probably go the same route.

Will take your advice, and add a few more drops of dye on my next layups.

[jarhead]

Originally Posted by Lycosaurus

I bought a small tube of dye from the local boat supply place (and I though aviation was expensive!)

You know what "boat" stands for, right?

Break Out Another Thousand
(dollars, that is...)