epoxy and dye - what kind to get and how much to add?

[Dave S.]

I was planning on doing some fillets with Rocketpoxy and wanted to know about adding red dye to it.

On amazon there are quite a lot of different liquid and powder dyes available for use with epoxy.

Does anyone have any recommendations on what kind to get and how much you needed to add to make the epoxy opaque?

I noticed that some of the dyes say something about being translucent, but I wanted to have the epoxy be a solid opaque red color. Or whatever other color I choose to make them.


Thanks!

 

[Steve Shannon]

Look in the West Systems epoxy manual. They sell dyes for that purpose. It doesn’t take much but I’ve never used it.

 

[Banzai88]

I used the dye that comes with RP. It was a red/black/yellow set.

1 drop goes a looooooong way, especially the black!

 

[cwbullet]

Start small.

 

[OzHybrid]

Wear gloves. A tiny amount can make a massive mess. Resist the urge to scratch anything itchy until you're clear of the dyes. We used to keep all the dye bottles in a Tupperware container away from everything else. The inside of that tub was a mess.....
Don't know if you use silicone moulds? A single drop of dye in one part is a good way of ensuring you can tell when you get a complete mix. When the colour streaks are gone and it's all one colour it's mixed and ready for either degassing or a high pour. ( A high pour is where you pour the silicone in a thin stream from highish height into the mould. It stretches out the bubbles and breaks them.)

 

[teepot]

I bought some liquid dyes from Amazon. It's a variety box. It has 28 small bottles. All it says on the box is epoxy resin pigments. I mix the epoxy and put a couple of drops in it and mix. I keep adding a drop or two at a time until I get the color I want. No mess no fuss.

 

[tsmith1315]

A single drop of dye in one part is a good way of ensuring you can tell when you get a complete mix

It’s also a good way of keeping track if you’re layering over existing epoxy, and then when sanding to keep track of how much you’ve taken off.

I’ve used alcohol dyes and food coloring, but they’re probably not as opaque as what the OP wants.

 

[David Schwantz]

I also have the rocketpoxy die kit. Can send you the red if you'd like.

 

[jsdemar]

This is what I use for epoxy and casting resins... very opaque, a little goes a long way.
https://www.alumilite.com/dyes-colors/alumilite-dye/
Available on Amazon.

 

[Back_at_it]

I've never tried liquid dyes but I have used the good old fashioned RIT powder stuff you get a the grocery store. Some years back I working on an RC Car project and wanted to epoxy some aluminum strips onto a chassis. The chassis was red and the aluminum was anodized red so I figured I'd give it a shot. A tiny, tiny pinch in about 4 grams of BSI 30 mins turns a nice bright red and looks amazing. It didn't seem to have any affect on strength as I beat the snot out of that truck for years without issues.

 

[prfesser]

I would avoid liquid dyes on general principles. The liquid component/solvent may not be compatible with epoxy. Some liquid may "sweat" out onto the surface (been there, done that) and could interfere with a good bond. Volatile solvents may take a very long time to evaporate from the interior of the cured epoxy, possibly resulting in shrinkage over time or reduced strength.

Powdered pigments are a better choice IMHO. Metal oxides such as (red, yellow, black, or orange) iron oxide, (red or black) copper oxide, etc. can be very inexpensive and readily available from pottery supply houses. For more brilliant colors, the dyes used for colored smoke in fireworks are expensive but a good bet. And as @Back_at_it suggests, plain old RIT dyes probably will work a treat.

Caution: do trials with small amounts. I recall adding manganese dioxide to about a half-cup of epoxy. The MnO2 didn't react itself but it catalyzed the curing reaction...extensively. Had to put it down on the sidewalk to avoid burning my hand. Smoke emitted did not smell good and probably wouldn't have been good to inhale.