Need help adding colors to Epoxy

[dat2zip]

Not sure if this is the right place for this topic. This is for my DC/DC converter current mode converter that will be used to drive one or more Luxeon LEDs in future mods.

I am making several version of my new converter that will be coming out shortly and have decided to color the thermal epoxy I will be gooping the top of the board. The IC and components can get pretty hot so I need to goop them to help distribute the heat. Since I need to do this step I have decided to try to color code the epoxy to designate the different output currents that will be available.

Yellow will be 400mA drive.

Green will be 500mA drive.

Violet or purple will be 700mA drive.

These colors correspond with the same resistor color code scheme and it makes identification easy.

Question is: What can I use to color the epoxy?

A person buying something at the local hobby store said I could mix any oil based hobby paint and it would work fine.

My mix is already 50% 2 Ton Epoxy and 50% Arctic Alumina which makes it look like white paint.

Any thoughts would be appreciated.

 

[DSpeck]

I've coloured epoxy with the pigments used to colour fiberglass, and that works fine. I got them at the same place I got the epoxy, which is a boating supply place. I understand you can also use acrylic paints for this purpose.
You don't need a lot of any pigment to make the epoxy change colour.

 

[Slick]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by dat2zip:
A person buying something at the local hobby store said I could mix any oil based hobby paint and it would work fine.<HR></BLOCKQUOTE>

While I haven't actually tried this, it sounds like it would work seeing as how the epoxy still sets up when you mix in thermal grease. You probably wouldn't have to use much paint in your mix to be able to tell the difference anyway.

 

[McGizmo]

Wayne,

Fiberglass Evercoat makes pigments for polyester resins and they will also work with the epoxies. West Marine handles these as do any of the independent boat suply stores. I have red, yellow, blue and brown collecting dust in my shop. E-mail me.

- Don

 

[sflate]

dat2zip - Just out of curiosity, does this mean that the MADMAX1674-ADJ will push 700ma at wide-open? I didn't think it was that high.

 

[Silviron]

I've tried all kinds of stuff for this- from solid pigments like lampblack and powder coat powders to enamel modeling paints.

They have all worked to one degree or another although the enamel paint additive took "forever" to dry, even with a heat lamp baking it.,, IMHO, the best choice is a powdered solid, followed by the stuff for coloring polyester resins.

 

[dat2zip]

sflate,

This is for the new converter and not for the existing MADMAX series. To be clear this info is for the almost ready to be released BADBOY converter which is a current mode regulator.

BADBOY is currently being targeted for the new 5W Luxeons if they ever ship.

Don, Looks like we might have to get together again

Last night I tried adding green from some hobby paint and it seemed to work fine.

-WayneY