Re: [CAD_CAM_EDM_DRO] Epoxy

>
> Bill: I use Shell Epon 815, a "pourable" epoxy. Comes in gallon jugs,

and

> uses "TETA" (some organic chem. name like "tetra-ethyl-tri-acetate" or
> whatever) as catalyst. Mix 10:1. Must use a balance-scale, and be within

a

> few percent. Too little TETA, and the result is soft. Too much, and it
> "floats" to the top, and leaves droplets all over the top of the pour,

which,

> when "sponged off" after hard, leave semispherical dimples where the drops

of

> TETA were floating. This is a very hard, stable "plastic", nearly

colorless.

> Mixes readily with any powered pigment such as soot, copier toner,
> chalk-powder, any dry powder paint-pigments, etc. Also, lithographer's
> liquid black-out mixes fine, too. Softens result a bit, but doesn't take
> much of it to make it reasonably opaque/black.
>
> Bubbles? I built a plexiglass "bell-jar" (rectangular box with open-side
> with pourable-RTV rim, to seal against flat surface (another slab of
> plexiglass/Lexan) for placing such inside, and drawing vacuum on it. That
> makes bubbles expand so they float readily to the top, and after quarter
> hour, release the vacuum and let the pour cure in the atmosphere. Makes a
> trememdous difference! I also tried using an electric stirring-rig

inside

> the vacuum, to mix the epoxy so it wouldn't "mix-in" air, and this "kinda
> worked", but it was so much hassle that I didn't continue that method.
>
> Lotsa luck!
>
>

Thanks Jan, i'll try it out, and the vacuum trick too.

Bill