Doug,

I would recommend against using microballoons for the filler in the seams. Microballoons are a non-structural filler and could weaken the joints significantly. Why are you wanting to use microballons? Other fillers would work much better for that application. If you want to use them to save weight, I would think smaller fillets are better than using a non-stuctural filler for a structural joint.

As for tinting the filler black, it would be a good idea to pre-seal the panels before assembly. That way any runs can be removed without sanding down into the wood. If you do not pre-seal the panels, you may get some drips that soak into the wood and becom impossible to sand out, depending on how far the epoxy penetrates.

Mike

: I'm thinking I could use a microballoon filler for all of the seams. I have
: to check that the filler can be colored properly. If so, the microballoon
: epoxy can be applied to the seams using a putty knife. The microballoon
: filler easily squeezes into tight seams. I'll mask the seams prior to
: application. Using the masking tape and the easy-to-sand filler, the
: application should be very clean.

: I'll going to think about this a bit more, and maybe even contact the epoxy
: manufacturers to see what they say.

: cheers