I have been working on a Super Firecat purchased from Frank Macey in 2005. It is a laser cut kit. I pre sanded all the part before assembly to remove the scorching. After assembly and more sanding I coated the wood with Balsaloc, which is the adhesive used for the Litespan covering I am using. After coating the rib edges to wood turned black in spots again. There was no black anywhere after sanding and now the black refuses to leave after sanding again. Since the covering will be semitransparent the stains will show through. Anyone have any ideas?

Don

Don.
How about painting the edges of the ribs with a contrasting color to make them show out.  This solves the problem of irregular coloration through the covering.
BTW, I use as little power on the laser as it takes to make the cut.  On 1/16" ribs, this is about 12-15% power, depending on the density of the balsa.  Much reduced ash that way.
Pat Johnston
Skunk Works

I'm not sure what you can do.  I'm pretty sure that what happened is that the carbon was in the wood, hiding down in the grain.  Then when you put on the Balsaloc it made the top layer of wood translucent and -- (expletive deleted).

Sanding out the dark spots and reapplying BalsaLoc is probably all you can do.  You may end up with little flat spots in your ribs everywhere that you have to do this, though.  Whether it's worth your while is your call.