Sanding of plywood before epoxy

On Mon, 14 Jul 2008 11:59:16 -0400, "Morgans"
wrote:


"Stealth Pilot" wrote

sanding breaks the fibres.
well what do you think cabinet scrapers do???

According to what I read, the fibers breaking is not the probem It is the
sanding dust filling the pores of the wood, so glue does not soak in as
well.

When this came up before, one of the builders did test blocks, and found the
same results as was present in FPH.

I sand every joint face in every piece I glue and never ever have I
had a glue joint break in a test piece.

the important things in joining with epoxy arent sanding or scraping.
they are....
absolutely no oil contamination of the joint.
no wax contamination.
no water contamination.
both pieces of wood at the same moisture content.
no loose dust in the joint area.
epoxy correctly mixed.
epoxy joint clamped in position with an appropriate gentle pressure.
joint not clamped so hard that the glue is squeezed totally out of the
joint.
absolutely no joint movement until the epoxy is fully cured.

and lastly but most importantly
cure the epoxy in the proper temperature range.

Agree with the above, in practice, anyway. The difference between a flat
sanded surface and a flat scrapped or planned surface has got to be pretty
darn small, and like I said, in plywood, the difference is likely not very
important.

most certainly blow all the dust out. thinner (hotter) epoxy
penetrates best.

Stealth Pilot