I used a couple of coats of that on my aquarium stand to seal the exposed PB
(back) and it seems OK. But it's only been a couple of months. I don't
imagine this stuff can be painted over too well though, Shellac is probably
a better choice if you want to paint it after.


No, no need to paint it. As with thinning glue for that, why not thin
the spar so it soaks in further...?

I tried coating a saw handle with it, it's like really "plasticky" stuff. It
has to be sanded between coats and no good, just comes right off. But
this may work with thinning.

Alex