Little black marks

There are a few small black marks under the varnish of my scorp and i would like toget rid off them, a freind told me that you can just sand them away but another told me theycan come back if you do this. does any one know how I can sort this problem?

Hi Stuart,

You could try masking off, sanding back, drying out, solution of oxalic acid crystals (from chemist shop) and water, dry out and leave, clean up with meths or other spirit to neutralise, dry out, fine sand, epoxy, fine sand, multi varnish job.

If you can get to the under side of the job, it is worth checking that the damp is not working its way to the top side from the under side, if it is, sand back dryout, epoxy and paint/varnish job. It's a good idea to find out what caused the problem in the first place, if the problem is due to flexing, some beefing up may be required.

Ian   (Yorkshire Dales S.C.)

Edited by iansmithofotley

k thanks for the help guys i'll try all that 2moro

 

Yes, epoxy can be sanded, but it will be harder than sanding varnish (start with reasonable coarse grit sandpaper). I don't know it there are potential interactions between epoxy & turps etc so it would be worth testing that out first.

Oxalic acid is a well known bleaching agent. I have used it on Firefly's and it works well.

Be careful it is poisonous if swallowed and is a severe irritant if inhaled or absorbed through the skin.

The link below gives a detailed description and precautions.

 http://www.jtbaker.com/msds/englishhtml/o6044.htm