oxalic acid advice

[SAWDOC]

hi
Should i sand varnished washboards before applying oxalic acid? wondering if the varnish will hinder penetration. TIA

 

[BlueSkyNick]

Why would you apply Oxalic to varnished wash boards????

Can only assume there is some discolouration under the varnish, in which case the whole lot has to be sanded back to bare wood, ..... and then you won't need the oxalic anyway.

 

[VicS]

Yes you will have to remove the old varnish but be careful sanding if they are ply as the surface veneer can be very thin sometimes. A varnish stripper might be a better idea.

See the instructions on the AG Woodcare website http://www.agwoodcare.co.uk/gbu0-prodshow/oxalic_acid.html

 

[bazobeleza]

A good thin cabinet scraper will remove varnish, oxalic acid is a wood bleach that needs to sink into the imber to acheive its lightening effect.

also don't forget to was it off with plenty of water once its done its job

 

[alec]

[ QUOTE ]
Why would you apply Oxalic to varnished wash boards????

Can only assume there is some discolouration under the varnish, in which case the whole lot has to be sanded back to bare wood, ..... and then you won't need the oxalic anyway.

[/ QUOTE ]

After stripping old varnish etc I always use oxalic acid to lighten the wood. Only because most coatings seem to darken the finish.

Having said that, I am now a total convert to Sikkens Cetol Light. Not a Steinway finish , but looks pretty good and so much more sailing. Particularly as there does not seem to be a varnishing season in the UK now.

 

[SAWDOC]

Thanks everyone
Good advice as usual. couple of dark patches taking from their appearance.