Oak and Acrylic varnish - a cautionary tale:

[Scrums]

Been making up a cabinet for a customer - didn't have a lot on at the time, did it on the cheap.....

European Oak, not big - not many pennies per hour but still pennies per hour.

Customer wasn't sure of the finish they wanted, but seemed to be going with my Danish oiled advice.

I 'phoned to let them know it was finished - and would they confirm their finish......varnished !.....yuk!! (...but the customer is always right - aren't they ?)

It required a final sanding and then the finishing, in this case (!) 2 x coats acrylic varnish (let down 50/50 with water) rubbed down in between then a couple of top coats - ending up looking more like laminate flooring than real wood.

Then it happened.......during the final sand I must have touched one of the stretcher brackets that were to attach the top. I didn't think anything of it at the time, I brushed the whole thing down, vacuumed it and gave it a wipe over with a cloth.

Quite honestly, I was glad to be on the finishing straight and getting it out of the way - I put on the first 50/50 coat and got on with something (hopefully) a bit more profitable....I got back to it about 2 hours later to see if it was ready for de-nibbing......and it's got measles !

You've probably twigged by now - tiny bits of steel, thrown everywhere by a sander, spread everywhere by me and my brush - tiny little black polkadots everywhere ! ( Courtesy of the water based varnish and the ferric in the steel)

The moral of the story is this: keep ANY form of iron away from Oak, be it sash slamps/screws/G clamps/ or even metal dust....

 

[dedee]

Oh Dear, that sounds costly. What did you do/will you do to recover it?

Andy, who only used wire wool on oak once.

 

[woodbloke]

Scrums - Ooooops.....I'm very wary now about wire wool and stuff like that on oak. I did use once tho' some oxalic acid in solution to neutralize the black marks and then that was itself neutralized by somat else but I can't think at the mo what it was :? - Rob

 

[johnnyb]

oxalic acid is allowed to dry and repeated if necessary. you will have to do the whole peice. then wash off with water.

 

[Scrums]

Wish - I'd had that info previously !

I will never ever use acrylic varnish on oak again, even an add-on piece that the customer requested (had iron/steel no where near it) managed to have a purple black tell tale mark on it!

The customer picked up today, they were thrilled with it ......I lied through my teeth, blamed it on a reaction between the tannin and the varnish and implied it was their fault for insisting on a change of finish. They were understanding and I think felt a little guilty, paid cash and asked for some leaflets to give to their friends.........phew!

To be perfectly honest, the marks weren't too bad - honest guv'

Chris.