Polyurethane on Oak

[Bigbadmarky]

Morning All,
I hope you are all well on this fine Monday morning.
I have a question regarding finishing of Oak. I've made a table top out of some reclaimed oak flooring and thus far, have finished it with 2 coats of shellac and about 4 coat of (water based) polyurethane (Ronseal trade), de-nibbing between coats. I de-nibbed the last coat with 0000 steel wool before adding a final coat of poly but when I've checked on it today the finish is full of little black dots. Hopefully you can see them in the image below:

I suspect it might be teeny tiny bits of steel wool which have rusted under the poly coat.
Has anybody any other suggestions as to what it might be? FYI: My workshop is uninsulated and did get quite cold during the night. Could that be a factor?
Does anyone have any solutions that don't involve me having a proper man-tantrum and stripping back to bare wood?

While on the topic, assuming I can strip back and get rid of the black dots, what wax should I apply over the top to finish over the poly. I want to avoid the plasticky look that poly can have and thought a sheen of wax might be best. Anyone any recommendations?

Many thanks,
Mark

 

[Racers]

Its bits of wire wool and water in the waterbased varnish and the tanin in the oak that have caused the problem, I use a scotchbrite pad and danish oil, the foam and pad pan scourers work very well for appling danish oil.

Pete

 

[marcros]

I agree with Pete. The only way to fix this is to remove the finish and the bits of wire wool.

 

[Phil Pascoe]

Wire wool on oak or chestnut is a no no. Not good on sapele, either.

 

[marcros]

An aside to the OP, is wire wool an advantage over scotchbrite on anything? I have the mirka version which has one as fine as (I think) 1500 grit? For a finer buff/burnish than that, I would sometimes use either a brown paper bag or a handful of fine shavings (particularly when turning).

 

[Bigbadmarky]

Thanks for the replies all. Please excuse me while I throw a wobbler: AAAARRRRRGGGGGGHHHHHHH!!!!!!!

Right I'll strip back the finish and look for some scotchbrite.
Thanks for everything. Its good to have an information resource like this on hand for a novice like me.

 

[OldWood]

Bad luck BBM - I'm afraid I guessed the tannin as being the source. I hope you have no other steel in contact with the wood. Tannin is oak's way of protecting itself against bugs - machining wet oak is a particular problem as all steel will collect a black surface.

I had no idea chestnut did the same - is that sweet or horse chestnut as they are different species?