Removing woodworm treatment stains in beams

[GroundFig]

This is a bit of a random one and I'm not certain that there is much that can be done, but thought it's worth a punt. We have some wooden beams in one of our rooms, which have some kind of stain around holes which have been drilled in them. I presume these holes were for some kind of woodworm treatment, but do not know for sure.

I don't know if these stains were caused by the treatment itself, or by interaction with the woodstain on the beams or whether the beams were stained afterwards and it somehow built up more strongly around the holes. Anyway, I wondered if there was anyway of perhaps removing or lightening these stains. Sanding lightens them a small amount, but they must be pretty deep.

I wondered about some kind of wood bleach, but don't really know anything about it and wasn't sure how easy it would be to apply to beams in any event.

So, just wondered if there was anybody who had experience of anything like this and whether there were any possible solutions. Final resort is probably just to paint them white as they are very low (1.8m) and make the room very dark, but I'd prefer the look of wood (without stains!) if it's possible.

 

[dickm]

Those look remarkably like tannin stains around iron nails - has the beam been de-nailed at some stage?

 

[lurker]

That's what I thought too . Tho holes don' t look like worm holes either

 

[GroundFig]

I don't know the history, unfortunately, this is what we inherited with the house. The previous occupier was pretty "inventive" when it came to DIY and so any kind of mad stuff could have happened. I don't think the big holes are worm holes, but thought that perhaps they had been drilled for some kind of woodworm preventative treatment. However, this is all supposition as (if you hadn't guessed already) I have no real idea what these holes are.

Now I look closely at some of the beams it does look like there might actually be some bits of nails left in a couple of the holes:

But if they are nail holes, why would someone put nails in in such a crazy way?

The beams we have in another room are much older (it would appear, at least) and also have holes in them in a similar type of pattern, though a little more orderly, but no (or not very visible at least) stains:

These beams are I think a different wood than the ones with the stains, though, and have been stripped back bare it seems.

 

[Bod]

Lath and Plaster ceiling.
The ceiling itself has been removed, leaving the nail holes that held up the laths.
To cover the gaps in the floor above, infill panels have been fitted between the beams.
Normal course of action is to stain/paint the beams, dark brown, almost black. Think olde worlde pub décor!

Bod

 

[rafezetter]

I would also say nail holes and as for the "crazy" pattern it's possible it's either had several lives or whatever was nailed to it may have rotted out and a replacement nailed on into fresh wood. (edit - lathe and plaster makes more sense)

If you aren't fond of the look, then a simple ebonising solution made of white vinegar with wire wool dissolved into it over the course of a week (then filtered through coffee filter) will make the whole thing uniform - if you are not sure of the strength (and therefore colour) you want then maybe do a tester after only a couple of days and if that's too light add more wire wool and leave it another few days. This will make the wood go dark as per the stains you already have to a greater or lesser extent.

This type of staining doesn't work in the normal way of modern stains (more coats = darker) as the colour result depends on the strength of the solution (how much wire wool is dissolved into it) and the amount of tannins present in the wood - you could get a strong colour reaction with a very weak solution if the wood has a great amount of tannins present, and conversly you might get a very mild effect from a very strong solution because the wood has few tannins.

I'm not an expert on wood species and cannot say for sure what those beams are to advise which is the more likely result apart from you are correct to say that in your second post the two beams look like different woods, hence why one has stains and the other dies not; but I do know that oak / ash = very strong effect.

If you prefer the lighter wood effect, then you could try oxalic acid - mixed into a paste then brushed on - but keep in mind at best you'll only reduce the staining and never get a totally uniform effect.

 

[blackrodd]

+ 1 more for nail holes. As other posters have said, these stains are from nails likely made by the local Smithy,
And were used to fix the split wooden "laths" that preceded the plasterboard of today.
You'll have a job to get those stains out, normal practice is usually to stain to the darker colour, making it all
one shade, here in Sunny Devon.
Regards Rodders

 

[GroundFig]

Aaah, so that makes sense! Thanks all! Shows I really didn't know what I was talking about, which is not a surprise.

I might have a go with some Oxalic Acid just to see what effect it has, but can see that darkening them is probably the only way to hide the stain fully. They're already probably a bit too dark for the room, given that they are so low (1.8m) and that there is only one small window. I may have to end up painting them white after all.

Thanks again for clearing up the mystery, much appreciated.

 

[blackrodd]

The softwood beams aren't really old as the straight saw lines show a bandsaw used, the pit saw marks,
on the older rafters and beams are angled and more irregular.
Here's a link to whet you're appetite, they don't have to be black!--
The most stunning I've seen were a white ceiling and grey painted beams

https://www.google.co.uk/search?q=paint ... AS2vkJw%3D

Regards Rodders

 

[acowboy]

Hello,
I have seen this stain before in quite a few restores.
Results of iron nails+moisture reacting with the natural tannins in wood.
Oxalic Acid should work but can be some nasty stuff even diluted.
Myself, I have had some great results using citric acid, lemon juice in fact.
I would give that a shot before using the Oxalic Acid.

 

[GroundFig]

Thanks, I'll give it a try.

 

[Zeddedhed]

I've seen a guy using that fizzy stuff for removing stains on clothes (Vanish?) to get dark marks out of Oak. Seemed to work.