Oak fuming question.

[JJ1]

I would like to have a go at fuming Oak. Is this the correct stuff for the job?

http://m.therange.co.uk/homecare-ammonia-liquid-500ml/wipes-&-cloths/The-Range/fcp-product/69684

Thanks

 

[marcros]

that will do the job. I have used very similar stuff.

One point to note is that you must put a polish on top, or it will look a very green colour. With the polish- an oil for example, you get a very rich brown.

Worth running some samples so that you can see the colour variation with time exposed.

 

[JJ1]

Thanks Marcros.

 

[Mike Jordan]

I've only ever had one go at fuming oak, I used a similar product from the local chemist, the oak and a shallow tray of ammonia were put in a large plastic bag and placed in the back of my transit size van. The colour change didn't take long to occur but the results were disappointing. The colour was a muddy looking brown that didn't seem to enhance the timber at all. Perhaps I overdid it! I suggest a few trials with scrap material before committing the workpiece.

 

[JJ1]

Thanks for your input Mike. Out of interest, how long did you find your wood?

I'm just off out now to pick up a bottle of ammonia. Not expensive, so I've not got much to loose, apart from a bit of time experimenting, which I enjoy anyway.

 

[Mike Jordan]

As far as I can remember it was only about 45 minutes but it was a very warm day, I think that speeded up the process.
I would be interested to hear of your results and thoughts on the colour you get.
Mike.

 

[marcros]

the temperature certainly makes a difference. By contrast to mike, I got a very nice rich brown. I have done it a few times, and it has usually been a couple of hours or more, and on a cooler day than "very warm" (IIRC).

some other points to note
where the ammonia cannot reach, it wont fume. so anything that is in contact with anything else will leave an unfumed bit.
try to get your project from a single board, failing that make sure that anything that is next to something matches- so if it was a table, try to get the top from a single board- different trees take the fuming differently.
I would start off with about 10 samples in the tent, and then take one out every 30 mins and apply some oil. then you will be able to see the different colours. they dont need to be big.
The last time i did some, i used the wheelie bin on its side, and a plastic takeaway carton with half an inch of ammonia in it. The work was supported on painters pyramids, on a place that wouldnt be seen when it was done.

I cant promise that you will like it, but it is well worth trying for what it will cost to give it a go. The finish is very typical of antique oak, of a certain era (which, I know not!).

 

[Beau]

I've only ever had one go at fuming oak, I used a similar product from the local chemist, the oak and a shallow tray of ammonia were put in a large plastic bag and placed in the back of my transit size van. The colour change didn't take long to occur but the results were disappointing. The colour was a muddy looking brown that didn't seem to enhance the timber at all. Perhaps I overdid it! I suggest a few trials with scrap material before committing the workpiece.

Had a similar experience with fuming but I was making it up as I went along. Had better results with wiping on a potassium dichromate solution.

 

[JJ1]

Thanks again for the additional info

A quick update: I bought some household ammonia for the grand some of £1 and at the same time I bought an 89p clear plastic mixing bowl to use as a cover.

The plan is to try and get a slightly aged, golden brown colour to a desktop I've just made for a 1950's oak office desk. The desktop is 19mm crown cut oak veneered MDF with 6.5 cm wide solid oak edges.
So as a sample I've glued some solid oak to the veneered mdf and made lots of sample pieces. I sanded to 180 grit, dampened to raise the grain, re-sanded to 180 grit. I put about 1/2 " of ammonia into a small glass bowl and stood my sample an inch or so above it, popped up by a couple of pieces of MDF. Clear mixing bowl on top and sealed at the base with some masking tape. I left the sample fuming for 2 hours, removed it and applied some Osmo Polx Oil. I was very pleased that it seemed to 'colour' very quickly and easily. On the oak veneer it took on a nice aged, brown colour, very similar to what I was looking for, albeit a bit darker than preffered, but easily rectified next test run. The solid oak also coloured up nicely and to a similar degree as the veneer. The only snag was, the solid wood took on a slight greenish tinge which was quite obvious next to the browner veneer. It's not really surprising as the bare wood before treatment does appear a bit 'greener' than the veneer anyway. So I guess the fuming has just bought out and accentuated the underlying colour. I wasn't really surprised or expecting the solid wood to match the veneer. in fact I didn't even know if it would work at all on veneer, so I'm pleased to have discovered that it does.
I'm not sure how I can overcome the green tinge using this method. Maybe I'll try a very pale brown stain on the solid wood first and then try fuming to see if that works and colour matches slightly better. I'm not really bothered if it doesn't as I'm enjoying experimenting and the learning curve.
I have some Van **** Crystals arriving in the next day or two so I'm looking forward to trying that method too.


Marcros, if your still following this thread. I noticed from reading some older forum posts that you've had success using washing powder in addition to Van **** crystals. I'll have a go at that method too but I was wondering what sort of ratio of washing powder/water/van **** crystals would you recommend as a starting point. Specifically, how much washing powder to water to use.

 

[marcros]

check the thread, but it wasnt me- I have never used Van ****. I think it is probably just to break the surface tension of the water, so a drip of washing up liquid would do the same.

you may struggle colour matching the veneer to the solid. you have 2 problems- matching the colour of the fumed oak parts, so that the oil can work equally on both.

A few things that i would research are gel stains which sit on top of the finish, possibly tinting the oil on the solid with a bit of red (to take out the green), or do something with the solid to make it non-green, and put some stringing between the solid and the veneer- rather than disguise it, make it a design feature.

 

[JJ1]

Thanks for the suggestions Marcros. Looks like I'll be busy experimenting tomorrow

 

[tomatwark]

Having done a bit of fuming over the years, I have found that some Oak is better than others depending on the tannin in the Oak.

I have never had much success in getting an even colour using American White Oak and will always use European Oak when we do fumed stuff.

Some solid Oak does come out with a slightly green colour to it, but I find after about 6 months or so the colour evens out to a nice brown colour, I always warn my customers of this when we do fumed stuff.

 

[JJ1]

Thanks for the info Tomatwark. It'll be interesting to keep an eye on my sample pieces and see if there's much colour change over the coming months.


I've decided to put any further fuming experimenting on hold for a while. Reason being, my Van **** Crystals arrived this morning and initial test results are very promising indeed. The resulting brown colour came out very well and is exactly the colour I was looking for.