More fuming experiments (update 2!)

[mikekeswick]

Ammonia is the usual thing to use for this kind of thing.
You just put the stave in a sealed container with an open pot of ammonia.
I presume that Simson is doing the same thing???

By the way when your mate passes you a bottle of ammonia with a grin and says 'have a smell of this stuff'.....don't!!!

[Cloudfeather]

Hmm, I find that incredibly fascinating. I'm in love with that dark chocolate look on the Osage.

[Onebowonder]

Any further testing done yet???

OneBow

[Willibow]

What sorts of materials are safe and commonly used as a container for fuming a bow?  I'd like to give this a try and was thinking a large piece of PVC piping with caps on each end would be an easy way to fume a bow.

[simson]

Any further testing done yet???

OneBow

Yes, I do permanently experiments on that things. I will post a fumed elm HLD bow soon. And I#m trying to get an osage chocolate bow

What sorts of materials are safe and commonly used as a container for fuming a bow?  I'd like to give this a try and was thinking a large piece of PVC piping with caps on each end would be an easy way to fume a bow.

Any plastic foil pipe or a hard plastic pipe will work. As Mike said it must be sealed - no damps should come out. Work carefully, the stuff is dangerous. Post your experiments!

[Willibow]

If the hickory bow I'm working now survives the tillering process I think I'll be trying this 

[lebhuntfish]

Very cool, thanks for posting this simson! I have been wanting to try something like this for a while now. Patrick

[DC]

Have you tried soaking it in tea for a bit, maybe up the tannin content. Although now that I've said that you would have a tough time getting me to soak a finished bow in tea

[Willibow]

I did some further research and it looks like HDPE is non-reactive with ammonia. Some plastics will be eaten up by it.  PVC is listed as "not recommended" for contact with ammonia solutions, so be careful if you're thinking about using pvc pipe to seal the bow up. Go with HDPE.

Now I've got to try this :-)

[simson]

Have you tried soaking it in tea for a bit, maybe up the tannin content. Although now that I've said that you would have a tough time getting me to soak a finished bow in tea

I have tried to increase the reaction with soaking before with tannin acid. No good result, all the fine structure have been gone, only a one tone color came out.

I did some further research and it looks like HDPE is non-reactive with ammonia. Some plastics will be eaten up by it.  PVC is listed as "not recommended" for contact with ammonia solutions, so be careful if you're thinking about using pvc pipe to seal the bow up. Go with HDPE.

Now I've got to try this :-)

I use a 25% solution of ammonia. There is no direct contact with the fluid and The pipe /foil. Only the fuming damps are inside. Til now no problem at all. But thanks for the tip!

[joachimM]

That's wicked.

Cloudfeather (bit late to answer your question, but what the heck): Fuming will temporarily loosen the hydrogen bonds among the cellulose molecules (and other molecules), allowing to bend the wood without affecting tension properties a lot.
After the ammonia has evaporated, new hydrogen bonds are made, but at other places.
In non-fumed wood that's being bent, the stacked wood fibers are being put under considerable strain. Ammonia-fuming allows these stacks to glide over each other a bit (the hydrogen bonds have dissolved) during bending, as a result of which you can bend the wood in a crazy fashion as the wood is strained considerably less than with heat-bending. Once the ammonia is gone, the wood stays in that shape and new hydrogen bonds are being formed among the new neighbouring stacks of cellulose molecules.

As a corollary, the ammonia also affects the tannins in the wood, see https://en.wikipedia.org/wiki/Ammonia_fuming

[Willibow]

So it sounds like you may be able to get some more extreme bends using ammonia.  Has anyone ever tried this?  I've had a rough time flipping tips using dry heat in the past and would be interested in hearing the land-mines associated with bending with ammonia.

[joachimM]

Willibow, ammonia is extremely irritating to about every part of your body, especially eyes and respiratory system. Not to be used without utmost precautions. That's quite a "landmine"
http://www.ccohs.ca/oshanswers/chemicals/chem_profiles/ammonia.html

If you have trouble bending wood using dry heat (like I do), that's often because of a lack of patience (heat gun too close to wood, heating the wood too fast... Result is that wood is not heated evenly to the centre of the stave).
To flip tips, I prefer steaming the ends for 20 minutes or so, and immediately bend the tips over a caul. Boiling the tips should also work.

[simson]

I had two bows in the fuming tube, an osage and a black locust. Both were in the tube for 5 days. Look what a beautiful chocolate came out. On the osage is a white earth pigment rubbed in, it stays in the rough early wood layer and gives a cool effect to the wood.
I'm astouned the BL color is not far away from the osage.
There is no dye and no stain on the woods.

[alwayslookin]

That is awesome I might have to try this out. Explain what u did with the white pigment. What was used? How you applied it?