ammonia? Poison?

[squirrel]

Hi guys!

Ammonia is poison, that is right.
Oak floors , here in the country , used to be treated with ammonia or with fume of ammonia to get them darker.
What if I want to make dishes for food looking older by placing them in a closed box filled with damp of ammonia? It will darken the dish but will my dish be poisoned? I do not place a finish on it.

Probably it is too risky ... but it is worth a thought.
Squirrel

 

[Paulloseby]

Oak and ammonia

Hi Squirrel - it will make oak darker the longer you leave it in there but it is dangerous stuff. Household ammonia isn't as strong and will take longer but you still need a chemical mask on. If you go for the industrial stuff, it really is imperative that you have a full face chemical mask suitable for ammonia. I used it to darken some oak collection and memorial plates for a church but really I wish that I had stained them now - far less of a problem

Regards

Paul

 

[john lucas]

I can't answer you with any authority but I don't think the actual item being fumed will be poisen. I will try to look it up and see what I can find. The gas itself is definitely bad.

 

[Jarred Hoffpauir]

It has been my experience that my pieces I fume with household ammonia will smell like ammonia for about 2-3 weeks and then the smell fades. My understanding is that the fumes interact with the tannin in the wood changing the color. Once you remove the ammonia the chemical reaction stops and the ammonia fume content will fade to nothing.

This is simply my observation and has no real scientific proof.

 

[MichaelMouse]

Ammonium nitrate, in either anhydrous or hydrated form is a strong oxidizer, caustic and poisonous. That said, it has been a standard in cleaning materials for years because it cuts grease (making soap) and rinses away. When it rinses away, it's an excellent fertilizer. Death is in the dosage, for plant or animal.

Fuming oak has been around for many years as well. http://www.djmarks.com/stories/djm/Fuming_Wood_47692.asp http://codesmiths.com/shed/workshop/techniques/oakfuming/ NOTE: standard charcoal filters will not be enough if you work in a confined space. Ammonia needs a special filter or very good ventilation.

If you can get Ammonium Hydrate in 25per cent concentration, you can fume for shorter times. Standard store ammonia will take a day or two. Once the air has cleared the fumes, no problem with residual toxicity. It reacts with the tannins.

 

[Joe Greiner]

I don't know how it would work on oak, but lye (sodium hydroxide) accelerates darkening of cherry, which takes longer in sunlight. A vinegar (acidic) wash afterwards neutralizes the lye (basic).

Lye solution is also used as a warm pre-soak before baking pretzels, to create the hard shell, which (yuk) is chemically equivalent to the shell of a cockroach.

Since your pieces are small enough to fit in an oven, soaking in lye plus baking would be a worthwhile experiment. And lye is the major component of oven-cleaning products, such as Easy-Off, so you clean the oven at the same time. (Easy-Off also works on cherry, BTW).

 

[John Torchick]

Interesting thread. New to this woodworking stuff and turning but I think it would be easier and safer to stain the wood.

 

[Greg Keddy]

You can darken oak using vinegar and rust. If you soak iron in vinegar it creates a solution that you can wipe onto the wood and created a darkened effect. Two notes: 1) vent whatever container you use to react the iron / vinegar as gas is created during the reaction and allowing in to escape allows the reaction to continue more quickly (and is probably safer) and 2) If you happen to use steel wool, rip it into several pieces as it is sometimes treated to prevent corrosion (which is what you want to happen) and ripping it exposes non-treated metal surfaces.

Also note that the effect of treatment is not immediately obvious and you should test it and leave it overnight to check if you've created a solution with high enough concentration and also what colour you are going to end up with.

This solution works in a similar manner to ammonia, that is, by reacting with the tannins in the wood, so you will get a greater or lesser effect depending on the tannin content and the number of applications.

 

[squirrel]

Hi,

Thanks a lot for the comments.
Ammonia and lye are both poisonous. I know that.
But I don't know if the wood treated with the fume or baked after a soak of lye will be poisoned.
Surely I should not dare to eat out of dishes soaked in lye - not before I got really scientific proofs.
But I have the feeling that there is a chance that fuming with ammonia will not make the fumed bowl poisoned. Be aware: I'm talking about porridge or soupbowls.
Staining is no option as the stain will leave the wood during use.
I also could wipe some vinegar + ironsolution on it ... I do not know if this is harmfull for health.

Let us think practical: when you look to medieval soupbowls they have an 'antique look'. Why? Because centuries of contact with the air made the wood grey and brownblack. Because the bowl was washed in water during years. Because all the grease and acidity of the food made the bottom black, and the sides grey.
So, if I would like to make a modern copy of this (grey matt sides and black, half polished bottom) what would you do to obtain that effect?
I tried to leave the bowl in water for a year or so but the obtained dirt washes away very soon and then the bowl looks like new.
I could put some ammonia in the water but I'm afraid the bowl will be poisoned.
Some iron and vinegar probably will make it completely black ... although maybe I can take it partly away and then put some ammonia smoke on it, or lye as described above. Probably several acts has to be done... no finish will be on the wood.
Does somebody has some more suggestions and ... by preference suggestions that will not poison my bowl?

Thanks a lot - Squirrel

 

[Robert Arnold]

Fuming

I regularly fume many white oak items I make. The process works best with white oak, you will notice very little change with red oak. I purchase my ammonia from a blueprint supply shop and it is 25% concentrate. I always work outdoors. If it is a smaler item I use clear trash bags. Place the item in the bag try to lift it up so as much of the surface area is exposed as possible. Also try to keep the bag from making contact with the item. I usually put block in the bag that will lift the plastic up andkeep it from coming into contact with the item. I pour some ammonia in a small bowl and place this in the bag with the piece. I then roll the end of the bag shut and use a couple of spring clamps to keep it closed. You could start to notice results in as little as 2 hours but I usually leave most of my pieces in for 10-12 hours. After I am done I take the ammonia out and either pour it back into the container or dump it if it is a small quantity. I let the piece I fumed sit out for about 24 hours and this will get rid of the smell of the ammonia. When the piece first comes out of the bag it will have a greenish tint but as soon as you apply any type of finish it will bring out the brown color and darken. I typically use just clear wipe-on polyurethane without any stain and the color comes out beautifully. Pay attention to where you have heartwood and sapwood in the piece because the fuming will bring out more contrast between these areas. The wood is not poisonous after the fuming. As with too many other things these days I should probably state the Do Not Drink The Ammonia, use proper personal protective equipment when working with the ammonia.

Robert

 

[MichaelMouse]

Hi,


Surely I should not dare to eat out of dishes soaked in lye - not before I got really scientific proofs.

You do already. Ammonia is used to clean and sterilize equipment used in food preparation.

Dilution, as they say, is the solution to pollution. You can let the air dilute, or the water.

 

[Bill Boehme]

Squirrel, I think that you are barking up the wrong tree.

The dark finish that you get on white oak from fuming with ammonia, ammonium tannate, sits mostly on the surface and is rather fragile -- meaning that it is unsuitable if you intend to leave the wood unfinished. Between cleaning in hot soapy water and hot porridge most of the fumed color will quickly be washed away either down the drain or down the hatch. While it is not particularly water soluble, neither is it strongly bound to the structure of the wood. At best, it has the durability of a wipe on pigment stain which is essentially what it is, but with the disadvantage of not being very user friendly to apply.

There is also the consideration that most woods do not fume satisfactorily anyway.

 

[Bill Boehme]

Ammonium nitrate, in either anhydrous or hydrated form is a strong oxidizer, caustic and poisonous. That said, it has been a standard in cleaning materials for years because it cuts grease (making soap) and rinses away....

I think that you have confused ammonium nitrate with ammonium hydroxide. Ammonium nitrate which is derived from nitric acid is used in fertilizers among other things. Ammonium hydroxide, the solution of ammonia in water, is used as a cleaner and many other things including fuming.

.... Surely I should not dare to eat out of dishes soaked in lye - not before I got really scientific proofs....

You do already. Ammonia is used to clean and sterilize equipment used in food preparation.

He said lye. While lye is used in soap making, when done correctly there is no residual lye in the soap. However, I have used home made lye soap that was not so carefully made.

In very low concentrations, the toxicity of ammonia solutions does not usually cause problems for humans and other mammals, as a specific mechanism exists to prevent its build-up in the bloodstream. Ammonia is converted to carbamoyl phosphate by the enzyme carbamoyl phosphate synthetase, and then enters the urea cycle to be either incorporated into amino acids or excreted in the urine.

 

[MichaelMouse]

Later I say ammonium hydrate, as you might have noticed. Explanation didn't fit the nitrate, so it was a pretty obvious finger fault.

He does eat from containers which contained lye if he eats the soft pretzels of Austria and Germany, or the Bagels of Poland. They're traditionally boiled in lye water. Ammonia (ammonium hydroxide, if you please) is often used to wash out food prep equipment.

Watch the cleaning ammonia. Lady thought if ammonia was good, ammonia and bleach would clean her shower better. Stuffed a tube and bagged for a while and got her back, though I don't imagine her stay in hospital was any fun with what her lungs suffered. Keep the stuff away from anything but water.

 

[Bill Boehme]

Later I say ammonium hydrate, as you might have noticed. Explanation didn't fit the nitrate, so it was a pretty obvious finger fault.

He does eat from containers which contained lye if he eats the soft pretzels of Austria and Germany, or the Bagels of Poland. They're traditionally boiled in lye water. Ammonia (ammonium hydroxide, if you please) is often used to wash out food prep equipment.

Sorry, I missed your correction/update.

I think that the whole discussion, however, has gotten sidetracked onto chemistry and sort of skips over whether fuming is a good solution for what Mr. Squirrel wants to accomplish. I have read a lot about fuming, but decided to not try it myself. My understanding is that care must be taken after fuming to avoid disturbing the patina which apparently is not particularly durable without a finish to help protect it. It is interesting that some furniture makers who have used the process on A&C furniture warn about handling because the oil in fingerprints can leave smudges while at the same time they apply an oil finish -- presumably a varnish finish is applied later. The oiling part seems odd given that it will further darken a surface that is already dark from the fuming process.

Your mention of lye in processing foods reminds me that it was also used in making hominy although there are safer methods used now that are just as effective. The lye method required several hours of rinsing and boiling to get the ph back to normal.

 

[Dean Center]

I don't know how it would work on oak, but lye (sodium hydroxide) accelerates darkening of cherry, which takes longer in sunlight. A vinegar (acidic) wash afterwards neutralizes the lye (basic).

Be aware that alkali, such as lye, is extremely destructive if it gets in your eye. And there's not much the ER doctor can do to prevent the damage. (An ophthalmologist can do a corneal transplant later, if you're lucky) If you are going to use lye for anything, wear reliable, full coverage eye protection.

Secondly, if you neutralize an alkali with an acid, it will give off heat. How much will depend on the strength of the acid and alkali, how concentrated the solution, and how much of either chemical is present. It can also give off toxic fumes, depending on which acid and alkali are involved.

 

[Robert Arnold]

The chemical reaction that takes place when fuming the wood actually penetrates the wood quite well, this is of course dependent on how long you leave the item exposed for. It penetrates the wood better than typical stains. This is one of the primary reasons I like it for furniture. In my case apply a clear polyurethane as my finish. If this gets scratched< even down into the surface of the item, it can typically be repaired pretty easily by sanding and re-applying the polyurethane. No need to worry about trying to match a stain. You can also apply an oil finish over fumed oak if you are looking for a food safe finish on something like a salad bowl.

Robert

 

[squirrel]

Ok, thanks guys!
I think the most important things are said about this subject. It seems clear for me now.
Best regards - Squirrel.