ammonia fuming

[John Harte]

1 hour ago, Jim Bress said:

John, for your tests you describe zero, mild, and long term. What were the ammonia concentration and durations of the mild and long term treatments?

Thanks, Jim 

I have been worried that someone would ask me this...

As I have mentioned this happened a while ago.  I still have all the samples in a box somewhere.  Notes may also exist but I wouldn't know where to begin looking for those.

What I do recall is a small glass petri dish that would have contained no more than 10ml of ammonia being placed in the bottom of a screw topped closed glass jar which I would guess would have been around 1.5 litre volume.  Each of the two fumed samples were suspended in the jar using some sort of thread (cotton, linen, polyester???  Probably whatever I was using for bow rehairing at the time..)  The mild fuming would probably have been around 1 to 2 hours and the long term upwards of 12 hours.  It could have been a day or two.

The ammonia was bought from a chemical supply company and is described in a list of chemicals that I have as “strong ammonia”.  Having said this, this bottle of ammonia was periodically opened outside for short periods over the years for the purposes of fuming boxwood peg shafts so would likely not be as potent as it originally was.

I see in amongst the microscope photos a sample recorded as NH3 + heat.  I am guessing that this was an attempt to get rid of the residual smell of ammonia or maybe add a more complex colour aspect to the spruce.  I have no idea of how much the heating may have impacted the ammonia reaction, both in the short and long term.

[Jim Bress]

Thanks John, that was very helpful. 

[Melvin Goldsmith]

There is ammonia fuming and ammonia fuming. Some top end peg and fittings makers stain box wood simply by strong ammonia fuming. Likely this wood is proven to withstand nitric acid and ammonia attack

To accentuate sun tanning the weakest ammonia will do. Piss into a barrel and let the urine go stale and fume in that or find a cattle or horse stable in winter and hang there. If you want to use 50% proof ammonia on maple or spruce please be expecting the wood to go crazy...

[Peter K-G]

On 9/19/2022 at 2:48 PM, nathan slobodkin said:

Peter what do you mean by "it will never stop"? Doesn't the ammonia dissipate and stop being effective over time?

 No it won't, it continuos for a very long time! 

[Michael_Molnar]

Jeesh. You guys got the answer from the horse’s mouth, @David Burgess that ammonia treatment is detrimental.

I do like the evidence presented here. Good job.
 

I bet in a year someone will still advocate ammonia. 

[Michael_Molnar]

22 hours ago, Michael_Molnar said:

Jeesh. You guys got the answer from the horse’s mouth, @David Burgess that ammonia treatment is detrimental.

I do like the evidence presented here. Good job.
 

I bet in a year someone will still advocate ammonia. 

Wrong horse. I meant @Michael Darnton.

 

[JacksonMaberry]

Mike in general I agree, but I know several award winning cats that use some measure of ammonia fuming on finished instruments today. I don't do it myself and don't plan to join, but I've seen these fiddles new and older and they look and sound great. More water muddying unfortunately.

[Davide Sora]

26 minutes ago, JacksonMaberry said:

Mike in general I agree, but I know several award winning cats that use some measure of ammonia fuming on finished instruments today. I don't do it myself and don't plan to join, but I've seen these fiddles new and older and they look and sound great. More water muddying unfortunately.

I also believe that it is more a matter of common sense in the way in which it is used (concentration, fuming times) than of the intrinsic harmfulness of ammonia, which although it is a concrete thing, is common to many other things that can be put on the violins. People often say a "No No" to something like ammonia or nitrite, and perhaps use a commercial product whose composition is unknown.

 

[David Burgess]

I haven't found ammonia fuming to be harmful at all. Unlike the use of other strong acids or bases, it goes away rather quickly. But I haven't found it to be advantageous, either.

So my favorite has always come back around to using plain ol' wood. I can understand if this doesn't have much appeal to the OCD folks among us.

John Harte's photos suggest that the ammonia is doing more than nothing though.

[francoisdenis]

On 9/20/2022 at 4:09 PM, pbelin said:

I suppose most of us have tried some not so recommended chemicals but it's hard when you start :

You're told that

-ammonia makes the wood cardboard like. - Nitrites are so higroscopic they create huge problems.

-Nitric acid reacts for ever, makes the wood crumble and bleaches the purfling. 

-any sort of heat treatment just destroys everything

-a friend told me he now avoids UV because he feels it damages the wood too

-don't think of using oil directly onto the wood! 

-if you don't get rid of the acidity of the rosin you're in for big trouble. 

 

All that only after 20 years of course, so you're only gonna be able to see for yourself once it's too late. 

So what does a young maker have left, if he/she doesn't want to varnish on white wood? 

hi Paul

I realised one day that I could varnish on a white background  and get a nice color- it all depends on how I cooked the varnish

[JacksonMaberry]

Super nice!

[David Burgess]

4 hours ago, francoisdenis said:

I realised one day that I could varnish on a white background  and get a nice color-

That's what I'm doing too. When thick unmolested original varnish comes away on a Strad, before enough time has elapsed for the underlying wood or ground coat to get dirty, the wood underneath tends to be surprisingly light in color.

[francoisdenis]

On 10/19/2022 at 5:06 PM, David Burgess said:

That's what I'm doing too. When thick unmolested original varnish comes away on a Strad, before enough time has elapsed for the underlying wood or ground coat to get dirty, the wood underneath tends to be surprisingly light in color.

Good, I feel less alone

[David Rosales]

For the sake of violins everywhere, I hope all varnish remains unmolested!

[JacksonMaberry]

2 minutes ago, David Rosales said:

For the sake of violins everywhere, I hope all varnish remains unmolested!

Tell that to all the antiquers!

[nathan slobodkin]

On 9/30/2022 at 6:24 PM, Melvin Goldsmith said:

There is ammonia fuming and ammonia fuming. Some top end peg and fittings makers stain box wood simply by strong ammonia fuming. Likely this wood is proven to withstand nitric acid and ammonia attack

To accentuate sun tanning the weakest ammonia will do. Piss into a barrel and let the urine go stale and fume in that or find a cattle or horse stable in winter and hang there. If you want to use 50% proof ammonia on maple or spruce please be expecting the wood to go crazy...

I agree. The fuming I am talking about is 10 ml ammonia in a 700 liter space.

[Shunyata]

I would like to understand the chemistry here.  How does ammonia continue to attack wood and make it punky after months or years, but not immediately?  

Does the wood soak up ammonia to form a store that is chemically converted over time?

Does ammonia act as a catalyst for some other reaction so that residual ammonia permanently activates some other process in the wood.

George Frank, who made a lifelong career of wood finishing (albeit for furniture) was an advocate of ammonia fuming.  He was scientific and methodical in his approach and never mentioned any caution about ammonia.  He did however suggest a specific recipe.  Maybe Davide’s comment about sensible proportions has some part to play here.

[John Harte]

3 hours ago, Shunyata said:

I would like to understand the chemistry here.  How does ammonia continue to attack wood and make it punky after months or years, but not immediately?  

Does the wood soak up ammonia to form a store that is chemically converted over time?

Does ammonia act as a catalyst for some other reaction so that residual ammonia permanently activates some other process in the wood.

George Frank, who made a lifelong career of wood finishing (albeit for furniture) was an advocate of ammonia fuming.  He was scientific and methodical in his approach and never mentioned any caution about ammonia.  He did however suggest a specific recipe.  Maybe Davide’s comment about sensible proportions has some part to play here.

In an earlier post I mentioned this study and its Supplementary Information: https://heritagesciencejournal.springeropen.com/articles/10.1186/s40494-022-00718-

Quoting from the paper, “This study aims to fill the lack of knowledge about the effects induced by chemical alkaline pre-treatments. To this purpose, reference wood samples were treated with the fuming ammonia and the potassium hydroxide pre-treatments. A multi-analytical strategy was then used to assess the aesthetic and ultrastructural transformations of the treated wood.”

Long term or possible on going effects were not considered. Again quoting, “After the treatments, and to reach the equilibrium condition with the environment, the specimens were cured under monitored conditions (RH = 50%, T = 20 °C) in a storeroom for one month to eliminate the water absorbed during the KOH treatment and the entrapped ammonia.”

While I have found what you could term the initial chemistry and ultrastructural transformations revealed in this study to be of interest, it would also be interesting to know what might be different after one or two years.

[David Burgess]

1 hour ago, John Harte said:

While I have found what you could term the initial chemistry and ultrastructural transformations revealed in this study to be of interest, it would also be interesting to know what might be different after one or two years.

John, my understanding (and experience) is that the ammonia will quickly dissipate into the surrounding air, while the potassium hydroxide will not. So for long-term or continuing changes, might these be two separate and distinct scenarios?

[John Harte]

2 hours ago, David Burgess said:

John, my understanding (and experience) is that the ammonia will quickly dissipate into the surrounding air, while the potassium hydroxide will not. So for long-term or continuing changes, might these be two separate and distinct scenarios?

Yes they could very well be.  Retesting both samples after a year or two would likely give some indication.  Exposing the samples to an elevated humidity in the interim may also amplify any changes caused by residuals.  It would also be interesting to know what the outcomes might be for different strength initial treatments.  A low molar strength sodium or potassium hydroxide treatment may be close to fully expended in any initial reaction as opposed to what might be the case for higher molar strengths.

I'm not a chemist so this is way beyond my pay grade....

[Michael Szyper]

I too vote for the Ammonia (and its effects on wood) being highly fugitive. I made a simple test: Wood ponded in Ammonia solution (20%) and KOH solution (5%). Visual effect after ponding is similar at first: Yellow greenish discoloration and strong enhancement of winter growth. After 1 Week, the effect on the Ammonia wood is barely visible. KOH ponded wood did not change at all.