Household Ammonia

[Q A's Revenge]

I've read that some folks add ammonia to water to aid in plank bending. I already have a litre of household ammonia somewhere but was wondering how much you need to add to the water for best effect?

[dgbot]

You do not need ammonia.  it might stain your wood.  I just use water and a little heat.  Or make a fixture and put my wood in it.

David B

[augie]

As a rough estimate, maybe 5% of the water volume.  Usually it's just a last resort for a particularly tenacious or thick piece of wood.

[druxey]

If the piece is too thick to bend with heat /steam, then consider a laminated construction.

[HIPEXEC]

I use about 20% ammonia but my planks make bending steel look easy. I soak them 15 to 30 minutes and then use a heating plank bender with wet cloths to make steam. I then have to put the plank in a jig for the day, then re-soak it and bend it on the actual hull for a day until dry, then glue it. My planks are very thick sapele that came with the kit. Once on, they look great.

Rich

[bushman32]

I have heard that it will bleach out walnut.

   Ron W.

[src]

Q,

Be careful using ammonia on wood. Some woods have a high tannic acid content: mahogany, oak, cherry and walnut too I believe. The amonia reacts with the tannic acid and ages/stains the wood. I know we dont use oak here, but a lot of kits come with various species of Walnut or "Mahogany". Depending of how much ammonia and how long you soak for you could very easily darken your wood. Ammonia fuming was used extensively in the late 19th and early 20th centuries to color Art and Crafts/Mission style furniture.

Basically what I am saying is test first.

Sam

[Q A's Revenge]

Thanks for the input guys, most helpful.

[pirozzi]

I use 1 part ammonia and 9 parts water (10%). It does not stain the wood and makes bending very easy. I have planked several big ships this way and they all came out nicely. I have soaked walnut, boxwood, limewood and even balsa this way. I soak the planks for about an hour. If the wood is pretty thick (more than 2mm) an hour and a half works well.

 

Vince P.

Edited November 27, 2013 by Vince P.

[paul ron]

I find leaving my strips overnight in the toilet tank softens em enough for your sharpest bends... Jig em in till they dry n you are all set.

[src]

Brian, what does ammonia do to the ebony? Simply lighten it or??

 

Sam

[isali]

I've used /experimented with ammonia in very small quantities <5%, the wood began to look. Older and distressed, which mostly sanded out but I stopped experimenting, I didn't. Ned the extra flexibility most of the time. When I did, I found two things that really helped ,

 

1- i do significant bends in two or three soakings, ie, soak, bend in a jig, 1/2 or 1/3, or a reasonable amount for that piece of wood, let it dry then soak again, repeat, etc, I try to prop the wood in the corner of the water container to help hold the bend as it soaks each successive time.

 

2- if you aren't, spilling the planks take a look at the tutorials nin this section, they. Are really great (a big thanks to the writers) . Using a paper template, you get some wired and counterintuitive shapes but when bent they fit like a glove.

 

 

I'm not an experpert but this works for me.

 

 

Ira.

[amateur]

I only use it in 'extreme conditions':

 

The railing on the top is a walnut-strip of 0.6 mm thich, and 2 mm wide, bending without ammonia tended to result in an unevenly curve.

I soaked in it a 10pct ammonia solution for half an hour or so, and than I could almost make a knot in it without braking it.

 

It did however, result in severe bleaching of the wood, and the structure of the wood deteriorated (after drying it was more brittle than before)

 

Jan

[src]

Jan,

Nice bend. It made the walnut brittle, interesting, I wonder if it is oxidizing the wood. There are a couple of chemist here, hopefully one of them will have something to say.

Sam

[jud]

Would an application of linseed oil bring the life back. Used it on a foot long birch bark canoe model that some relatives had acquired in the early 1900, it was badly dried out and brittle, the linseed oil brought it back.  I use it on outdoor tool handles and it darkens the ash handles.

jud

[Richard Griffith]

The bleaching of Walnut is interesting, as is the report of brittleness. 

 

I soaked some thick walnut in 50/50 ammonia and water overnight and the walnut broke at the bluff bow.  Perhaps it was brittle.

 

I then decided to laminat the walnut with the 50/50 solution which worked but tripled my work on the Half Moon wales, quarter scale.

 

Although the liquid solution leaches out some the tanin, my wood did not have the bleached out look.  Perhaps the method affects various wood species differently.  So, as others have said, test it.

 

Duff

[Gabek]

i was about to experiment with using ammonia to make a pretty severe twist in a mahogany hull plank and came upon this thread.  The question was asked how does the ammonia work.  It basically dissolves lignin - the compound that glues cellulose fibres together, making them stronger and rigid.  From what I have read it also causes the cells in the wood to swell up, pushing apart cellulose fibres as well.  Once dry it does rebound, but the hydrogen bonds between cellulose have been affected.  That's why ammonia causes wood to be more brittle afterward - it took  out the glue and wedged apart the strands.  Like many things, there are conflicting views on how good this will be - so I think I'll give a test.  I'm not concerned about any bleaching - I intend to paint and copper the hull.

 

For some reading:

http://www.biotechnologyforbiofuels.com/content/4/1/41

 

Regards,

Gabe

[Jaager]

Lignin is soluble in pure Ammonia, not aqueous ammonia, and certainly not the 5% solution that is household ammonia.  For our purposes it is the heat that makes lignin pliable. Water/steam transfers heat much more efficiently than dry wood.  Using ammonia instead of plain water just adds an unnecessary component.

[kurtvd19]

The bit below was originally posted last year. 

Kurt

 

 

Posted 10 October 2014 - 09:12 AM

I have never used ammonia to bend wood - it just isn't needed.  The bit below is a reprint of part of my article on building the Gunboat Philadelphia kit in Ships in Scale.  I doubt anybody who attended the NRG Conference I reference has ever used ammonia since hearing it.

Kurt

 

 

AVOID AMMONIA SOAKING

 

At the 2007 Nautical Research Guild Conference in Manitowoc, Wisconsin Alex C. Wiendenhoeft of the U S Department of Agriculture Forest Services Center for Wood Anatomy Research at the Forest Products Laboratory in Madison, Wisconsin explained how and why this damages the wood.  After this length of time I do not remember all of the details of his talk, but the point was well made and I don’t think that any of the modelers who listened to his talk that day has ever used Ammonia again.  The very non-scientific points I remember is that soaking in Ammonia breaks down and liquefies the Lignin in the cells making the wood more bendable.  When the Ammonia evaporates while the wood is clamped in place to the desired bend, the Lignin solidifies in a somewhat degrade state weakening the wood.

 

Ammonia also causes some woods to discolor when they dry out.  This might not be critical when the wood is to be painted but if it is being stained or clear finished the discoloration would not be acceptable. Concentrated Ammonia fumes are used commercially to darken some woods with oak being very susceptible to this process.

 

Mr. Wiendenhoeft explained how and why soaking in water or steaming wood made it bendable while not damaging the cellular structure of the wood.  Again, a non-scientific explanation is that there is a chemical bond with water in the cellular structure of wood that varies between 0% and 30%.  Soaking or steaming wood with water raises the percentage of water within the wood, called “free water”, above the amount bonded within the cells temporarily.  This makes the wood swell and more easily bent.  When the wood dries out and the bonded water stabilizes back to 30% or less, the wood retains the shape it was formed to by the clamping while it dried while retaining its strength. 

 

I have only mentioned drying the wood while clamped in place but the application of heat using some sort of plank bending tool or other heat source works the same way as clamping just at an accelerated rate.

[Gaetan Bordeleau]

I have a newbie question?

Why ammonia is good to bend wood?

Is it  because of special ammonia properties?

Or is it because of the % water used in the ammonia?

[Jaager]

 

Why ammonia is good to bend wood?

It is not good to bend wood.

 

Is it  because of special ammonia properties?

The recommendation was based on a misunderstanding of a commercial process used in ship building:  pure ammonia (anhydrous ammonia) was used with heat and under pressure to bend wood.  This form of ammonia was also used for commercial refrigeration - ice houses and such.  There is no water in this form of ammonia.

 

Or is it because of the % water used in the ammonia?

It is the water and heat that allows the wood to bend.  Any ammonia present just adds an unnecessary negative complication - if it does anything at all.

[GuntherMT]

Ammonia breaks down the fibers inside of the wood which does allow it to bend easier, but those fibers never return to original condition when dry, so the wood quality is degraded.

 

I've never had a problem using just heat, or for extreme bends heat and soaking in distilled water to bend planks.  Don't want to deal with the fumes of ammonia even if it wasn't harmful to the wood.