Water vs. Ammonia? - moved by moderator

[sbrewer]

Hello All-

Can any of you comment on the advantages and/or disadvantages of soaking planks etc. in ammonia before bending vs. just water?  I have heard amazing things about bending with ammonia, but have not tried it.  When using ammonia, does one then use an electric plank bender like with water, or is a jig better?  Any thoughts would be welcome!

Thanks,

Stu

[lamarvalley]

Good day Stu,

 

I have only planked once but I tried a few variations and came up with my go-to method. 

 

I found soaking in room temp water for as little as 20 minutes but never longer than an hour worked for me. I then used an electric heat bender to slowly form whatever curve I needed. The heater was actually sold at HobbyTown USA under the usage of smoothing wing fabric? on model airplanes. It was heat/power adjustable and was shaped like a little iron and the thing worked great. Once the piece was formed I clamped it in place, let it dry and then tweaked angles/bevels and such if needed before glueing. 

 

This isn't to say that all the boards/planks bent like I wanted. Some snapped due to my impatience or too severe a bend as well as the wrong grain orientation for the angle. Different woods bend better than others too… walnut was a dream, cherry was passible most of the time although it needed more finesse and mahogany was difficult as it was more brittle. I think any wood can bend but some need a longer slower period with the final bend being a series of slow partial bends toward the finished end. 

 

Above all, there is more than one way to do just about everything in this hobby and sometimes the choice is more a matter of what works for you. FYI- I never tried ammonia so I can't speak to that.

 

Have fun.

[edbardet]

Using water and ammonia may help.

Ammonia reacts with the lignin in wood, which is the adhesive material holding fibers together. After soaking the wood in a strong ammonia, bend it to the shape desired. As the ammonia evaporates the water in the air replaces it in the lignin and restores to original glue strength. This is smelly and some people do not like the smell.

In an industrial / commercial operation, wood is placed in a strong vacuum resistant chamber and the air withdrawn. This takes the moisture with it. Anhydrous ammonia is then introduced and allowed to penetrate. The wood is then bent and allowed to replace the ammonia with the water from the air.

[Keith_W]

I have a question: does ammonia bleach wood?

[sbrewer]

Thanks everyone. Good tips. I will try a few methods and see what works best. I'm using mahagony so I hope I can find a way to deal with the brittleness.

[kurtvd19]

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.

[flying_dutchman2]

AVOID AMMONIA SOAKING

 

"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.

So true AND it screws up the wood. As it says, 'degrade" the wood. It becomes a 'different state', it no longer is the original piece of wood. In the long run the wood degrades and becomes wobbly.

 

There are many processes of bending wood but water/steam is still the one of best method to bend wood. It has been around for centuries. There are several Dutch naval painting's that show the bending of planks for ships. Some of the replica's that were built in the Netherlands (Amsterdam and the Utrecht), the bending of 3 inch thick planks were done with steam.

 

On a later date I will add another quote on chemical bending vs natural bending.

 

Marc

Edited October 10, 2014 by Marcus Botanicus

[mtaylor]

I'm wondering if alcohol will degrade the wood?   I was soaking some glued pieces in the stuff and found the wood became very pliable and then re-hardened after it dried.   Any thoughts?

[augie]

I'm really just speculating but the alcohols we commonly use for modeling (methanol, ethanol, isopropyl) have a tremendous affinity for water.  By soaking the wood in alcohol, that alcohol probably combines with the natural moisture in the wood (giving the softening effect).  But when it dries, the alcohol will take some of that natural water with it making the wood brittle.  If the wood sits around for a (long) time at ambient conditions, it will eventually re-equilibrate at it's 'normal' moisture content and come back to normal.  But the whole process is subject to so many variables (type of wood, original moisture content, type of alcohol, soaking time, ambient conditions during drying) that I doubt it could be used reliably for any specific purpose.

[kurtvd19]

I too am just speculating on the effects of alcohol on wood, but there is no need to use it for bending as water or water plus heat is all that is needed to bend wood and the wood returns to equilibrium leaving the original structure and strength.  If Marc wades in on the effects I will be all ears, but in my opinion, it's probably doing something to the wood that isn't going to make things better than before it was used.

 

I do use regular Isopropyl Alcohol to soften yellow carpenters glue (Elmers & Titebond)glue to undo joints.  Some say that the 90% stuff that needs to be obtained by special order is needed but I have never needed anything more than common and cheap Isopropyl.  I have never had the occasion to soak a glued piece of wood.  I apply the alcohol to the joint with a "Q" Tip or a syringe depending on how large the joint is - the more glue that was used the more alcohol that will be needed.  I saturate the area of the glue joint and wait a bit but I keep an eye on it so the alcohol doesn't dry our before I apply more.  I test the joint and as soon as it wiggles loose I remove the piece and I try to scrape any of the softened glue off the pieces.  I let them dry before re-gluing the joint.

 

Kurt

[Dwaing]

Consider the anatomy of the wood (xylem) and the physics and chemistry involved. The goal is the bend the wood and have it retain the new shape. I add a surfactant to water and soak the wood strips, I then heat the wet strips while wrapped in food wrapping plastic in the microwave for 15 to 25 seconds, depending on the wood thickness. I then bend the strip around the hull curve and hold it in place for a few seconds while it cools. The surfactant speed the  capillary action of water moving through the wood (xylem) cells. The microwave heats some of the water to boiling. The hot water melts and/or softens the lignin. Holding the strip on the hull with the correct curve allows the lignin to cool and solidify. The surfactant I use is a common product used to clean showers. I have not used the product name but you can easily guess it from the underlined words. If nit PM me and I'll translate it for you.

[augie]

Just for the record, 91% Isopropanol is available at good old Wal Mart (as is the 70% version).

[jwvolz]

I've only ever used hot water and have never felt it wasn't sufficient to do the job. 

[hornet]

I'm with Joe V! I'm on my 9th build. 7 of these are double planked and 2 are single planked. I only ever use water and my trusty Aeropiccola plank bender ( which is over 30 years old) and I've never had a problem. Two of my models date from the early 1980's and they are holding up fine. Why use smelly chemicals when you don't have to?????

[mtaylor]

I just asked about the alcohol based on an observation.  Since there's no data on what it will do the wood,  I'm probably going to stay with my current method of water and curling iron.  

[flying_dutchman2]

I'm wondering if alcohol will degrade the wood?   I was soaking some glued pieces in the stuff and found the wood became very pliable and then re-hardened after it dried.   Any thoughts?

Like ammonia, alcohol dissolves the lignin in the wood.

The other thing is that people used to use anhydrous ammonia, but that is a bit too dangerous to use so they started using household ammonia.

 

Forget all the chemicals to bend wood. Like Kurtvd19 says, 'water is still the best method'. Use the natural ingredients and not the man-made ones. Many of you have different methods that you use and it works for you. To me this is cumbersome. Too many steps and I am not in a hurry. When museums restore a model and or build one they use water only.

 

Plant physiology on a cellular level:

Water will soak and make the dry intact cell walls of the individual lignin spaces moist and pliable. You bend to form, clamp it and it will dry naturally. Leaving some of the cell walls intact and others cracked, but most of the individual cells are still there. Water evaporates but ammonia and alcohol melt the cell walls. Try spraying alcohol or ammonia on plant leaf and see what happens. Do it in 90 degrees F and see the leaf melt in front of your eyes. Once the cells and cell walls melt and the chemical evaporates it leaves larger holes here and there. The integrity of the lignin is gone and makes the wood wobbly. Meaning it has bubbles.

 

I will not bore you with the very detailed plant cell physiology of the steps of how wood deteriorates with chemicals. There have been many scientific articles written on this subject and the above is some of the basic information.

 

 

 

avsjerome2003 - Surfactant or sticker is pretty similar to dish washer soap like Dawn. In horticulture a surfactant is mainly used to make a herbicide stick to the plant. Once dry, the chemical does its job. Also there is a minimum run-off when spraying it on the plant, like they say a "sticker". Soap does the same thing and it is what I use.

 

If you want more details I can give you some links of some deep explanations on this subject.

 

Marc

[sbrewer]

I bent a piece of wood this weekend using ammonia (or tried to).  I soaked in an ammonia/water solution for around 20 minutes and then applied an electric bender.  The wood snapped.  This has not happened to me using hot water.  Guess that answers my question as far as I'm concerned.  Thanks to everyone for the comments.  Happy bending.  

[druxey]

1) Mahogany is not the best choice of wood for bending to the curves required on models.

 

2) Ammonia is unpleasant and, as many have already suggested, not the best choice or, in fact, any choice.

 

So, choose a specie of wood that will readily bend with either hot water or steam (or a temperature controlled hot iron). Then all will be happiness.

[Perls]

Hi,

 

I don't know about you guys but I strongly believe that alcohol has a much greater salubrious effect on the builder than the wood!

 

Steve

[thibaultron]

Years ago I needed to bend 1/8X1/4 stripwood edgewise around the rim of a model warship deck (1/144th scale). I made a tube out of PVC with a screw plug on one end. I filled it with water and then stuck the wood in, and screwed in the plug. A couple off days later the wood bent nicely. Used the same method on 5 additional ships. This immerses the entire surface of the wood, and doesn't spill if knocked over.

The wood rim held the deck in place securely so that the entire rest of the deck could be removed for access to the RC equipment. A couple of screws held it down.

[flying_dutchman2]

Here is a link from Jack Panzeca who is building the and his homemade steam gadget.

http://modelshipworld.com/index.php/topic/5712-oseberg-viking-ship-by-jack-panzeca-billing-boats-125-scale-9th-century-modified/page-11

http://www.rockler.com/steam-bending-kit-w-free-bentwood-carryall-plan-download

 

Marc

[sbrewer]

Years ago I needed to bend 1/8X1/4 stripwood edgewise around the rim of a model warship deck (1/144th scale). I made a tube out of PVC with a screw plug on one end. I filled it with water and then stuck the wood in, and screwed in the plug. A couple off days later the wood bent nicely. Used the same method on 5 additional ships. This immerses the entire surface of the wood, and doesn't spill if knocked over.

The wood rim held the deck in place securely so that the entire rest of the deck could be removed for access to the RC equipment. A couple of screws held it down.

 

I just built one of these too!  I didn't get the screw plug though, so my wood floated up out of the top until it became more saturated.  I'm going to go get a plug for the top!  

[hornet]

I've put these pics on another thread but will repost here. Another way to use a piece of PVC pipe to soak planks. I too used to use a piece of pipe with a screw on end but found getting the wood strips out a little fiddly at times. As a result I came up with a trough setup using a piece of scrap timber as a stand and a PVC pipe with the side cut out. It is more convenient to use.

 

 

[Jaager]

 

Years ago I needed to bend 1/8X1/4 stripwood edgewise

 

Rather than risk Physics and time working to reverse your efforts , spilling and scarphing would be a more harmonious way to contour a plank curve in the thick dimension.

 

How about using a rice / vegetable steamer to heat a plank?   There are some relatively inexpensive ones  and they have dual use.

 

I think a while ago, experiments showed that water alone was as effective as household ammonia in wetting wood for bending.  It is less deletorious to the wood also. Household Ammonia was only ever suggested because it was confused with the industrial anhydrious ammonia process.  They are not similar methods.

Edited October 15, 2014 by Jaager

[HIPEXEC]

With the very difficult Sapele, I used ammonia and water mix about twenty to one.

[kurtvd19]

Don't need a cap for the top of the tube - just use a small plastic clamp at the top end of the plank to weight it down and to grab it.  Will hold it submerged and you have a hany handle on the end too.

Kurt