Green versus Kiln Dried for Bending

[Scott Felicetti]

Hello, I'm sure this is obvious to the gentleman on this board but I need a heads up here. I'm working with plain sliced veneers. Hard Maple in thickness of 1/16" and Poplar of 1/8". I'm trying to turn them into a circle. The smallest circle has a diameter of 12". The length of each veneer is over 36" long to make the diameter. The width of each veneer is no more than 8". What I'm finding is the veneers are very brittle and are very difficult to bend to that radius into my steel mold. The 1/8" poplar isn't going to happen. All my veneers come from Kiln Dried Lumber. Question is how much more effective would it be to turn veneers of this dimension into a circle if the wood was Green and Not Kiln Dried? If it would help substantially, how difficult is it to find Hard Maple and Poplar that is Green and not Kiln Dried? I'm trying to avoid having to steam the wood prior to bending. Also I'm working with Hide glue and believe steam bending might compromise the gluing process. I'm following a process that was used back in the '20's through late '50's to make musical instruments. Everything I've read on the process shows that they did not steam the wood prior to bending the veneers in the steel circular mold. What am I missing here? Thank you in advance for any advice you can offer.
Scott

[Scott Felicetti]

How about soaking Kiln Dried veneers prior to bending into a circle?

[Jim DeLaney]

How about soaking the veneers in warm - or HOT! - water for fifteen or twenty minutes prior to trying to wrap it around your mold? You can add a few drops of liquid dish soap to the water to help break the surface tension, too.

Then - WITHOUT GLUE - wrap the veneers around the mold in the proper order, and let them dry for several days, or more.

Once they're dry, then remove them from the mold, apply glue, and put them back into the mold to dry again.

What hide glue are you using? For many years, I mixed my own from flakes, but lately I've been using the liquid hide glue from "Old Brown Glue.' It works very well and is much easier to use.

BTW: Making a banjo, I presume?

[Richard M. Wolfe]

Unless you cut and process veneers from a green board, everything you can get will be dry. It may be air-dried versus kiln dried, but I doubt that would make much difference, if any. Even if you cut your own you would have to work pretty quickly as wood that thin would dry pretty fast. I would try steaming and as was suggested soaking and make test runs with glueups to see if you are going to have any problems.

[Scott Felicetti]

How about soaking the veneers in warm - or HOT! - water for fifteen or twenty minutes prior to trying to wrap it around your mold? You can add a few drops of liquid dish soap to the water to help break the surface tension, too.

Then - WITHOUT GLUE - wrap the veneers around the mold in the proper order, and let them dry for several days, or more.

Once they're dry, then remove them from the mold, apply glue, and put them back into the mold to dry again.

What hide glue are you using? For many years, I mixed my own from flakes, but lately I've been using the liquid hide glue from "Old Brown Glue.' It works very well and is much easier to use.

BTW: Making a banjo, I presume?

Thanks Jim,
The mold is a female. I'm making a Drum Shell, similar to the ring on a Banjo I would Guess. Funny part is I think some very good banjos use a 3ply ring made from similar plys or veneers as I'm doing here. I'm mixing flakes also. Love the performance.

[Scott Felicetti]

Unless you cut and process veneers from a green board, everything you can get will be dry. It may be air-dried versus kiln dried, but I doubt that would make much difference, if any. Even if you cut your own you would have to work pretty quickly as wood that thin would dry pretty fast. I would try steaming and as was suggested soaking and make test runs with glueups to see if you are going to have any problems.

Thanks Richard,
I'm trying to get the process down before I invest in the resaw equipment. Some board members here directed me to the Minimax MM16. I think I could do a pretty good job slicing veneers on that. I could also go with a drum sander to sand to uniform thickness if my veneers aren't perfect. The problem with the green wood would be shrinkage. I spoke to a few lumber suppliers that said I could loose 3/4" on length alone. Soaking in hot water may be enough. When drum builders steam bend they are starting out with boards that are usually over 4ft in length and are over 1/4" thick. 5/8" is the typical thickness. Obviously, you are going to have to steam a board that thick to get it to bend. I'm working with much thinner material 1/16" maple and 1/8" Poplar. You would think I wouldn't have to resort to steaming. Anyone have a really big Microwave oven they would lend me.

[Bruce Wrenn]

Recently our WW club had a speaker showing how to make violins. She wetted the wood and then bent around a form that was heated by a propane torch. Wood immediately dries and retains it's shape. Some where I remember hearing about using fabric softener to help veneers become flexable.

[josh bjork]

Hide glue bonds to damp wood just fine. try knox gelatin, it works fine and isn't dark brown. if your stuff is breaking easily, it may just have too many grain violations for your purpose. it might be a lot easier to make the male form for the initial shaping than using a female one. Can you use different wood? Some perfectly straight grained white oak would make your life easier.

[Scott Felicetti]

Recently our WW club had a speaker showing how to make violins. She wetted the wood and then bent around a form that was heated by a propane torch. Wood immediately dries and retains it's shape. Some where I remember hearing about using fabric softener to help veneers become flexable.

Bruce,
Thanks for the heads up. My girlfriend is a violinist from Eastern Europe. She also worked in a violin makers shop. (auditioning the instruments for potential customers). Violin making is an amazing craft. I wet the 1/16" maple last evening and it was much easier to bend into the proper diameter. Also it air dried completely in a dehumidified room in in just 8 hours.
Thanks,
Scott

[Scott Felicetti]

Hide glue bonds to damp wood just fine. try knox gelatin, it works fine and isn't dark brown. if your stuff is breaking easily, it may just have too many grain violations for your purpose. it might be a lot easier to make the male form for the initial shaping than using a female one. Can you use different wood? Some perfectly straight grained white oak would make your life easier.

Josh,
Thanks, you are correct. My hide glue bonded to the damp maple veneer without incident. Everything is dry this morning and you would never know it was soaked 12 hours ago.

[Cliff Rohrabacher]

Recently I have read and studies my heart out on bending.

I have learned these things:

1.) Steam bending works because it gets the wood hot - that's it. Heat that softens the wood molecules allowing you to move 'em about with greater ease without tending to snap - they will however snap if you are too aggressive or don't get it hot enough 212Deg-F is about right.

2.) Water does nothing by way of facilitating the bending of wood other than act as a heat transfer medium. ERGO: Steam cause you don't have to saturate the wood. This may be less important when using thin sections that will dry fast.

3.) Ammonia attacks the molecules in the wood causing it to become pliable and once it sets in the bending jig there is little or no inclination on the part of the wood to return to it's former shape because Ammonia causes the molecule to literally reform itself in the new shape. This is unlike steam bending.

4.) The best ammonia to use is pure anhydrous ammonia. The reason is that since it has no water in it you can saturate the wood with the stuff and then before it all flashes off you can get the wood in the bending jig and set. Then it evaporated rather quickly - it's boiling point is 28- Deg F., so it's going to flash off quickly. &&& The ammonia soak vessel must be a welded up heavy steel pressure vessel.

5.) Ammonia bought retail about 90% water. This means that to use it you gotta either use it in a steamer - and it flashed off very fast - or use it in a long cold soak but your wood will be saturated with water all the way through and you'll have to dry it out.

6.) Anhydrous ammonia is dangerous and difficult to handle.

7.) steam may burn you but it's easier to manage.

[Scott Felicetti]

Cliff,
Wow you really did your homework on this. What you say makes alot of sense. But what about this: I took 1/16" Hard Maple. I tried to bend a 39" length into a 12" diameter circle (rough measurements). Snap, crakle, Pop. I took another veneer same thickness and measurements. Placed it in my pool (not very glamourous I know). Pulled it out after 20 minutes and could have bent it into any shape I desired. I put it in a crude cylinder mold. Glued the joint with hide glue and the next morning took it out of the mold. The wood was 100% dry. (thinness of wood helped I guess) and the wood held the round shape extreamly well. The water temperature of my pool water was no more than 90 degrees fairenheit. Trust me it is not steaming.
Next up I took 1/8" poplar. couldn't bend it at all. did the pool trick and had no problem bending it into an even smaller diameter circle. Drying time is going to be a little longer.
Question remains: If I'm using no more than 1/16" and 1/8" thick veneers what is the drawback to soaking for the 20 minutes prior to working with it.
Why can I bend it by just wetting it without increasing the temperature?
The amonia method sounds extreamly interesting. If I was going to bend 5/16" boards into a circle to make a solid shell drum that is what I would try.
thanks for your input,
Scott

[Tim Lynch]

Cliff,

Interesting discussion. I've heard that urea is used in the same manner as ammonia. Evidently in the early days it was gathered from horses...

I'm curious as to whether you came across any info on urea in your research.

Tim

[Jeff Raymond]

This is a great conversation going here with lots of great information.

I'm about to do some resawing/bending experiments. In building up a 3/4" x 4" wide table apron, the form I am thinking about would be built-up ply screwed to a kitchen-counter-top with Teflon spray on it to get it up after the glue dries.

Thoughts on that?