Bending Sides With A Heated Pipe

[pipercub]

Roughly how long should it take to bend the sides using a heated pipe? I realize that pipes are different, thicknesses of the wood can differ, temperature ranges can differ. But near as I can tell my temperature is 360 c to 400 c. The pipe is 2 " in diameter. The sides are 2.25 to 2.5 mm thick.

[JonWint]

180*C to 200*C is the recommended temp for bending. Shouldn't take longer than 15 to 30 seconds to bend a curve. I never timed it. Depends how you wet the wood and how much time you spend against the bender if you need to add more water by spraying.

[pipercub]

Thanks for the reply! Sorry I was in the wrong forum.

The pipe is 2" in diameter and is packed with aluminum foil around the heating element to conduct heat from the 250 watt element. The thermometer is just under the inner diameter of the top of the pipe when horizontal. I do spray with water. Maybe I am not aggressive enough. But I would sure hope not to break the wood (Indian rose wood). I also tried putting a cloth dampened on the pipe. It is certainly taking longer than 30 seconds.

[charles Tauber]

Someone skilled can bend a set of sides over a hot pipe in about 20 minutes. It is a developed skill, one that takes a "feel" to be able to do.

In general, the wood should be constantly moving when in contact with the pipe. Doing so heats an area of the side to be bent, rather than just a line contact. The surface of the pipe should be hot enough that drops of water jump on the surface of the pipe.

With sufficient heat, the wood will plasticize in about 30 seconds, as JonWit stated. If the pipe is too hot, the wood will scorch and burn. If the pipe is not hot enough, the wood won't bend.

2.5 mm thick sides is tending toward the upper thickness one usually bends: 2.2 mm is more typical. The thicker the sides, the more difficult it is to bend.

[printer2]

I do it a little different and dampen a rag folded in half, drape it over the pipe and as it steams I rock the wood over it. It takes a little longer till it first starts to bend but scorched sides are a thing of the past. As the rag becomes dry I just move a damp section to the top of the pipe. Depending on the wood and the size of the sides, maybe 15-20 minutes a side. Need to remove the rag, get it wet and ring it out. I also don't try to rush, it takes as long as it takes.

[B. Howard]

My first set took well over an hour.... Now as quick as 15 minutes if me the pipe and the wood are all "right". Type of wood and figure present will be the real determining factor once you know your pipe and have developed a feel for bending. I find it the most satisfying part of the build. Yet at the same time the most nerve wracking. It feels great but burn or scorch the side and it's all over....

Learning how different woods react to heat and water is another big part. Rosewoods bend different than mahogany and then there's quilted maple.

[JDaniel]

It's helpful when learning to bend with a pipe to get a pile of scrap wood and practice. That means breaking pieces, scorching some and making pretzel shapes. There is nothing like getting practical experience in knowing when and how the wood starts to give or break and what that feels like and how to set the bend, too. Two critical parts, IMHO, proper heat transfer and assessing the plasticity of the wood.

[pipercub]

Thanks for the replies!

I have practiced on different woods as I don't have extra Indian rosewood lying around and I did take it to the breaking point, hence my hesitation to put to much force on my side pieces. I will keep on going!