Wrinkles or Creases in my Waist Bends

My last two sets of sides have been from wood softer than what I'm used to, and I got some creases in the waist on both sets. I varied the heat and the amount of water to see if that helped, but the differences were negligible. I'm wondering if I need to add some support, like spring steel slats. The wood I'm having trouble with is African ribbon mahogany and peruvian walnut. Most of the creases occur when I'm on my 1" bending pipe, but I did get some on one set of peruvian walnut sides from my 3". Those sides got trashed. Second sanded out fairly well, third set, well I need to get a back and top on it before I can really sand those areas with any authority. I'll add some bracing in those areas internally to give them more strength, too.

Any advice? Maybe I just need to go more slowly? The little pipe gets hot, and I do tend to worry about scorching, but I've got it dialed back a bit more now, so that should help.

Matt,
I don't think I can help much because I have yet to bend on a pipe. When you say wrinkles do you mean flat spots? I bend with a heat blanket and was getting some compression at the waste from cranking the screw down too tight. It was compressing the wood fibers and that section would end up slightly thinner. Enough to cause issues when applying the binding because there was a small gap. I have solved that by not cranking like a banshee on the screw press.

Why are you using water? If the heat on you pipe is right you should be bending dry which will eliminate the tendency to crease. You may also be bending with the temperature too low...

I suppose if your heat is low enough you could probably bend without water as Pete mentioned. I've never had the cajones or the patience to try it.
My hunch is that creasing in the tight bends that you encounter in waists and cutaways is caused from the wood being water logged, especially in soft species. I think water in the side bending process is highly over rated but I do use some. I think the steam carries the heat better. When I bend with heat blankets I enclosed the slat in a canvas or duck envelope that had been wetted and all the water wrung out of it.

Moore Bettah Ukuleles said:

I suppose if your heat is low enough you could probably bend without water as Pete mentioned. .

Click to expand...

Chuck, is this what you meant to say? Thought the heat needed to be higher to bend without water.

No, I meant if the pipe temperature is low enough to bend without using any water. I don't have an electric bending iron; with propane it is harder to control the temperature and it always seems that my pipes are very hot. A bit of water helps to prevent scorching. But I do believe you can bend on a pipe that is not hot enough to burn wood without using any water if you take your time. A lot of time. I don't have that kind of time so I just use heat blankets and bend flawlessly. And using very little water.