Bending Questions
Posted: Sat Jan 28, 2012 4:33 pm
I have a bender made by John and I bent a sycamore side a month or two back just to get a feel for how to use it. Last night I bent a test side of mahogany for practice before bending my Cuban Mhogany sides. So so far all I've done are test pieces that won't be used on a guitar. I'm close to bending the Cuban Mahogany sides for the 00 I'm building so I want to ask a couple of procedural questions before I get started.
First, the flat edge of the side (that the top will glue against) I believe is usually lined up along the edge of the bending form. I assume it should be aligned along the OUTSIDE edge of the plywood bending form? I ask because the outside 1/4" of the blanket doesn't heat up so it made me wonder if possibly folks lign up on the INSIDE edge of the plywood side of the bending form.
When folks are giving temperatures to go by, it seems it would make at least a little difference where in the stack the thermometer is placed. The stack I've been using is (bottom to top): metal slat, paper, wood, paper, metal slat, bending blanket. I've been placing the thermometer between the blanket and the metal slat. Is that the best place and when most folks give there temperature readings is that the typical location folks are using? In one sense I think it would be better to place the probe against the wood.......but I don't want the probe to indent the side so I haven't done that. And it seems if the wood temps are different than the blanket temps, at least it's a fairly linear relationship so the blanket temp is still meaningful and useful (though may be a little different).
Any tricks for lining up the flat edge of the side, the slats, and blanket (lengthwise and parallel)? I finally lowered the waist caul to help hold things in place while lining things up and that helped prevent some of the shifting.
BTW, the method I used for pre-tapering the sides worked great! I'm surprised how accurate this turned out. Only thing I'll do different on the real sides is add almost 1/8" to the width measurements (to make sure I get the sides cleaned up by the time I've hit the width I want) and I'll be much more careful trimming the profile line on the bandsaw. May even leave a little excess and sand to the line on either my drum sander or 12" disk sander.
First, the flat edge of the side (that the top will glue against) I believe is usually lined up along the edge of the bending form. I assume it should be aligned along the OUTSIDE edge of the plywood bending form? I ask because the outside 1/4" of the blanket doesn't heat up so it made me wonder if possibly folks lign up on the INSIDE edge of the plywood side of the bending form.
When folks are giving temperatures to go by, it seems it would make at least a little difference where in the stack the thermometer is placed. The stack I've been using is (bottom to top): metal slat, paper, wood, paper, metal slat, bending blanket. I've been placing the thermometer between the blanket and the metal slat. Is that the best place and when most folks give there temperature readings is that the typical location folks are using? In one sense I think it would be better to place the probe against the wood.......but I don't want the probe to indent the side so I haven't done that. And it seems if the wood temps are different than the blanket temps, at least it's a fairly linear relationship so the blanket temp is still meaningful and useful (though may be a little different).
Any tricks for lining up the flat edge of the side, the slats, and blanket (lengthwise and parallel)? I finally lowered the waist caul to help hold things in place while lining things up and that helped prevent some of the shifting.
BTW, the method I used for pre-tapering the sides worked great! I'm surprised how accurate this turned out. Only thing I'll do different on the real sides is add almost 1/8" to the width measurements (to make sure I get the sides cleaned up by the time I've hit the width I want) and I'll be much more careful trimming the profile line on the bandsaw. May even leave a little excess and sand to the line on either my drum sander or 12" disk sander.