Side Bending Practice

[scamp]

Very nice on the Blues Creek Bender. Ultimately I think I will get one as it probably produces more consistent and better results. I built my thermal controller so I could use it with a bending iron or bending machine when I get one.

I wanted to try my hand at bending with an iron to develop the skill. Also I believe it’s nice to have an iron to correct any imperfections that may happen with the bending machine.

[Stray Feathers]

This discussion is timely for me. I recently bent two Australian Blackwood dreadnought sides which went fairly well, except I found a couple of spots on the lower bouts where the curves are not fair - there are bumps across the sides. I tried to even them out on a pipe but have not yet been successful - maybe not hot enough. I may try using an iron (thanks for that suggestion) to help heat the part of the side that needs correction while on the pipe (using that third hand all luthiers possess . . .) And here is maybe a dumb question: Has anyone ever put a bent side into an oven to preheat it to 275º or 300º before putting it on a pipe to correct the bend?

I am also wondering if making the form solid on the bending surface might help the curves bend true, but I have bent other sides without this problem. And I wonder too if I should be more careful to clamp the slat/side/blanket sandwich together with metal bulldog clips where, initially, it dangles past the bender, to make sure it heats up properly. Any thoughts appreciated - Bruce W.

[scamp]

I have the same issue with the sides I just bent. Not sure why. Shows up as ripple across the side. Seems to be associated with variations in the wood grain.

D6EA0338-0D9F-487B-AD5A-D712FAE3884E.jpeg

You can see it in the photo. Wood is shinny where it was up against the iron.

[Stray Feathers]

I wasn't very clear in my description - the bumps I'm dealing with run across the grain, leaving flat areas in between, like where a tire is flat where it sits on the pavement. But I have also experienced the lengthwise ripples you've got (even a little in this set of guitar sides, but I think these will sand out). The photo shows one of two Bitter Cherry ukulele sides that were so rippled I could not use them - the grooves were deeper than the thickness of the sides. I bent new sides okay, but I have not gone back to the rippled ones to see if I can salvage them. Bruce W.

[scamp]

My photo probably was confusing. I believe we are having the same issue. Here is a better shot showing the side to side variations. They are significant.

[scamp]

I think I’m going’s to try and press it flat by sandwiching it between my bending iron and a clothes steam iron. I suspect it’s being caused by weird grain issues in the wood.

[scamp]

I think I’m going’s to try and press it flat by sandwiching it between my bending iron and a clothes steam iron. I suspect it’s being caused by weird grain issues in the wood.

[Stray Feathers]

No - sorry, I was just acknowledging that I had experienced the same thing you describe, by showing you the ripply uke side. In my guitar sides, the arc of the lower bout is not smooth; there are flat spots along the curve. They do not show obviously in a photo but you can feel them with your hand.

[warren47]

Hope this is the correct place for my question. I am trying to bend mahogany sides on a pipe. I have tried to practice on old kiln dried mahogany used for home details. Resawn to 090 and planed down o 075. Cannot bend it on the pipe. I have tried temperatures from 250 to 450. I set that aside thinking it was the kiln drying that prevented me from bending. I'm now trying to bend cut offs from my guitar sides and am having the same problem. I have tried spritzing, wet parchment paper and wet cloths to no avail. What am I doing wrong?

[warren47]

Update. I opened Sloane's book and took heart. I took two samples of my old and new mahogany and put them in a pot. After two hours in boiling water both snapped while slowly trying to bend them around a 3 inch od pvc pipe.

My heat pipe is a 2 1/2 in dia piece of exhaust tubing. I have stuffed a 500 watt heating element inside and packed it tight with aluminum pellets. I have it on a rheostat and can monitor temp with an instant thermometer.