Primitive Archer
Main Discussion Area => Bows => Topic started by: stringstretcher on March 14, 2010, 01:51:47 pm
-
At what point during the tillering process is it best to heat temper a hickory bow. I am building a holmgaard from hickory, and have it tillered with the long string and at the point I can get the short string on it. And for hickory, is it better to use the heat gun or torch?
-
Probably one of the last steps you want to do. IMO, tempering helps you get more out of your wood by making it stronger on the compression side...which can help you reduce physical weight while increasing draw weight. Gordons build-a-long has a good technique for tempering while tillering.
Personally, I like tempering hickory. I do it over a fire (hot coals), though. Heat gun works well. Haven't tried a torch.
-
Heat Gun is the tool. Because of the moisture probs with Hickory I'm going to temper a bow first time it's on braceheight.
6" over the limb and about 30 ~ 45 min works well for me.
Hickory loves dry warm winds over the limbs O:)
-
I think I wind up tempering about 37 times these days. I start by bending the roughed in and floor tillered limbs to shape with a heat gun, whatever shape that may be (even if it's just straight or slightly reflexed). I tiller to brace, using heat as often as a rasp to get it to bend right, and then usually give it another bout of heat. After that I just try and keep the shape and weight, heating the limbs through every so often to full draw.
Not as effective as Marc's method, but I had several failures that way when I tried to correct the tiller after tempering. This way, no failures.
-
I usually take a stave down to brace height and then put it on my cull and give it a good heat treatment and that's it until the bow is finished . The only other time after that initial treatment would be only if the bow had a problem or if the weight was missed for some reason .
-
I usually floor tiller then do any heat straightening,not over heat just enough to get it down the handle and some reflex,then try and get it even out to 20/22 inches,then back to the form and heat treat it,I use a heat gun,Then give it a week or so to reconstitute and finish to draw length and weight. :)
Pappy
-
I do it after floot tillering, before I start compressing the belly by bending it much.
-
Make sure whenever you heat treat, whether it be after floor tillering or after first brace that you keep the heat gun around 4 to 6 inches away from the wood and move it back and forth a few inches while you temper. Holding it closer will only temper the outer layer which you will eventually scrape off while tillering. If you hold it around 6 inches away, you will heat the wood deeper and more thoroughly so you get a better temper. It takes alot longer to do but it is well worth it. The first couple I tempered I was holding the heat too close to the wood and only tempering the belly surface. :)
-
I agree with JOSH I use to do it different.I said use to becasuse I no longer use any heat, you only need it with white wood osage and other hand woods.These have good compression and toasting really doesn't matter.Althuogh some people do this.
I only toasted like this.I toasted it at floor till again at brace and a couple times while tillering then then again when I finish tillering it.This way your not compressing wood sells.As JOSH saided as you tiller your bow you scrape off the temper.I'd also keep it in a hot box with low heat as I finished it to keep the moisture down..
This along helps with the string follow and this is the main reasons this is done.Damaged COMPRESSION WOOD SELLS stressed limbs.This happens through Bad tillering and moisture.Tosting will help with this but a hot box and good tillering will do the same thing.If you don't damage the wood sells to start with you don't need to tost the bell.
I'm not saying it's wrong there just other ways that will end up with the samr results.
-
I think I wind up tempering about 37 times these days. I start by bending the roughed in and floor tillered limbs to shape with a heat gun, whatever shape that may be (even if it's just straight or slightly reflexed). I tiller to brace, using heat as often as a rasp to get it to bend right, and then usually give it another bout of heat. After that I just try and keep the shape and weight, heating the limbs through every so often to full draw.
Kegan, I'd be interested in seeing a buildalong. You've got me intrigued. Any chance of that?
-
Kegan, I'd be interested in seeing a buildalong. You've got me intrigued. Any chance of that?
Sure. I have a couple bows I'm trying to finish up for others, once they're done I'll do a build along for one.
-
I usually temper hickory,(with a heat gun), at floor tiller or brace height. I personally have trouble with hickory checking during the treating process,so I want to have enough wood to scrape during final tiller to remove the checks,so make sure you have a good deep treatment. Other whitewoods,such as the Elms or Hophornbeam,rarely check,so I may treat them again when I'm closer to final tiller. Tempering bellywood brings an amazing transformation to the stave in my opinion,just remember be careful not to scorch the wood,(it will break ),and, to give it 3 days to stabilize with the relative humidity.JMHO , God bless
-
Kegan, was that thirty seven times...or 3 to 7 times? If you temper a bow 37 times, when do you ever find time to tiller it ;D
-
Thirty-seven :D. I kept getting bows that stacked, which made aiming them harder past 20 yards (heck, even at 20). So every time I remove belly wood and get a good bend, I just brown the belly so that the back gets hot to the touch (takes about 30-45 minutes for the whole bow). Actually, since I've started playing with R/D bows, I'm using heat to adjust the limb shape to get the tiller right as often as I use a rasp or drawknife, and just give it a heating "through the limb" so that the shape holds. The first couple times I tried this I had to stop halfway through because I backed them, but right now I'll have the first finished example (we'll see if it works or not then ;D). Dunno how much it helps with compression strength, but the shape certainly doesn't seem to want to come out after the bow is shot in.