Heat treatment color change

[DC]

I was heat treating a Doug maple bow and it seemed to take a long time to get any color change. I did my normal 45 min per limb and it hardly had any color change so I did a test sample. I had the gun 4" from the wood. It took 15 min to get a light milk chocolate brown in one spot. I moved it 1/2" and it took 6 min to brown that spot and it continued on like that. 6 min for every 1/2" works out to around 4 hrs per limb, a little much. The test piece was 1/2" thick and the back was getting hot enough so it was uncomfortable to hold my hand on for long. Unless my gun has changed since the last bow, an OS that seemed to brown normally, should I be holding it closer? Do different woods brown quicker and if so should I be changing time/distance for different woods?

[PEARL DRUMS]

Its not the wood, IMO. Perhaps your heat gun is on the "blink". I have two Wagner guns and they don't work the same on the same setting. One is hotter, for sure.

[Pat B]

I agree with Pearlie but to me, some woods do seem to not get as dark as quickly as others. I have an old Wagner I bought at a garage sale for $5 about 15 years ago. I hand hold it about 2" above the belly and move it back and forth over about a 6" area until it gets the color I want. I then move to the next 6" and do the same, occasionally going back over the previous area. I do this out the limb keeping the whole limb hot with repeated heating and clamp the limb to the form as I go. Then I go to the next limb. If I'm putting in a lot of reflex or taking out a lot I'll work on one limb for one clamp then go to the other limb, heat and clamp so the in between areas aren't stressed to much, sort of keeping the stresses even on both limbs.

[DC]

I'll find a scrap of OS to test. I kind of know what to expect from it. I may try closer like Pat says but so far I've done all mine at 4". Maybe my guns gone west but it's only a year old.

[Springbuck]

  If it is the heat gun, like, say it's only reaching 600 degrees instead of 1100, or you have an element out, just move it closer to the wood.

[BowEd]

I bought a heat gun from harbor frieght once and it did'nt last a year.I forget the brand name.My wagnor  2 settings 500 and 1100 degrees has hung in there for at least 5 Years.Used it a lot too.

[BowEd]

I also bought a laser thermometer.You could check it that way.There not that expensive.I bought it originally to check heat temperatures on bearing of trailers when I was hauling things.It can check the temp of a bows' belly easily.

[huisme]

Locust changes color really fast, about half the time it takes my gun to darken hickory, but I don't know about many other woods.

[loon]

I finished my hickory self bow with tung oil and beeswax, would it explode or go up in flames if I tried to heat treat it? I've tried to heat treat it but it didn't change color noticeably and it's taken some set. Heat gun is something like 1100 or 1400 degrees but maybe it's defective or something. It took an eternity to soften PVC

[PEARL DRUMS]

Color change isn't really a solid indicator. Locust does change incredibly fast. And if your moving your gun just as fast you are not tempering the wood, only coloring it and charring the outside while you heat shape it.

[Marc St Louis]

I have cut the odd tree that didn't change colour as expected when heat-treating and it may be because of the amount of sugars in the wood

[Badger]

Color change isn't really a solid indicator. Locust does change incredibly fast. And if your moving your gun just as fast you are not tempering the wood, only coloring it and charring the outside while you heat shape it.

   Pearl what I started doing several years ago is moving my gun across the entire limb from one end to the other, speed is not all that important, it eventually goes into a tage where it starts to produce a smell like cooking and then the color will start gradually changing, the ends tend to get hotter than the center when going back and forth so my sweeping motion gets shorter as it changes color. I go for a barely visible "cooked" look but not really brown.

[PEARL DRUMS]

Steve I do something similar, but not the whole limb. Maybe 8-12" at a time. Smell, IMO, is a good indicator along with sight. Especially after you have smelled a 100 or so cooking, you just know.