Heat treating/ limb thickness

[DC]

I tried another test and this time it wouldn't even char the wood at 3" so I ran up town and got a new heat gun. Now I have to rebuild my gun holder because the new one is huge and has all kinds of features that I don't want or need. Stupid progress
SB I have a bunch of reflex in it and I would lose that if I didn't have it on a caul.

IJ One day I will because I think that's the best way but today it's blowing a gale and it's supposed to rain a couple of inches.

[Mo_coon-catcher]

When I hear treat I go slow and constantly move the gun. This give the heat time to travel through the cell layers of the wood before more heat is applied. It’ll take 30-50 min per limb depending on the wood type and how well heat travels through. But by the time I’m done the back is hot enough I can’t hold my hand on it. When I do it this way a second heat treat does nothing. The first heat treat I do after long string tillering to about 2/3 draw and as soon as I even out first full brace, but before I pull it back any at full brace. Especially with black locust (main wood I use) the limbs are about 3/8” thick at this point and this wood seems to transfer heat very well, so it doesn’t take long to get a good heat treat. Sometimes as quick as 15-20 min per limb. I’ve tried a second heat treat after tillering to full draw with no effect on weight or tiller. But the first heat treat takes my draw to point for a weight from, let’s say 20” draw at 50# down to 10-12” at 50#. It could just be the way BL reacts to heat,  it I have the same experience with hickory doing this. Now if I rush the heat treat the limbs do benefit from a second toasting later in the tillering cycle.

Kyle

[DC]

Thanks Kyle, that helps. My old arms won't take an hour of holding a heat gun so I'll have to stick with a jig and spot heating but the numbers still work. The new gun doesn't seem to work any different than the old one so I may return it. I don't know why this wood doesn't want to char. I treated one limb last night and had it up to 435°f and it was just light grey.

[IrishJay]

Don, have you tried a coat of veggie oil? Seems to help with penetration/browning.

[DC]

I'm not convinced about that. Just with my messing around here it makes me wonder how people know it improves penetration. It's not an easy thing to test. Combine my doubt with not wanting to contaminate a future gluing surface with oil. I dunno

[SLIMBOB]

Always used oil in my early days. I never use it now. The only difference I notice, is much less clean up.

[IrishJay]

The biggest benifit I get from using the oil is a more even toast, with no "hot spots" where I accidentally cook a spot too dark. I think this is because the oil conducts heat well, so even though the gun is hitting one particular spot the oil helps conduct the heat along the woods surface.

[SLIMBOB]

I’ll give that a maybe, but I don’t see it. Not on heat treating. For bending hooks I think there is a stronger argument, but even then I have gotten away from it. Just to much clean up for glueing and applying a finish. That’s just me though. If someone else sees a benefit worth the effort I say stick with it. I just quit using it 10 years ago or better.