Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on February 16, 2017, 01:12:03 pm
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A while back Beadman asked to see my radiant heater(a long while, sorry Ed), I finally got it out again to treat this yew bow. I just tore the element and insulating posts out of a 1500 watt heater. At about 2" away from the bow it took about 15 minutes to turn the bow brown. That distance might be a bit close. My laser thermometer said the bow was about 525 degrees F. I'll move it out to 3" for the other limb. The browning seems nice and even but maybe a bit hotter in the middle. It's not any good for limbs with any character so it won't replace the heat gun but I think it will be faster and make a nicer job once I sort it out.
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Just be sure the heat doesn't wrap around to the back.
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The whole reason for making this was my idea that radiant heat wouldn't wrap around the back. There is no hot airflow involved. As soon as it comes off the caul I will check for that. Another 10-15 minutes :D
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Very interesting DC
Bjrogg
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No sign of scorching on the back at all. It seems to be hotter in the middle. I don't know if that's a characteristic of a heating coil but I'm going to have to bend it a little ore to move the middle farther away. Second limb was 3" and took substantially longer, about 20 min. I'll go for a walk and see how the reflex hols when I get back.
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Good idea hope it works out !
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is that a hollow limb bow? never did understand those...
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No it isn't, it's the browned part looks like a shadow. I never noticed it until you mentioned it.
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Very interesting
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Interesting yes.That will work for bows that are worked down enough that you can clamp down right away to the profile you want.20 minutes is'nt long.
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It seems that electric heater coils get hotter in the middle. So it charred the center of the limb but not the end or the fade and I couldn't bend it enough to even the temp. I had to stagger the coils, there are two, which meant tearing it all apart. I'm testing it now to see if it chars a board evenly.
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You can still get some wrap around on the heat, if the form is too wide, but less for sure. I use an electric griddle that had a removable griddle part over the elements, but it only does half a limb at a time! I'm Jelly.
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I like how many creative people we have on this site. Might not solve all the worlds problems but sure solve ours.
Bjrogg
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You can still get some wrap around on the heat, if the form is too wide, but less for sure. I use an electric griddle that had a removable griddle part over the elements, but it only does half a limb at a time! I'm Jelly.
Do you put the limb over the heat or the heat over the limb? The way mine is the air flow from convection would be going up, away from the bow so the back will always be in cool air. That's my theory anyway :D :D
Thank you Bjrogg.
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I been planning to scavenge heating coils and do something like this myself. Best bow toaster i've had was actually a gas spaceheater in the last house I rented. It had the ceramic diffusers that made this beautiful wall of evenly distributed heat, and it was wide enough I could set my bow on the form sideways in front and toast the whole limb in under 20 min. Sure beats sitting with the heat gun for hours. It also created a very uniform charring, no hotspots at all. Of course the belly is curved on the form, but that I think was good because the hardest working parts got toasted more, then it tapered off toward the tips. I sure miss that thing. :'(
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Was it one of those catalytic heaters? I didn't know they came in long and narrow.
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DV asked for some pictures of my scraper. I made it. It's a foot long. The blade is 3". The wood is some hardwood from the pallet my metal lathe came on, the blade is cut from a 7 1/4" skill saw blade. I was going to use a jointer blade but they were too pricey. I think they would work really well. The blade is bevelled just like a jointer blade. The white wood is a piece I glued on to make the cutting angle better. I cuts really well. It's half way between a scraper and a spoke shave. Let me know if you need anything else.
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Nice scraper!!
This is similar to the heater I was talking about...
(http://i1216.photobucket.com/albums/dd374/k-hat/hearthrite-infrared-heaters-2.jpg)
It was about 24" wide along the heating plates, so plenty for a bow limb.
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I see there are 5 sections. Makes me think there might be a way to make it bend a bit. Do they have a name that I might Google? If they came in a baseboard type that would be nice.
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I found some with google. They are kind of pricey, about $400 for something I could use. So that's out.
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Yeah, they are cost prohibitive for just bowmaking lol. The landlady in the last house i had purchased it, but it wasn't identical and may have been cheaper. The only way I WOULD buy something like that is if i actually had a workshop (other than my garage) and it doubled as a heat source for those cold Texas winters ;-) I'll keep dreaming on about all that!
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Thanks DC for the pics of the scrapers gives me some ideas and direction to go.