Heat treating by radiation

[simk]

Hey Bowyers

Thought there might be too little heat treating threads around here  therefore starting another one:

Heat treating mostly seems to be done with the heat gun. Me myself having bought my third heat gun now in two years...got a little annoying. Also there is always the hot-air-flow-issue endangering the back, not talking about the lame-shoulder-effect after a heat treating session as badger does it and i also did 

bought a cheap quartz radiator for 20 bucks last week (1500w 1200w).

I did heat treat a whole bow which worked really really well and comfortable. The radiation is heating only the wood in direct sight - the back in the shade remains completely cool until the heat having creeped through the whole bow. The result was a very evenly heat treating as you see on the pic. Today I did a heat correction on a little elb - pic 2.

I must say heat treating by radiation works very very well. I will still use the heat gun but only for smaller spots.

Cheers 

Edit: Temp is regulated with distance - for the heat correction on the elb I didn't need too much heat. For the real heat treating the distance was about 2-3" and the heat treating took about 10-15 min until the back of the bow was untouchable...

[Deerhunter21]

Hmmmm, I was going to buy a heat gun today but now im rethinking! ahhhhhhhh! the indecision!    What made you think about doing this. Like what made you think about using a radiator?

[simk]

deerhunter: i thought about this already long time...but to be honest, it was also b2w who reminded again me when we talked about it this summer 

[Bayou Ben]

Thought there might be too little heat treating threads here  therefore starting another one:

I just watched the documentary and series on Chernobyl so I was a little nervous seeing your title. 

Do you have to move the bow a few times?  How long did it take vs a heat gun?

[simk]

Ben: Don't need to move the limb - after 10 minutes the wood starts to get brown, then it starts vaping, then the back gets really hot and you are done. don't have much expierience yet. still have to experiment with the 2 variables (time and distance). have fun!

when I used the heat gun it took me about 15 min for a whole limb - i did it lmoving up and down very close with my 2000w heat gun.

[Deerhunter21]

so the belly is supposed to smoke/steam? sorry but i'm heat treating a bow for the first time.

[simk]

yes, after a certain time the whole bow starts steaming/fuming - like your pizza when coming freshly out of the stove 

you should try it with your problem bow and will be surprised, i'm sure about that. me myself have had several miracles with heat treating and i'm also still a beginner

The radiator for me is a multi-purpose gadget: It will solve the gelling-problems when sinewing from now on and I will never freeze again in my shop in the upcoming winter

[Badger]

  That sounds like the perfect solution, Heat scorching the back has been a constant annoyance. I think I will go this route

[DC]

I made one of these(sorta) a few years ago although mine was made with an old 1500 watt heater(wire coil type). It works great for straight bows but if they are a bit wonky  mine wasn't wide enough. Yours has that covered I think but what about reflexed limbs. Mine would heat the center(end to end) more than the ends, sometimes way more depending on the amount of reflex. Is there a difference between radiant and the coil type heater I used?

[simk]

steve: i'm feeling honoured 
don: yes, that's a point to consider - the bow I heat treated was a d/r, so i had this problem. in that case i had to do the limbs in two steps. you either then change the bows position or the lamps position so that the distance is always good. i finally got the middle of the bow slightly double-treated that way, what wasn't bad anyway to better preserve the reflex-bend. there are no perfect solutions in our imperfect world - still adjusting and fooling around is needed also this way. Sure you will find solutions...
In this case I clamped the bow on the caul then put the radiator in position. Did lot's a hooks on the ceiling so that i can easily change the radiators position to where its needed.

by the way: buy a radiator long enough. I was impatient and just bought the one they had, which is slightly too short for longer limbs. I will look for a longer one then...
cheers

[Badger]

 If someone could build a flexible radiant heater that could be adjusted to any shape I bet we would all get one.

[DC]

I can bend mine slightly to compensate for reflex but too many bends will probably break it. It's only 2" wide so sideways stuff is a problem. I don't want to jump all over simk's post but I've had this in the back of my mind for quite awhile and maybe many minds can come up with a solution. I hang mine from chains so i can just hook it in different links to vary the height.
Simk, you mentioned that yours is too short. How short do they come? Maybe two or three of them end to end might be a solution. Mine is pretty critical of height/distance above the bow. Having them hung by chains I also thought that maybe a mechanism that would swing the heaters lengthwise would even out any hot spots. I tried just swinging it but it only goes for a few seconds.
Anyway here's mine.

[Deerhunter21]

I dont know if i can find a 20$ one like you simk!

[DC]

Best I can find is $100-$200

[simk]

quick update before work: when i first looked the www. the price range was chf 150-250. i found one for around chf 70.-
when i went to the big store there was this absolute white label product from china for chf 19.95
i also was offered a second hand radiator for chf 25
IMPORTANT: MINE HAS ONLY 1200W (checked again - sorry) AND ITS PLENTY SUFFICIENT
cheers