torch under vent...depth and proper venting?

[lunesse]

My dad has started building my bench.

The torch will be 26-7" inches below the hood my question is, should the torch be right underneath the hood? Should the table extend further out than the hood? It's one of those standard glasscrafts,and hangs against the wall, so the back of the hood is the back of the space.

[Dale M.]

If you get down and look at line (angle) torch is in, if line is pointed low on wall, it is not good, if line is near bottom of hood (high on wall) or pointed into hood, you should be good to go. Main danger here is the wall getting to hot, not if hood/fan combination should draw fumes from torch. Remember heat (burnt gases) rises and you should have suction help it.

Dale

[lunesse]

If you get down and look at line (angle) torch is in, if line is pointed low on wall, it is not good, if line is near bottom of hood (high on wall) or pointed into hood, you should be good to go. Main danger here is the wall getting to hot, not if hood/fan combination should draw fumes from torch. Remember heat (burnt gases) rises and you should have suction help it.

Dale


Just the man I was hoping to hear from. Thank you so much, Dale!

[MikeAurelius]

The face of the torch can certainly be outside the coverage of the hood. The burning gasses are being expelled from the torch at quite high energy levels, and directly above the face, there are very little in the way of fume escaping. The bulk of the flame, of course, should be under the hood.

[lunesse]

Thanks Mike! Since I have the chance now to truly customize where stuff is...I want to get it right.

[BillBrach]

You could always add an additional piece of sheet metal hanging off the front and sides if you find it necessary. I'd make it U-shaped and out of one piece of sheet metal, and attached on the sides as well as the front.

But, before I'd do anything, I'd do a "smoke-test". Set your torch up where it is supposed to be, and with the torching running as normal, stick the corner of a small piece of scrap wood in the flame where you would make a bead. Sit where you would normally too. Now WATCH the smoke and see if it is being drawn out, and also see if you can SMELL burning wood. Some people recommend incense, but it doesn't produce enough smoke for me.

Also, be aware that if you have a lot of your makeup air coming from BEHIND you, that there might be air current eddy's between you and the torch, that may mess with the even flow of air past your torch.

I've even noticed with my setup that occasionally, when heating a rod, that I get a tiny puff of combustion smell. I attribute this to the rod (and my nearby hand) disrupting the flow near the torch.