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Old 2017-02-10, 2:21pm
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Speedslug Speedslug is offline
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Join Date: Mar 21, 2009
Location: Winnebago, MN
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The make up air part I was thinking of is where the make up air from out side (or in the attic in this case ) is drawn into the ducting to get it TO the work bench. The idea there is so that the exhaust air doesn't get looped back in a circle into the make up air intake.


As for the make air position I have seen it placed to one side of the torch or the other and even inserted in the table with a flush mounted grating like a floor register but that position can tend to swallow anything that slips out of your hand which sucks.


The sizing choice you make for the fan is what is supposed to keep the exhaust air moving fast enough that the particulates don't get a chance to settle in the ducting.
There are pages and pages of discussion about how fast is fast enough and how big the duct work has to be and how long is the maximum length for a given size and length.

If you are stuck with a minimum length of 30 feet you are going to want to go with very very fast fan power (large cfm flow) and with fast fan flow you will need to stay in the bigger diameter ductwork sizes.


The kinds of particulates we dealing with can be classified as hazardous if they accumulate which is why you want to keep them moving until they reach the open air where wind and rain can disperse and dilute them.

There was a big commotion last year when they figured out some of the major glass makers smoke stacks were allowing too much of the particulates to settle on the ground in the surrounding communities. Like to the point that one or two of them had to stop making glass altogether / go out of business bad. I think it was Portland OR.

The stuff that give glass its color and melting characteristics are things like cadmium, sliver, lead and a good dozen others that you really don't want anywhere near humans in any quantity. There are / were even some made with uranium at one time.

You don't want to have to have to hire a hazardous waste company to remove and find a place to dispose of this ductwork if it is contaminated once you are no longer lampworking and you are trying to sell the house so it is important to keep the exhaust air moving fast enough to not let the particulate settle in the duct work.



I know that a lot of folks don't go to all the trouble to make sure they are absolutely safe in every respect with melting glass but I thought you should at least know what your choices are and what they mean when its all said and done.

Just about every situation is going to be unique as is the budget and the individuals tolerance for details.

Good luck and keep asking questions.

A lot of us were educated by others and passing along the knowledge is what being a community is all about.
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Last edited by Speedslug; 2017-02-10 at 2:24pm.
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