Casting setup and ventilation, what do you think of this?

[AJ Peacock]

I am setting up a casting area in my basement and am contemplating solutions to the ventilation issue. I will only be casting with clean lead/alloy ingots in the basement (no smelting etc.).

Our house originally had an oil furnace which we replaced with a natural gas furnace a few years ago. The original metal flue/chimney was capped, as the high efficiency NG furnace used a small PVC exhaust.

I'm considering using the original furnace chimney as the ventilation for my casting pot. I'll attach a 6" metal flue to the cap and run 10' of ductwork to the casting area. The cap sits about 6' off the floor and about 8' from a workbench along the same wall. I'll have an inline duct fan at the cap and 10' of 6" flue running at a 30 degree angle along the cinder block basement wall to my work bench. An adjustable elbow will sit over my Lee 4-20 to draw off any fluxing fumes etc.

The inline fan is similar to this one, but has 250cfm rating. http://www.homedepot.com/h_d1/N-5yc1vZ1xr5/R-100067594/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

When I'm not casting, I'll simply cap the 6" flue at the old cap and leave the "casting chimney" open at both ends.

What'dya think?

AJ

[Dale53]

Years ago, a good friend had a casting set up using the flue from his gas furnace. He hung a discarded range hood over the casting bench and ran it into the flue (using the built in fan). It worked perfectly for many, many years and many thousands of bullets cast. I consider it one of the better operations I have seen.

Another uses an aluminum dryer vent pipe with an inline fan to the outside with perfect results.

Your plans seem quite workable.

Dale53

[Lawnjockey]

What is the source of heat for your casting? If you are using some sort of flame you need to be careful to have a good source of combuston air and make sure you are sucking out the cumbustion byproducts. If you don't it is like running a hose from your exhaust pipe of your car into the passenger compartment. People who do that tend to wake up dead.

Jocko

[AJ Peacock]

What is the source of heat for your casting? If you are using some sort of flame you need to be careful to have a good source of combuston air and make sure you are sucking out the cumbustion byproducts. If you don't it is like running a hose from your exhaust pipe of your car into the passenger compartment. People who do that tend to wake up dead.

Jocko

Electric Lee 4-20 pot.

AJ

[MT Gianni]

You are moving a lot of air in what I believe may be an unnecessary cause. That air is heated at your cost. 10 cfm should be adequate to remove odors and byproducts from fluxing.
Be absolutely sure that nothing else is vented in to that flue and make sure you return it to what it was or brick over your work when you sell. Water heaters were allowed to be vented in conjunction with an oil furnace.
Heated air vents best when it is given a maximum rise at it's source [appliance or casting pot] then given 1/4" per foot rise. Due to the flow spirals taken by rising gases, a 30-45 degree rise flows many times less air than a 3' rise and 1/4" per foot. If you want to do this I would use 4" or 3" if you can find it. Most hate to work with 3" as it is a pain in the rear to do anything with.
i would terminate at your pot with larger than a 6" ell, look for an older 4" x 14" register boot for better gathering capacities.

[nonferrous]

Plus 1 on installing your duct pipe with rise. How about going to the thrift store and getting a used range hood for about $5.00. You would have a 2 speed fan and gain a light.
Watch out for downdrafts.

[AJ Peacock]

Thanks for all the input.

Nothing else is connected to the chimney, it was used only for the old oil burner.

Thanks again,
AJ