Metal Casting Zone

Ok ... I'm lost.

Pictures my friend! I'm a very visual learner! Not to mention the lack of "shop knowledge"

Here's one like it I did on my woodgas burner. This will let more air in when open and less when closed. Not a very good picture, it's a 1" tee with a 1/4 X 20 hole tapped in the edge and a piece of sheet metal for the cover.

Now I'm completely confused. I thought that the blower supplied the ventilation. Wait ... so you're saying when I open the sheet metal flap it will slow down the air blast and when I want more air I cover it? (counter intuitive)

Plus is this a "top down" picture view?

This thing totally needs a chat room!

Sorry, it's the same type of gate. Mine is drawing air in by a venturi effect. Where if the air was blowing in through the Tee and you opened it it would lower the amount of air going into the furnace by letting some of it out the tee. Now are you more confused?

Uh ... the picture is kinda blurry. I think if it were larger it would be crystal clear. (I think I may have the gist though) But that's the least of my worries. I just got back from Lowe's and they don't carry any 1-1/4" black Iron pipe in less than 10 ft sections... and I don't want to pay 20$ to buy a 5$ item. (no 1-1/4 tees either)
However ... they had Galv Pipe for days. I'm guessing that the Gal. Pipe is a no no?

Naw, galvanized will work. You must be near the worst Lowes in the country. Some zinc might burn off the end, but you will probably not even notice. Jammer's pic has it right on, basically you need something just to dump excess air. A screw holding a disc of sheet metal is all that it is. This way you can use a vaccuum cleaner exhaust or a leaf blower and not blow the charcoal right out of the furnace. Look in the yellow pages and find a plumbing supply place around, it's pretty common stuff.

Sweet ... thanx

I'm looking at pouring the refractory this weekend! (maybe sooner!)

Galvanized works but I've had a problem getting it apart if it got very hot.
Here's another bad drawing.

Thanx Jams ... Sweeeet drawing ... crystal clear now

I've decided to use the fire clay, sand, perlite combo.
So when I'm mixing and packing my refractory should I:

Mix it ... wait a day or two and pack it
Mix it, pack it, wait a day or two the fire it
Mix it, pack it, fire it.

Plus ... it says that it should almost be the consistency of green sand. Great, I've never made green sand either.