Building a new forced air forge questions

Txcwboy

Well-Known Member
I started this a long time ago but just got an anvil. It's this design http://indiangeorgesknives.com/building_a_forge.html. mine is an air tank.

I bought the burner elbow section pre-made by someone ( maybe one of you ?) The pics show a longer piece going into the forge than 6" but the plans say 6". I bought a 12 " piece and figured I would cut it down if needed. What does the longer pipe achieve? I can no longer find a cheap blower that's 100 cfm. Anyone have an option for another blower ? Could the blower be table mounted and hose run to inlet of burner ?

I have all parts now to finish the burner and koalwool. Just need blower and stuff to seal koalwool inside forge.

Thanks

Dave
 
Personally, I like a longer piece of pipe/burner going into the forge versus a short one.... in conjunction with with that, I prefer to have the gas/fuel input closer to the blower. (I'm not a fan of having the gas inlet/jet coming inline with the burner portion.... I'd rather have it enter at a 90 closer to the blower) The reason is that you get a better fuel/air mixture, and it produces a more even burner, which is easier to control.

Speaking from experience, don't look for a "cheap" blower. Typically, a "squirrel cage" type blower will burn out fairly quickly (unless you don't use your forge very often). Most cheap (squirrel cage) blowers are not intended to handle ANY back pressure, which you will have in a forge application. Back pressure on these type blowers will reduce airflow, and in turn, cause the windings to overheat/burn out. I used "squirrel cage" blower early on in my career, and was replacing them on a monthly basis, until I finally gave in and purchased a blower that was specifically made for forge applications..... it's been in service for over a decade now, with zero problems. My recommendation for a blower is something like http://www.blacksmithsdepot.com/products/forge-fan-fuel/blowers.html
Yes, they are expensive when compared to a cheap "squirrel cage" blower, but you'll only have to buy one.

All that being said, you can mount a blower just about anywhere you want, as long as you get the air to/through the burner, get a good air/fuel mix, and ENSURE whatever you use for air tubing/piping is heat proof. The problem with a "squirrel cage" blower and remote mounting is the fact that the longer the run, the more back pressure, which means less air to where you need it, and the faster the blower will burn out. Folks might argue, but experience has taught me that with a squirrel cage type blower, it's not a matter if it will burn out, it's a matter of when.
 
$100 isn't too bad for the 2" . My pipe is 1.5 so that's the closest fit. Here is what my burner tip looks like. It's not like what is in plans. 20170107_143513.jpg
 
Not sure how you are going to hook up a blower to that burner, maybe I'm not getting the whole picture. But of a cheap blower you can look for a used bounce house blower and regulate the air flow with a gate valve.

Doug
 
Uh..... is that galvanized pipe? If so, that's very bad stuff to be using on the end of the burner that gets hot.....gases emitted when galvanizing burns are poison!
At the very least, change that end out to NON GALVANIZED black iron.
 
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Im not completly done with the 2nd one. But if you have any questions I will do my best to help out.

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Ed, yes galvanized. I thoughts you can burn it off and then it wouldn't be an issue ?

What fan is that? the big grey one .I went to put my wool in and noticed my entry into forge is pretty high. That be an issue?

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Crappiew.. nice set up ! That's similar to what I am building.

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Uh..... is that galvanized pipe? If so, that's very bad stuff to be using on the end of the burner that gets hot.....gases emitted when galvanizing burns are poison!
At the very least, change that end out to NON GALVANIZED black iron.
I couldn't find black pipe 1.5" here. Galvanize doesnt burn off ?

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That's the problem the zinc burns off and can effect your lungs. You could see if you could soak it in muratic acid and dissolve it off the steel. By the way, why do you need a 1 1/2" burner tube. My large forge with a blown burner, built in a large mailbox, only has a 1" burner tube. My small forge which has a 4"X7" fire box only has a 3/4" burner tube, it's also blown.

Doug
 
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That's the size that was in the plans I was following. I bought the burner tip elbow from a knifemaker that was custom making them. I've used galvanized stuff in the past and always did a burn in process. I wasnt near it during the process.

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