ZBarrett Posted April 11, 2021 Share Posted April 11, 2021 So I'm looking at getting a new blower for my coal bottom blast forge. Right now I'm using two old bathroom fans that give me about 140 cfm. I put a manonimeter on and found I have 0" w.c. even with the gate fully open. I know I should have pressure and not cfm. I have another fan that might up the pressure, but it would add another 70 cfm. My other option is I just buying a sunlar 110v 250w blower. I'm just looking for some feed back. I have tried some experiments with blow up motors to no avail and a air mattress pump after seeing that Lucky swears by them, but still not getting over 1" w.c. I need to keep my costs down as this is a hobby/ potential way to make a bit of money. Any advice would be appreciated. Just took some measurements if it would help with advice. My tuyere is 3" by 8" long. Quote Link to comment Share on other sites More sharing options...
Stash Posted April 11, 2021 Share Posted April 11, 2021 I'm running my bottom blast with a recycled bathroom blower, rated at 115 cfm. It comes out of the blower at 4", reduces to 2" then goes 3" and up to the fire. I run it thru a dump valve just downstream of the blower- a blast gate on one leg of a 4" wye, providing back pressure to the other leg, to feed the fire. I haven't put any kind of meters on my system- I hold my hand over the firepot, feel the breeze and say "yup, thats fine". I usually choke the dump valve down halfway unless I want a lot of heat, choke it down completely and I get some major heat. Does your setup work? Not work? Kinda work? It seems to be real complicated. Show us some pictures. I like to keep things simple and not over think things. Steve Quote Link to comment Share on other sites More sharing options...
ZBarrett Posted April 11, 2021 Author Share Posted April 11, 2021 This is my set up. It heats steel fine, but it can blow the coal up easily. I'm attempting to forge weld and I'm afraid I'm using an oxidizing fire that burns my steel before its at true welding temp. Quote Link to comment Share on other sites More sharing options...
ZBarrett Posted April 11, 2021 Author Share Posted April 11, 2021 Sorry really really messed my measurements up. All pipe is 3" it's about 1 1/2 foot run from each fan. Yes I know it's very very rough. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted April 12, 2021 Share Posted April 12, 2021 Your picture didn't come through. Quote Link to comment Share on other sites More sharing options...
ZBarrett Posted April 12, 2021 Author Share Posted April 12, 2021 Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted April 12, 2021 Share Posted April 12, 2021 You are getting hung up on measurements; what you need is enough of a blast to run your forge and note that that will differ depending on what you are trying to do; how many pieces are in the forge, the fuel you are using, etc and so on. I've been forging for 40 years now: electric blowers, hand crank blowers, bellows; never once had a gauge or checked the cfm. If your current system will blow coal out of the firepot you have enough of a blast! Now you need to figure out how to meter what you have and how to use it! Quote Link to comment Share on other sites More sharing options...
ZBarrett Posted April 12, 2021 Author Share Posted April 12, 2021 Thank you Thomas. Your right, I need to learn how to used what I have to get the desired results. Now to figure this out. Thank you again. Quote Link to comment Share on other sites More sharing options...
Irondragon Forge ClayWorks Posted April 12, 2021 Share Posted April 12, 2021 That blower will put out more air than needed. An air gate will help control the blast going to the fire pot. Quote Link to comment Share on other sites More sharing options...
ZBarrett Posted April 14, 2021 Author Share Posted April 14, 2021 I have a very basic air gate just off of the ash dump. I just need to learn how to use it efficiently. Covid has really messed up my ability to go to my local smith's shop to learn fire management and what a good fire looks like, and how to tend it efficiently. But that's for a different forum lol. Quote Link to comment Share on other sites More sharing options...
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