Building new forge. Blower question

SteelSlaver

SteelSlaver

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Feb 17, 2007
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I am going to built a new forge out of a propane tank. Going to be a vertical and I want a good blower. I have a some burners with 1 1/2" gate valves. Would like some links to some good blowers.
I have the burners set up now swedged down to 1" and they don't make the heat I think they should, but, I am thinking it is crappy blowers and not the smaller tips or am I wrong?
 
I have had issues with burners not putting out enough heat and it always boils down to a blower that is not made to deliver air against resistance. A regular squirrel cage type blower can move a decent volume of air in an unrestricted application, but there is no force to work against restriction, centrifugal blowers like forge blowers cost more generally but they are made for working pressure

-Page
 
I have the blower Stan posted as well. It's a good blower. I have mine choked about all the way off with a gate valve to keep the mixture correct.

--nathan
 
The one Stan linked to is the same one on my forge Jim :) As you've seen, it works real nice.

Definitely a lot more money than the ones from places like Surplus center, but great for a high temp forge. I have a simple squirrel cage on my salt bath forge that works very well...but for my forging/welding forge, I much prefer Grant Sarver's blower. :thumbup: :cool:
 
So does that mean all you guys just use air gates and gate valves to control air flow? Do you gate the intake side, the output or both?

Can you put a rheostat or variable transformer on those to actually slow the blower down or is it always turning full speed?
 
I use the same blower as Stan and Nick. It is a stable source of air into a fairly tight forge. That is it will maintain the airflow when you close your forge doors or brick up all exits vents from your forge. Squirrel cage fans very quite a bit in air delivery when the exit flow of gases from the forge is reduced. I believe that there are 3 sizes of the blower available. The smaller version is adequate for most forges....Take care...Ed
 
Phil, I tried a rheostat to adjust airflow for this blower for my two stage burner control, but found that it doesn't respond well. It is very slow to adjust, and your control is very limited. I built a two stage burner control like Stacy has posted before and just keep the blower at a constant setting and use a solenoid controlled by a pid to turn the high stage on/off. On my forge, at least, there is really very little difference in gas flow between hi/low stages, so your atmosphere doesn't change that much.

Most people i know use a gate valve on the output side of the blower to control airflow. I've found that I have much better control that way than using the swing gate on the intake side. So basically a gate valve on the output side of the blower and a needle valve on your gas line is all you need to achieve pretty tight control on a properly set up burner/forge.

--Nathan
 
I also use one of those blowers....here's what I've found over the years...

"Squirrel cage" blowers are designed to work with NO back pressure. When these type of blowers are choked down, either via gate valves or even due to the back pressure present in most forge applications, the air input is dramatically reduced, the motor heats up, and the life of the blower is dramatically shortened...when I was using them, I would burn one out about every 2-3 months.

I use a "dimmer" switch to control the speed of my blower, (the 164 cfm model from The Blacksmith's Depot) but it's not the average dimmer switch you would use on lights...long duration using that type of dimmer switch on these blowers will result in burning out the motor. The "dimmer" I use is a ceiling fan speed controllers....it performs essentially the same function, however, the ceiling fan speed controller is built differently, and does not cause the motor to overheat. It's more costly...around $20, but compared to the cost of the blower it's cheap insurance.
The only other method to control the air flow that I would recommend is choking down the blower intake...it may seem that there would be no difference between doing this and using a gate valve down stream, but there is a huge one. Choking down the intake does not induce back pressure in the same manner that a gate valve does...and the blower motor does not heat up.
 
Thank you all for your comments. I will be getting the blower that Stan and Nick are running.
 
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