Thought I would add to this thread and show you what I use for a burner in my welding forge. Before we get to that, I just want to mention something that I feel is VERY important with any burner you use in a forge… KEEP IT SIMPLE! I’ve spent countless hours trying to help folks with forge burner problems, and I’ve come to fully believe… The more you overtake the plumbing, the easier it is to stop up the drain. The vast majority of problems I’ve assisted with/solved concerning forge burners can all be directly related to over complicated burner designs. Just keep it straight forward and simple… and your life will be much nicer.
I choose to use a very simple, single burner with a blower on my welding forge. Easy to build, very few things to go wrong, and it just plain works.
It all starts with choosing the correct blower for the application. While I know that many folks use “squirrel cage” blowers, otherwise known as Shaded Pole Blowers, that are very inexpensive, and easy to find, I personally think that is one of the least desirable blowers a person can choose. Squirrel Cage/Shaded Pole Blowers are NOT designed to function with ANY amount of back pressure… something that is always present in a forge burner application. Here’s what happens: As back pressure increases, air flow decreases, and causes the motor to heat up, and burn out the windings. Don’t get me wrong, some folks who use their forges very little, have gotten away with using this type of blower for years, but for those who do any kind of higher volume or prolonged usage of their forge(s), they can be a real pain. I know, because I did just that… used Shaded Pole Blowers. They worked fine, as long as I didn’t run the forge much, but as I got into longer and longer days at the forge, blowers started burning out. At the time I simply didn’t know any better, so I just kept replacing them… and kept burning them out.
Finally I broke down and purchased a blower that is specifically designed for forges. At the time (over a dozen years ago) I believe I paid $125 for this one.
It cranks out 164 CFM, and has been going strong for all these years. If you’re going to use a blower on a forge, I highly recommend this one/type.
Here’s a pic of the entire burner I use in my welding forge:
From the blower to the forge, the parts are:
-164 CFM electric blower, wired into a ceiling fan speed controller (DO NOT use a typical light dimmer, it will cause the motor winding to burn out… you’ve been warned!)
-Pipe Flange with 2″ threaded fitting
-2″ X 12″ piece of blade iron pipe, threaded both ends
-2″ X 1 1/2″ 90 degree elbow (this is a very important part of the burner… the reduction from 2″ to 1 1/2″ aids greatly in the fuel/air mixing, and increases velocity at the burner end for better control and high temps)
-1 1/2″ X 18″ black iron pipe (this is the pipe that goes into the forge and is the “burner”)
Propane is delivered through a common rubber propane hose, controlled with a propane needle valve (there is also a ball/shut-off valve located at the propane regulator). I far prefer a needle valve to a ball valve at this location. Its far more controllable, and makes fine adjustments MUCH easier. The 2″ pipe has been drilled and tapped to accept the 1/4″ pipe nipple. The nut you see next to the burner pipe is to “snug” the pipe nipple in place. I DO NOT USE ANY TYPE OF ORIFICE IN THE PIPE NIPPLE. I tried several differ sizes of orifice, and found that with the needle valve, they were totally unnecessary, and made the forge much more difficult to “tune”.
After a bit of experimenting with this burner, I installed 3″ concentric pipes in the burner end… I found that it quiets the roar of the burner nicely, and it gives me a better flame pattern, with a wider adjustability than without the concentric pipes.
Finally, the burner holder is an important part of the equation too. You want something solid and heavy gauge, that will be able to withstand the high/long endurance heat. It need to be welded solidly to the forge body, and be of the proper I.D. to “fit” the burner you’re using. In my case I used a piece of schedule 80 pipe, and using a boring bar, enlarged the size to about .030″ larger than the O.D. of my burner pipe size. This allows for expansion of the burner pipe, but isn’t so oversized that it allows flames to come out the burner holder. I drilled and tapped three 1/2-13 holes approx 120 degrees apart, and use 1/2-13 bolts to hold the burner in place.
The new forge has been curing for a couple of weeks now. I’m guessing that in about another week it might be cured enough to do some test firings and see how things are going to work. The current plan is that once the castable refractory is cured enough, give it a good cleaning with a brass brush, blow it out, and apply ITC-100.
Once I get it ready, I’ll add to this thread as things move along.