Jump to content
I Forge Iron

First forge and burners


Recommended Posts

I've recently decided to build a small forge as a compliment to my other metal working. Traditional blacksmithing wasn't a priority, I was more interested in adding annealing, heat treating and some hot work (bending, twisting, etc.) to my projects. To that end I started reading up on forge and burner design here and elsewhere. I've built two 1/2" burners and a preliminary forge shell which after fitting the burners and test lighting one, I'm beginning to think are mismatched. The finished size with lining was going to be 4" round by 16" long. I'm still waiting for my refractory material and co monitor so I moved on and finished my burners. Instead of raiding my mig welder for tips, I turned mine from 3/8" brass round with a multi angle tip and 1/8" npt threads, the holder was made from 18ga sheet metal and the extra holders that come on my pellet stove ignitors, the rest of the burner turned out to be a 1" by 1/2" reducing coupling, 1/2" by 8" nipple and a 3/4" by 1/2" reducing coupler. I came to this from starting with ideas and some math from here and elsewhere plus a bit of trial and error as I worked through different variables one by one. The jets are drilled #61 which I worked up from the original #70 I drilled. I'm wondering where I should be in forge size with these, in particular a D shape seems appealing. Here's a pic of one of my burners running in open air.



Link to comment
Share on other sites

Construction wise, it's a good burner. Design wise the burner has several mistakes. Fortunately, the mistakes can be eliminated one at a time, if you are dissatisfied with performance in the forge. A "D" shape forge is a good fit for burners with excess secondary flames, so continue on that path.

Also, be sure to allow a generous amount of space around the burners for secondary air to be sucked into the forge; you're burners are going to need it.

Link to comment
Share on other sites

Thank you Mike, I just did a quick test after work and the secondary air requirements are definitely a problem. To run with my 30psi regulater tapped out I needed to hold the burner 3/4" outside the shell to draw enough secondary air in. Not really a solution in my mind but proof of the problem. What would you suggest as parameters to play with? I'm not adverse to building another set of burners for the forge I'm working on and doing a D shape forge for these ones. The tinkering is pretty enjoyable!

There is no reason to quote the post just prior to your reply. The quote feature

Edited by Mod30
Remove excessive quote.
Link to comment
Share on other sites

  • 2 weeks later...

Finally received my refractory materials and was able to move ahead. Mistakes were made and fun was had.

I put my linear burner design aside and played around with laminar flow in an ejector design to induce more primary air. I won't put up a pic of it because although safe in a vertical position, in horizontal it absolutely is not.

The second burner port is plugged with left over insulation, two 1/2" burners running 0.025 mig tips is too much. The rear door can't be used and way to much external flame. I rejetted this burner by giving it a crush to a true 0.025 with a collet.

Temperature wise on one burner with the door closed my IR thermometer would only greet my with a Hi which is 1200f and above. So I ran it with my test piece behind the flame and was able to hit critical (non magnetic) on both the coupler and rebar, performed a brass melt but was not successful with copper, only melting what was close to the flame (this was with the richer jet last night).


Pic 1 is warm up running 15lbs

Pic 2 is melting brass at 10lbs

Pic 3 is scale formation left is the brass melt, right was last night with richer jetting.

Pic 4 is forge opening with rear door closed.

Pic 5 is with rear door open.

Pic 6 is for the CO safety guys, 2.5' from forge.









Link to comment
Share on other sites

Ditto, CO exposure is cumulative and takes a considerable amount of time to be flush from your system. If you're a smoker you're living with low level CO exposure so even a small bit extra can be significant. I know when I smoked I felt the CO lip buzz a log time before other guys around me, at the forge or other such efforts, the road maintenance crew had a number of pieces of equipment that had darned rich burners under them, the patch truck asphalt pan for instance. 

My sensitivity to CO went way down after I quit smoking but it's back up or I notice it sooner since the TBI.

Frosty The Lucky.

Link to comment
Share on other sites

I was dosed once 30 years ago due to a rotted muffler on a grain auger. stumbling out of a building is not something I'd like to repeat. More ventilation and less production are in the program. On another note, I used my collet trick on the other mig tip and got it down to a true 0.025 ID, I'm now running on both burners with the door closed with some room to tune mixture by damping.

Link to comment
Share on other sites

Especially since the detectors are so cheap! Even the ones with an LCD display are dirt cheap on eBay (£5-12) from known brands.

I highly recommended the LCD display, as it allows you to keep an eye on the levels all the time. My coke forge seems to be variable on what I can get away with. Some days, I can forge with just the two windows open in my shed (at 0PPM) which will keep my neighbours happy by reducing the noise. Other days, I watch the level creep up and have to forge with the door open to keep it at 0 PPM. Perhaps depends on the atmospheric conditions, draw on flue, etc etc.


Looks like the OP has this all covered with a decent detector. Forge looks great (though I know nothing re/ gas forges).

Link to comment
Share on other sites

At one of the hotels I work at the exhaust ducting in the laundry where I spend most of my time was in need of a good cleaning and I started to notice I would get a headache and feel generally ill whenever I worked at that location. We have since gotten CO detectors for both locations and cleaned the exhaust and I haven't had the problem since. Don't take even low levels of CO lightly as it will cause problems after continued exposure. As frosty said the effects are cumulative. 



Edited by pnut
Link to comment
Share on other sites

  • 2 weeks later...

Thank you, it's come a long way since the first idea was hatched. Found a couple weak spots, burners should be closer to each other and the shell should be larger diameter to give space to improve the refractories but it works and 10psi seems to be the sweet spot for forging with it. Now's it's on to building an anvil stand. Here's the finished forge and my first flux spoon.




Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...