built my forge - couple quick questions

S

SkaerE

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Sep 9, 2001
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so i said to heck with it and threw out the idea of the 4 brick forge built a firebrick forge from 9 firebricks and a real burner instead of propane torch. Has a 4.5'' x 9'' x 4.5'' chamber and one of the EZ Burners (Reil design) hooked to a 20lb propane tank. i fired it up and could heat rebar to orange in under 10 minutes.

questions:

1.) when i built the burner i used a .025 mig tip instead of a .035 (I misread the directions) will increasing the diameter of the propane jet increase the heat substantially?

2.) at what color should one begin to shape steel? red seemed very hard to get the metal to deform, orange was much easier. Do you only get three or four good strikes in before the metal cools?

3.) burner ran great outside the forge when i was tuning the flare, when i put it into the forge it sputtered at low PSI and high PSI, ran great at 15PSI though. thoughts? I also put a choke/air restrictor on the back of the burner....what should the forge look like when at its most efficient? I could keep all of the flame inside the forge or close the choke down halfway and have it shooting out the front.

4.) the kaowool forges i've seen have a bit of the wool around the burner to keep extra air from sneaking in through the burner hole. Is that needed? i have mine set screwed into a 2'' pipe nipple coming straight in the top like this one:

http://www.zoellerforge.com/firebrickforge.html

i'll take some pictures in a bit....

thanks!
 
Ummmm 15psi???? Did I just read that right???

Judging color is hard to describe because we see it differently and the ambient light plays a part. I start forging at what I see as bright orange almost yellow then work at cooler temps as I go further along. My smithy gets no sunlight to the forge or anvil. I try to judge the color against the interior of the forge to have a consistent background.

Your initial heats will be shorter because your tooling isn't warm... the anvil is cold, the hammer is cold. When I finish a long day forging my anvil is pretty dang hot, you're not going to lean on it for dang sure.

I use a vertical forge so it's a little different but I prefer ummmm "little tongues" of flame curling out of the forge door. Not shooting out just a little wisp or two. My burner has a little skirt of kaowool where it enters the forge body, mainly to make sure nothing comes out that hole but I guess it keeps stuff from entering.
 
yeah, 15PSI. why? i'm brand new to this but from my reading it seems people operate the Reil burners between 2 and 50PSI depending on what they're doing and whether they are forcing additional air... guy i took the forge design from (see link above) said he was running 20 PSI on his for that last picture.

i had no flames coming out of the forge unless i choked some of the air
 
15 psi is not an uncommon pressure range for simple venturi burners to run. 15-20 psi is the high end of the pressure range, for forge welding or quick preheating. A well insulated forge with a well made venturi should not need to run that high, though. For general forging you should be looking at the 5 psi range.

What mig tip is appropriate will depend on your burner tube size. I'm assuming that you used 1" pipe. In that case, the .035 tip will work better for you. This may also help your burner sputtering issues. If you are indeed using a 1" tube on this, it seems like a pretty small heat chamber for the burner. A 3/4" tube would work better, and in this case the .025 tip would be more appropriate. If you have a threaded 1/8" pipe nipple the tip screws into, just try both and see which works better.

To get a fairly neutral burn, you may have to choke it a bit. You should see some yellow flame coming out the door, not a lot and it should not be blue. The fact that with the choke half closed you have flame shooting out aggressively may indicate that the burner is too big, as well.

Your flare should fit the refractory well. If there is a significant gap (I'd say 1/8" or more) inswool is good to stuff it with.
 
thanks! it is indeed a 3/4'' tube w/.025 tip. The tip is simply threaded into the 1/8'' pipe run through the 1.5'' reducer. I read after that perhaps i should have silver soldered it in... opinions on that?

i made the EZ Burner version of the flare using a section of 1'' pipe and 1'' coupling (to cinch it down on my 3/4'' tube) so the 2'' nipple is a pretty tight but certainly not airtight fit. but the hole i bored in the top of the firebrick is only very slightly bigger than the flare so i would think its ok.

perhaps messing with the choke and different pressures will allow me to work more efficiently and eliminate the popping. would adding a tube to force some air be beneficial?

about how long does a 20lb tank last anyhow?
 
Interesting, I went and looked at that Zoeller brick forge. It's pretty cool, I notice he's using a 3/4" burner in it, but that the TWECO tip he uses IS the .035. So that should work, I've bought a couple sidearm burner kits from Larry in the past and they work great. I've also built Reil EZ burners, which are OK.
 
So, try to swap it out for an .035 tip. You say it's threaded in, so it must be a sched. 80 nipple to be internally threadable for 1/4x20. That's the best way. It's possible to get a glob of solder partially obstructing the flow inside the injector, or to solder it in out of line a bit.

You should be able to run that thing on pressures from 2-10 psi mostly. If you don't run wide open all the time, a 20 lb. tank should last you a good while. I go through a 100lb. tank in about 6 months with my little venturi forge. You do mean 20lb., not 20 gal, right?
 
You might be running higher pressure because of the need to push more fuel through the smaller orifice of the .025 tip in order to achieve your temps. The above link I posted has a great tuning tip from Stacy, as follows...

A venturi burner is tuned to get the proper mix. The simplest way to set it up is to clamp it in a vise or such to run it out of the forge. Obviously this has to be done in such a way as to not ignite the place. Turn on the gas and ignite the burner. Adjust gas pressure to get a steady flame.Open the choke plate about 3/4 the way. Move the gas jet in and out (if possible with the burner you have), to get the smoothest flame. Reduce the pressure until it starts to sputter. Adjust the choke and jet position again. Keep this up until you have the burner running at the lowest pressure that it will run smoothly at. Then adjust the air choke to get the best looking flame. Now the burner should run good at higher pressures, as well as at its lowest pressure. The next step is to re-install the burner and adjust the flare position for the best chamber flame.It may need a little adjustment of the choke once re-installed to compensate for any back pressure.

When all this is done and running right, make a few knives. After selling a couple, build a blown burner and keep the venturi burner for some other project ( or when there is a total blackout for days). You will never regret going to a blown forge, especially if you are going to do Ht with it.
Stacy

Stacy E.Apelt
 
not sched 80 that i am aware of, i tapped the sidewall of the 1/8'' nipple for the MIG tip (Reil reducer burner has 1/8'' running perpendicular to the burner tube as opposed to parallel like the Zoeller)

thanks for the link! i guess one of the downfalls to the EZ burner is that its not nearly as adjustable as some other types. i can adjust the choke and the flare and that's about it. :)

yeah, 20lb... like for a propane grill.

the only other thing is perhaps i am running it WAAAY hotter than I need to. Again, I have no idea how long it should take a piece of steel to reach red, or orange. I can only tell you that currently 5/8'' rebar hits orange in probably less than 3-5 minutes after the forge has warmed up.
 
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