Author Topic: Propane Tank Forge (Read 8055 times)

KensAuto · « **on:** December 02, 2018, 10:54:27 PM »

I built this a couple years ago, found the pics, and I'll try to remember the details.
First, started with a propane tank, empty, with the valve out. I stuck a flame to the opening after it sat for a while, and it still lit. Good thing it was a brown pants day...sorry no video of me screaming .
I tried to scrape the paint off after soaking it in paint remover, to no avail.
Welded on some brackets so it would sit flat.

Then carefully cut one end off, retaining the inside lip. This will become the door.

KensAuto · « **Reply #1 on:** December 02, 2018, 10:56:58 PM »

Sometime in the middle I built a fire to remove the paint. Better now than when trying to forge.

KensAuto · « **Reply #2 on:** December 02, 2018, 11:01:18 PM »

..then a hinge for the door on one side that allows for the door to lift off. I took an old farmer wrench, bent it, and welded a bolt in the socket end to make a latch on the other side.

KensAuto · « **Reply #3 on:** December 02, 2018, 11:12:40 PM »

Next up was building the burners. I copied this design off the web...seems to be one of the most common ones.
Iirc I used 1" black pipe and 1-1/2" bell reducers for the nozzles and 2" for the mixing chambers/venturis.
First I milled out the threads ( I think this was a mistake. Pretty sure the threads would allow better mixing, via turbulence, for the propane and air )

stlaser · « **Reply #4 on:** December 02, 2018, 11:14:02 PM »

Did you use a mig welding tip?

KensAuto · « **Reply #5 on:** December 02, 2018, 11:26:53 PM »

...then a few 1/8" brass nipples in different lengths, including a shutoff valve between the two nozzles, in case less heat is needed.
I drilled the reducers on center the best I could, welded nuts on the sides, and added set screws to hold the "jet tubes" in place, also allowing them to be adjustable (very important)
The "jets" in this case, are .045 mig tips.
The first ones I tried were too short, and my flame was popping back up into the chamber. The longer tips fixed that, but I had to mill some flats on them to be able to use a wrench to tighten. They were then loctited in place.

KensAuto · « **Reply #6 on:** December 02, 2018, 11:32:07 PM »

I got a cheap regulator, hose, and gauge off of amazonia and started the tuning process. I can't remember where I found pics of the desired flame patterns (oxidizing, neutral, etc.) , but I based my adjustments on those pics.....

KensAuto · « **Reply #7 on:** December 02, 2018, 11:34:43 PM »

...lift off

stlaser · « **Reply #8 on:** December 02, 2018, 11:35:21 PM »

A quick tip in case you like your undies white, you can fill the tank up with water b4 cutting and it won’t blow up. Never just purge with air though as that can actually make a bigger boom if the original gas isn’t fully purged.....

KensAuto · « **Reply #9 on:** December 02, 2018, 11:37:27 PM »

Then built some burner mounts out of stainless, with aluminum inserts.

stlaser · « **Reply #10 on:** December 03, 2018, 08:22:53 AM »

Looks like you had a quality build Ken, too bad about the cement. I had read about people using the wrong kind too.

KensAuto · « **Reply #11 on:** December 03, 2018, 09:22:20 AM »

Quote from: stlaser on December 02, 2018, 11:35:21 PM

A quick tip in case you like your undies white, you can fill the tank up with water b4 cutting and it won’t blow up. Never just purge with air though as that can actually make a bigger boom if the original gas isn’t fully purged.....

Yeah, but that takes the fun out of it.
It is pretty amazing how propane can get into the pores of steel, just like gasoline. :embarrassed

KensAuto · « **Reply #12 on:** December 03, 2018, 09:17:33 PM »

Next up, made a port for a cheapo temp gauge thermal coupler....and made an aluminium plug for the hole when not in use.

Flyin6 · « **Reply #13 on:** December 03, 2018, 09:26:12 PM »

Purdy darned good work, Ken!

KensAuto · « **Reply #14 on:** December 03, 2018, 09:28:46 PM »

...cut a hole in the rear of the tank, added set screws for the burners (so they can be adjusted in or out), and bought the wrong cement. This stuff is meant to be used in thin layers, but didn't realize it until later.

KensAuto · « **Reply #15 on:** December 03, 2018, 09:38:15 PM »

...raised up the floor with fire bricks, with the lighter, higher temp fragile ones on the top.
...and started layering in 1" ceramic fire blanket .

KensAuto · « **Reply #16 on:** December 03, 2018, 09:45:33 PM »

Oops, got things out of order. I finished off the back end before laying in the bricks.

KensAuto · « **Reply #17 on:** December 03, 2018, 09:53:37 PM »

Mudded the blankets in not only to make it look finished, but more importantly, to keep the ceramic fibers from becoming airborne. ...nasty, hazardous material according to the armchair Phds on the web.
I then fired it up after sitting for a few days, hoping to not have trapped moisture, that might cause failure of the cement.

KensAuto · « **Reply #18 on:** December 03, 2018, 10:03:47 PM »

...and it still failed. ..several large bubbles formed, then cured in that position. Where there were no bubbles, it cracked pretty bad.
So I cleaned it up, took out the chunks, and started layering in thin coats with my daughter's help.
I figured the only way to dry the trapped moisture, from 3" of blanket material acting like a large sponge surrounded by a steel tank, was to cut slots around the tank itself. Not sure how long it set before I fired it back up, but steam did come out of those slots, and the cement cracked less than before.

KensAuto · « **Reply #19 on:** December 03, 2018, 10:11:57 PM »

The other depressing result is that I had the burners tuned pretty good in the vise, but once installed within the confines of the chamber, the flames would blow out, no matter what I tried.
Ended up installing air control plates on top of the mixers. Again, I believe removing the threads might have created this issue.

KensAuto · « **Reply #20 on:** December 03, 2018, 10:14:41 PM »

...then finished the door.

KensAuto · « **Reply #21 on:** December 03, 2018, 10:24:02 PM »

I decided that I didn't have an extra bench to rest a forge on, so a stand was required.
...a gate dolley axle, rubber tires, disc, and an old white spoke were the first ingredients. A 3" pipe for the upright.

KensAuto · « **Reply #22 on:** December 03, 2018, 10:26:34 PM »

...welded a coupler on the bottom and that finished it.

KensAuto · « **Reply #23 on:** December 03, 2018, 10:30:53 PM »

An adjustable tool rest for the front, and a rear handle, both made with the greatest, most universal steel in my shop, finished the last of the welding requirements.

KensAuto · « **Reply #24 on:** December 03, 2018, 10:36:31 PM »

Some stove paint to cover up the welds...ur... I mean, to finish it off.

KensAuto · « **Reply #25 on:** December 03, 2018, 11:45:45 PM »

Quote from: Flyin6 on December 03, 2018, 09:26:12 PM

Purdy darned good work, Ken!

Thanks boss !

stlaser · « **Reply #26 on:** December 03, 2018, 11:49:49 PM »

I agree, very nice. A lot of labor went into that build.

KensAuto · « **Reply #27 on:** December 03, 2018, 11:59:34 PM »

Thanks bud. I finally did a max temp reading today with the gas turned down to 8psi. She hit 2187°, then customers started showing up and had to shut it down. That temp meter only goes to 2200 but I'm guessing 10-12 psi will get it up to a good welding temp.

stlaser · « **Reply #28 on:** December 04, 2018, 12:13:39 AM »

TexasRedNeck · « **Reply #29 on:** December 04, 2018, 06:07:13 AM »

Good job Ken. So now that you’ve built that. What have you made so far?

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wyorunner · « **Reply #30 on:** December 04, 2018, 07:03:09 AM »

If there was a production quality forge out there, this would have to be close to that level. Nice work!

I’d like to have one to build shovels, garden tools and the like. Was almost talked into building one by a friend back home.

Let’s see the first run of your knife you started!

cruizng · « **Reply #31 on:** December 04, 2018, 07:47:37 AM »

Nice work Ken. Should be a nice winter project. Being the armchair DOT that I am..... what is the purpose of the door if the opening on the door is the same size as the forge opening? How do you close the actual opening on both ends if you want to increase the heat?

KensAuto · « **Reply #32 on:** December 04, 2018, 08:56:19 AM »

Good question Mike. I needed to cut one end off for access, so I could weld it back on, or make a door...and originally there was only supposed to be 2" of insulation.
It is larger inside, but shouldn't need to use the door for knife work.
Tex, just this one so far. Ordered scale pins yesterday...thought of you when I made the purchase.

Flyin6 · « **Reply #33 on:** December 04, 2018, 10:07:05 AM »

This is fascinating!

KensAuto · « **Reply #34 on:** December 04, 2018, 11:01:48 AM »

This pic is for Mike, to show the size of the interior, and threw a block in back to see if it gained an appreciable amount of temperature...
..right before it ran out of propane.
I can add shelves for fire blocks in the future, if needed. So far the temps look good. It hits almost 2200 in 12 minutes. I tossed in a spike and it was yellow in less than 5.

KensAuto · « **Reply #35 on:** December 04, 2018, 08:38:12 PM »

Tried hammering on something a little softer than leaf springs...a low carbon railroad spike ...just for additional practice. Probably give as a Christmas gift to a future son in law that loves knives.

cruizng · « **Reply #36 on:** December 05, 2018, 07:47:20 AM »

Very cool. I would be curious how fast it would eat a tank of gas.

Flyin6 · « **Reply #37 on:** December 05, 2018, 02:27:58 PM »

Quote from: cruizng on December 05, 2018, 07:47:20 AM

Very cool. I would be curious how fast it would eat a tank of gas.

I'm thinking PDQ

stlaser · « **Reply #38 on:** December 05, 2018, 03:29:11 PM »

Easy fix, bigger tank

KensAuto · « **Reply #39 on:** December 05, 2018, 03:49:24 PM »

Looks like it eats a gallon per hour or a 20lb tank in 5ish hours. She's hooked up to a 30 lb'er now.

Bob Smith · « **Reply #40 on:** December 05, 2018, 09:10:02 PM »

That is still a good burn time for what you are doing

stlaser · « **Reply #41 on:** December 05, 2018, 10:05:10 PM »

I agree on the burn time, more than adequate

KensAuto · « **Reply #42 on:** December 05, 2018, 11:37:06 PM »

I may have ordered one of these, to help the knife making adventure. I also may have put it on a shop tool account.
...at least it's not the 3600.00 one I originally wanted, made locally.

http://www.grizzly.com/products/Grizzly-Knife-Belt-Sander-Buffer/G1015?gclid=Cj0KCQiAi57gBRDqARIsABhDSMo7FtgI_aUkNgIYvRrCGeNiPUT2zllLPsuKtOc6JmARwRTCO67839QaAi9uEALw_wcB

stlaser · « **Reply #43 on:** December 05, 2018, 11:48:07 PM »

It’s on my list, please do a thorough review

HARV KOSO · « **Reply #44 on:** December 12, 2018, 09:20:44 PM »

Forge on!!!

KensAuto · « **Reply #45 on:** December 13, 2018, 07:20:23 PM »

Holy cow...5 burners!!!!

Bob Smith · « **Reply #46 on:** December 13, 2018, 08:31:32 PM »

And look at the twin tanks Ken...

stlaser · « **Reply #47 on:** December 13, 2018, 08:47:45 PM »

That’s long, sword making?

cudakidd53 · « **Reply #48 on:** December 14, 2018, 07:12:50 AM »

Quote from: stlaser on December 13, 2018, 08:47:45 PM

That’s long, sword making?

I’m guessing yes Shawn by the height of the quench tank next to the forge.

HARV KOSO · « **Reply #49 on:** December 14, 2018, 07:24:46 AM »

Just prepped for when I get good enough to make a sword long than 30”

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