YAPBF (Yet Another Propane Bottle Forge)

[MT Hammer]

YAPBF (pronouced /yæp bʌf/  as Bloom County’s Bill the Cat would)

I debated whether to pollute either the ‘101’ threads or the entire forum, but decided on the latter, not wishing to add to the 96 and 64 pages already in the threads.  As one who has tried to scan/read/comprehend all those posts, I tnink my questions would not add value to the archive.  In any case, here I have finally managed to complete my first forge build. My journey has taken me years (I have too many projects).

While I know I’ve made mistakes, I’d like to know how serious they are, and what to do to mitigate them.

When I started out, all I had was Michael’s book, so I started building the 5-gal bottle forge.  Then when I found this site, I learned that I really wanted a smaller volume, so to make up for it I just added a xxxxxxxx of castable.  I’ve got well over 1” thick in many cases.

 

I painted Matrikote on the castable (although the directions say not to, but the concensus here is to do so). It seemed to go okay, but then felt fragile and powdery days after air drying.  Heating seems to have improved to adhesion.

I decided the Frosty T was the best burner for a novice like me.  The burner flares are cast into the shell. The biggest problem a newbie like me has with the Frosty T is the need to tune them in the forge environment.  Kinda chicken and egg deal when you’re building both at the same time and ya need the burner to cure the forge but the burner needs the forge to run.  Hmm…

I manged to get things cured and running reasonably well (I guess).  From cold, it’ll get pretty orange hot in a couple minutes at 5 PSI. 

I’ve read all I can about reducing, neutral, and oxidizing flames, but I’m still pretty hazy as to what exactly to look for.  Here’s the forge right on startup from cold:

 

And here it is a couple minutes later:

 

The dragon’s breath when it’s hot:

I live at 5,800’ elevation, and am using .035 mig tips. They are trimmed about halfway if looking straight through the "T". Don’t know if I should try .030?  

The burners are probably too close together, but I’m not sure if they’re at a decent angle or not. 

This is running at 7.5 PSI:

Any help, critique, or even laughter is certainly welcome!

[Mikey98118]

Okay, you asked for it, so...nice flames; nice heating job; nice forge. No, I ain't listening to no alibis; you'll just have to live with it, so there!

So, what do you plan to do the the exhuast openings? For a heat reflective coating? Just cause you did a find job so far, don't mean we can't bug ya

[MT Hammer]

Thanks for the comments.  I’ve at least managed to squeeze my way into the ballpark then, it seems

The frame around the tank will be used to support some K26 bricks to be used as doors. I decided upon this route so it could be modular and also support front or back porches, etc.

I hope the Matrikote serves well as a heat-reflector. I also coated the door bricks with that, both for IR reflectivity and also to strengthen them a bit.

[Mikey98118]

I don't remember the number, but Matrikote may not be use rated as high as you need. If so, Plistex is cheap. I have every confidence that you will finish that forge as neatly as you've begun.

[Frosty]

You're a cruel person, present a forge and burners to critique that doesn't have anything wrong with it. You could maybe play with tuning if you like to tinker but it looks pretty darned good from here now. 

Trimming mig tips isn't hard with the burner mounted, I disconnect the copper tubing at the flare fitting on the burner then unscrew the brass fitting with the mig tip from the T. Then I put it in my drill press and trim with a file at an angle so the file's teeth carry the cuttings away from the jet orifice. A quick stroke from the threaded end with a torch tip file deburs it and it's ready to test. Yes, you CAN use a drill press like a lathe as long as you don't put pressure sideways on the quill, they don't have thrust bearings to take the pressure.

Seriously it takes longer to write the description than actually trimming the jets.

I don't know what happened to Matrikote as a recommended kiln wash, it used to be held as a close equivalent to Plistex 900 but nobody talks about it anymore. Well, I DO toss it out as a good kiln wash, serviceable anyway. It does require a good hot  firing to vitrify it into the: hard, chemically resistant, durable, ceramic that we need to armor our forges, just like Plistex. 

Frosty The Lucky.

[MT Hammer]

Thanks to you esteemed gentlemen for the kind words. I'm sorry I did not present something more criticizable!

Luckily, there's trouble in paradise... my kiln wash has cracked and spalled. That this is my fault is no doubt, but I don't know the reason. It could be that I applied it too thick, or maybe didn't cure/fire it properly.  It air dried over a week before I applied any heat.  I first warmed it some with a map gas torch. Then fired the forge to 1/3 heat, cooled, 2/3 heat, cooled, then orange hot.

 

Now Ive got to fix this mess.  I should probably post this question in the Insulation and Refractories section, but how dangerous is this?  The MSDS for Matrikote freaks me out a little when it states, "After exposure to temperatures above 1600˚F, Cristobalite and Tridymite are formed."  Yikes!  But these horrible lung eaters are not aerosolized normally I would guess?  Now when I try to scrape and clean this failed attempt, I am guessing I should be pretty careful?

On 1/22/2021 at 6:20 PM, Mikey98118 said:

I don't remember the number, but Matrikote may not be use rated as high as you need. If so, Plistex is cheap. I have every confidence that you will finish that forge as neatly as you've begun.

By as high, you mean as I want welding temps, it is not rated that high?  

Of course, the two reasons I applied the wash in the first place was to make it more efficient, and also to protect the floor from direct flame impingement and flux damage.

[Mikey98118]

Use good ventilation, and wear a dust mask while striping out the mess. Keep falling dust contained and  then swept up. I would not advise taking a lot of time putting another finish coat on. Plistex is cheap and fast; it is good past any temperature an air/propane fueled forge is ever going to reach.