New forge

[Wulfaz]

I am new to this forum. I just finished up building my new propane forge. When I was planning my build I looked all over for ideas of what to do and what not to do. I figured I would post pictures of mine to return the favor and allow people who are looking to get ideas of what they want to do and what they don't want to do.

It is 1/4" metal welded together (my first time welding so it's not pretty) with scrap angle iron to hold the bricks in and a scrap square tube up top to hold the torch. 

The bricks are k-26 bricks except the bottom. They are a harder fire brick. The square tube is welded to the forge. I drilled holes in the 4 sides then welded nuts to it to use as threading for the bolts (seemed easier than threading the tube itself) the bolts hold the torch tight but allow it to be adjusted/removed. Sometime in the future I will weld a bolt to the top of the torch so I can adjust the airflow. 

There is also a door/opening on both sides covered with a brick in case I forge to longer metal.

[Frosty]

Welcome aboard Wufaz, glad to have you. Not a bad first propane forge, well done my hat's off to you. Most of us don't do nearly so well on our first (couple few in my case) It can be improved though. 

The hard fire brick while tougher is a major heat sink it will take more fuel and time to get to temperature and being a poor insulator will lose heat by radiation. If you replace the floor with K 26 it will get hotter, faster and cost less to operate. A kiln wash like Matrikote or Plistex will improve IR reradiation an help armor the brick agains mechanical and borax damage. K 26 is pretty invulnerable to hot borax but every little bit helps. A kiln shelf floor is a serious improvement it laughs at molten borax, is tough as all gitout at temperature and re radiates IR well. 

The bushing reducer between the bell reducer air intake and mixing tube on your burner is hurting efficiency. The abrupt reduction in Dia. causes turbulence that inhibits induction of combustion air. More air more fuel per second meand more heat per second. Yes?

Assuming it's a 3/4" tube, it'll be repeat work but if you replace the bell reducer with a 3/4" x 2" or larger it will be a much more effective burner.

How long is the mixing tube? The ratio is L= 8x Dia. So a 3/4" mixing tube should be 6" long. Longer loses efficiency due to skin friction. More is definitely not better.

Make sense? Got questions give a shout.

Frosty The Lucky.

[Mikey98118]

Make that Plistex on the floor, because Matrikote is only rated for 2500 F, so you don't want to point your flame directly at a surface covered with it.

Speaking of flame, if you drill out the side hole in your burner's cross pipe, and thread the new hole for a .023" MIG contact tip (1/4-27 or 1/4-28 thread; either thread will work), which you can screw  into it from the reducer's small opening, while the cross pipe is in place, the flame will get much hotter.

[Wulfaz]

16 hours ago, Frosty said:

Welcome aboard Wufaz, glad to have you. Not a bad first propane forge, well done my hat's off to you. Most of us don't do nearly so well on our first (couple few in my case) It can be improved though. 

The hard fire brick while tougher is a major heat sink it will take more fuel and time to get to temperature and being a poor insulator will lose heat by radiation. If you replace the floor with K 26 it will get hotter, faster and cost less to operate. A kiln wash like Matrikote or Plistex will improve IR reradiation an help armor the brick agains mechanical and borax damage. K 26 is pretty invulnerable to hot borax but every little bit helps. A kiln shelf floor is a serious improvement it laughs at molten borax, is tough as all gitout at temperature and re radiates IR well. 

The bushing reducer between the bell reducer air intake and mixing tube on your burner is hurting efficiency. The abrupt reduction in Dia. causes turbulence that inhibits induction of combustion air. More air more fuel per second meand more heat per second. Yes?

Assuming it's a 3/4" tube, it'll be repeat work but if you replace the bell reducer with a 3/4" x 2" or larger it will be a much more effective burner.

How long is the mixing tube? The ratio is L= 8x Dia. So a 3/4" mixing tube should be 6" long. Longer loses efficiency due to skin friction. More is definitely not better.

Make sense? Got questions give a shout.

Frosty The Lucky.

Thank you for the advice. I plan on upgrading it once I get more involved. The suggestions help! 

As far as bricks does anyone know where I can purchase them around the Springfield, Mo area? A friend gave me the K26 bricks I have now used from his kiln. The place he got them went out of business. So I am unable to get more for the floor or replacements unless I find somewhere. 

I didn't like the bushing reducer but it was all the hardware store in town had and to be honest I was impatient and figured I would change it out once I came across the right bell reducer. 

The mixing tupe is 3/4" x 8" long. I actually hadn't heard that 6" was better. Every plan I saw used 3/4" x 8". So that's good to know that 6" will be better. I will definitely change that out. 

Thank you for the advice! Everything helps!

4 hours ago, Mikey98118 said:

Speaking of flame, if you drill out the side hole in your burner's cross pipe, and thread the new hole for a .023" MIG contact tip (1/4-27 or 1/4-28 thread; either thread will work), which you can screw  into it from the reducer's small opening, while the cross pipe is in place, the flame will get much hotter.

I had seen people add the MIG tip to it but was unsure how much it would actually help. For now I just drilled a .040" hole. I was also unsure the correct threading for the MIG tip so this helps. Thank you for the advice! I will definitely be adding it soon. 

[Frosty]

Check with a HVAC or boiler service company, if they don't sell refractories, brick, etc. they can direct you to someone who does. 

Don't buy plumbing at a hardware store, especially not a big box. Hit a plumbing supply store they have the real deal parts, not what some middle management beancounter the other side of the country decides has the best bottom line.

Lots of people postinng how to make a burner video don't know what they're doing. Probably the #1 mistake is not understanding what 8 x the dia. means. 8 x 3/4 is not 8. It used to upset me till I started getting students, high school grads who couldn't determine the area of a square. Every too often you see guys post here who don't know circumference from diameter from radius or any of them. 

I haven't seen a Youtuber talk about burner ratios yet, don't sweat it. Read here instead of Youtubing. 

Frosty The Lucky.

[HojPoj]

Depending on the MIG tip type you get it may be metric.  The ones from harbor freight for their cheap flux core welders are an M6 thread form.  Pretty darn close to a 1/4 thread, just depends on how easy you wanna screw it in.

[Mikey98118]

You basic constructed a Riel burner; if you look up his burner pages on the Web, you will see the MIG tip change over, and read just how much of an impact it made almost twenty years ago.

[Frosty]

Metric  contact tips! Again go to a welding supply, they'll have contact tips in the sizes you want AND they'll have the correct tap behind the counter for it. Mig guns often need the threads chased as cross threading the contact tips seems to be a tradition. 

Big boxes and even good hardware stores rarely have everything you need, they don't have room to stock everydarnedthing so selection is going to be the fastest movers. 

Frosty The Lucky.