Mapp gas or propane torch for small forge?

C

CShepherd

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Feb 27, 2006
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Hello all,

I've done some searching here but haven't been able to find what I'm looking for.

What I'm doing is building a small forge out of part of a 30mm mortar tube. I have a basic plumbers propane torch but I don't believe that will be hot enough to heat up the forge. The forge is approximately 7" in diameter reduced down to a 5" x 9" opening for the blade after putting in the Inswool liner and base stone. Is a Mapp gas torch hot enough, or perhaps one of the Bernzomatic JTH-7 torches, or should I invest in one of the forced air or venturi burners from Ellis?

Any help is greatly appreciated here.

Thanks,

Charles
 
In air, MAPP gas does burn noticably hotter than propane (i recommend one of those swirl-flame torch heads), but if your going to be mixing with oxygen, I'm not sure how noticable the difference in temp is between the two.

That said, I always refill my (very little) cutting torch with mapp and not propane (its an oxy-mapp torch). I also tend to use mapp with my regular swirl head torch.

So yeah, I suppose I'm recommending to use mapp.
 
You would most likely end up with a hot spot and uneven heating. MAPP is hot but there just is not enough BTU's to evenly heat that size of an area.

A 150 degree ceramic heater will heat a room faster then an acetylene torch will.
 
I am using a two brick forge that is about the same size you are talking about. the Bernzomatic JTH-7 torch for propane works great for heat treating haven't tried welding billets. This torch will bring a 3/16" x 1 1/2 x 6" to non magentic in less than 10 mins and I have been getting about 3 knives done with those small camping bottles of propane. You can purchase a hose kit to fit the twenty pound bottles
 
Thanks to all who have replied. I am absolutely grateful for everyone who knows what they're doing and are willing to share it with newbies like me.

I picked up the Bernzomatic JTH-7 and a bottle of Mapp gas. Boy is it hot. Now I just have to finalize my design and get the lining material and I'm in the heat treating business (at least after I learn what I'm doing with that).

Happy New Year to all,

Charles
 
I have to second the use of the JTH-7. I tried with a smaller torch from the local Home Depot, and it just didn't make enough heat. I've used both propane and MAPP gas. Both work, but I like MAPP gas for larger blades (the Propane can't keep the ends of the brick hot enough).
 
I make alot of small frontier folders that have 2" blades. To HT them I use two MAPP gas torches and aim the flames to converge together. It's not worth firing up the forge for that size of blade.

A good forge is an evolving process and it will take alot of tinkering to come up with one that will suite your needs. Don't be afraid to try several designs out.
 
Remember, the flame on Mapp gas substitute that is available since Mapp gas production stopped in 2008 is only 130F hotter than Propane gas.

MAP-Pro gas burns at a temperature of 3,730 degrees Fahrenheit, while propane burns at 3,600 F.
 
I just want to add that temperature is almost insignificant. You are forging at 1800-2200F, welding at 2300-2400F, and HTing at 1450-1550F. Every torch made gets much hotter than this. A Bic lighter reaches 3600f.

What does matter is BTUs. It takes a well engineered torch to give the most BTUs. Compare BTU/hr ratings when shopping for torches. Also, the torch head size, which controls flame volume, is important. Generally, the wider the torch head, the more BTUs it puts out.

Finally, running a torch on a regulator with a bulk propane tank of 20 pounds or more is where you get the most BTUs as well as control from a torch. The adjustment knob on a torch is barely more than an On-Off valve. The disposable bottles are low pressure.
A 20 pound propane tank initial purchase runs about $45. Exchanges are around $20 from then on. If you belong to Costco/Sam's/etc. the exchanges are around $16.
You probably have a propane tank already for your grill, or empty ones can be found at yard sales for a few bucks. Buy an empty tank (it doesn't matter how bad it looks) and exchange it for a full tank for $20. ​

The best hand held torches are barely big enough for a small forge. The best on the market for a small forge is the Brenzomatic TS800,which puts out around 20KBTU with MAPP gas. They run around $90 today. Other fancy sounding disposable bottle torches may sell for more, but some only deliver 3KBTU/hr.

This is why I suggest buying an Atlas burner setup from Charles, at Atlas Knife and Tool. They come with a burner, hose, regulator, (some have a regulator gauge) … all for about what you spend for a cheap hand held bottle torch. You can pick different size burners from him to meet the needs of your forge - 30K, 100K, 150K. The complete kit for a 30KBTU burner is $60
http://www.atlasknife.com/product/atlas-30k-burner/

 
Stacy E. Apelt - Bladesmith said:
I just want to add that temperature is almost insignificant. You are forging at 1800-2200F, welding at 2300-2400F, and HTing at 1450-1550F. Every torch made gets much hotter than this. A Bic lighter reaches 3600f.

What does matter is BTUs. It takes a well engineered torch to give the most BTUs. Compare BTU/hr ratings when shopping for torches. Also, the torch head size, which controls flame volume, is important. Generally, the wider the torch head, the more BTUs it puts out.

Finally, running a torch on a regulator with a bulk propane tank of 20 pounds or more is where you get the most BTUs as well as control from a torch. The adjustment knob on a torch is barely more than an On-Off valve. The disposable bottles are low pressure.
A 20 pound propane tank initial purchase runs about $45. Exchanges are around $20 from then on. If you belong to Costco/Sam's/etc. the exchanges are around $16.
You probably have a propane tank already for your grill, or empty ones can be found at yard sales for a few bucks. Buy an empty tank (it doesn't matter how bad it looks) and exchange it for a full tank for $20. ​

The best hand held torches are barely big enough for a small forge. The best on the market for a small forge is the Brenzomatic TS800,which puts out around 20KBTU with MAPP gas. They run around $90 today. Other fancy sounding disposable bottle torches may sell for more, but some only deliver 3KBTU/hr.

This is why I suggest buying an Atlas burner setup from Charles, at Atlas Knife and Tool. They come with a burner, hose, regulator, (some have a regulator gauge) … all for about what you spend for a cheap hand held bottle torch. You can pick different size burners from him to meet the needs of your forge - 30K, 100K, 150K. The complete kit for a 30KBTU burner is $60
http://www.atlasknife.com/product/atlas-30k-burner/
Click to expand...
Awesome Information! thank you i will check them out! stoked we are! Aloha
 
Stacy E. Apelt - Bladesmith said:
The best on the market for a small forge is the Brenzomatic TS800,which puts out around 20KBTU with MAPP gas.
Click to expand...

I suspect that's the torch I've got - Bernzomatic TS8000? Is that 20K BTU with the true MAPP gas that was discontinued in 2008? OR, the replacement MAP-Pro gas that's available today? I've used both the replacement MAP-Pro gas and Propane and can't really tell all that much (if any) difference. This is NOT in a small forge, but general heating, soldering, etc.

edit: I just found the info: BernzOmatic® TS8000 Max Heat Torch, 12327 Btu/hr MAPP, 12936 Btu/hr Propane, Cast Aluminum

https://www.nhbragg.com/2991714/pro...tu-hr-mapp-12936-btu-hr-propane-cast-aluminum

Darn, that doesn't make sense, it shows Mapp = 12,327 btu, with Propane as 12,936 btu - and a couple of times on the page linked it shows this same thing. I wonder if they got the numbers reversed? Even if so, 600 btu isn't enough to worry about.
 
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