I want to make a new forge that will be efficient, borax resistant and will have a welding temp.

The body will be made with a 20# propane tank. The insulation will be 2 inches of wool, Kast-O-Lite and Metrikote. Thank you Wayne for the good advice.  The front and back opening will be closed by insulated brick.

I want to use my Oliver burners, see the thread : https://www.iforgeiron.com/topic/51613-oliver-upwind-burner/

The small ones are ¾ inch while the big ones are 1¼ inch

Here are the pictures of the burners and their flame

The small one :

The big one :

Small vs. Big :

 

My question is what would be the best burner's set-up for that forge ? Should I put, 2 small, 1 big or 2 big ???

Sounds like you have the construction down pat. What's the interior volume? I'm not going to go out and measure a propane tank to do the math. 

The 1 1/4" burner will be more than it needs but you can always turn it down. Two 3/4" burners should be enough but not knowing the internal volume I can't say for sure.

Frosty The Lucky.

14 minutes ago, Frosty said:

What's the interior volume? I'm not going to go out and measure a propane tank to do the math. 

Between 480 and 560 cubic inches depending on the thickness of wool I want to put

 

The general rule of thumb is one each well tuned 3/4" burner for every 300-350 cu/in. Two 3/4" burners is overkill but within reason and will make for even heat throughout the chamber.

A 1 1/4" burner is about equivalent to four 3/4" burners and the flame would be concentrated in one spot. I'd call that unreasonable overkill.

Frosty The Lucky. 

And I agree; it is total overkill. One 3/4" burner, with that flame, should bring a forge, properly constructed from a five gallon (20 lb.) propane cylinder to yellow heat. If you wanted more even heat throughout, you would need two 1/2" size burners (of that potency).

32 minutes ago, Frosty said:

I'd call that unreasonable overkill.

Frosty The Lucky. 

Thanks Frosty.  That's what I was looping for

So, It'll be 2 x 3/4

Openings and base done !....  Next burners posts.

Refractory cement and infrared reflective paint have arrived. Tomorrow, holes for burner supports, wool installation and cement layer.

Thank you Wayne !

We'll patiently await pics. 

Frosty The Lucky.

I'm new here. I have the same tank, I got it today to make a forge. I've been reading and reading! I'm so glad I saw this thread!! Eagerly waiting for more pics!

I do not have time to do all i want....

I only installed the burner ports. I use electric box nipple. To hold the burner, I take selftaping screw and once the hole drilled, I cut the tip and put the screw back. This holds everything in place.

On 8/28/2017 at 9:11 PM, cbrianroll said:

I'm new here. I have the same tank, I got it today to make a forge. I've been reading and reading! I'm so glad I saw this thread!! Eagerly waiting for more pics!

Welcome aboard Brian, glad to have you. If you'll put your general location in the header you might be surprised how many of the gang are within visiting distance.

Coming along 450. More pics please.

Frosty The Lucky.

Those burner holders are zinc plated.  Not likely a great idea there.  They may or may not get so hot that it causes problems but it's best to avoid the risk.  Strip the galv before the final assembly.  You don't want zinc poisoning sneaking up on you when you do some long hot forging.

Or I might be missing the point if they're just "placeholders" for something else later.

On 2017-08-30 at 2:44 AM, Kozzy said:

Strip the galv before the final assembly.  You don't want zinc poisoning sneaking up on you when you do some long hot forging.

Don't worry, it will be 

Don't forget to rigiddize your insulation.  Cheap and easy

One more step done !  2 inches bottom + 2 inches all around.  Tomorrow : Kast-O-Lite !!! 

I applied the Kast-O-Lite, it went well but I concluded that I should have done it on 2-3 days instead of the same day.

I should have done the third part of the bottom, wait until it is dry, turn a third, repeat for a third and finish the last third.

To think that it is quite dry and to continue quickly is a mistake IMHO.

My result looks OK, but the next one will be done with the sequence of thirds.

The only way people build a forge, without thinking about how they would do better next time, is to thoroughly understand a well mapped out plan, and to follow it exactly, down to listing down each step before starting construction. This is very hard to do, no matter how good our intentions are. It flies in the face of the very creative urge that drives us to build the equipment in the first place Shrug it off, and move on.

I remember drilling out some pop rivets and adding some more insulation wool at some point during my last build, then finding I was out of rivets to close the shell up again. Looks familiar this learning curve thing.

 

I hope you aren't planning on using anything larger than two 1/2" burners; not with those flames.

@Mike my plan is 2 X 3/4 burner... I will put a valve on each, so I will be able to use just one... or 2... if needed.

As you can see trying to roll 2" thick blanket makes large wrinkles, 2 layers of 1" are smoother, easier and easier to rebuild down the road. Rushing is almost always a mistake. I screwed up  my last forge by laying the KastO-L-ite floor and not waiting long enough to flip it over and line the roof. The floor in that forge bulges enough I can't make partitions to size it so it's 2x larger than I need for 90% of what I do.

Yeah, stripping the galvy off those fittings won't hurt a thing. They may not get hot enough to burn the zinc but better safe than sorry. I have a category of: actions, tools, equipment, etc. I call. "Can't hurt, might help" A motto I live by is: "It's better to have it and not need it than need it and not have it."

Frosty The Lucky.

3 hours ago, Frosty said:

A motto I live by is: "It's better to have it and not need it than need it and not have it."

Frosty The Lucky.

Mine is : «I am too poor to buy bad quality»

Tonight : Kast-O-Lite touch-up... 

 

How about: "It is generally better to buy top quality used tools than low quality new ones!"

26 minutes ago, ThomasPowers said:

How about: "It is generally better to buy top quality used tools than low quality new ones!"

We're at the same place.