Is 17.2" (43cm) too much for a single burner?

[Combobulus]

I'm building a forge, and have already bought a single burner. I'm planning on using the core of a large hot water heater. The diameter is roughly 43cm wide (without the insulation.) With insulation it'll be around 30cm. I'll probably make it around 30cm long as well (I have well over a meter of length available). Is this too much for a single burner to handle? Burner is the basic Devil's Forge DFP burner. 

I was also wondering whether or not something like 2 layers of 2" insulation is too much for a forge, haven't seen or heard anyone mention it anywhere. 

Cheers

[Simian]

I'm sorry to say that that burner won't even get a forge that size warm. I have a devils forge with 2 DFP burners, it's about 5"x5" and 16" long. 2 burners will get this hot, but it's not great.

That's a huge forge, what are you planning? I'm relatively new to this (only a few years) and have learnt that smaller is better when it comes to forges - build the smallest forge you can realistically use. 

Also, put your location in your profile, it helps everyone with specific advice.

[Buzzkill]

On 7/30/2023 at 1:47 AM, Combobulus said:

Is this too much for a single burner to handle?

Way too much.   By my calculations you'd need 4 of them for the size of forge you have planned.

What you have described is a gas guzzling monster of a forge.  Unless you are planning to do production work where several people will need to be heating things in the forge simultaneously or you have a very specific need for a forge chamber that large you should seriously consider a forge with a smaller chamber.   Just because you have something you think would make a good outer shell does not mean you have to use it - or all of it anyway.

Everyone has their own preference depending on what they do, but for reference's sake my current forge chamber is about 23cm wide, 10 cm high at the apex (it's roughly half a cylinder), and around 20 cm long.  That's about one fifth the volume of the forge chamber you're planning to build, and your plan is about 3 times the volume that Simian is using 2 burners on.

On 7/30/2023 at 1:47 AM, Combobulus said:

I was also wondering whether or not something like 2 layers of 2" insulation is too much for a forge

It's hard to have too much insulation from a functional point of view.  However, there is cost associated with it.  The conventional wisdom is that 2 layers of 1 inch thick each is the point at which we get the most benefit for our money.  If you're just trying to decrease the internal volume of the forge chamber, you can add extra layers or possibly even use rockwool insulation for the outer layers and save the ceramic blanket for the inner 2 inches.  You can also consider using something else for your outer shell.  It doesn't need to be particularly robust.  The main functions are to keep the ceramic blanket contained, and to keep it from being damaged.  I've used sheet metal thin enough to be flexible for the outer shell on a couple forges and that's worked fine. You can build brackets from angle iron or other stock to support your burners/mixing tubes. 

I agree with Simian.  For a gas forge it's better to build the smallest forge chamber that will still allow you to do what you want to do.  That will save you money on the initial construction, but will save you a LOT of money in fuel in the long run.

[Mikey98118]

You have time and work invested in your way too large cylinder. Rather than scrapping your planes, consider building a "D" forge, instead of a tunnel forge; that puts it interior down to easily handled by one 3/4" burner (workable), or two 1/2" burners (a much better choice).

Yes, scrapping planes is a great waste; so are scrapping plans

[Irondragon Forge ClayWorks]

Like Mikey said, modify the plans to be a D shape. Then with 2 burners you could block off the rear portion with fire brick and turn off the rear burner. That way it will be more economical, to do most of the work with just the front burner. Then you could open it up for larger stock and turn on the rear burner. Seeing as the cost of propane keeps going up & up that would be important to me, being frugal as I am.

I can't control the wind, all I can do is adjust my sails.

 

[LeeJustice]

I have not had my tanks refilled for some months.  Nevertheless I have noticed that Ace and Wally world are at 20 bucks for an exchange.  Not too bad.

[Mikey98118]

cutting your forge's cubic area in half will more than cut your fuel bills in half.

During the time that you are only running one burner out of the two, that fuel bill will be quartered.

Finally excess flame heats up your shop; that can be a pain even in December; in July this could lead to foul language and a poor attitude

[Frosty]

Worse than foul attitude and poor language it gets REALLY FRUSTRATING when it's so hot out you cant keep your work hot long enough to get it to the anvil for sweat falling on it!

Frosty The Lucky.

[Mikey98118]

Good one, Frosty; nice word picture

[Frosty]