Shape of gas forges

[Justin Topp]

I apologize if this has been posted before. Please redirect me If so. Should a forge be  a box or a cylinder shape and what is more efficient? or does it not make much difference.  

[Frosty]

I'm not being flippant nor dismissive when I say your question is like asking what's the best vehicle to buy? It's too general a question for a meaningful answer and we like to help folk. 

Here are some factors to consider in your question: What kind of work would you like to do? If you want to make blades than a cylinder works nicely, you can orient the burner to induce a strong vortex for even heat through out. However if you wish to do ornamental work you might want a more open volume either wider for say scrolls or taller for more 3D projects like wall sconces. 

Some work you don't really need or want even heat having a hot spot in the forge allows for easier riveting or sharp bends.

It goes on and on.

Frosty The Lucky.

[Mikey98118]

Size if the forge also depends on what you want to use it for.

Your question is a good one, as it shows that you understand that you don't know enough; this places you ahead of others who assume that they do

[Irondragon Forge ClayWorks]

Our first forge is a twenty pound old propane tank. It has served well, however somewhat limited in the shape of the project being made. The next forge we build will be an oval or half oval for a little more width.

[Justin Topp]

Thanks frosty! 
sorry for lack of detail. I’ll give some more now. 
 

im looking to do decorative more than knives but an occasional knife. Hammers are something I’d like to do more often 
Im using a ribbon burner. Square might be better

 

just trying to get all the info I need

[Frosty]

HEY, that's two apologies in two posts!  CUT IT OUT! 

I wasn't twitting you it was a decent question for not knowing what to ask. 

You'll probably want a larger forge, in the 300-350 cid range about tops for a 3/4" NA burner. I'm not a big fan of cylindricals but it's a personal choice. I like D or mailbox shaped forges, they give you flat floor and the round walls and roof promote vortex in the flame and the IR is sort of focused on the floor. (maybe)

On the other hand if you don't know what you want then a brick pile forge might fill the bill. This is a refractory table top you stack IFB (Insulating Fire Brick) in whatever shape forge you want or need.  I build brick pile forges when experimenting with burners, or size and shape of forges. 

Another advantage of the brick pile is the openings. Being as it's all on a flat surface doors are as simple as blocking the opening with a IFB and getting forge openings right can be tough to get right so it's nice to be able to adjust things.

Then once you know what works for you you build a more permanent forge. KEEP those bricks though! You never know when a new project will come up and it sucks to have to build a permanent forge for a one off project or one that turns out to be a dud.

Frosty The Lucky.

[Justin Topp]

thank you! I think I’ll do that and try some different configurations with ifb 

[Frosty]

You're welcome, it's my pleasure to pass my mistakes along so you can make new ones that weren't even possible when I was picking this stuff up.

I realize I forgot an important detail. Regular IFB isn't rated for typical propane forge temperatures and doesn't take rapid thermal cycling well usually beginning to crumble in a couple firings and turns to gravel. Morgan Thermal Ceramics, K-26 IFB has a working rating of 2,600 f. and is insensitive to rapid thermal cycling. It's becoming more commonly available, check with a local HVAC service or supply and ask. If they don't carry K-26, they'll know who does.

It's the same for ceramic wool blanket refractories, check with HVAC service and supplies.

Frosty The Lucky.

[Justin Topp]

I’ll look for some tomorrow!

[Mikey98118]

4 hours ago, Irondragon Forge & Clay said:

Our first forge is a twenty pound old propane tank. It has served well, however somewhat limited in the shape of the project being made. The next forge we build will be an oval or half oval for a little more width.

Wat about a brick pile forge, if it's only an occasional need? Not that I'm arguing against your choice (just love oval and "D" forge designs), but your burner would seem very suited to a brick pile for occasional use...

[Irondragon Forge ClayWorks]

The only draw back to that is all the fire bricks we have on hand are soft kiln bricks, which don't hold up in the rapid thermal cycling of a forge.  We would have to buy some Morgan K-26 bricks. Everything to build a D forge is on hand.

[ThomasPowers]

One thing about gas forges is that they are pretty easy to make and have limitations on the work that can be done in them due to size and shape.

So instead of trying to get *one* forge and expect it to do everything. Get one that does well some of the things you want to do  and expect to build others as your needs change.

Think of it like Vehicles: would you try to buy *one* vehicle to win drag races, go off roading, haul gravel and carry a troop of Boy Scouts to camp?

[Justin Topp]

Alright thanks Thomas. I think I’ll m are a mailbox shaped own like Frosty suggested because it should suit most of my needs and i can always use the coal forge if i need to make something that wont fit in the gas forge. 

[Mikey98118]

I never heard it put better, Thomas