Jump to content
I Forge Iron

Advice Needed For First Propane Forge Build..Cylindrical Or Square?


MrMedieval

Recommended Posts

Hi everyone, i thought it best i start a thread in regards to getting the best advice and guidance to building my first propane forge.

I was thinking of purchasing a propane forge but i realised with a bit of time and effort i could build a much better forge and actually save a few hundred bucks along the way.

So the forge i want to build will be primarily used for medieval swords. but also other things like plant hangars, fire pits, steel gate's, etc.

I have a terrible sword fetish, most will be simply wall hangars, some for a medieval display and one or two for some backyard cutting.

I was going to build a square forge around 21"-25" long, 8"-9" wide...dimensions roughly based from a Majestic Forge..but after looking at the burner specs from a supplier they say the forge should be cylindrical in shape because there would be a deviation in function and performance?

One question I would love to ask is..would i need a 3-burner forge for what i need...or would a 2-burner forge be sufficient? 

I attached a mocked up photo of some steel i picked up after recently getting myself an oxy torch and brazing tips, gauges, etc and thought ooh this would be great for the forge..but again after reading the specs for the burners they say the forge should be cylindrical in shape for optimum performance. That's fine and everything..but it would be great to hear what you guys think..if i need to build cylindrical that's easy also. I can easily weld, drill and tap, cut steel, etc that's why in the end i would much rather build my own forge...and well as you all know building is great fun and it's something i really ,enjoy. 

I suppose my 2 biggest questions are cylindrical or square..and 2 burners or 3?

I was going to use an old beer keg i have which is 316 stainless steel, but it's too large and would need way too much insulation to fill it.

I thought i could purchase 2x9kg gas bottles and weld them together to 

I have a feeling I've almost answered my own questions..cylindrical with 3 burners might be the best choice...but would love to hear everyone's thought's on this and would greatly appreciate any help thank you. :)

 

steel for square forge?.JPG

2 burners or 3?.jpg

 

 

Edited by Mod30
Remove Copyright image
Link to comment
Share on other sites

Have you read through the Forges 101 section? The pros and cons of your ideas have been discussed many times over the years. 

There are a couple points you need to consider. First is forging and heat damage. You can only forge a few inches, 4-6 at a time and heating steel to near critical without refining the grain (crystal structure) causes embrittlement. You WILL lose steel to scaling (rapid oxidation) every time it is exposed to ambient air at red heat or more, the hotter the more loss faster. Then you lose carbon to oxidation at high temperature. 

Using a long forge seems to make sense working long stock but is rarely beneficial, even heat treating. How are you going to monitor the blade temp in the center of say, a 30" forge chamber? Single nozzle burners will ALWAYS produce a hotter zone nearer the burner. This can be mitigated by the fame pattern in the forge but it is still an issue. 

Another issue just occurred to me. How do you plan to keep a sword from sagging (bending) in or when you draw it from a horizontal forge? Of course, no matter what you do bending will be an issue if you hold a HOT sword horizontally. Lots of sword makers mitigate this issue by using a vertical forge but this leaves them climbing ladders, step stools, etc. with H O T steel to check or draw the blade for quenching, etc. 

Round or square isn't really much of an issue in a long narrow forge, tangentially aligned burners will swirly the flame on it's path out of the forge mitigating uneven heat to a degree. Lots of smaller burners is the simplest answer to uneven temps in long narrow chambers. Ribbon burners are just that carried to their logical conclusion. 

Those are the gross factors to consider where long narrow forges are concerned.

Damage to the steel through over heating without refining the grain. 

Supporting long projects.

Consistent even temperature and monitoring the work.

Safe handling while manipulating the stock.

Frosty The Lucky.

Link to comment
Share on other sites

Hi Frosty thanks for the reply.

I spent a bit of time going through the Forges 101 section..i guess i will have to do more searching but i never really found what i was looking for..guess i will have to keep digging.

Yep I'm aware i can only forge a few inches, 4-6 at a time all good there...but what made you think my forge is going to be 30" long? In my post i mentioned it would only be around 21" long.

My steel would not be sagging..forge thick grind thin and i have forged before..please remember this is  about building my first propane forge..not being a first time wannabe bladesmith/blacksmith.

If i was running a coke forge i never would have made an account here.

I'm 6ft 4" and have very long arms so i don't need step ladders to achieve a vertical quench, that would be an easy feat for me.

Good to know a square forge wont be an issue thank you.

I will spend more time reading through the Forges 101 section.

Moderators can delete this thread thanks.

 

 

 

Link to comment
Share on other sites

I will avoid the discussion of shape, since Frosty is handling it. Instead I would like to bring up steel forge shells; I'm a BIG fan of them...when their is good reason behind their use. Mainly, a forge shell provides external support of internal parts; this is primary. Providing a physical barrier to impacts is such a long way second that it should be vanishing in the distance.

  Why should this be so??? Because the main protection for your whole shop, and for the forge within it, is to keep animals, druggies, children, and morons out of it!

  You seem to be contemplating a box shaped forge; that's good, becuase in resent years insulating firebricks have come a looooooong way :)

  However,unlike tunnel, and "D" forges, every internal surface can be at true right angles to every other surface. So, there is ZERO good reasons to yes ceramic blanket as secondary insulation in an outer layer. Bricks, bricks, beautiful bricks are the refractory of choice. This is truly the time for brick pile forges to come into their own.

One of the advantages of this kind of forge is that they can very their shapes and sizes...unless they are contained in a metal box :(

Just don't go there; don't do that to yourself.

All a brick pile forge needs is some angle iron, or even flat bar, some nuts and flat washers, and the imagination to enjoy there surprising usefulness.

Link to comment
Share on other sites

Hi Mikey thanks for the reply.

I never would have thought of using bricks, i will look into them but bricks would be kind of heavy i think...but still i like that idea of using them still..good excuse to mount the forge on a trolley. 

I have plenty of angle iron and flat bar..hmm time for more searching and researching thanks again. :)

Link to comment
Share on other sites

I think Mikey is referring to Insulating Fire Bricks (IFBs) that are light weight, easy to cut and drill, and have really good insulating properties. If your fire bricks are heavy, then you've got the wrong ones.
They are often used for peoples first Propane forges, (which is why they are known as "Brick Pile" forges,) as you can build a square tunnel out of IFBs, which are held together with angle-iron and threaded-rod, and can get up a good heat.

The downside is that IFBs are not mechanically tough, and can easily crack due to thermal cycling.  There are brands (Morgan Ceramic) that are meant to be longer life, but if you seal the IFB surface with a decent flame-face coating (Plistex, Matricote, etc.) that protects the IFBs, they last much longer.

I think Mikey was suggesting that you could build any shape of forge you like out of IFBs and angle-iron, and easily try out what works best for you, and maybe not need a steel shell around it.

I built my first Propane forge out of IFBs so I could try out single-port and multi-port burners and see what size and shape of forge worked for me. It was only after that, that I designed and built an oval Ceramic-wool lined forge to take my multi-port burner, and that is now my go-to forge.

Hope this helps,

Tink!

Link to comment
Share on other sites

Sorry, I got lost in my own head and just grabbed 30" for purposes of discussion, my bad. 21-25" it is. I went back and re-read your OP again, correct me if I'm wrong. You wanted to know, round or square. And 2 or 3 burners. Yes?

As far as I'm concerned square or round aren't different enough to make a lot of difference. You might consider a D shape, it combines improved swirl with a flat floor. Check with the local propane supply company about picking up a couple out of certification or failed 9kg. cylinders. The two locally will let them go for scrap or gratis. They remove the tank valve with a torch to make sure it's out of commission permanently. Or just keep your eyes open at garage, yard, boot(?) sales. They're everywhere around here.

My NARB forge is nearly as large as you propose at just under 19" x 5" x 6 rectangular and is powered by two 3/4" T mixers screwed into home built ribbon burners. NARB stands for (Naturally Aspirated Ribbon Burner.) You can see more of NARB in the "NARB Lives" thread. The NARB burners do not put out as much heat as the same mixers as single nozzle burners. However the flame velocity is lower so the fire stays IN the forge longer to transfer more energy to the forge liner. I figure the difference is a wash.

If your main goal for this forge is heat treatment I'd go with 3 burners aligned to create a strong swirl in the chamber. Then use a muffle to heat treat in. If you aren't familiar a "muffle" in this case would be a piece or reasonably heavy wall pipe large enough to fit the sword blade inside and small enough to fit in the forge with sufficient room to allow free flame circulation around it. 

The muffle being thick walled heats reasonably evenly making a much more even and controllable internal temperature for the sword. 

I see I'm taking a long time replying and others are filling the gaps I'm not thinking of. Below is  picture of the brick pile forges our club built in a 2 day burner and forge build clinic. It's made with IIRC 10 Morgan Ceramics k-26 IFBs and powered with a single 1/2" T burner it's approx. 170 cu/in and reaches welding temperature in about 3-4 minutes from dead cold. Each IFB was buttered and Plistex was applied to the flame face only. The thermal baffles are 3,000f split hard fire brick because at the time split K-26 weren't available and nobody wanted to saw full k-26. Porches were made by simply laying full thickness brick in front of the ends.

This build is a collaboration there are things I would've done differently but they work very well as built, a few of the professional bladesmiths have all but retired their previous propane forges. A 1/2" T burner uses a little less than 1/2 as much propane as a 3/4" T.

Frosty The Lucky.

766103867_Noweldforge08sized.thumb.jpg.f581ea8495556570266ac2fdea1ad33a.jpg

Link to comment
Share on other sites

I should have mentioned Morgan K28 bricks. We have been using Morgan K26 bricks, but the increased temperatures that the latest home made burners are capable of creating indicate a need for tougher refractories. Both of these bricks are insulting and considerably lighter than regular firebricks. On the other hand, if you intend to employ the burners in your photo, Morgan K26 bricks are just fine.

Link to comment
Share on other sites

Many thanks for the replies everyone. :)

Thanks Tinkertim for letting me know the bricks aren't heavy, but in all honesty i would much rather use steel and insulate that because i already have the steel, but i will have bricks for the floor.

Thanks for the advice Frosty, i was concerned about heat treatment but the use of a muffle is a great idea. 

I recently saw a forge for sale online at amazon and was interested by the shape of it, it's neither square or cylindrical.

It's called Mr Volcano Hero 2. The reviews are really good for it, of course i wont be buying it for it would cost way too much to have it sent here from the USA but i like the design.

Basically i have the steel to easily make that shape, what do you guys think of that kind of set up?

Their supposed to be better than the Devil Forges that also resemble the Majestic Forges.

 

Screenshot from 2022-11-22 08-43-15.png

Link to comment
Share on other sites

1 hour ago, Mikey98118 said:

if you intend to employ the burners in your photo, Morgan K26 bricks are just fine.

Ooooh SNAP! Good shot Mike!

Mr. Volcano is excellent value for the dollar, one of the brothers who own the company is a member here and we've talked about them.

I recommend NOT using Satanite for the flame face refractory. Satanite is mortar and unsuited for use as a flame face. The manufacturer says so in so many words on their website in response to people asking and complaining about it as such. 

Plistex actually IS a high alumina flame face refractory and laughs at most anything a propane flame can throw at it. 

I also recommend using split K-28 IFBs for the floor further armored with Plistex. 

The rigidizer that comes with is good stuff, does what it's supposed to.

I really like this forge, two of the guys in our club have the single burner model and I can from personal experience they are HOT and well made. It'd be hard to make one this size for less.

Frosty The Lucky.

Link to comment
Share on other sites

I don't think most guys can make a forge for less; perhaps some super scroungers, with decades of accumulated stuff in their barn might, but their work to do so would still make it a poor bargain.

There are now so many good forges and good burners on the market, for good prices that building your own forge is only worthwhile as a learning experience, or to craft exactly the equipment you desire; most guys aren't interested in either one.

Of course I love those guys; the special fellows who let me lead them down to the deep end of the people's pool :)

But I realize that most people are practical, and just desire to get on the the job :P

This just ruins my fun; but, if the must, they must :(

2 hours ago, Frosty said:

Ooooh SNAP! Good shot Mike!

Nah; it weren't a shot, but if it had been it would have been a good sorta nasty :rolleyes:

I don't care what people decide to use; only that they make their decisions with their eyes wide open. Those burners are sufficient, and only a picky-butt would diss them. Oh wait...I is a picky-butt from way back, ain't I? :rolleyes:

Link to comment
Share on other sites

52 minutes ago, Mikey98118 said:

building your own forge is only worthwhile as a learning experience

Beg to differ, I managed to build mine for $150 total, thats, kaowool, refractory and regulator the shell was made from pieces of sheet metal from the scrap bin. A gas forge in New Zealand would have cost me $500 minimum. Although this is New Zealand and getting anything for a price that won't break the bank is nigh on impossible. 

Link to comment
Share on other sites

No, that was a shot Mike, I know a shot when I read one. You were just being subtle, you can't pull the wool over my eyes THAT easily. :rolleyes: 

That's pretty good Bayard, about what it costs me to make one and you live more remote than I do. Mike on the other hand lives within reasonable driving distance of some of the best salvage on Earth. When I started making my first forge and later the T burner $500 was a cheap forge a good forge was way more. 

When we say Mr. Volcano makes great value for the dollar we're speaking for ourselves, I'm betting shipping to NZ would push the price up a couple few hundred. 

Frosty The Lucky.

Link to comment
Share on other sites

Shipping close to doubles prices here. I built my 2"  72" belt grinder as part of a club grinder build clinic. I was using an under powered motor on it until I took apart our old dead hot tub, treadmill motors are okay but hot tubs have 3+hp motors driving the pump. Once you pick up ONE of most anything they seem to sprout and grow multiples. I got my next hot tub for the cost of the dump run to dispose of what I didn't take. Same for treadmills but I've stopped accepting them if it isn't at gun point. As it stands I have 5 AC motors over 3 hp. 

Scrounging and making things myself is sort of an affliction of mine. :ph34r:

Frosty The Lucky.

Link to comment
Share on other sites

13 hours ago, Frosty said:

No, that was a shot Mike, I know a shot when I read one. You were just being subtle, you can't pull the wool over my eyes THAT easily. :rolleyes: 

I wouldn't never do no such a thing :unsure: It may have just slip outta my bad boy side...:ph34r:

After  a couple years of running across his ads, and being astounded that he thinks they are doing just fine...it could have bubbled up from indigestion. You know, kind of like a gas attack, right? :rolleyes:

I mean, they could be much worse; instead of merely underwhelming they could have been malformed. Oh dang, you're probably going to call this another shot. Perhaps I should just shut up about his marginal burners...er, I mean his, uh... wait a while. I'm sure to find something positive to say on their behalf. They don't fall apart. See there is always something positive to say for every occasion. Next time I can say that they don't smell bad; yes, I'll hold that one in reserve :D

Link to comment
Share on other sites

I didn't disagree did I? I'd like to find one of the intake bells for an acceptable price to experiment with, maybe be able to help folk who have them get something effective going. 

I remember hunting in the Boeing R&M with Dad. When he we lived in Seattle he picked up Inconel to spin high end jet/rocket engine components, often sold them to Boeing. Later after moving to the San Fernando Valley in S. Cal, largely because it has a strong aero space industry we used to shop at an aero space scrap/salvage yard in Burbank. It had more cool stuff than a sci fi freak like me could drool over without severe dehydration risk. there were at least 30 Apollo capsules in various stages of dismantling, the Gemini and Mercury capsules were shells with a few danglies left. There was at least an acre of the spiked ball sea mines stacked 20-30' deep. It was crazy cool place. Dad picked up lots of stuff for the shop, mostly "Nu Die V" to turn permanent tooling from, he did a LOT of hot spinning and dies that could take an oxy acet torch on them all day was a good thing.

I envy you your access to aero space salvage, I can't even shop old auto salvage here. <sigh>

Frosty The Lucky.

 

 

Link to comment
Share on other sites

Actually, there are two different sellers of those same castings to buy from; they are both listed on Amazon.com. I will try to bring up their ads again, and post them here.

There are still two ads left on Amazon.com by one of the previous two sellers. Enjoy, Frosty.

MENSI High BTU Sand Casting Aluminum Venturi Burner 1"BSP Without Fittings DIY Commercial Industry Forge Burner Spare Parts 1 PCS $15.90

MENSI 1/2" BSP Aluminum Sand Casting Propane Gas Forge Venturi Burner Head Hardware Machining Industrial Heater or Boiler High BTU Parts $11.99

 

Link to comment
Share on other sites

So, how to improve these burners? Trap the next smaller size mixing tube in them, but drilling and threading several places for socket set screws, and putting an internal bevel in that end of the smaller mixing tube.

Why? because what is wrong with the present design is that their air intrances aren't large enough.

Link to comment
Share on other sites

Hi BayardStrachan i feel your pain in regards to shipping.

We are very remote from the USA that's for sure.

The Mr.Volcano Hero 2 forge has VERY good reviews, people have been really impressed with it.

What surprises me is the cost, it's a xxxx of a bargain and being made in the USA is even more appealing.

I'm actually torn between building my own now...hmm decisions decisions.:lol:

 

 

Edited by Mod30
Language
Link to comment
Share on other sites

Hi Mikey, with Amazon Prime they offer free international shipping, so would only be a total of $344AUD.

If i were to buy the 2 burners and the refractory materials here it would cost $448.

But i would need 2 offerings of the refractory materials so the cost would actually be $667 excluding shipping, so around $700AUD all up. 

The cost of the refractory materials alone cost more than the forge-$448AUD.

The only thing that might be a problem is the propane connection..would it actually fit the bottles we have here.

Even if it didn't fit, it would still be cheaper for me to have the Volcano shipped here and i simply change the connections to suit.

 

 

Link to comment
Share on other sites

It should be cheaper to build your own burners, than that; Should be depends on how much they want for local materials. Still, we can help you build very hot burners, if you wish. However, you will have time invested to decide what burner design is best for the materials available in your area, and to learn how to build the burners properly, and then to actually construct them. Thereafter, you will have to change out their flame retention nozzles about every six months, if you run your forge full time. So, what will work out best for you will depend on what building materials, such as pipe, and pipe fittings, including stainless steel couples (which might save you a lot of money and time, if used as flame retention nozzles). Or, you may want to just use stainless-steel pipe as the outer tube of flame retention nozzles, if you can buy small amounts of S.S. tubing or pipe at reasonable prices; it all depends on how reasonable material suppliers are in your area.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...