Forges 101

[AngryDaddyBird]

Because it works so well I already have plans on the next build. Stainless housing, stainless burner and stainless wrapped hoses. I’ll build a stainless stand somehow. Even though I had burners already I been trying to figure out how to make a burner similar to the torch head I made. Getting stuck on ideas. 

[Mikey98118]

If that's what you want, I would suggest building a 3/8" size burner; these take a 1/2" size pipe or tube. You will find a cylinder-mount 3/8"  Mikey burner a few pages back in Burners 101, or you can down size any other design you like instead. The point of stopping with this size is that, because the have such a long turn down range, going any smaller makes no sense.

[AngryDaddyBird]

I’ll take a look at that burner. I do have a few atlas burners I may use. 

[AngryDaddyBird]

On 1/15/2019 at 5:15 AM, Mikey98118 said:

It is always good to point out that what is needed to make a great little forge like this can be considered a minimum. 

For my micro forge items needed would be:

1)large family size pork&beans can or similar size can. 

2)Kast-O-Lite 3000

3)Koawool 1” thick

4)Metrikote

5) high power propane torch or build yourself a micro burner like the 1/2” T-burner. That’s pretty much itfor this build I did. 

[AngryDaddyBird]

 

Mods if I’m posting this in the wrong place please let me know or just delete it and I apologize.

Here’s another pretty simple one I made after the Micro forge. It’s been drying for 7 days now. I have to put the burner on it and it’s ready. I attached the Atlas 30k with atlas regulator hose but think I’ll try my modified torch first?? I think its ready anyway???

This Build was made with these items:

1) housing (4” steel square tube”) 14.5” long 1/8” wall thickness  

2)Kast-O-Lite 3000

3)Metrikote (this was the final chamber coat)

4)2 steel 3/4 bars 12” long and 1/8” thick bent at the 4.5” mark from each end to make legs

5)nuts12), bolts (4)and lock washers(8) to attach legs  

6)burner, I haven’t decided what burner to use? I was planning to use my modified torch head but think I might just use my atlas 30k burner assembly? 

7)2.5”-2.75” tube( I used a 2.5 outer diameter pipe for the burn chamber

The build was easy enough.

Fist cut the square tube to length. Then locate and mark where your leg bolts will be. Then mark your burner location. Drill all holes. Important to do this next 2 steps! Install the bolts for your legs! Either seal or put a tube into the burner port till it reaches the chamber pipe! Ok now seal one side of the housing (square pipe) with blue tape. Now flip the sealed side down and coat your chamber pipe with oil or pan! Now center your chamber pipe in the housing (square pipe) making sure it’s centered on both ends! The pipe needs to be longer than the square tube housing! Mix up Kast-O-Lite 3000 to texture like mortar and start packing it in around the pipe and ever 2/3” be sure to pack it down nice and good! I tamped it with a wooden dowel every 2-3” until ful to the top and level. Leave it a couple hours to set up firm then you’ll be able to move it to a better place to cure. You might want to remove or at least twist the pipe to get it out easier but I left mine in until the next day. After a day I twisted the pipe and it did. So after a day I decided to take the chamber pipe out. It took some time but it came out without damaging the chamber! I mean it TOOK SOME TIME! But hey it’s only my second attemp at a forge! After the pipe was out I peeled off the blue tape from the opposite end and let it dry another day by the heater. After dry I mixed the Metrikote with water until it was like latex paint and coated the burn chamber and both open ends. I let it sit for DAYS Next to my garage heater and today is Day 7! So I think I can try to fire it up starting at low heat for few seconds or minutes eventually bringing it up to forge temps over a few hours time OR I could just wait another few days or a month to be sure it dries haha! Anyhow I still have enough supplies to make yet a third forge. I’ll really think about it before I do. Now when making this one I didn’t think much about heat reaching the outside housing as you can tell by the thin walls haha. If I had to do this build again I’d use 6” diameter square or round pipe  to make sure the outside walls wouldn’t get to hot. I’m sure any forge eventually get veryhot but I think this would have helped. So what size is this thing considered? Micro or mini? How about “Micrini” like Mee-Cree-Knee haha. What burner will I use? Well I might just use my torch but at use my atlas burner instead! It fits right in there perfectly as seen in a picture. But who knows. All I know is it might be full of flaws but thought you’d all enjoy see my mistakes so you don’t make them same ones. I’ll keep you all updated when I fure it up! Enjoy the pictures! 

 

 

[Another FrankenBurner]

There is a heat cycle to finish kast o lite.  Most people let it dry for a week or so and fire their burner for a minute and let it cool, then 2 minutes, then 5, then 10, and so on.  I did something similar with mine and it turned out well.  Just don't turn the burner on full blast and let it go as the water escaping quickly causes problems.  If my forge has sat for longer then a few days, I also start up slowly as I once read that refractory materials absorb moisture.  

It sounds like this forge does not have the 1" of ceramic blanket that your can forge had.  This adds to the mass and reduces the insulation which will require more fuel to heat and may lower your temperature limit.  It looks like you have a higher output burner to heat it so it may not matter if you don't care about fuel usage.  Your outer shell may also get quite hot.  I look forward to your update to see how it performs.  

[Frosty]

You're over doing the cure time and heat cycles guys. KastOLite does not dry, it is a water setting refractory and for maximum strength treat it just like concrete. After it sets keep it at 100% humidity for as much as 7 days. Also like concrete the wetter it's mixed the weaker it is when set. 

Once it's set and you've given it a day or two at 100% humidity to cure. (I sealed mine in a plastic trash bag with a few soaked rags) Once cured fire the burner for a minute or two stop shy of red heat and let it cool. Fire it and let it soak for a bit at red and let it cool. Then you're good to go.

None of us cares about getting maximum physical strength from Kastolite 30, we're not running rail cars full of scrap over it. 

As for observing "proper" set and cure procedures the stuff is intended to trowel or gunnited onto furnace walls  that have only been shut down and cooled enough men in aluminized suites can make repairs. 

The stuff doesn't require careful handling at all, just don't get silly.

AngryDaddyBird:  I'd be concerned about the round chamber in the square shell, the large difference in liner thickness being the issue but I don't think Kastolite cares all that much. The aggregate in the mix is there to allow steam to escape and movement during thermal cycling.

Again the refractory is water setting, it does NOT dry so any moisture is the product of condensation and capillarity WILL draw it into the liner proper. You can't keep it out so it needs a way to escape. 

Frosty The Lucky.

 

[Mikey98118]

2 hours ago, Frosty said:

Again the refractory is water setting, it does NOT dry so any moisture is the product of condensation and capillarity WILL draw it into the liner proper. You can't keep it out so it needs a way to escape. 

It should probably be okay on this issue. The tube will always expand faster and farther than the refractory does, creating room to vent steam.  If there were end pieces on the forge shell, that would be more of a concern, and a vent hole would then be a good idea. As things stand, I think he's alright.

[Another FrankenBurner]

5 hours ago, Frosty said:

I'd be concerned about the round chamber in the square shell, the large difference in liner thickness being the issue

What issues would this cause if it were a material which cared?  Differential expansion top/bottom/left/right vs the corners?  

[Mikey98118]

One of the design factors I like about both forges, is that he has arraigned for the flame to enter the forge a little high, so that it can miss small parts, giving it time to finish combustion before impacting on work pieces; little details like this can make a big difference in how well a forge functions.

[AngryDaddyBird]

14 hours ago, Another FrankenBurner said:

There is a heat cycle to finish kast o lite.  Most people let it dry for a week or so and fire their burner for a minute and let it cool, then 2 minutes, then 5, then 10, and so on.  I did something similar with mine and it turned out well.  Just don't turn the burner on full blast and let it go as the water escaping quickly causes problems.  If my forge has sat for longer then a few days, I also start up slowly as I once read that refractory materials absorb moisture.  

It sounds like this forge does not have the 1" of ceramic blanket that your can forge had.  This adds to the mass and reduces the insulation which will require more fuel to heat and may lower your temperature limit.  It looks like you have a higher output burner to heat it so it may not matter if you don't care about fuel usage.  Your outer shell may also get quite hot.  I look forward to your update to see how it performs.  

I was going to use the 1” wool like my micro forge but decided to save it for a bigger forge. I did the The cycle curing with my first forge and plan on doing it again. As for the hot housing I figured it be hot that’s why I made legs.  But it was more of a last minute build. I do have the atlas 30k and others to play with in it. I’ll keep this updated. 

7 hours ago, Frosty said:

You're over doing the cure time and heat cycles guys. KastOLite does not dry, it is a water setting refractory and for maximum strength treat it just like concrete. After it sets keep it at 100% humidity for as much as 7 days. Also like concrete the wetter it's mixed the weaker it is when set. 

Once it's set and you've given it a day or two at 100% humidity to cure. (I sealed mine in a plastic trash bag with a few soaked rags) Once cured fire the burner for a minute or two stop shy of red heat and let it cool. Fire it and let it soak for a bit at red and let it cool. Then you're good to go.

None of us cares about getting maximum physical strength from Kastolite 30, we're not running rail cars full of scrap over it. 

As for observing "proper" set and cure procedures the stuff is intended to trowel or gunnited onto furnace walls  that have only been shut down and cooled enough men in aluminized suites can make repairs. 

The stuff doesn't require careful handling at all, just don't get silly.

AngryDaddyBird:  I'd be concerned about the round chamber in the square shell, the large difference in liner thickness being the issue but I don't think Kastolite cares all that much. The aggregate in the mix is there to allow steam to escape and movement during thermal cycling.

Again the refractory is water setting, it does NOT dry so any moisture is the product of condensation and capillarity WILL draw it into the liner proper. You can't keep it out so it needs a way to escape. 

Frosty The Lucky.

 

Some good info. 

4 hours ago, Mikey98118 said:

It should probably be okay on this issue. The tube will always expand faster and farther than the refractory does, creating room to vent steam.  If there were end pieces on the forge shell, that would be more of a concern, and a vent hole would then be a good idea. As things stand, I think he's alright.

I almost covered each end but didn’t because I figured it needed the open end to try and air it out and help expansion. But I obviously don’t know much at all. 

1 hour ago, Mikey98118 said:

One of the design factors I like about both forges, is that he has arraigned for the flame to enter the forge a little high, so that it can miss small parts, giving it time to finish combustion before impacting on work pieces; little details like this can make a big difference in how well a forge functions.

That’s exactly part of the reason I did that. The other is to try and get the flame/heat to swirl in there like my micro forge does and that one dies it very well! I already got a 6” square pipe and if I can find one I want some kind of round refrigerant tank. But no luck finding one. I may just wait until I can find one or justuse the 6” square?? Either way the next build is being built like my first one. 1” Koawool then kast-o-lite, ect. I do want to try and keep the flame swirling if at all possible. I rather not it boast directly on whatever I put in the forge. I’m not forgewelding(yet) so I’m not after welding temps. 

[Mikey98118]

Non-refillable refrigerant tanks from air-conditioning contractors, non-refillable helium tanks from party stores, bladder tanks from old hot water heaters. and half a car muffler are all candidates for such mini-forges. 

[AngryDaddyBird]

5 hours ago, Mikey98118 said:

Non-refillable refrigerant tanks from air-conditioning contractors, non-refillable helium tanks from party stores, bladder tanks from old hot water heaters. and half a car muffler are all candidates for such mini-forges. 

I’ll look into those. 

[Another FrankenBurner]

Call around to the HVAC service and restaurant appliance repair companies in the area.  You will probably find some refrigerant jugs for free with a few phone calls.  They may insist on drilling a hole in the tank or cutting off the valve, this is for liability to prevent using the tank as a pressure vessel.  If so, ask them to drill the hole in the top or bottom as you would be cutting that section off anyway.  

That is what I do for a living.  If you happen to head to the Boise area, I can give you several.  

If you get one, the jug may still contain a small amount of trapped refrigerant.  It should have been reclaimed/evacuated but be cautious of it still.  If you burn refrigerant you can produce some bad/toxic gases.  Open the valve and make sure it has no pressure.  If it does, return it and advise the company.  The cylinder will have a safety blow disc on the top.  It is easy to center punch through or drill through as it is thinner then the rest of the cylinder.  With the valve open, push some compressed air into the hole you made so it sprays out the valve for a few seconds.  You are now safe to plasma, grind, weld on the cylinder without possibly producing poisonous gas.  Don't be scared away by this, it is easy to be safe.

The only other caution I have read is about the paint on the cylinder.  I have read that during removal, the paint dust is an irritant.  I don't know it to be true but I wear a respirator and do it outside when removing the paint.  I found a wire cup brush makes this a fairly easy task.

The cylinder is 9.5 inches in diameter.  If you use 2 inches of ceramic wool and a half inch of kast o lite and metrikote, you end up with about 4.5 inches ID by 12 inches (190 cu in).  I do most of my forging in this sized forge as it is small enough to not be too fuel hungry but big enough to accommodate a lot of different projects.  If you worry of shell thickness, you can ask for the jug to be R-410a refrigerant for a thicker shell.  I don't worry about it though, any refrigerant cylinder is plenty thick to support itself and burner mounts and makes for a lighter forge. 

 

[Mikey98118]

After making the exhaust openings, I fill cylinders half way up with charcoal and light them off in a safe area; that pretty well takes care of old paint. Afterward a wire disc in an angle grinder rapidly gets things down to bare metal

[AngryDaddyBird]

12 hours ago, Another FrankenBurner said:

Call around to the HVAC service and restaurant appliance repair companies in the area. 

I just drove through Boise almost 3 weeks ago! I do pass through every month or so and I’ll contact you!

Good info on the tanks! It sounds like the perfect size for my intended use! I like the chamber of 3.5”-4”x12”-15”

and sounds like those tanks are a winner!

11 hours ago, Mikey98118 said:

After making the exhaust openings, I fill cylinders half way up with charcoal and light them off in a safe area; that pretty well takes care of old paint. Afterward a wire disc in an angle grinder rapidly gets things down to bare metal

Sounds easy enough. Better than taking a torch to it!

[Another FrankenBurner]

Sounds good.  Let me know how many you want ahead of time so I keep them, as we normally scrap them.  They will have been properly evacuated and purged when you get them.  

[AngryDaddyBird]

4 hours ago, Another FrankenBurner said:

Sounds good.  Let me know how many you want ahead of time so I keep them, as we normally scrap them.  They will have been properly evacuated and purged when you get them.  

Sounds like a plan! I’ll let you know in advance. Won’t be for another month or so. 

[AngryDaddyBird]

Here’s the flame. Looking better after playing around and adjusting depth ect. It get very hot!! Pictures are from start just out to full power! Also a picture showing flameout the back and front. Is it looking ok?? I never had a production firge so have nothing to compare to?

[Another FrankenBurner]

Based on the large exit flame at the burner end of the forge and the small exit flame at the other end, I would guess that a lot of your heat is coming out of the burner and blowing right out the front door.  It may have been hotter if the burner were closer to the center of the forge.  I finally went and looked up the atlas burners you were talking about and see that your forge looks similar to theirs, in terms of burner placement.  Perhaps aiming it more towards the rear would cause it to push more heat that direction.

The atlas forge looks to be lined with drilled out soft fire brick.  Depending on which firebrick they used, it's durability may be very poor.  I am also not the biggest fan of their burner design.  I don't own any of their stuff, so I have no clue about them.  Based on your burner, I'm sure their forges get hot enough to work, they just need more fuel to get the job done.  In smaller forges, this probably matters less to people.  

That said, your forge looks hot.  Nice job again.  Don't mind my rant.  If you are happy with your forge, it's a good tool.

[Mikey98118]

You would get more heat if you could get a neutral flame; that will take more secondary air. On the other hand, your work is probably coming out of the forge with a lot less scale. Also, you haven't put a brick wall in front of the openings yet; that would also raise forge temperatures. Not that they aren't in good shape, but you could get a little more, if you want it.

[AngryDaddyBird]

49 minutes ago, Another FrankenBurner said:

Based on the large exit flame at the burner end of the forge and the small exit flame at the other end, I would guess that a lot of your heat is coming out of the burner and blowing right out the front door.  It may have been hotter if the burner were closer to the center of the forge.  I finally went and looked up the atlas burners you were talking about and see that your forge looks similar to theirs, in terms of burner placement.  Perhaps aiming it more towards the rear would cause it to push more heat that direction.

The atlas forge looks to be lined with drilled out soft fire brick.  Depending on which firebrick they used, it's durability may be very poor.  I am also not the biggest fan of their burner design.  I don't own any of their stuff, so I have no clue about them.  Based on your burner, I'm sure their forges get hot enough to work, they just need more fuel to get the job done.  In smaller forges, this probably matters less to people.  

That said, your forge looks hot.  Nice job again.  Don't mind my rant.  If you are happy with your forge, it's a good tool.

I don’t mind any feedback! Thanks

47 minutes ago, Mikey98118 said:

You would get more heat if you could get a neutral flame; that will take more secondary air. On the other hand, your work is probably coming out of the forge with a lot less scale. Also, you haven't put a brick wall in front of the openings yet; that would also raise forge temperatures. Not that they aren't in good shape, but you could get a little more, if you want it.

I had the brick 1/4 away from the rear opening. But I also add a lip to keep the rear ending closed a bit more than the front. The flames out the rear and Fron are almost equal in amount. The burner is faced towards the rear but When I angle the burner even more that way flame only comes out the rear. I tried closing the ends withbricks and it seems to hold heat but the way it’s burning now is very hot. I know now what your saying about neutral flame. I can get it to do that when I pul the burner out and leave a gap for air to come in with the flame. But it actually took longer to heat up and when I put anything in the chamber it blowed the flame back out that gap. Likeghechamber is pressurized. Weird. The forge gets hot! I have a 6” square pipe same length as this forge and I think I’ll use it and put this little one in the6” one but first wrap it with Koawool. Maybe that will help it retain some heat? Not that I think it needs it because it gets way hotter than my micro forge!

[Mikey98118]

I think the design you went for has big advantages, but will also create its own limits; nothing is perfect. You have a winner here. If you want to experiment, I would suggest coffee-can or half-muffler forges, with 3/8" homemade burners. I think you would be very good at that. You started out with a highly successful forge; I don't think you would get much of a kick out of incremental improvements to it; that is slow work.

[Mikey98118]

To buy or build?

Buying can be the right choice for several reasons. But sticker shock isn't the only or even the main downside to it. I think a lot of people suspect that buying the right forge takes almost as much research as building the right forge; they are right too. But just as with building decisions, some are more fatal than others.

When you purchase a forge, you are stuck with the burner(s) that come with it. Presently, only Chile Forges come with first class burners. The burners in other brands range from merely acceptable to outright dreadful. However, most forge burners are replaceable; this gives you plenty of time to upgrade afterward. If a forge has we;ded in burners, keep on looking.

Refractory is a consumable, which is why most commercial forges have replacement kits available; so, you have plenty of time to learn what your doing, and upgrade that too.

Bad design is not something you can replace later on. Some of the best known forge brands have designs that haven't changed in fifty to seventy years; that is simply too much of a problem to overcome. How do you keep from ending up in this trap? Turn a deaf ear to  people complimenting a forge brand. Only listen to complaints, and then think them over long and hard.

[AngryDaddyBird]

23 hours ago, Mikey98118 said:

I think the design you went for has big advantages, but will also create its own limits; nothing is perfect. You have a winner here. If you want to experiment, I would suggest coffee-can or half-muffler forges, with 3/8" homemade burners. I think you would be very good at that. You started out with a highly successful forge; I don't think you would get much of a kick out of incremental improvements to it; that is slow work.

I thank you for encouraging  words.  I’ll do just that. Okay aroundwith coffee can or muffler firges and small burners!