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Alex Middleton

Building a new forge. Thoughts?

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I'm currently working on designing up a new forge.  I put a different blower on my existing forge and it doesn't quite get it up to a welding heat.  There's a few things that I don't like about my old one, and it's in dire need of a relining anyway, so this is a good excuse to build a new one.  My plan is to make this one with a 5.5" inner diameter and 10" long. I'm thinking of squaring the bottom off using hard firebrick as a replaceable floor to keep from having issues with flux burning through my lining.  It would end up with an internal volume of right around 200 cubic inches.  I'm planning on making the entire thing out of 11 Ga. 304 Stainless.  I still have some design work to do on front and rear doors, but this is my initial concept:Forge2.JPGForge3.JPGForge1.JPG

 

I'm a little leary about having the brick tray in the bottom, but I think it'll hold up alright as long as I keep firebrick in there and don't try to run the forge without it.

 

 

Thoughts?

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I think rather than the brick, use kast-o-lite.  You can still make "bricks" out of it so they can be replaceable, but the kast-o-lite is much lighter and, more importantly, less of a heat sink.  

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That's a really good idea Alan.  I hadn't thought of that.  That would let me tweak the chamber some since I won't have to design around the fire bricks.  I'd prefer a smaller flat spot on the bottom to allow for a better swirl.

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Check out the Build a Gas Forge and the Ribbon Burner attachments on the Forge Supplies page at www.WayneCoeArtistBlacksmith.com.

Let me know if I can help you.

 

 

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I made a few tweaks to the design on this.  It's now 5" for the inside diameter and still 10" deep.  It comes out at right around 190 cubic inches of internal volume.  I incorporated @Alan Longmire's castable brick idea, as well as changed the angle of the burner tube to come up at 45 deg. angle instead of being horizontal to save space.  With any luck, I should be able to downsize the cart that my forge sits on and hopefully include my heat treat setup and 100 lb. propane tank along with it.

 

Assembly2.JPGAssembly.JPGAssembly3.JPG

 

 

It's a different configuration of the air/gas line than what I've used before, but if anything I would think that having the airflow do a hard 90 degree turn would allow for an even better air/gas mixture before entering the forge.

 

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I like it!  If the mix seems inconsistent, you can always add some pipe between the gas inlet and the 45 degree elbow.  I've even heard of, but never seen, people sticking a copper dish scrubber pad in there to really mix it up.  

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Interesting.  I wouldn't have thought of adding something inside to increase the mix.  I'm hopefully going to get everything cut out and formed before the weekend so I can get it fit up and welded.  I have to switch it to mild steel though, trying to get ahold of the stainless has proved problematic. 

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Alex, I like this design as well. I did a rather primitive home made forge years ago and ran my pipe as you are thinking I only did forging at that time and lacked real experience in materials, etc. But it produced a very good even heat in the chamber and little scale. (I also had I pointed toward the back a little, not sure if really necessary though). 

Now, I am building a new forge myself for forge welding, so I am pleased to see your post. I am also considering the pipe direction as you are because of weight and space. I have the ceramic-wool 2” and trying to decide on KOL or good old Satanite as a coating, maybe even Mizzou (even though it’s called a castable). I want something that will mix well and apply well to the blanket in the beginning and later if I need to patch, etc. I’d like to apply it with a flexible knife/spatula if possible.  

Any good input is basically what I am rambling about !! :wacko: 

 

Gary LT

 

 

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I used Satanite on my first forge and I would say it fits what you're looking for.  I did learn the hard way that you need to be careful during the curing process or you will cause massive cracks that are almost impossible to patch.  That being said I plan on using it on this forge as well.  I'm still undecided on a top coating like ITC-100 though.  I didnt use it last time and never really had cause for regret.

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Thanks Alex, I am leaning to Satanite. I assume it needs to dry out on its own and not be pushed by firing up? I am also thinking of ITC-100. 

Looking for a reputable supplier of both who would ship combined and on time as I pay prompt.

 

Gary LT

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Last time I used www.hightemptools.com and was extremely happy with their service.  There is a pretty detailed FAQ section that gives a clear cut curing recipe for the Satanite (I'll probably actually follow it this time), but basically slow and steady is key.  There is also Wayne Coe from this site who replied earlier in this thread.  I'm not sure if he carries Satanite but it would be worth checking out his site too.  I'm sure that theres others as well, I just dont know them off the top of my head.

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Do you want that pivoting/swing door on the front vs a hinged? Just seems like it could easily get in the way as a pivoting set up. I feel like a swing up/toward you door would work better. Never forged before, but just thinking of designs I've seen previously, and there must be a reason for the designs.

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I actually gave quite a bit of thought to that.  I have a bad habit of not thinking a process through all of the way and then having to adjust on the fly.  I can easily see myself needing to make the opening larger while the forge is already running.  I'd much rather be able to swing the door out of the way with a something then worry about having to open the door and manipulate a catch while the forge is blowing flames.  It'll actually probably run closed 90% of the time unless I'm doing something that won't fit through the opening.  On the rear opening I have a combination of pivoting and hinge. There is a smaller pass through port that hinges upward and then the rest of the door will swing out of the way if I need to open it up completely.  Honestly, I'm not even sure how well the doors will hold up overtime.  I may end up having to take them off and replace them will good old firebricks if they start to distort too badly.

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Got it welded up today.

 

20191109_213214.jpg

 

I need to grab a couple of fittings from the hardware and she'll be ready to finish up.

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Looks good Alex. 

On 10/28/2019 at 8:11 AM, Alex Middleton said:

 Honestly, I'm not even sure how well the doors will hold up overtime.  I may end up having to take them off and replace them will good old firebricks if they start to distort too badly.

Sorry for not chiming in earlier, but I just came across this thread.  The above was my main concern, but it looks like you've already thought about it.  

 

My only other concern (and you've probably already thought of this) is to make sure the brick tray is a bit shorter than the actual brick you use to help prevent someone from accidentally touching the hot steel frame.

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Good call Billy.  The tray should be a bit shorter if I remember correctly, I wish I could say I had done it for that reason though :D.  I did get in a hurry while I was assembling it and managed to weld the trays in upside down.  Now the bricks wont fit :angry:.  I haven't decided if I'm going to try and cut them off, or just go with it.

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3 hours ago, Alex Middleton said:

Now the bricks wont fit :angry:

If you have access to a masonry or tile saw, you can cut the bricks to make them fit. 

And maybe 1 1/2 bricks will give the tray clearance mentioned above.

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1 hour ago, billyO said:

If you have access to a masonry or tile saw, you can cut the bricks to make them fit. 

I do, and I'm going to go that route.  I would almost have to destroy it to get the holders off.  It just pisses me off when I realize that I didnt pay attention to something and then have to work around a preventable mistake.  Thankfully, since the bricks are just for a shelf, they shouldn't need to be replaced very often.

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1 hour ago, Alex Middleton said:

It just pisses me off when I realize that I didnt pay attention to something and then have to work around a preventable mistake

 

Welcome to my world....:rolleyes:

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I ended up redoing the plumbing to save space on my forge cart.  I just need to make sure that the blower is the first thing turned on and the last thing turned off.  It's always been my habit so it shouldn't be a big deal.

 

First real test fire to cure the initial coat of Satanite:

20191119_185739.jpg

 

I think I'm going to like this forge.  I was able to tune it down to the point that it just barely sustained a "tiny" flame.  It'll take some playing, but I'm thinking I may even be able to control it to the point that I'll be able to hold a low enough temperature for proper soaks during heat treat.  Time will tell I guess.

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Looks like a really solid build!!!! Well done

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