CoyoteGear

New gas forge build (pic heavy)

16 posts in this topic

Well I had everything set up to build this forge and then got side tracked with a forge off of e-bay that was only a few miles away, it ended up blowing out, Link below.

and I decided that I would finish the project I had started and one day possibly salvage the other one to have a monster forge!! But for now this little guy is all I really need. So sit back and enjoy some pictures and I'll take you through what I have done so far. Please feel free to offer guidance as this is the first forge I have built. I've just been going off of this page and learning as I go!

Step 1, get a shell, I scored this old air tank at St. Vincent for $3 its the same size as a 5 gal propane tank but it had an extra valve and no fear of blowing up from a spark when I cut into it. WIN WIN!

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I took some 1" square tube and welded it on as feet so Harrison Forge could stand on his own, these will be visible when we move down and he gets flipped over.

For my first layer of insulation I used 8# 1" thick 2700 degree Inswool HTZ from HighTempTools. It's doubled up in this photo.20160405_202817.thumb.jpg.18615f98601dc9

I used a K28 kiln brick for a floor. Side note. I layed down a layer of kast-o-lite under the brick to give it a flat surface under it, you can kind of see it on the left side of the brick here.

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And a packed in a bunch more Inswool, I used 2x 1" pieces, and packed the scraps in around the front and back of the brick.20160405_210318.thumb.jpg.b8fa72fd525f58The back side, which I think will become the front because I like the big open hole... Giggity.20160405_210324.thumb.jpg.af920b5963a4b8

I had some K24 kiln bricks that I was just going to stack as the doors but then decided to take a little extra time and weld up some brackets to hold them while I had everything out and was in fab-mode.

Door's being measured out. I wanted them to stay on the bracket when full open. A top bracket will be added for extra stability later.20160406_083743.thumb.jpg.de6f8a5b238012

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Now to get my supports measured with my super high tech method of "Calibrated Eye" and prep them for welding on the belt grinder.

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Now it's time to set them up and weld them in place on the forge. Weld area preped!20160406_084541.thumb.jpg.218836c021e897

I measured where the brick would be centered for the door then using a level and soap stone etched a line to guide my holder placement. I did the same on the other side, in the effort to save picture over load it is not shown, but looks remarkably similar.

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Getting everything lined up.

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Once in place a quick tack weld to hold it until the other side can also be put in place. With one side tack welded, I moved on to the other and made sure it was all squared away using the first one as a reference point.
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Now with both support arms in place I can measure exactly where I want my brick holder to be.20160406_090516.thumb.jpg.1e64229f0f0a8620160406_090533.thumb.jpg.71f8d6d9185730

It's hard to tell in this pic but there is about 1/8" gap between the brick and the front of the forge. I wanted a good enough cap so that when I added the kast-o-lite the brick would still be able to move freely.

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With the door all tack welded and everything still square I finished up the welds on all fronts.

Now time for some Kast-o-lite!! I didn't get any pictures of the mixing with this becuase it ended up being a lot faster than I thought it would. I don't remember if I read it here or saw it on youtube but it stuck with me that someone said you only have 15 minutes once you mix it to get it how you want it before you're times up. They weren't kidding, I'd say 10 is probably closer to it. But it was super easy just mix with water and it feels like that stuff from Nickelodeon Kids, Squand maybe? Anyways I only had a 5# bag from HighTempTools and it ended up being plenty for this little guy. And I have some left over that will probably go to patching up my farriers forge.

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All in all it's about 1/2"-3/4" thick, I went back and stuffed it around where the bunner lets in just to make sure there was NO unprotected Inswool.

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I started building this forge because my antique NC tool Farrier forge wasn't able to get up to welding temp and I wanted something with just a little bit more room for stock. But I have read on here many times about how hard flux is on your floor and I knew I wanted a floor I could take out and throw away when it got to laden with flux and such. So I took a K28 Kiln brick and cut it into 3rds (Using the calibrated eye again!)20160406_184011.thumb.jpg.b4aaf3a38170e5

One of those I then cut in half to make up for the total length of my floor. I like this as 1 brick yields 2 full forge floors. And for about $5 a brick is only $2.50 for a new floor. Small price to pay for the sweet satisfaction of a weld well done!20160406_184031.thumb.jpg.a9029477e7aa0a

With these I can just set them in the forge and when they get ruined swap them out, very quick and easy.20160405_210728.thumb.jpg.966f119a56b4a2

Right now my Kast-o-lite is setting up, and I am waiting until tomorrow to do my burn in to let it have a full 24 hour cure time.

I know Frosty The Lucky talked about replacements for ITC-100 that were a little more affordable, so I am still looking into what I will coat the inside of the kast-o-lite in.

As far as burner I cheated ad also got one from a blacksmith school in seattle. I originally planed on making my own but by the tie I got everything to build it i was around $30 plus time and effort. And a ready to go 150K BTU burner was only $50 so I said "To the Birds!" and just bought one.

Big thanks to everyone who contributes on this group, I love learning form everyone here.

-Coyote

 

 

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I'll be interested to see how those bricks stand up to thermal cycling. They ARE insulating brick aren't they? If not they're going to be big heat sinks, lowering the top temp in the forge and increasing fuel consumption. I would've wrapped the insulwool all the way around and laid high alumina kiln shelf on the floor.

How many cubic inches in the chamber volume?

Oh, be sure you LET IT DRY before firing it even briefly. Hang a light bulb in it to do a thorough job and let it hang a couple days. It's not like you live in the desert you know. ;)

Frosty The Lucky.

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Good post thanks for making the effort

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On Thursday, April 07, 2016 at 11:58 PM, Frosty said:

I'll be interested to see how those bricks stand up to thermal cycling. They ARE insulating brick aren't they?

How many cubic inches in the chamber volume?

Yes they are, they're made for insulating a kiln and I believe the Dane bricks that most heat treating ovens are made from. 

Internal volume souks be should be about 270 ci. With the floor tiles, or 324 ci. w/o.

Originally I had planned on Inswool all around, but I was worried that it would be too soft and cause cranking when it flexed under the weight of the stock (never played with Inswool before) So I went with the kiln brick.

They're not the fire bricks that my old forge had as doors, those are very heavy dense. These are nice and light, and cut very easily. 

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The soft bricks are more sensitive to thermal shock than the hard ones (expanding and shrinking during heating/cooling), most of the prototype forges I built cracked after just a couple of firings. A good kiln wash will lengthen the life of soft brick, in my limited experience, but not by much. Both Frosty and Mike recommended kiln shelf, which I use as a floor now. It holds up much better. I do agree that processing the soft brick is more pleasurable than trying to get a desired shape from the hard ones though :).

 

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I'll be watching for your report on how well those stand up to thermal cycling. Pottery kilns come up to heat and cool VERY slowly so thermal shock is pretty minimal. Forges come to heat in minutes and cool in an hour or so, that's pretty darned shocking. I wonder if there's a water setting bubble alumina refractory, that'd add a layer of insulation between the contact layer and the brick to ease thermal shock. Mixing a healthy % of Zircopax might make it a killer good kiln wash or hard inner liner.

If it doesn't stand up, a high alumina kiln shelf laying on Kaowool (etc.) is plenty strong enough. Potters stack pottery on it standing on little ceramic legs a LOT more spot weight than a hobbyist's forge is likely to apply. It's a good and proven forge floor.

Nice build you have going, just a little tweaking and she's going to rock.

Frosty The Lucky.

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Next time I'm in Seattle I'll swing by the pottery supply store and check out this kiln shelf, so far the only problem I've had is being easily broken. I poked a long piece of stock through and knocked one of the back doors off and it shattered upon impact with the ground. Lucky me, I've got a 5 gal bucket full of fire place brick shop I used those to replace it, I really need to get the top part of my doors welded on!

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@CoyoteGear I have a tile saw that cuts stone and brick like butter, and I can curve the edges if needed for future bricks or other projects... as you know, we're not far apart.

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I replaced my floor about a month ago, I'd say it held up rather well. Forging with it about once a week (avg) I had some flux drip onto it and finally killed it, that stuff is like acid on the brick. I also have had to repair the castable refractory once this time. A particularly long piece of stock got knocked off of my stand (out side of the forge) causing the end inside the forge to smack into the roof and make a nice gash the length of the forge. I have not re-coated with ITC100 yet. I did a patch job with plaster of Paris and sand. I'd like to get that out and replace with kastolite before re-coating with valuable ITC.

Thank you all for the help and guidance! 

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I would consider that patch material, plaster of paris and sand, to be about as effective as using that for a house roof patch material.

Just low grade campfire temps will change plaster of paris back into it's starter form---It's how they find old indigenous campsites in White Sands, the campfires reset the gypsum and then the rare rains allow it to set up and then the winds blow the dunes around leaving a raised mushroom as a campsite marker.

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Can you tell me how the fire brick doors are holding up? I have the same plan for mine, hope to get it finished this coming Sat. My plan is to cut a notch out of each brick so when closed there will still be a small opening for viewing and exhaust. I may attempt to hinge the bricks to avoid having to fight with hot, sliding bricks.  Need to have somewhere for the exhaust to exit so can't close the bricks all the way anyway can you?

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sharp interior angles speed the cracking process

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@bigb, the doors are still doing good, make sure to add a top bracket, I've knocked the doors over with just a bottom bracket. Luckily they only have about 2" to fall, but if they were to fall to the ground it would be game over.

@ThomasPowers, I agree with the plaster being a POS liner. Which is why I didn't waste ITC on it. As for the sharp angles, it's a cylinder so I'm not sure how to get less of an angle...

Anyway once it's redone in kastolite I'll be re sealing with the ITC and continue forging on.

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OK I read "My plan is to cut a notch out of each brick so when closed there will still be a small opening for viewing and exhaust." as a possibly sharp cornered shape and not a cylinder.  (I might have used "cut a semicircle" to differentiate from a "notch")

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2 hours ago, ThomasPowers said:

OK I read "My plan is to cut a notch out of each brick so when closed there will still be a small opening for viewing and exhaust." as a possibly sharp cornered shape and not a cylinder.  (I might have used "cut a semicircle" to differentiate from a "notch")

Thomas that was me, I am planning to cut a small notch out of each brick on my forge doors, see drawing

firebrick doors.PNG

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Here's a couple pictures of the door frame that we made at a gas forge building workshop.

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