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Rough draft forge design, sanity check. W/ drawing


ipsullivan

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Hello,  

New the the forum, aspiring blacksmith. I just purchased an anvil and I am starting to put the next piece of the puzzle together.

I have been surfing around looking at different options regarding forge size, shape, burners, insulation etc. Originally my first instinct was to build a simple forge that accommodated an all fire brick liner. Soft walls and ceiling with hard shelf/floor.  Quickly realizing my dimensions would be more limited without having a puzzle of fire bricks.

Attached is a rough draft of the forge body design.  My goal is to build a forge that will have a good life span and the ability to support growth in my currently non-existent skill set.  I don’t have any specific focus on what I want to make, would rather gain skills by starting with the basics.

-4.5x8x14” interior or 504 ci., with the ability to run 1 burner and block off the back 5”. More or less, approximately reduces the size to 4.5x8x9” or 324 ci.

-3/16” plate for body, 3/8” full width exterior shelves, depth to be determined.

- base and ceiling:2” Kaowool + 1” refractory cement

-Left and right walls will be soft fire brick

-2x 3/4” Frosty T burners, held in places with a collar with set screws.

-The top will recess into the base 1/2” and sit on a shelf, making for a sturdy structure without permanent welds between the top and bottom. 

As far as burner placement,  I am thinking 5” from the doors, leaving a gap between the burners of 4”.  Is this adequate spacing for a forge this size? Would angled offset burners benefit me? I like the idea of being able to run 1 burner and filling the back half with fire bricks when working on smaller items.

Any and all feedback will be much appreciated!  I won’t move forward until I have a solid design.

 

Thanks,

Ian
 

 

 

 

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I would recommend less castable for the sides and roof.  There's really no need for a full 1" unless you intend to knock the crap out of the walls.  As for the jenga of bricks it's pretty simple for the size forge you have designed.  k26 2.5"x4.5"x9"  your floor and roof is 4 of them stacked as two sets of 2 == side by side then your walls is just a single brick on the edge.  I have some brick in the garage i'll go take a photo for you in a bit.

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I can see the floor and walls working with bricks.  Are you suggesting the same for the ceiling? Not sure how you could span the 9” width of the chamber with a 9” brick.  Maybe I am misunderstanding what you are saying. 

Also, Would 2.5” of IFB be better than 2” Kaowool + refractory?

 

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I cantilever IFB from each side to meet in the middle. The guys made angle iron frames joined with all thread and clamp the IFB together for the club gas forge build. Clamping works nicely with K26, old type IFBs not so.

They washed the club forges with Plistex, I used straight Kastolite 30. both flame faces are holding up nicely.

Frosty The Lucky.

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Ordered 2” Kaowool, rigidizer from Glenn, and Kast-o-lite 30.

Should have enough insulate all interior with 2” Kaowool and 1/2” of refractory.

For the time being, I will be getting some K26’s for doors. Trying to find somewhere local to buy them.

Is it recommended to put some sort of reinforcement between the blanket and refractory? Just thinking in terms of having something for the refractory to grab on to.  

 

 

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kastolite has no issues grabbing on to EVERYTHING.  as for the blanket just ridgidize it first.  that will stiffen it up plenty for the kastolite.  I have also been putting a layer of zirc wash on to my blanket before my refractory as of late.  It seems to give me a little faster heat up time, but it could just be old eyes and insanity.

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You missed the recommendations to use 2 layers of 1" ceramic blanket rather than 1 layer of 2"? too late now I suppose but layers of 1" is beneficial in a couple few ways. For a round or vault liner where the blanket has to bend around a curve, 2" wrinkles more so causes problems casting heat shadows. 2 layers rigidized makes the entire depth of insulation stiffer and stronger. 1" is easier to handle from cutting to installing.

But, you have it coming so it's what you use. It's not a serious problem if you're building a square forge.

Kastolite is sticky as all get out. I thought it'd clean off a milk jug but oh NO, it wouldn't even break off after it'd dried. Just butter the blanket before applying the Kastolite and you're golden. 

You do know about buttering don't you? Buttering is spritzing on whatever you're applying rigidizer or any kind of castable refractory, mortar, cement, etc.. If you apply any masonry mortar, etc. Kastolite behaves like concrete but it's a LONG shot different. Anyway if you apply to a dry surface the castable flash dries on contact so it doesn't hydrate properly and leaves a thin layer of dry dust between the two. This is a BAD thing. Yes? By buttering the water on the material dilutes a portion of what you apply and it flows along fibers or into crevices where it forms a strong bond. If you watch brick layers you'll see them dip bricks, blocks, etc. in a bucket of water and give the surface in place a swipe with a wet brush and butter them both before applying mortar. It works just the same with forge refractories and blanket.

Frosty The Lucky.

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Frosty,

I did gloss over the 2 layers of 1” previously.  I now understand the advantage and will apply that on any future forges.

Thanks for the buttering tip. I remember reading that a couple weeks ago, it makes more sense now.  
 

I made some progress on the forge body today. Photo below.  The shell is all tacked together. Next weekend I will be adding brick shelves and some sort of tabs to prevent the two halves from shifting during use.  
 

I strayed from the original plan:

- 4.5x9x14” volume,  567 ci

-.250” plate for body(had material laying around)

- for simplicity of fabrication, the two halves sit flush on each other instead of recessing the top.

I purchased everything to make two 3/4” T burners.  I am trying to figure out the flare, I would like to just get a couple of thread protectors but I can’t seem to locate any locally. I was thinking of modifying a coupler.

 

Thanks,

Ian

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  • 8 months later...

Update!

 

This project was put on the back burner for most of the warm months.

Knocked out a mobile stand last week. I wanted to be able to store the forge against the garage wall and move into place in the overhead door opening.  Originally it wasn’t going to have casters, but it was pretty heavy to be sliding around the garage.  Managed to make it from free material.

Finalizing plumbing is next, followed by paint and insulation.  

 

 

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  • 7 months later...

Got the plumbing hooked up and test fired one burner.  I am having issues keeping the burner lit.

I followed The Frosty T Burner Build PDF.  
-1”x3/4 T

-3/4”x6 nipple

-.035 mig tip

-using a stainless 3/4” coupler for a flare 

-0-30 psi regulator

-manifold setup as shown 

-compression fitting on the top of the burner are temporary.  Switching to flare once I tap them.

 

I started with a full length jet (.035” tweco) and attempted varying pressures up to 10 PSI, with and without the burner flare.  No luck.  I then shortened the jet about 1/8” and repeated the process. No luck. I continued the shortening and testing process about 1/8” or so at a time. No luck.  The air/fuel seems to rich as choking the burner does not help.  I got the jet to where it is shown in the photo and stopped.

I was using a MAP gas torch to ignite.

 

Any ideas? 

 

 

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I don't run burners that low unless they're connected to the ribbons. 

 A couple points, trimming in 1/8" increments is WAY too large. Once the jet gets about to the center of the intake ports as seen looking through them it's time to start trimming by the file stroke.

Did you remember to deburr after each trim? It's very important the jet is a clean round opening so the stream of propane makes a smooth even cone as it flows down the mixing tube.

From the pic it looks like your jet is misaligned. Being aligned straight down the center of the mixing tube is the most critical thing to get right.

If a flame is burning rich, choking is exactly the OPPPOSITE of a solution. It's like stomping the gas pedal to the floor because your car is going too fast.

Frosty The Lucky.

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Could be but the pic from a distance looks cocked the same direction. I don't like compression fittings, they can move and throw things off too.

IP: How about a couple pics of the burner burning? No need for more pics of your regulator or gauge I believe you when you say 10psi, no reason to show me a pic of a gauge. Too many people have to pay for bandwidth so we try not to cost them money if we can help it.

You ARE going to pull your burners the heck OUT of the forge yes? ALL but about 1/4" of the ends of your burners showing in the second to last pic should be on the other side of the shell. Let the holes in the refractory act as final flares and keep the flame itself away from the burner.

Frosty The Lucky.

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I will take a look at the T and see if the 1/8” pipe thread is misaligned or 1/4”-28 mig tip threads are tweaked.

I am going start over with a fresh mig tip and ensure to deburr the orifice thoroughly each time.  Also, will go with smaller increments if I can manage to hold a flame.

Frosty, I do plan on moving the burners up once I have the insulation completed.  I was planning on 1/2” of refractory to be exposed In the bore or potentially the entire nozzle bore to be lined with refractory if I can pull it off. 
 

Thanks for the tips, will report back later in the week with results.

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You need to tune is very small increments or you're depending on luck to get it right.

I don't understand what you mean by having 1/2" of refractory exposed in the bore. 

The common terms we use for the hole in the forge shell and liner for the burner and flame is "Burner port". Flame port is just as valid and we're starting to see it more often. If that's what you're referring to it might be just as valid a term but I don't know of anybody but you using it. 

That's why I have to ask you to explain what you mean. Everybody using the same terms, "Jargon" is so we can communicate clearly without having to spend more time explaining what we mean. 

Make sense? 

Just in case what I THINK you said means what I THINK it does I'll guess at an answer. If my answer confuses you it'll be a good example of why speaking the same language is so important. ;)

I HIGHLY recommend you treat the flame port just like the inside flame face of the forge chamber. It WILL be in direct contact with a propane flame and exposed to that highly reactive chemical environment. I cut the hole large enough to apply a 3/8" layer of Kastolite and a final kiln wash. It's a hassle but it has the added advantage of being easily shaped into a proper burner flare that won't burn out. 

Make sense?

Frosty The Lucky.

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  • 4 months later...

I snapped some photos and video.  I have started with a fresh MIG tip and tediously removed length (including deburring the orifice).  No luck in getting it to hold a flame.  I tested pressure between 2-10psi.  I can only get it to hold a rich flame when almost choking out the t-burner completely. 

The 2nd video shows me gradually decreasing the choke amount until the flame pushes out too fare and extinguishes.

The 1st videos shows attempting to light the burner with no choke.

Maybe I need a different orifice size?

I family painting it with some high temp paint.  I haven’t done the insulation yet, as I would like to confirm the burners will work. Just trying to avoid tearing the thing apart after insulating.

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I don't know. It's been 4 months I don't remember what size mig tip you're using. But if you have to choke it so much to get a flame to stick to the burner it is grossly out of tune. Maybe out of tunable range altogether.

I think I said this before but it's ben 4 months. I don't watch videos of burners, it's almost never worth the download time and won't tell me anything I can't see in a still pic. 

Why will finishing the forge mean you'll have to tear it apart if a burner doesn't work out? Don't mount the burners permanently they should just slip in and be held by set screws or a clamp.

Frosty The Lucky.

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What's the mixing tube diameter and length and the T dimensions?

Have you opened the burner ports in the forge shell large enough to get the thread protector through? 

With the problems your burner is displaying you're not going to be able to use a tight burner port it's going to need secondary air. 

What you're describing, a (silly low psi flame blowing off the end of the flare) means it's inducing crazy air. Having to choke it almost to death confirms it's over drawing. 

I've been making the T burner for probably 35 years and I've never had one run so lean it wouldn't burn unless choked. The opposite is almost universally the case they almost never draw enough air, let alone too much. 

I'd really like to know how you pulled it off.

If I sound impatient it's because it's been 4 months since your last post and you still have the same problem. I know I've asked the above questions and suggested the obvious steps to correct the problem and here you are, no progress asking things about actions I wouldn't have suggested in your situation. 

So yes I am a little irritated. I'd like to help but I don't know if it's making any difference. I sure don't see results. 

Frosty The Lucky.

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