Single T burner forge build

[M.G.]

It has been a while since i have been regularly active here on ifi, if yiu care ill catch you up. If you just want to check out the build feel free to skip ahead.

"Cue flash back music" 

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I had just barely started my journey in to blacksmithing (maybe about a year deep) when I was stopped in my tracks, and forced to forge a new path forward. Two years ago i was told i would be loosing my workshop space. I tore down my forge, and started looking for a property. My wife and I found a home to buy and fix up to make our own. We're talking full remodel of living spaces in the home. But, the property came with a workshop. In need of much repair its self, but that is a long process. Anyway, after a year and a half of making the home habitable and dreaming of the day I can finally have enough of the responsibilities out of the way for long enough to start setting up the smithy once again. It's finally time to do some work for Me. 

~~~~~~~~~

So, here we are. Its time to build my first gas forge. 

I've chosen to build a naturally aspirated propane 3/4" T burner, as close to the "Frosty T burner" as I could with avaliable fittings. I followed Frostys' design to a T (pun intended) from the jet to the nozzle. From the jet back to the regulator was cobbled together with what was available at the box store. 

I'll save you the details, if you want em, go read Frostys posts. All of them.

I got the burner running pretty well for being in open air, and not contained in a forge. I'll insert a video if the internet gods will let me.

 

The forge body will be a 2 part construction, a 12"x12" floor. Made from angle iron and sheet metal  Consisting if 2 inches of kayowool, then about an inch to inch and a half of satinite castable refractory, coated with ITC-100. The and ceiling will be an arched top filled with the same composition of insulators and refractory. 

Over all forge cavity should be right at 332.5ci. 7" wide 6" tall and 10" deep. I will be using fire brick for doors. 

~~Which brings us to the present.~~

Today I welded up the frame for the floor, as well as got all of the sheet metal cut. 

I am still waiting on refractory to show up in the mail, then I will finish out the body and post updates as they come.

 

[Mikey98118]

Satanite castable refractory?

[M.G.]

Sorry Mikey, the specific product I have coming is a high alumina castable refractory cement, going by the specific name TABCAST-94, it has a temp rating of 3270°F.

Sorry for the confusion. Hope that clears it up.

 

[Frosty]

Why did you hang all those fittings off the jet fittings? None of that is in my burner plans you want to keep as little weight hanging from the burner as possible or the jet will become misaligned and performance will really suffer.

That is some expensive refractory, $99 for 22lbs.! Did you look for a supplier in the yellow pages and call to find out what was available? I get all my refractories from Distribution International in Anchorage. They have an outlet at the address below. A 40lb. sack of Kastolite-30li cost us about $60 last time I checked.

19039 NE Portal Way, Portland, OR 97230, United States

Kastolite is water setting high alumina bubble refractory. I kiln wash to improve IR re-radiation rather than to protect it from Borax based welding fluxes, it is not susceptible to caustics and the "bubbles" provide insulation in addition to the Kaowool. 

Not that I'm trying to convince you to use something else but before you spend more on your next forge you might want to give DI a call. Forget about most large companies responding to you on their "contact" link, email, text, etc. unless you want to buy a truck load quantities. Pick up the phone instead, you'll get a human and if you don't waste too much of their time they'll tell you just what you need to know.

Frosty The Lucky.

[M.G.]

Frosty, thanks for stopping by.

The fittings from the jet, back.. (as noted above are not to the plans, but everything else is)

Unfortunately this was the only way I could get from my jet, to my shut off valve, and out to my regulator. With the available fittings locally. I am planning on building a support bracket to prop the fittings and to relieve any undue stress on the jet assembly. 

(I think my location hasn't been updated. I'm about an hour from Portland now.)

As far as the refractory goes... not sure why I picked this over that. Next time I will save my money.

Thanks for the advice. I always look forward to hearing from you. 

 

[Frosty]

Put the shut off valve on the regulator and plumb the hose to the jet, ONE common fitting even in most big box stores. The corner HVAC/plumbing supply carries exactly what you need. kay, maybe two common fittings, it depends on the hose you have, if it has two female ends you'll need to sub it to the regulator unless you have a reg. with a male outlet.

You probably picked it because it has a higher % of alumina, the same reason I spent more $/lb. for Greencast 97 than you did. Then Distribution International started carrying Kastolite 30 about the same time they stopped carrying the old type Insulting firebrick for Morgan K-26. I imagine they're carrying K-28 now. 

Frosty The Lucky.

[M.G.]

Yeah Frosty, that IS why I choose the TABCAST. It had a really high alumina content.  How did the Greencast do ya? Guessing it didn't perform as highly as the cost would have suggested?  

And I'll take a look at re configuring the jet plumbing next time I make it in to town. 

 

And here is my update for today. 

I got the forg body put together. Just some light sheet metal, reclaimed from an old oil drum, cut and pounded to shape.  I'm using a floor flange and 1.5" nipple that I drilled and tapped with set screws to hold the burner.

[Latticino]

Kastolite 30 is an insulating castable refractory.  Greencast 97 is a castable refractory.  It will hold up quite well to flux, but can be prone to thermal shock, so be careful rapidly heating or cooling to avoid cracks.  As cast it has very limited insulating value (compared to ceramic blanket, Kastolite 30, or even soft firebricks).

[Mikey98118]

Thermal shock is its weak point? Guess I'll keep hunting for a good refractory to make burner parts from.

[Frosty]

I used the Greencast 94 just like I always do, as a flame face over Kaowool outer liner. IIRC it didn't heat check and I was running 2 of my hotter T burners in a 500- 550 cu" chamber. I was going for a forge that'd weld large stock easily. It turned out I didn't like the forge so only used it till I made the next one. Not long, a couple months maybe. 

What I liked about the Greencast was the aggregate being rounded it troweled easily and cast smooth in thin sections. If Kastolite hadn't worked for NARB I would've used the Greencast. I have No experience with it as a burner part, not even NARB.

Frosty The Lucky. 

[M.G.]

Latticino, thanks for the clarification.

 

Ps. I got some kast-o-lite 30 on the way, after reading these responses and reading a bit deeper into the Tabcast I ordered.  I decided to go with the tabcast for the forge floor,and I will use the kast'o for walls and ceiling. 

 

I saw somewhere in my digging, that ITC-100 is not ment for forges... I was going to coat all my surfaces with it, but now I'm not so sure. Any thoughts...??

[M.G.]

Ok, time for an update.

Thanks to some great input from you guys I finally have a running gas forge.

Over the last couple days I got the insulation wool installed and rigidized. Got the refractories cast and set. Went through the process of baking off the residuial moisture. And finally upd to full heat. And was registering about 2200°F consistently.  

I still have some work to do before it is put into service but it's looking bright. I still want to lay on a couple coats of ITC 100, then I will weld on a couple bits of angle iron to act as brackets to hold brick doors in place. And I'll fashion a work rest for longer stock. As well fab up a portable stand of some sort.

  Here are a few pictures and short video clips from the last couple of days.

I used firebrick and tabcast 94 for the floor. I may do insulation wool and tabcast 94 when I end up having to refine the floor at some point down the road.

The body is lined with insulwool and kast-o-lite 30

The first firing super low, short run time. To start evacuating the excess moisture from the refractories. 

 Started to crank it up a little bit after about an hour or so of cycling on and off. I delt with the burner going out from time to time on the initial firing cycles. But here it is running more steadily.   AND finally after a long day of babysitting and slowly bringing it up to temp, it's finally flying.  

Hope you all enjoy, ill throw up some more updates as I wrap up this project over the next couple weekends.

[Mikey98118]

The first video shows an excellent single blue flame surrounded by an orange flame. However the orange flame seems to be generated around the burner opening, rather than by the burner. All the succeeding videos only back up this impression because of its opaqueness, and the fact that it only grows into what I think of as an internal atmosphere, rather than a flame envelope; this idea is backed up by the nearly white incandescence that your forge can achieve; that kind of heat cannot be provided by a burner with tertiary flames. So, your dragons breath should slowly fade out over time. Congratulations on building a fine forge. Yes, you win the blue ribbon at the county fair  

Why would the dragons breath go away in time? I think that opaque orange flame is from some out-gasing in the refractory surface.

[Frosty]

Ayup, that's what I call Screaming HOT! Well done.

The calcite binders used in alumina refractories burn with an orange flame, just like that. It'll fade but might never go away, it hasn't in the NARB forge.

Frosty The Lucky.

[M.G.]

Thanks Mikey! And thanks Frosty! 

You two have been a great helping hand and voice of reason. 

I am pretty happy with the results so far. I can't wait to put it to work.

Hopefully I'll be posting updates soon.

[Mikey98118]

Has it faded somewhat at least?

[Frosty]

NARB? Oh yeah, when I first fired it up it was blowing almost opaque orange dragon's breath, now it's faded transparent orange but still definitely orange.

Frosty The Lucky.

[Mikey98118]

I wonder how much more it could be chocked off with the right sealant coating.

[M.G.]

Hey guys,

 

I've got a quick question. 

 

How much should I worry about the gap around my burner and mounting bracket at the entry point on my forge?

Wondering if heat loss and or excess O2 intake will have any negative effects on general operations or when trying to reach forge welding heat..

 

Any thought or input would be appreciated. 

[Mikey98118]

To begin with, how serious either problem becomes primarily depends on the force of your burner's flame; If it was a Mikey burner, that would be a lot. "T" burners have softer flames. Multi-flame burner nozzles would generate very little problem at all. The differences in these three burner types is high high versus medium flame velocity in the first two burners, and the fact that many small flames generate little secondary air in the third.

Too much secondary air induction is what cools off forge temperatures, ecsess secondary air also will provide super-heated excess oxygen molecules to reach work peices, creating scale.

That said, I doubt that you have serious problems, of either kind. If your burner was drawing in much excess air, I doubt that you would reach yellow-white surface incandescence. However, it is a simple thing to stuff a little ceramic wool around the opening to see what happens in the forge

[M.G.]

Thanks Mikey, 

That was kindof my line of thinking. 

Good to hear some confirmation. 

 

[Mikey98118]

I took a second look at the last video, and have revised my opinion; your forge has white incandescence. I would estimate comfortably over 2650 F. You should be able to melt steel in it.

[M.G.]

According to my IR thermometer I was hitting about 2240ish at that point in the test, and slowly starting to decline, which I think was due to my tank freezing up. I can't really vouch for how accurate my laser thermometer is, so it could be running hotter as stated. And if that's the case, hot dang. I'll take it.

[Latticino]

On 1/19/2023 at 3:43 PM, Mikey98118 said:

Thermal shock is its weak point? Guess I'll keep hunting for a good refractory to make burner parts from.

Just recall that thermal shock can also be reduced by reducing the thickness of your casting, taking care with the geometry to avoid rapid changes in thickness and crack initiation points, and allowing the burner head to warm up and cool relatively slowly.  This is why I prefer the Joppa style cast burner heads over the Pine Ridge style that everyone seems to be using these days.  

[Mikey98118]

All good Points, Latticino. However, my complication with refractory nozzles is the same problem that differentiates refractory in forges from refractory in glass heating equipment; short heating cycles. The problem is only exaggerated by use in flame retention nozzles.

The Joppa Glass nozzle is a much better design for longevity than ribbon burners, as you pointed out. However those same ribbon burners due just fine in forges; Why? I think it must be the cast refractory everyone on IFI is building them from. Kast-O-lite 30 is famously crack resistant. Unfortunately, the way most guys employ it, the finish surfaces would be no dang good for flame retention nozzles. What to do? In the first place, I NEVER plaster it onto ceramic wool anymore. I always cast the refractory into mold forms; this leaves their surfaces much smoother.

One guy on the Net also vibrates his molds, allowing him to successfully create thin cast refractory forms; Could this refinement be enough to use Kast-O-lite 30 in Joppa Glass style flame retention nozzles?

Of course the simple solution is to just drill multiple holes in stainless-steel discs, to create the next generation flame retention nozzles. However, I am thinking down the road to much hotter burners. Eventually, burner nozzles will all need to be made of refractory; fortunately, we still have time to ponder.

You probably have a lot more left than I do. Or is that a very old photo of you?

So, what is the point of ever hotter burners, since the only way to achieve more heat than we get from single primary flame envelopes is by using oxygen enrichment and/or hotter (as in more expensive) fuels? The hotter the flame the more it can be reduced; the more it can be reduced the slower the gas flow can be, leading to less heat loss out the exhaust opening. Efficiency is the goal.