Ed's Editorial

Final Installment, Building a Vertical Welding Forge (WIP)

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Over the past week I have been slowly firing the new welding forge… starting out below 1000F several times, shutting it down, and allowing it to cool. Day by day I inched up the temps to 1200F, 1400F, then 1600F… letting it cool down fully after each firing. Today I decided that, for better or worse, I would see what it would do. Any time you build a new forge, that differs as much as this one did from my previous welding forge, there is always some doubt about how it will perform… those thoughts are now long gone! :)

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After starting the forge and letting it idle for about an hour, I inched the temp upward a bit at a time, and, at about 1950F, the steam started rolling, water was dripping off the front and back openings, and out of the burner holder. I just about shut it all down… JUST ABOUT… but took a chance and kept going. The temp stalled for a while right around 2100F, but I suspect it was due to all the steaming/dripping going on. The forge ran, holding at around 2100F for about an hour. As the steam dwindled, the temp started rising again, and before I knew it, the temp was 2430F!

After a sigh of relief, now knowing that this forge is going to reach the level of heat I was hoping for, I tweaked the fuel and the blower a bit, and it just kept climbing. I honestly do not know where “top end” is on this forge… my pyrometer tops out at 2499F… and there have been times when I check the temp readout and nothing but a row of “EEEE” shows… telling me the forge temp has topped 2500F!

And this was WITHOUT any coatings on the interior! I’m going to pull the forge off the table this week, and give a coat of ITC-100, and that should make it even better! :)

The forge actually got to 2490F, and I figured I’d better not press my luck. So I dialed it back a bit, and used it to forge down some 410SS that, in the future, will become laminated with Mosaic.

So, now you know everything about how I built this type of welding forge and burner. If it works for me, there’s no reason it shouldn’t work for you too!

Ed's Editorial

Installment #6, Building a Vertical Welding Forge (WIP)

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Thought I would add to this thread and show you what I use for a burner in my welding forge. Before we get to that, I just want to mention something that I feel is VERY important with any burner you use in a forge… KEEP IT SIMPLE! I’ve spent countless hours trying to help folks with forge burner problems, and I’ve come to fully believe… The more you overtake the plumbing, the easier it is to stop up the drain. The vast majority of problems I’ve assisted with/solved concerning forge burners can all be directly related to over complicated burner designs. Just keep it straight forward and simple… and your life will be much nicer.

I choose to use a very simple, single burner with a blower on my welding forge. Easy to build, very few things to go wrong, and it just plain works.

It all starts with choosing the correct blower for the application. While I know that many folks use “squirrel cage” blowers, otherwise known as Shaded Pole Blowers, that are very inexpensive, and easy to find, I personally think that is one of the least desirable blowers a person can choose. Squirrel Cage/Shaded Pole Blowers are NOT designed to function with ANY amount of back pressure… something that is always present in a forge burner application. Here’s what happens: As back pressure increases, air flow decreases, and causes the motor to heat up, and burn out the windings. Don’t get me wrong, some folks who use their forges very little, have gotten away with using this type of blower for years, but for those who do any kind of higher volume or prolonged usage of their forge(s), they can be a real pain. I know, because I did just that… used Shaded Pole Blowers. They worked fine, as long as I didn’t run the forge much, but as I got into longer and longer days at the forge, blowers started burning out. At the time I simply didn’t know any better, so I just kept replacing them… and kept burning them out.

Finally I broke down and purchased a blower that is specifically designed for forges. At the time (over a dozen years ago) I believe I paid $125 for this one.

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It cranks out 164 CFM, and has been going strong for all these years. If you’re going to use a blower on a forge, I highly recommend this one/type.

Here’s a pic of the entire burner I use in my welding forge:

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From the blower to the forge, the parts are:
-164 CFM electric blower, wired into a ceiling fan speed controller (DO NOT use a typical light dimmer, it will cause the motor winding to burn out… you’ve been warned!)
-Pipe Flange with 2″ threaded fitting
-2″ X 12″ piece of blade iron pipe, threaded both ends
-2″ X 1 1/2″ 90 degree elbow (this is a very important part of the burner… the reduction from 2″ to 1 1/2″ aids greatly in the fuel/air mixing, and increases velocity at the burner end for better control and high temps)
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-1 1/2″ X 18″ black iron pipe (this is the pipe that goes into the forge and is the “burner”)

Propane is delivered through a common rubber propane hose, controlled with a propane needle valve (there is also a ball/shut-off valve located at the propane regulator). I far prefer a needle valve to a ball valve at this location. Its far more controllable, and makes fine adjustments MUCH easier. The 2″ pipe has been drilled and tapped to accept the 1/4″ pipe nipple. The nut you see next to the burner pipe is to “snug” the pipe nipple in place. I DO NOT USE ANY TYPE OF ORIFICE IN THE PIPE NIPPLE. I tried several differ sizes of orifice, and found that with the needle valve, they were totally unnecessary, and made the forge much more difficult to “tune”.

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After a bit of experimenting with this burner, I installed 3″ concentric pipes in the burner end… I found that it quiets the roar of the burner nicely, and it gives me a better flame pattern, with a wider adjustability than without the concentric pipes.
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Finally, the burner holder is an important part of the equation too. You want something solid and heavy gauge, that will be able to withstand the high/long endurance heat. It need to be welded solidly to the forge body, and be of the proper I.D. to “fit” the burner you’re using. In my case I used a piece of schedule 80 pipe, and using a boring bar, enlarged the size to about .030″ larger than the O.D. of my burner pipe size. This allows for expansion of the burner pipe, but isn’t so oversized that it allows flames to come out the burner holder. I drilled and tapped three 1/2-13 holes approx 120 degrees apart, and use 1/2-13 bolts to hold the burner in place.

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The new forge has been curing for a couple of weeks now. I’m guessing that in about another week it might be cured enough to do some test firings and see how things are going to work. The current plan is that once the castable refractory is cured enough, give it a good cleaning with a brass brush, blow it out, and apply ITC-100.

Once I get it ready, I’ll add to this thread as things move along.

Ed's Editorial

Installment #5, Building a Vertical Welding Forge (WIP)

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With the forge curing nicely, I figured I’d better get busy and build the lid. I cut off a 3″ tall section of the same diameter pipe that I used for the forge body… split it, then filled in the sides/gaps with 1/4″ plywood to make it match the outside diameter of the forge. Laid the form on a piece of plywood, and used nails to ensure everything stayed put. I decided to build the lid just the reverse of the forge… putting Kawool on the inside, and making the rest out of castable.

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The pieces of bent rebar will be handles for the lid… inset into the castable.

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Next, I mixed up some castable to a very soupy consistency, and basically soaked the Kawool in it. Then I laid the Kawool in the form, and mixed up a thicker batch of castable.

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Then it was just a matter of filling the form with castable, and putting the rebar in place.

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I got the castable way more wet then I wanted… but I guess “it is what it is”. Now it’s just a matter of curing time before I can do anything else. Once I get it in place and fired, I’ll update the thread with how it works out.

Ed's Editorial

Installment #4, Building a Vertical Welding Forge (WIP)

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After checking on the new forge this morning, I was pleasantly surprised to find that it appeared cured enough to remove the forms… so I did. It wasn’t too tough of a job. I cut the tape with a razor knife, and pried the forms out of the “door” areas. Luckily, everything came out smoothly.

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I suspected there would be some dressing up needed on the door openings, so I grabbed a ceramic tile file that’s been in the shop for years…

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After a bit up filing, I got the front and rear openings cleaned up nicely…

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I’m thinking that forming in a “flame channel” might have been a good thing. Guess I’ll find out when it cures enough to put in place and fire. A little bit of the duct tape got hung up in the curing refractory, but my guess is that won’t be any big deal… it should just burn out when I fire the forge for the first time.

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Looks like my measurements worked out correctly for using fire brick in the front and back “doors”. Here’s a pic of the front door… from inside the forge.

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I’m thinking that after it cures, I’ll take the torch to the inside to burn away all the stuff left over by the forms… gotta make sure the surfaces are fairly clean prior to coating the interior with ITC-100. :)

MORE TO COME!!  STAY TUNED!!

Ed's Editorial

Installment #3, Building a Vertical Welding Forge (WIP)

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OK… ONWARD!

Had to weld the burner holder in place… Used some sch 80 pipe, then drilled and tapped three 1/2-13 holes located approx. 120 degrees apart…

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Next I built the forms. 10″ diameter concrete tube form from Home Depot. 19″ piece, split down each side. I used some 1/4″ plywood ($5 for a 1/2 sheet at Home Depot), and cut 6″ wide X 24″ (just because it was that size) pieces to fill in the rest of the form.

I used duct tape to put the form together… hopefully that will make it easier to get the forms out once the castable cures enough.

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I also picked up a 2″, sch 40 PVC conduit, 90 degree. I had to heat and form it to get the radius I needed. But the idea was/is to form a channel in the castable that will “guide” the burner flame around the inside. After getting the dent I needed, I sawed the PVC with a taper around the curve that terminates about mid way on the opposite side of the forge from where the burner enters.

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I also used the 1/4″ plywood to fill the front and back “doors”, trying to ensure that castable would cover most of the steel portions of the doors… again… used duct tape to keep things in place.

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Since I had a limited supply of castable, I decided to do a “hybrid” forge… used 1″ of #8 density Kawool next to the shell, and used the castable for everything inward from there.

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5 bags of Mizzou 3000F castable later…

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Now to leave it alone for at least 2 weeks… then try to take the forms out. After that I suspect it will be a month or so before it will be cured enough for some firings.

NOTE: YOU MUST LET CASTABLE REFRACTORY CURE NATURALLY!  IF YOU TRY TO RUSH THE PROCESS BY FIRING THE FORGE, YOU WILL SERIOUSLY DEGRADE THE LIFESPAN OF THE REFRACTORY, AND, IN SOME CASES, IF YOU GET TOO OVER ZEALOUS, HAVE TO TEAR IT ALL OUT AND START AGAIN!!!!!

Ed's Editorial

Installment #2, Building a Vertical Welding Forge (WIP)

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Here’s the 2nd installment of building a Vertical Welding Forge.

Finally got started pouring the new welding forge today. I’ve never built one this large…..so it’s “learn as I go”. :)

At first, I wasn’t going to put a steel floor in it… but figured – since it’s likely going to take a forklift to move this one – it might be a good idea. I’d hate to see all that castable pop out of the bottom and end up as a pile of rubble on the shop floor!

I gathered my mixing tube, castable, water, and homemade tools for mixing and getting the castable in place. I put a thin layer of castable in the bottom, then added 5 fire bricks as “filler” to save as much castable for the walls as possible. I spaced the bricks, filled the gaps, then put about a 1″ layer over the top. Now it’s going to be about a week of cure time before I can position and install the burner holder, followed by building the interior forms, and then, hopefully, I can “fill ‘er up”. :)

More to come!

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Ed's Editorial

Installment #1, Building a Vertical Welding Forge (WIP)

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I thought this information might help some folks along. This is the 1st installment of a WIP (Work In Progress) of the last vertical welding forge I built…

 

It’s time to build a new welding forge! For several years I’ve been using a Kawool insulated welding forge, mainly due to the high cost of castable… but seems I’m doing much more forge welding these days, and the lining only lasts a couple of months… in short I’m just tired of repairing, and being down for a week until things cure enough to use the forge again. So, time to “bite the bullet” and spend the money on a forge that should last several years.

First order of business is a “shell”. My pal, Steve Kelly, donated an old air compressor tank to me a while ago…..and it’s just the ticket for this project. 16″ diameter X 24″ long. First thing was to cut the ends out, and then split it down each side…
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I’ve been forging larger and larger billets, so I decided I wanted a “chamber” size of at least 16″ long X 10″ wide. Since the castable needs to be at least 3″ thick to perform well, the 16″ compressor tank is just right. In order to achieve the distance I wanted, the tank was split lengthwise. First I built the openings of 3/4″ X 6″ A36, making the front door 10″ X 4 3/4″. This allows me to stack standard sized firebricks to make the opening smaller, or remove them to enlarge it… depending on how large the billet is.

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I also built a “back door” that is 5 1/4″ X 4 3/4″… that way it can be closed off with two firebricks when not needed as a “pass through”.

Once the “doors” were welded to the shell, it was time to add in 8″ extensions on each side to create a large oval.
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Now it’s “bite the bullet” time… shelling out the approx. $500 for Kast-O-Lite 3000F castable refractory, and the FOB (shipping cost) to get it here. The best deal I could locate was $58.90 per 55lb. bag, and $150 FOB whether they ship one bag… or an entire pallet. I’m getting 6 bags, which should do the entire lining of the forge, and give me a left over bag for future needs.

Once the castable arrives, the first thing is to pour the floor, and let it cure for a week, then get the burner holder placement set, and the forms built for the inside. I’ll get more pics at it goes along and continue on this thread.

This is the first installment… more to come!!!