Author: Ed Caffrey

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.

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

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.

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

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.

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.

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…

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

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.

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.

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!!

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…

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.

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.

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.

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.

5 bags of Mizzou 3000F castable later…

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!!!!!

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!

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…

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.

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.

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!!!