My first forge build... looking for feedback

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brodbeckrt

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Feb 25, 2016
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DISCLAIMER: As I have said in other threads I am new to all of this.
So I have started my forge. I chose a blown propane setup. Looking to add a controller later. I have tacked up a the first rev of the forge. I am using an 8" Dia stove pipe. I have a 1" ceramic fiber blanket that I will be Insulating up to 2" thickness. I am then planning on coating the internals with refractory mortar. As far as a frame I am using 2" SQ steel scraps I had laying around the garage. I am planning on using hard fire brick to close the ends so I can open them if need be. The burner is similar to the one Stacy has spec'd out on here. I am still working on getting a pressure gauge for the propane. Other than that I am good to go with a 0-15 PSI regulator on it. One thing I am stuck on is the placement and angle of the burner. There are a lot of designs out there from what I have found in my research on here. Please anyone feel free to comment on the burner or the design. I would rather improve things now instead of after welding up everything. Thanks!
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You really don't want the burner coming in straight. You want it angle either towards the front or the back, depending on who you ask.

Either way, you want it about 1/3rd the way from the end, angled so that the flame will swirl around the chamber towards the "long" end of your forge. That way the flame will heat the interior of your forge more evenly.


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The biggest problem is in the burner placement and attachment.

1) The burner should be about 20% from the front or back end. It shpukd be angled at about 15° toward the center. It should be at a tangent to the chamber. This makes the flame swirl around the chamber and makes for a more even heating. As you have it it will make one hot spots in the center and the rest will be much less hot.

2) The burner should enter through a tube that allows it to be moved in and out a bit. This allows the fine tuning needed to get the sweet spot where it runs right.

3) On a blown burner, you don't need the flare you have on the end. Just a straight pipe into the forge. Shape the wool at the burner entry so it has a slight flare and rounded edges as it enters the chamber I always describe it as the shape of a clarinet bell). Make sure to make the hole through the wool big enough to build up a good coat of satanite and make it as smooth as possible.

4) Don't forget to put a gate valve on the top where you add blower, so you can adjust the air flow.


Other additions:
Add two 1/2" tubes on each side ( on top of the square tubing) and use them to hold an adjustable slide that will have a work rest the height of the front port. Thsi can be pulled out to support work of any length. The slide is two lengths of 3/8" rod and the work rest welded across them.

Build in a TC port where the burner is currently sitting. It can be just a 3" piece of 1" pipe welded on the stove pipe. In the beginning, you can plug it with a wad of wool or a plug made from soft fire brick. When you are ready, add a TC, sheath, and PID to read the forge temperature. Then , when ready, add a solenoid and make the forge PID controlled for temperature control.
 
Thank you everyone for the input. I should be working on it again this weekend. I will post the updates.
 
Do the same placement recommendations apply when using a ribbon burner? (20% from front or back, angled 15 deg. towards center, tangent to the chamber)
 
Ribbon burners are different systems. They are either places facing down on the top, running the length of the forge, or on one side of the floor and the heat going up a semi-circular domed chamber.
 
All
I was able to get some work done on it this weekend. Things I have added/changed: Shortened chamber to 18", moved burner to 4" off of the end (~20%), 15 deg angle(from vertical) towards center, moved burner tangent to chamber, removed flare on the burner and flared the refractory mortar, positioned my clamp so I can adjust the burner in and out of the chamber to fine tune, added adjustable rest(level with the chamber), and added a 1" hole on top for a TC. I still need to get a piece of tube to weld to it. I bought a PVC ball valve to limit the blower flow. The only other thing I am missing on the burner is my propane pressure gauge due in next week and a way to connect my blower, valve, & burner.

Questions:
Does the TC port(tube) need to be threaded or anything?
I was given a blower, but I am not sure if it is big enough. It is a Fasco Blower No. 7121-6743 Type U21B. 1/50 HP 115V 60Hz 1.1Amp 3000 RPM. Will this work? I cannot find the CFM specific to this blower but a couple similar models were about 80-90CFM.
I put one coat of refractory mortar on the inside. I built up as much as I could get to stick. I also put it extra thick around the burner and on the floor. Should I add a second coat? How thick should it be throughout the chamber?
Updated photo below:
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If you haven't already look up Wayne co. He's a cool old man that sells refractory, itc 100 , kaowool ect.

I built my forge based off his clam shell dragon design.

Basically a 20 lb propane tank with the ends cut off for doors with hinges.

And I sliced it in half (pretty cleanly for using a portaband! ) Then I tacked 2 more hinges on it .
So if I ever have a big piece I Wana play with I can pop the pins and prop it open (this only really applies to bigger blacksmithing projects but I figured the option is always there.

I have yet to order my burners and she still is isn't insulated as I have been busy soon though :)
Iforgeiron.com ( if this is a problem mods please delete)
Bladesmithforum.com
Great places for info as well
 
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The big thing I see which I have found can cause a problem is you burner location. I don't mean offset like the previous advise I mean straight on top of the forge. Remember heat rises and crazy heat rises crazy fast. Once you shut the burner off the forge is going to draft right up and out your burner and get it VERY hot. Any hoses will melt off of the fittings and any blower in direct contact/path could get damaged. Your forge as it sits needs to rotate clockwise 90° Which will stick the burner out the right side and will reduce the heat going up the burner. With your setup I would strongly advise when shutting it down that if you don't rotate it then leave the blower running till the forge is cooled off.
 
I agree that the side entry position is more common and better when home building a forge, but it is surprising that not much heat actually drafts up the manifold on setups like his. Look at the many commercial and industrial forges that are pretty much the same as his and you will see that it really isn't an issue. My NC forges have top down burners, and I can lay my hand on the manifold. Mankle and many others use the top down position, too.

My big issue with his photo is that the burner tube looks like it is still fully vertical. It should be forward angled at about 20°.
 
Must just be the angle of the photo. The angle of the burner measures about 18 deg. from vertical. I can always rotate everything 90 degrees for a side entry. It's just grinding out 2 welds on the upright. I was going with the vertical entry burner, as I have seen on several production models, to save space on overall footprint and to keep the whole thing more balanced. I didnt think about the heat after I shut the blower off. If I leave it vertical, one thought is to add a Y with a cap on top of where the blower enters. When I shut the burner off, just pop the top off of the Y and let the heat escape. Either that or I can just leave the blower on until things cool down as JT suggested.

Do any of you guys have a recommended cart to put the forge on? I thought about either building or buying one from HF and modifying it slightly to fit a propane tank.
 
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