Jump to content

Big Blade HT forge build


Recommended Posts

A while ago I said I would make a HT forge for longer blades out of a well bladder tank. I started this project recently and thought I would show the process.

I started with one of these two tanks

 

Well tanks.JPG

 

And cut it in half with a angle grinder. Then I curved 6 pieces of 1/8" flat strap to make some tabs to locate the halves back together and welded them in place.

 

1 Tank Halves.jpg

 

The tank already had a nice 1" threaded connector welded in the center of the bottom. Most of these are built by bringing the burner in from the side at a funky angle to circulate the heat. I thought it might work well to bring it in the bottom and but a baffle plate over it. Here is the 1" burner with the upsized 1-1/4" Tee fitting. After playing around with it, I did get it to light and stay lit.

 

2 Burner.jpg

 

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

Link to comment
Share on other sites

I purchased a roll of Superwool. It's 1" thick, 24" wide and 25 feet long.

 

Superwool (1).jpg

 

Cut to fit inside the bottom, line with chicken wire, and hold it to the tank with self-tapping screws.

 

6 Bottom lining (1).jpg

 

The pipe in the center is the burner.

 

6 Bottom lining (2).jpg

 

Today I made to top port (where the blade gets inserted) and a 2x2 vent.

 

5 Top Half.jpg

 

Tomorrow, I will try and put the lining on the top half.

Edited by Joshua States
  • Like 3

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

Link to comment
Share on other sites

Well, I really haven't a clue what I'm doing. I am hoping that 1" of wool with a layer of refractory slurry will be sufficient. I hope I have enough Mizzou

 

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

Link to comment
Share on other sites

You'll definitely want a baffle plate on the bottom. Something to make the flame shoot up the sides Like you I was shooting in the dark when I made mine, but I found (by accident) a 3/8" thick baffle plate works great. With the thermal mass of the plate, when I heat up to the correct temp (and "over shoot" by about 5 degrees), I can turn the gas off and have enough residual heat (checked with thermocouple) to give me a 1-1.5 minute soak at temp before pulling the blade out. Takes freaking forever to get up to temp originally though. Of course mine is just a little 10 inch in diameter 20 inch long forge powered with a 1/2" aspirated burner so YMMV. 

 

On 1/16/2022 at 8:56 AM, Alan Longmire said:

1" of wool is fine. You don't want these to be too efficient!  

Second this. And working in 22F weather helps too :lol:.

Link to comment
Share on other sites

12 hours ago, Bill Schmalhofer said:

You'll definitely want a baffle plate on the bottom.

You mean this thing? I forgot to post this pic. It's 8" diameter and 3/8" (maybe 1/2"?) thick.

 

4 Baffle plate.jpg

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

Link to comment
Share on other sites

20 hours ago, Joshua States said:

You mean this thing? I forgot to post this pic. It's 8" diameter and 3/8" (maybe 1/2"?) thick.

Yeah, that thing!:D

Link to comment
Share on other sites

I started coating the inside with some Mizzou and got around halfway done when I ran out of refractory cement. The new bag arrived today. I will try and finish this up over the weekend. I burned up one of the two temperature probes I had left, so I need to order two more for this thing.

Bottom

 

Coating started (1).jpg

 

Top

 

Coating started (2).jpg

  • Like 1

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

Link to comment
Share on other sites

Got the coating finished this morning. Now a few days to let cure while I wait for the temperature probes to arrive.

 

Coating done (1).jpg

 

Coating done (2).jpg

  • Like 3

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

Link to comment
Share on other sites

  • 1 month later...

I got this all finished and the temp probes and PIDs arrived. So, today I test fired it. The burner is a homemade venturi design. The orifice is a .030" hole in the brass tube. Running at 15psi. With the top vent closed.

venturi burner.jpg

 

After running for about 20 minutes, I could only get the temp up to a little over 400*F. I could get it to about 600*F, but only if I capped the vents in the top.

 

capped vents.jpg

 

Something isn't right here.

 

Edited by Joshua States

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

Link to comment
Share on other sites

Hey Joshua.  I think you need more burner I have a fluidized sand pot I was messing with it's about 10 ×36 inches with an 1 1/2 blown burner and it struggles to heat up. I was thinking about adding a second small burner.

Link to comment
Share on other sites

My heat treat furnace is a bit smaller but it gets up to forging temperature easy with just a weedburner, I need to choke it down to almost nothing to get heat treat temps.

 

I used 1 inch ceramic blanket without any refractory ( biodegradable wool so less health hazard.)

I have the burner at a tangent to create a swirling flame, my burner hole is way oversized, it might be yours is not getting enough air.

At first I had the setup vertical like yours, but it never worked nicely, once I turned it horizontal it worked way better.

 

Do you know how much your furnace weighs? it might also just have a lot more thermal mass than a 55gallon drum and thus take longer to heat.

Link to comment
Share on other sites

4 hours ago, Alan Longmire said:

I suspect the right angle at the end is messing with flow enough to keep it from getting hot.  If I'm interpreting the design right, that is...:huh:

You are correct, that is the design. I have heard these concerns before and never gave them much credit. Gas piping systems often have multiple right angle turns in them and the flow rate isn't compromised in any way. I have also made venturi burners from gas pipe with the same right angle just before the forge chamber with no ill effect. EDIT: This may in fact be a problem. I will investigate

 

5 hours ago, Gilbert McCann said:

with an 1 1/2 blown burner and it struggles to heat up.

This sounds crazy. A blown burner that size should be able to melt steel in a small chamber like that. Is the chamber vertical or horizontal? Where is the burner located?

 

3 hours ago, Pieter-Paul Derks said:

Do you know how much your furnace weighs? it might also just have a lot more thermal mass than a 55gallon drum and thus take longer to heat.

A lot. Right now the thing probably weighs close to 200 pounds. This maybe a reasonable consideration.

Edited by Joshua States

“So I'm lightin' out for the territory, ahead of the scared and the weak and the mean spirited, because Aunt Sally is fixin’ to adopt me and civilize me, and I can't stand it. I've been there before.”

The only bad experience is the one from which you learn nothing.  

 

Josh

http://www.dosgatosdesignsllc.com/#!

https://www.youtube.com/channel/UCdJMFMqnbLYqv965xd64vYg

J.States Bladesmith | Facebook

https://www.facebook.com/dos.gatos.71

https://www.etsy.com/shop/JStatesBladesmith

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...