MEMBER ITEMS FOR SALE
Custom Knives | Other Knives | General Items
-------------------------------------------
New Posts | New PhotosAll Photos



Go Back   The Knife Network Forums : Knife Making Discussions > Custom Knife Discussion Boards > Ed Caffrey's Workshop

Ed Caffrey's Workshop Talk to Ed Caffrey ... The Montana Bladesmith! Tips, tricks and more from an ABS Mastersmith.

Reply
 
Thread Tools Display Modes
  #1  
Old 01-24-2009, 07:45 PM
tomh tomh is offline
Skilled
 
Join Date: Aug 2007
Posts: 310
burner help!

Didn't want to bother Ed again on the weekend, so here it is for anyone who could help.

I built my first venturi forge. I am having trouble getting it to burn completely. Big yellow flame coming out the front, only getting up to 1500F
My burner tube is 12" long 1" pipe, bell reducer is 1.5", orifice is #53 drill bit size. 6 psi on the propane regulator.
orifice is shoved as far as I can get it in the bell. It burns worse the more I slide the orifice out of the bell.
I think I need it to pull more air, or reduce my orifice size.
Will a bigger bell reducer give me more or less air flow/velocity?

I can't wait to get this going good, it has such a nice swirl going on!

Any help is appreciated!


__________________
ABS Apprentice
www.tomhalloranknives.com
Reply With Quote
  #2  
Old 01-24-2009, 08:32 PM
Ray Rogers's Avatar
Ray Rogers Ray Rogers is offline
Founding Member / Moderator
 
Join Date: Jun 2002
Location: Wauconda, WA
Posts: 9,838
A bigger bell would probably make your situation worse. You didn't say that the burner was mounted inside the forge at the time you were testing it but you gave the impression that it might not be. If not, it won't work well at all usually, they need to be mounted in the forge to work well.

Finally, I'd say you need a lot more gas pressure than 6 psi. I built a very simple venturi with a 3/4" pipe that was 12" long with an orifice about like yours and a 1.5" bell. Running 10 to 15 psi it works like a champ. Sophisticated venturi burners can work on small gas pressure but the simple ones may need more. The whole principle of a venturi is based on the speed of the gas creating enough of a vacuum to draw in the air it needs. So, that means you need more pressure and a slightly smaller pipe (3/4") should also help .......


__________________

Your question may already have been answered - try the Search button first!






Reply With Quote
  #3  
Old 01-24-2009, 09:31 PM
Ed Caffrey's Avatar
Ed Caffrey Ed Caffrey is offline
Super Moderator
 
Join Date: Jun 2002
Location: Great Falls, Montana, USA
Posts: 4,393
Send a message via AIM to Ed Caffrey Send a message via Yahoo to Ed Caffrey
Tom:

From what you describe, and the conversation we had earlier, my opinion is that you need to try to following:

1. Increase the size of the "bell" from what you describe, your getting a very fuel rich mixture.

2. DECREASE the size of the 12" pipe to 3/4" (you can use a reducer on the "bell")
(this will have the same effect as increasing the bell size, but will be cheaper and easier to do)

In the morning I will check the specs on a couple of my burners and let you know about them.

Next bit of information we need: whats the INSIDE diameter of the forge, and what is the length.

We'll get this figured out for you, it might just take some playing around


__________________
WWW.CAFFREYKNIVES.NET

Caffreyknives@gmail.com

"Every CHOICE has a CONSEQUENCE, and all your CONSEQUENCES are a result of your CHOICES."
Reply With Quote
  #4  
Old 01-25-2009, 12:17 AM
tomh tomh is offline
Skilled
 
Join Date: Aug 2007
Posts: 310
I tried turning the pressure up, it just got a bigger flame out the front of the forge. I think the smaller pipe will be the ticket.

The forge ID is about 3.5" and length is about 16".

I had fire brick stacked at the rear opening and it got hot enough back there to turn them red, but the middle and front were not hot at all.

thanks!


__________________
ABS Apprentice
www.tomhalloranknives.com
Reply With Quote
  #5  
Old 01-25-2009, 07:56 AM
Crex's Avatar
Crex Crex is offline
Moderator
 
Join Date: Sep 2002
Location: Acworth, GA and/or Hanging Dog, NC
Posts: 3,581
What kind of flare are you using (degree-wise)? Dropping back to 3/4" should help some, however, it sounds more like your jet orfice is to large and you are throwing too much fuel in the mix (Ed's observation). Higher pressure might correct the burn issue, but you will have more trouble regulating your forge at lower temp levels and burn way to much fuel. Smaller dia. and shorter torch tube, smaller orfice with a good flare ratio and lower pressure will work more efficient and give you more control top to bottom. The smaller set up should work just fine in your interior dimensions although you might need to use two torches for more even heat with that length.
What material lining/insulation did you use? If its as "insulated" liner ie.-Kwool or soft firebrick it should heat up fast, but if you are using a mortar lining or hard brick which have to warm up to be efficient then you might just need to let your interior come up to heat for the torch to settle in and work correctly.
Lots of little variables to tweak, but once you got it, it'll rip.

Also if you just want to test and ball-park tune your torch before insertion into the forge,
you can camp it in a safe direction in your vise install the flare loosely and light her up. Use pliers to adjust flare and jet positions for optimum burn. This will allow you to trouble shoot your torch set up easier. Let it cool and either mark or lock in place (however your's is made). There will still be a minor amount of tweaking after insertion with depth of insertion and air intake, but that's easy stuff.


__________________
Carl Rechsteiner, Bladesmith
Georgia Custom Knifemakers Guild, Charter Member
Knifemakers Guild, voting member
Registered Master Artist - GA Council for the Arts
C Rex Custom Knives

Blade Show Table 6-H
Reply With Quote
  #6  
Old 01-25-2009, 08:15 AM
brucegodlesky brucegodlesky is offline
Steel Addict
 
Join Date: Dec 2006
Location: w Pa
Posts: 189
I much prefer having interchangeable orifices on my burners. I do this by using Tweco mig tips. Makes it a lot easier tweaking the fire. It's a major PIA to be fooling with the fire when I could be making knives.
Attached Images
File Type: jpg tools and machinery 064.jpg (87.1 KB, 21 views)


__________________
I love all of God's creatures, right next to the mashed potatoes and gravy.

www.BirdogForge.com
Reply With Quote
  #7  
Old 01-25-2009, 08:52 AM
Ed Caffrey's Avatar
Ed Caffrey Ed Caffrey is offline
Super Moderator
 
Join Date: Jun 2002
Location: Great Falls, Montana, USA
Posts: 4,393
Send a message via AIM to Ed Caffrey Send a message via Yahoo to Ed Caffrey
Tom: With the inside only being 3.5" ID, the 1" pipe is WAY TOO BIG. On my venturi forge (which is 6" ID with the kawool installed X 16" long) the burner tube is only 3/4" dia, with a bell size of 2.5" ID...... and I'm running 10-13psi, with a .0595 orifice (#53 drill bit).

I have a little "brick forge" that was built out of two soft fire bricks.....the the chamber is 1.25" dia. X 4" long...... the venturi burner for it is 1/2" pipe with a 1.5" bell....and that is almost too big for it.

Down size the burner tube, and up size the bell.....you may even have to reduce the orifice size to get things burning correctly in something that small.


__________________
WWW.CAFFREYKNIVES.NET

Caffreyknives@gmail.com

"Every CHOICE has a CONSEQUENCE, and all your CONSEQUENCES are a result of your CHOICES."
Reply With Quote
  #8  
Old 01-25-2009, 09:42 AM
tomh tomh is offline
Skilled
 
Join Date: Aug 2007
Posts: 310
thanks guys! it looks like I have some work to do, and yes I would much rather make knives than fiddle with this! I think I might just build a bigger forge as well as re do this burner.


__________________
ABS Apprentice
www.tomhalloranknives.com
Reply With Quote
  #9  
Old 01-25-2009, 10:38 AM
Steven Kelly's Avatar
Steven Kelly Steven Kelly is offline
Steel Addict
 
Join Date: Oct 2005
Location: Bigfork, Montana
Posts: 203
Tom,

I have a 2 burner N.C. Tool Knifemaker Forge .. It is running 2 cast venturies that are basically 3/4" pipe.. I have to run between 12 and 15 psi gas pressure to get it to run. If I was to reduce my pressure down to 6 psi it would begin to back flash and burn in the tube. There are also a couple of issues you are going to run into going with a venturi type forge in your shop. For one thing, I have learned that you will never be able to get the gas company to plumb in that much pressure to your shop, should you ever want to run a large capacity tank instead of those smaller bottles that you have to have filled yourself. The second thing is that you may as well go ahead and purchase a 100lb. bottle now. Don't even bother using the 20 lb bottle off your bbg. The reason is that because you are pulling such a large volume of pressure off the bottle, it is going to freeze up when you get to about half empty. That means you will only be able to get about 2 gallons out of the bottle and then you will have to change it out and let it thaw for a couple of hours.
I'm not trying to discourage you from a venturi forge. I am just letting you know what I have gone through for the past 5 years...


__________________
Steven Kelly
A.B.S. J.S.

S.K. Knives
11407 Spotted Fawn Ln.
Bigfork, Mt. 59911
(406)837-1489
www.skknives.com
Reply With Quote
  #10  
Old 01-25-2009, 11:17 AM
tomh tomh is offline
Skilled
 
Join Date: Aug 2007
Posts: 310
Thanks for the input Steve. I am running a adjustable regulator, does that make a difference on using the huge tank instead of smaller bottles?


__________________
ABS Apprentice
www.tomhalloranknives.com
Reply With Quote
  #11  
Old 01-25-2009, 12:16 PM
cdent cdent is offline
Master
 
Join Date: Aug 2005
Location: aiea, hi
Posts: 805
Hi Tom,
If you're thinking possible redo, take a look a the venturi style called the modified sidearm burner (3/4"). It's an easy set up with little to no fiddling, and plans are readily available.

Good luck with it, Craig
Reply With Quote
  #12  
Old 01-25-2009, 01:04 PM
tomh tomh is offline
Skilled
 
Join Date: Aug 2007
Posts: 310
ijust realized I am using a 3/4 inch pipe, so I bought a 1/2" pipe and a new cap to make a smaller hole in. I will post results later. Thanks!


__________________
ABS Apprentice
www.tomhalloranknives.com
Reply With Quote
  #13  
Old 01-25-2009, 01:25 PM
Ray Rogers's Avatar
Ray Rogers Ray Rogers is offline
Founding Member / Moderator
 
Join Date: Jun 2002
Location: Wauconda, WA
Posts: 9,838
An adjustable regulator will allow you to pull more gas out of the bottle but, if you're using a small 20 lb bottle the pressure will still drop off quite a bit. Another advantage of using a 100 pounder is that they do not have OPD regulators in them like the smaller bottle do. This means you can adjust pressure with your regulator as you wish without having to worry that the OPD will shut off the gas if the back pressure drops too low. Also, the larger tank is much more difficult to freeze. With my 100 lb tank attached to a fair sized forge and two forced air burners I can run the forge about 20 hours. Obviously, if I were using 20 lb tanks that shut off before they were empty I would have a hard time forging for even 3 hours without interruption ....


__________________

Your question may already have been answered - try the Search button first!






Reply With Quote
  #14  
Old 01-25-2009, 02:28 PM
cdent cdent is offline
Master
 
Join Date: Aug 2005
Location: aiea, hi
Posts: 805
Hi Tom,
You may want to stick with the 3/4" and make it work. I think a 1/2" burner wouldn't quite heat the internal size of your forge.

The recommended mig tip for a 3/4" venturi seems to be .035", but there also seems to be an advantage to the shape of the tip.

Good luck, Craig
Reply With Quote
  #15  
Old 01-25-2009, 03:23 PM
tomh tomh is offline
Skilled
 
Join Date: Aug 2007
Posts: 310
just found out the 1/2" won't get hot at ALL!


__________________
ABS Apprentice
www.tomhalloranknives.com
Reply With Quote
Reply

Tags
forge, forging, knives


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -5. The time now is 01:21 AM.




KNIFENETWORK.COM
Copyright © 2000
? CKK Industries, Inc. ? All Rights Reserved
Powered by ...

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
The Knife Network : All Rights Reserved