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 03-11-2008, 08:12 PM
doublearrow doublearrow is offline
Skilled
 
Join Date: Feb 2003
Location: Pampa TEXAS
Posts: 470
my forge

When I first started knifemaking I wanted nothing to do with forging just something i didn't want to do. I just figured I'd buy damascus. Then I started talking to more and more customers and an ABS mastersmith and decided I'm going to jump head first into this knifemaking and decided to make a forge. Making things is another thing I had trouble with I didn't have the time I wanted to build it so I was going to buy them. That line of thinking can get expensive fast.
After getting started on building this I have no idea why I didn't want to try forging earlier. I haven't even received my insulation yet and I'm nine kinds of excited about this. I used Ray Roger's website and Indian George's tutorial. The only thing I couldn't find within a reasonable price was a blower. I looked at them on ebay, surplus houses, and what not and if they weren't trashed they were expensive (>$100) so I started looking at leaf blowers. This one is rated at 250 cfm and was 39 bucks at walmart and 30 at the local hardware store. I've got an extra gate valve lying around so I'll probably install it and a "t" between the blower and the adjusting valve incase I need to bleed off air to avoid too much backpressure on the blower. I cut 3.5 inches off the end and used a benzomatic to heat the black tip to make it fit over the nipple (the tube was more oval). Let me know what you think and if I should change something before I insulate it.
I didn't put the inlet at much of an angle my figuring was after 2" of insuwool and the coatings then it would line up with the top of insuwool enough to roll around the insulation. I maybe wrong but that's my figurin. Sorry for the rambling I'm just trying to waste time for the UPS man to show up with my oder from Darren Ellis.




__________________
Ryan Minchew
www.minchewknives.com
Reply With Quote
  #2  
Old 03-11-2008, 09:14 PM
Woodchuck Forge's Avatar
Woodchuck Forge Woodchuck Forge is offline
Skilled
 
Join Date: Feb 2004
Location: Salem Oregon
Posts: 634
First, 250CFM blower is way too much. I run my welding forge with a 75cfm blower that is choked back to almost nothing. The noise alone from that blower would drive me right out of the shop. I just got a brand new dayton 75cfm blower from Grainger for $65 delivered. I needed it for my salt pot project. I really like the fact you are using a Gate Valve, It provides great control. I would however put in a mixing chamber. This consists of a larger piece of pipe coming out of the gate valve then necking back down to your final burner size. The pressure difference helps mix the air/gas and prevents some of the problems with backflash. As with many things involving setting up shop, there are many different ways to accomplish it. Find the one that fits and run with it. i do feel however that leaf blower will provide entirely too much flow and is not meant to run for 8 hours continuously. Even 1-2 hours may burn it up. Not to mention the noise again.....


__________________
http://www.woodchuckforge.com
Avatar, Scott Taylor Memorial Scholarship Knife
Photo by Bob Glassman
Chuck Richards ABS J.S.
Reply With Quote
  #3  
Old 03-11-2008, 09:22 PM
doublearrow doublearrow is offline
Skilled
 
Join Date: Feb 2003
Location: Pampa TEXAS
Posts: 470
Thanks for the advice I figured the leaf blower would be too much so that's why I'm thinking of installing a second vavle with a t to let any excess off. Do you think 75 cfm is enough to run a 10" diameter by 16" long? From my reading I just planned on getting a 100 cfm and couldnt find any so I found a cheap 250 and went with it. Again I appreciate it.


__________________
Ryan Minchew
www.minchewknives.com
Reply With Quote
  #4  
Old 03-11-2008, 09:46 PM
Woodchuck Forge's Avatar
Woodchuck Forge Woodchuck Forge is offline
Skilled
 
Join Date: Feb 2004
Location: Salem Oregon
Posts: 634
Mine is 8" ID x 18 inches long. Also the blower is choked back a great deal. I would guess it is putting out 15-20CFM at most. I tried a higher output blower with a bypass valve that I was using as an air curtain. Just could not stand the noise and it was very hard to adjust. I burned up a 100lb bottle of propane in about 2 hours. Not the results i wanted. Went back to the drawing board and just copied Wayne Goddards design. Works great and lasts a long time. I have made some modifications to allow more control at lower temps but it still comes up to temp fast and is very economical.

PS been using it for over 8 years now.


__________________
http://www.woodchuckforge.com
Avatar, Scott Taylor Memorial Scholarship Knife
Photo by Bob Glassman
Chuck Richards ABS J.S.
Reply With Quote
  #5  
Old 03-11-2008, 09:49 PM
doublearrow doublearrow is offline
Skilled
 
Join Date: Feb 2003
Location: Pampa TEXAS
Posts: 470
dang after reading about the guys looking for 100 cfm blowers I figured i needed something around that. After your first post I started looking for the squirrel cage blowers. I found out the actual name is shaded pole blower or if it's not it did show up with a handfull of cheaper blowers. I really appreciate the advice.


__________________
Ryan Minchew
www.minchewknives.com
Reply With Quote
  #6  
Old 03-11-2008, 10:09 PM
ranger1's Avatar
ranger1 ranger1 is offline
Hall of Famer
 
Join Date: Dec 2005
Location: Lexington,NC
Posts: 2,414
My forge is 10 X 18 .I got my blower off E-Bay for $23.oo. The forge kicks BUTT. I do have the blower cut way back. Its a squirrel cadge with a homemade adapter.


__________________
Andy Sharpe
I ruin perfectly good steel!!
www.sharpeknives.com
Reply With Quote
  #7  
Old 03-11-2008, 11:09 PM
Doug Lester Doug Lester is offline
Hall of Famer
 
Join Date: Sep 2006
Location: Decatur, IL
Posts: 2,563
Cheap blowers can be rare as hen's teeth sometimes. I got one that works well of Ebay for I think around $75 that was rated at 80cfm. This seller usually has one or two for sale and I'm happy with mine. It's a squirrel cage blower with a choak plate on the front. It comes with a power cord that you have to wire up to a switch. I just screwed a plastic terminal box to a board and just wired the motor and the cord to a regular wall switch. The only thing is that the motor is not wired with a ground but the cord and plug has one. One of the men at the local Lowes told me to run a wire from a screw on the housing of the blower to the ground terminal on the switch along with the ground wire from the plug wire for safety. Even with some of the more expensive parts that I bought, building my own forge was considerably cheaper than buying one ready made.

Doug Lester


__________________
If you're not making mistakes then you're not trying hard enough
Reply With Quote
  #8  
Old 03-11-2008, 11:13 PM
Ed Caffrey's Avatar
Ed Caffrey Ed Caffrey is offline
Super Moderator
 
Join Date: Jun 2002
Location: Great Falls, Montana, USA
Posts: 4,254
Send a message via AIM to Ed Caffrey Send a message via Yahoo to Ed Caffrey
I agree with Chuck. I list a 100cfm blower in my forge plans, but that is mainly due to folks not understanding that most of the smaller blowers are not built to handle back pressure, and will only pump out about 1/2-2/3rds of the rate cfm when used in a forge application. The easy way to tell about a blower is to turn it on, and then cup your hand over the outlet (not tightly) and see if the blower forces air out....most of the time the smaller blower will just run faster, but not push air past the obstruction of your cupped hand. I was having major problems with that issue, and finally went to this blower.......
http://www.blacksmithsdepot.com/Temp..._Parts/blowers

Its a bit pricey, but will handle back pressure, and my current one has been in service for nearly 5 years with no problems.


__________________




Caffreyknives@gmail.com
"Nobody cares what you know.....until they know you care."
See me at table 2Q at the Blade Show!
Reply With Quote
  #9  
Old 03-12-2008, 10:22 AM
Ray Rogers's Avatar
Ray Rogers Ray Rogers is offline
Founding Member / Moderator
 
Join Date: Jun 2002
Location: Wauconda, WA
Posts: 9,802
That's a really thick forge body you have there. Nothing wrong with that, but I eventually figured out that even a shell that was only .030 thick will work just fine.

What I want to talk about is the burner design. The design you have might work OK because you have a 250 cfm blower and that should supply enough velocity to the gases to function with that very large diameter outlet you have. As has already been pointed out, it would probably be far, far too much but it could function correctly I'm guessing. As others have said, less than 100 cfm will work for a forge but I don't believe it will work well with your burner as it currently sits. The easiest modification I can see would be to reduce the portion that inlets into the forge body to 1". This would create the mixing chamber Chuck mentioned and, just as importantly, it will increase the velocity of the gas as it passes into the fire chamber. A low pressure, low volume blower won't have much velocity at the mouth of a 2" outlet. Consequently, the fuel will burn at the mouth or perhaps even back inside the burner which can be very dangerous or at least very inconvenient. The leaf blower could overcome this but you already know that's not the solution.

Whether or not you need 100 cfm depends on the design of the rest of the forge. On my forge, my blower is just barely adequate because of my unusual design requiring the use of the long narrow hoses I use to feed my two burners. I think if I were going to use your leaf blower (since that's what you have) I would hook it up through a long hose to get the blower outside and away from me (the noise issue) and also bleed off some pressure as you originally planned. At the outlet into the forge body, you should feel air pressure similar to that from a hair dryer (rather than a leaf blower tornado) to start with, then adjust from there....


__________________

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






Reply With Quote
  #10  
Old 03-12-2008, 11:46 AM
doublearrow doublearrow is offline
Skilled
 
Join Date: Feb 2003
Location: Pampa TEXAS
Posts: 470
Too many pipeliners running around here so that's how I ended up with a thick piece of pipe. It was free so I took it.

I have 1.5" pipe burner with the 1/4" nozzle i guess it what is is called going into the forge held in place by a 2" pipe with a set screw. Is 1.5 pipe going into the forge what I need to take down to 1" or is it the 2"? If I take the 1.5" pipe down to 1" and install a squirrel cage blower (if I can find a decent price) will that get the velocity I need? I used the size parts Indian George did in his tutorial, but I'm rethinking it now after reading ya'll's advice. My forge will look pretty much identical to Ranger1 only a couple inches shorter and my welding is not as nice. I appreciate the advice and any additional help.


__________________
Ryan Minchew
www.minchewknives.com

Last edited by doublearrow; 03-12-2008 at 11:52 AM.
Reply With Quote
  #11  
Old 03-12-2008, 01:49 PM
Ray Rogers's Avatar
Ray Rogers Ray Rogers is offline
Founding Member / Moderator
 
Join Date: Jun 2002
Location: Wauconda, WA
Posts: 9,802
Free is good, I'm very fond of that price.

You lost me with the 1/4" nozzle reference. I see the gas feed at the elbow in your picture but I don't consider that part as 'going into the forge'. For that, I mean the tube that actually extends into the forge body, through the wool insulation, on into the fire chamber - the actual orifice that admits the gases into the chamber. You would hope to see a tight looking flame sitting on top of a small section of clear (not yet ignited) gas which itself is sitting on the end of the burner tube. Most forced air forges use a 3/4" or 1" tube for this burner tube. Unlike venturi burners, there is no 'nozzle' or pin hole type aperture in a forced air burner, just a 1" open tube.

So, I can't see what goes into the forge but if it's a 1.5" tube then, yes, I think you should reduce it, probably to 3/4" since a ratio of 2:1 is pretty common. Yes, a squirrel cage blower can do the job if, as Ed pointed out, it is capable of handling the back pressure. Unfortunately, it is very rare to find a squirrel cage blower advertised with a pressure rating so it's often a shot in the dark if you buy one. Notice that the blower that Ed recommends (the same blower I use) is advertised as providing 40 oz of pressure and 164 cfm. For that reason, you should probably follow the links others have provided to their blower source so that you get a blower that's known to work ....


__________________

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







Last edited by Ray Rogers; 03-12-2008 at 01:56 PM.
Reply With Quote
Reply

Tags
forge, forging


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 12:58 PM.




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

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
The Knife Network : All Rights Reserved