Adding a blower to a forge....

McClellan Made Blades

McClellan Made Blades

Well-Known Member
This might be a dumb question, but I'm used to asking them, so here goes, how is a blower added to a gas forge? I'm working on building a new forge, and I really want to make sure I get to welding temps. Is it an additional port that feeds the forge after the burners are lit, seems like that would be the only way since the blower would blow the lighter out <duh> see what I mean! Any advice would be helpful. Thanks Rex
 
Generally a blower is incorporated into the burner assembly of a forge. It requires that you design the forge with the blower in mind. Forges are all about "balance"...meaning that the components are specifically sized to achieve the desired burn/heat.

Routinely the blower is the first component in line....then the fuel inlet, most will use a 90 degree elbow next to ensure a good fuel/air mixture, then a piece of pipe that goes into the forge.

Weldingforgeblower.jpg


If your trying to add a blower to a venturi burner, it can be done, but I don't think it's worth the hassles that go along with it, and the long term issues it can cause.
 
The gas in a blown burner should never be on without the air supply running. Lighting a blown forge can be a little tricky, at least compared to a venturi burner forge, because the air flow will tend to blow a match out; you will also get your fingers scorched. One method that I used to use was to light a bit of paper in the forge before turning on the gas. This frequently resulted in burning paper being ejected from the mouth of the forge. Now I just use a burning propane torch to ignite the forge as I turn on the gas at the ball valve which I install before or ahead of the needle valve that Ed shows on the gas line to his forge. I like the ball valve for two reasons. One, it allows me to turn off the burner immediately if needed, like of I loose power to the blower. It also allows me to light the forge without always having to readjust the needle valve each time.

Doug Lester
 
So with a blown gas forge you have to have the blower on all the time? I'm starting to think it would be better to fork out the bucks for a T-Rex burner now as this seems a little complicated, I'm probably complicating it myself more than necessary, such is my nature! Thanks for the help, Rex
 
Yep! The blower is always the FIRST thing turned on, and the LAST thing turned off. It's actually less complicated than a venturi burner.....you don't have to be as precise in matching components as you do with a venturi.
 
Ed,
After studying that picture with the blower, the line going into the pipe that the blower is feeding looks like it might be the propane line, is that right? Is there anyone building this kind of set up reasonably, something I can safely put into service? I was looking forward to building my own, but I'm a big chicken when it comes to gas (w/fire) and fittings. The stuff I have no experience with makes me a but leery, I've read several tutorials, and I tend to get lost in all of the tips, nipples and valves. Thanks for your help, it is greatly appreciated.

BTW Ed, I owe you a BIG THANK YOU! You probably won't remember me or my wife, I was working the KD booth at last years BLADE, I'm a big lumox, my son you might remember, cute little blond headed boy, everyone was calling the "Pup". You took a second to speak to my wife, who was not having the best time in the world and you made her feel welcome, it was our 2nd Blade show and I volunteered to work the KD booth. I know that's not an unusual act for you because you did the same for a friend of mine the year before, Thank You for going out of your way to make her feel welcome! The BLADE show is a huge deal to me as well as most of the guys that want to be called knife makers, and those of us that are married, it can be difficult to keep the wives happy during it. A happy wife can make any show a blast to never forget, and UN-happy wife at a show can destroy the entire day, or worse if your committed to be there for several days. You simply speaking to her did make a difference, I just wanted you to know that, it means a lot to me that you cared enough to make the effort. You are a class act my friend, Rex
 
If you want to buy a blown burner go to www.elliscustomknifeworks.com, he can supply one either finished or in a kit. All you have to do is supply the blower. He also supplies some of the harder to find parts for making one if you can't locate them at a hardware store. BTW, yes that is the gas line going into the black pipe and that is the only thing that needs to be drilled and tapped. It's sealed with pipe dope or plumber's tape. The other valves just have screw connections to join into the gas line. Two other things that are not shown on that gas line is the POL connector that goes to the tank (just as a heads up, it has a LEFT hand thread-don't ask), a regulator to step down the pressure, and a pressure guage, which is not 100% essential but is darn handy. Ellis also supplies these. Another BTW, pay attention to the in and out side while assembling the fittings to the regulator-again, don't ask.

Doug Lester
 
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Hey Guys thanks for the tips, I emailed Tim Z., to get a price for his forced air set-up, but what Darren Ellis has looks like the one for me, with a 1" burner it should get the heat I need. Thanks so much, I was about to give up on this notion and go with the more expensive option of the T-Rex Burner, while it does cost more, I believe it is just about the best burner made, I'll let y'all know how it comes out.

Ed, since I building a brand new forge, I would appreciate ALL of your input, I read on your web site that the round forge design was the best way to go, so I've got an 8" pipe, that's 14" long, for the insulation I went with Super Wool, they claim it's safer than Kaowool, as it doesn't emit fibers in the air while it's burning, then I'll add a layer of Satanite, and after that is cured, a coating of plistix. I'm planning on angling the burner at around the 1 to 2 o'clock position, I guess that's about 10 degrees to the right of center. Now Ed, this is what I've got planned, I value your knowledge and expertise so please if there is anything I have that's not right or could be better, please advise! Thanks so much, Rex
 
Hi Rex,
The T-rex is a great burner but it won't match a blown burner.
I built one of Larry Zoeller's 3/4" modified sidearm burners for about $25. It actually
has a few more BTU's than the T-rex according to the posted figures for each.
For welding apps I simply switch the mig tip from .035 to one I drilled out to 1/8".
I add a gate valve to the intake for air control and hook up to the exhaust on my
shop vac. It makes for a nice, inexpensive multi-purpose burner capable of handling
just about all scenarios. Here are some pics.
http://i1198.photobucket.com/albums/aa453/dcr135/Forgeatweldtemp.jpg
http://i1198.photobucket.com/albums/aa453/dcr135/000.jpg

Hope this helps,
David
 
I would discourage the use of Satanite for coating a forge lining with. It is a mortor, not a refractory and it's not very robust. I did one of my early forges with it and I was constantly having to recoat the matting. I'd get a small bag of Mizzou or Cast-O-Lite from Ellis Custom Knife Works, I think that he sells both in 5lb bags that will fit in a small bulk rate box. It will stand up to use better and you'll have to recoat the inside of the forge a lot less often.

Doug Lester
 
Sorry for taking so long to get back to this thread! I've had a student in the shop for the past few days, running daylight till dark.

OK, I'm gona be really frank on my opinions about forges.....first and foremost, the simpler the design, and the fewer devices and fittings you use....the better! I've spent a LOT of hours on the phone with some of these folks who insisted on building a PID controlled forge or something similar with lots of fittings and devices installed....the more you overtake the plumbing, the easier it is to stop up the drain!

Next, for an all purpose forge, I think that 8-10" pipe is the way to go. Length wise, if you're using a single burner, about the max length you can effectively heat is 15-17".
Insulation/refractory: Whichever you choose, you want the highest heat rating you can get for the chosen material. Here is where I will step on some toes....if you choose ceramic blanket, it should be 1" thick X #8 density.....NOT 2", nor two layers of 1". You can do it if you want, but your just wasting your money. 2" of ceramic fiber blanket requires a longer heat up time, and uses more fuel to maintain a given temp within the same interior dimensions.
Personally, I choose NOT to use the "safe wool" because the temp rating is so low compared to standard ceramic blankets.

Next, interior coatings...this is where it's going to be a "give and take" situation. Generally the "coatings" that resist flux the best, suffer in the area of insulation qualities...and those that provide the best insulation qualities suffer in flux resistance. I'm always experimenting to find the "magic bullet", but so far have not found it. Since I do this for a living, it's more important for me to have the heat when I need it, and durability takes a back seat to that. With that in mind, I use a slurry of ITC-100 to coat down the interior of my forges. ITC is not very flux resistant, but I can pull 500-1000F extra with it, versus without.
An idea that I'm going to try the next time I reline my welding forge is a slurry of Mizzou (which has very high flux resistance) over the wool, and once that cures, try going over it with the ITC-100 slurry.
If you're wanting one forge for all around use, I think a forced air burner is the only way to go. You can always turn down the air/fuel for general forging, and you will have the "umph" to weld when needed. Venturi burners simply cannot match the heat output and the economic fuel consumption of blown burners.
In the end it, you want something that first and foremost fits your needs. But you also need to consider reliability and ease of care. The burner image that I posted earlier in this thread has been in service, basically unchanged for over 10 years. The ONLY maintenance it has ever required was changing a burnt out blower, and pulling the gas line once, to remove a tiny particle from the orifice (it no longer has an orifice..the needle valve accomplishes the same function).
 
Ok, so far I've got most of the items you mentioned NOT to use already bought, I've been picking up items along the way for a year or so now, I've got Plistix which is supposed to comparable to
ITC-100, I've got Super Wool, in 2 inch thickness, and of course Satanite. So I will need to scrap all of these items and buy the other items mentioned...., I guess the way I feel about it is, that I asked for your expert opinion, I'd be a fool not to take it. Besides most of these items aren't real expensive, it's just buying all of them at one time that gets into the hundreds of dollars! I believe in doing everything I do to the best of my ability with the best of my knowledge, I'm sure I can use the Super Wool on another project that doesn't require as high a heat, as this will be my primary forge, I want it to get to heat fast and I want to reach welding temps when needed. I've had a thing for Damascus since the first time I saw it, it doesn't have to be anything fancy, my favorite is ladder pattern and rain drop, probably the easiest to make as far as patterns go ayway. The Satanite I've been using for clay coating so that has always had a place in my shop, so that's no biggie.

So my shopping list will read:
1" Kaowool, about 10 feet (?)
10-20pounds of Mizzoulo and/or Cast-O-Lite, probably go with the Mizzoulo for the bottom and cast o lite for the top and sides.
Ellis's blown forge assembly, which includes a 1" burner,
I haven't heard back from him on what CFM blower I need, I've found one that is 110cfm, for 20 bucks!!!

Another question I didn't ask Darren or Ed, how does the blower attach to the blower assembly? I know it has what looks like a 2" pipe with a turnoff valve there that looks like it's threaded inside, can PVC be used for that end provided it's far enough away from the heat? Looks like I'll be stimulating the economy, at least some! I think I will start posting some of my knives for sale in the very near future (if for nothing but off-setting the costs to keep making), that is one of my goals for this year. I really wanted to make sure they were good enough when I realized that I'm not the only judge of my work, it's the folks that are willing to spend their hard earned money for my work that will make that decision.
 
I'm not familiar with Darren's burner design, but on mine, I threaded on a "pipe flange" and then drill holes to match those on the blower housing, then bolted the blower to the flange. Mine has a small bead of RTV gasket maker to seal it up. For safety sake, DO NOT use PVC pipe anywhere in the assembly! It's just too big a risk. I don't say this to scare you or anyone else, but you have to realize that a propane forge is nothing more than a controlled explosion, with lots of potential for disaster....be smart and keep yourself safe!

I'll send you a PM on some other info I think you need.
 
EdCaffreyMS said:
...An idea that I'm going to try the next time I reline my welding forge is a slurry of Mizzou (which has very high flux resistance) over the wool, and once that cures, try going over it with the ITC-100 slurry...
Click to expand...

I think this could be a good strategy. Maybe you make a little Mizzou brick, coat it with the ITC-100 and let it ride along in the forge for a bit and see how it holds up. I've seen refractory coatings slowly heat up, while a thin ITC-100 coating immediately starts glowing, I think by reflecting the heat back in where it helps. My puppy forge stays comfortable to the touch with one inch of blanket, satanite and the light coat of ITC-100.

Mc, you may as well run what you brung. After you use your forge for a bit, you'll probably have ideas on things you'd want to change and you'll have tons of chances to buy rebuild materials. On a side note, I think there's differences in the ceramic fiber blankets. I've seen clouds of powder shake out of the kaowool brand that I would guess isn't much good for breathing in.

Good luck with it, Craig
 
cdent said:
I think this could be a good strategy. Maybe you make a little Mizzou brick, coat it with the ITC-100 and let it ride along in the forge for a bit and see how it holds up. I've seen refractory coatings slowly heat up, while a thin ITC-100 coating immediately starts glowing, I think by reflecting the heat back in where it helps. My puppy forge stays comfortable to the touch with one inch of blanket, satanite and the light coat of ITC-100.

Mc, you may as well run what you brung. After you use your forge for a bit, you'll probably have ideas on things you'd want to change and you'll have tons of chances to buy rebuild materials. On a side note, I think there's differences in the ceramic fiber blankets. I've seen clouds of powder shake out of the kaowool brand that I would guess isn't much good for breathing in.

Good luck with it, Craig
Click to expand...

Craig thanks for the input,
I checked on some of the prices, the price for 2700 degree Inswool HTZ is 16.50 for 2 square feet, I don't think that'll make me any poorer than I am! It's "high temp Alumina-Silica-Zirconia insulation" The main thing I pointed out is that I asked Ed for his opinion, and being that I value his opinion, AND the fact that I asked for it, it seems rude to me to not use it! That being said, I also want to increase my odds of success, why not learn from others experiences? In this wonderful knife making world of "share every ounce of knowledge you have", why not benefit from others experiences? The Super Wool I have will get put to good use, as I also want to build another forge for my son, once he earns it, but that's another story. Oh and Craig, call me Rex,
Does the ITC-100 act like the Plistix? My first forge is square, (before I knew better) and it was difficult at best to coat the enterior of it, and even once I felt like it was coated well enough, I couldn't really tell. It does seem to be getting hotter than what it did, but now it seems my burners are going out, after a short time on they start "huffing' like the tank is low, when it isn't. I've been burning this eBay bought forge for over a year now and it has served it's purpose for a newb that didn't know anything, to a newb that knows a little more and can make a servicable blade! It's just time to graduate to a better (hopefully) more efficient forge, with more capablities. Thanks Rex
 
EdCaffreyMS said:
I'm not familiar with Darren's burner design, but on mine, I threaded on a "pipe flange" and then drill holes to match those on the blower housing, then bolted the blower to the flange. Mine has a small bead of RTV gasket maker to seal it up. For safety sake, DO NOT use PVC pipe anywhere in the assembly! It's just too big a risk. I don't say this to scare you or anyone else, but you have to realize that a propane forge is nothing more than a controlled explosion, with lots of potential for disaster....be smart and keep yourself safe!

I'll send you a PM on some other info I think you need.
Click to expand...

Thanks Ed,
I want to say I seen that somewhere else, where the pipe from the blower was PVC, I don't remember where I saw it, or who did it, it's simple enough to use the same iron threaded pipe everything else is made of.
I've emailed Darren twice now, if I don't hear something from him by tomorrow, I think I may go with a different set up. I'm thinking about building my own burner, does anyone know if the Zoeller plans will work with a blower? I'll check his site to see what I can learn, thanks Rex
 
I think that Zoeller's burners are plans are venturi but any of his forges should work with a blown burner, if that's your question. If you already have 2" thick 8 pound or better ceramic fiber matting insulation, I would recommend that you stick with it. When it comes to relining the forge, which will eventually happen, you'll just have to strip out everything instead of just the top layer. One inch thickness is also a little easier to work with. The Plistix can still go over the castable refractory. You can always choke down the air flow on the 110 CFM blower. That sounds like you are getting plenty of refractory to coat the matting with. Keep the leftover dry; you will have to do some patching occasionally.

Doug Lester

What I have to connect my blower to my forge is a piece of flexable 2" plastic hose with one of those rubber connectors on each end. I'm fortunant that my bower has a round outlet that one end will clamp over and the other end is clamped over the 2" pipe on the base of the burner. I run this hose so that it stays out of the way of anything hot. The adjustable ring gadget that tightens with a screw driver allows me to easily switch the blower from one forge to the other.

Doug Lester
 
Hi Rex, I think you've gotten great advice. I'm glad you can do something with your original supplies, just hate to see stuff go to waist.

I think those venturi burners have a lot of guts in them that just isn't needed on a blown burner. He might be able to tell much better, but I think Ed's picture earlier is pretty much a parts list that doesn't have anything hiding on the inside. I use a sidearm burner and I think it's the cats meow, but it's not for welding and it runs a small forge.

Glad it's coming together, Craig
 
Craig's correct about the pic I posted, the ONLY thing you cannot see is that the end of the pipe which goes into the forge has concentric pipes for the last 3"....the pipe itself is 1 1/2" ID, with a 3" piece of 1" inside of that, and then a 3" piece of 1/2" inside of that. About the only thing it does for the burner is cut down on the "roar", and creates a more stable flame pattern.
 
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