JKeetonKnives

Blown Burner Build & Introduction

Recommended Posts

Hey guys... so I'm new here. I'm a weekend warrior knife maker in West Texas. I do mostly stock removal knives right now, but am looking to venture more in forging. I use my forge mostly for heat treating currently. I'm happy to have found this community! I'm mostly active on bladeforums, but I'm staring to branch out some. I figured I'd try and start strong with a burner tutorial. I've also done a Frosty T burner build, but it looks like this forum is saturated with guides on those. 

 

I've really enjoyed my blown burner vs the venturi because it allows me to run the forge at lower temps. This has really come in handy for forge heat treating... which is most of what I currently do with my forge. The blown burner also has a "higher top end" than my small T burner and it can do so at a much lower PSI. 

 

If found in building both blown and venturi burners that it's more cost effective to get the fittings online... Supplyhouse.com has better prices than my local big box hardware stores and they have more options. I also got a ESD fail close solenoid for this system off of amazon... in case the power goes out during operation. 

 

Cheers to all! Have a great Tuesday! :D

 

48386989342_607a06fe97.jpg

 

48386848176_1f390a98cc.jpg

 

 

Share this post


Link to post
Share on other sites
Posted (edited)

 welcome aboard.   I think the point of Frosty's t burner was simplicity. He's a member here so he could tell you more about it than me.

Pnut

Edited by pnut

Share this post


Link to post
Share on other sites

Where in West TX?  I'm currently moving from La Union NM (El Paso lite); but have some contacts in that area. Including one fellow who gets paid and plane fair to do mosaic damascus demos around the USA.

I must admit that I tend to buy my fittings at the ReStore and scrapyard as they are generally MUCH cheaper than on-line; like all the pipe fittings for under US$5.  I don't use a pressure gauge as I tune by eye and ear.  Of course I haven't used my blown burner in a long while as my current shop is electricity deficient and so I switched to my NA forge for most of my propane work. (I just moved one of my coal forges under the chimney before I headed into town to mooch internet from my church's wireless---with permission of course.)

Share this post


Link to post
Share on other sites

I like the concept, and use a similar forge myself. I'm curious about the nozzle (pipe?) entering the combustion chamber. Steel doesn't tend to last long in that type of environment.

Share this post


Link to post
Share on other sites
3 hours ago, Ted Ewert said:

I like the concept, and use a similar forge myself. I'm curious about the nozzle (pipe?) entering the combustion chamber. Steel doesn't tend to last long in that type of environment.

So the pipe nipple that enters the forge recessed back some from the kaowool lining. The kaowoll and satanite are shaped in such a way to almost create a nozzle. If it ever fails, it would be as easy as replacing a nipple I guess. Haven't seen any indication that it will be an issue though. 

 

Cheers! 

3 hours ago, ThomasPowers said:

Where in West TX?  I'm currently moving from La Union NM (El Paso lite); but have some contacts in that area. Including one fellow who gets paid and plane fair to do mosaic damascus demos around the USA.

Around Odessa B)

Share this post


Link to post
Share on other sites

I think you'd do well to eliminate as many brass fittings as possible in your NA burner. Say, put the pressure gauge directly after the regulator and 1/4 turn shut off valve. Sub to the solenoid directly after the hose then a manifold and copper tubing to each burner. If you''re running more than one burner then a 1/4 turn ball valve on each burner's final supply line, followed by a needle valve for fine control. 

The 1/4 turn ball valve after the regulator is your emergency shut off if things go really :o B A D. The ones at the manifold are individual burner shut offs. 

I like copper tubing to the burner as it's flexible, strong and can't burn. It's safe. 

All those brass fittings only weaken the device structurally, there is too much bending moment on all those fragile brass fittings, they are only strong in ONE direction, tensile so bending them tends to crack and break them. A BAD thing when playing with flammable gas under pressure and you don't want to use the emergency shut off for real do you?

Gun burners are easier to make and you learn to tune them by practicing every time you change the output. I find gauges pretty much just decorations on gun burners, it's not like you have a gauge or meter on the air flow so what's the use? 

Subbing your air supply line down between blower and the burner doesn't effect anything you might just as well save money and buy your final burner nozzle diameter all the way. A blower as drawn is a "Transparent" compressor, meaning  blocking input or output doesn't make the motor stall, heck they're not moving air, they actually speed up. You can blow straight through the blower without inhibiting the flow. It's fluid flow transparent. 

Anyway, you can sub directly from the blower to your burner nozzle dia. pipe and put at least one 90* turn after the gas jet to help mix the fuel air, two 90*s is better but no good reason to get carried away.

Good to see drawings, they are much easier to understand than photos. All in all well done.

Frosty The Lucky.

 

Share this post


Link to post
Share on other sites
14 hours ago, Frosty said:

Subbing your air supply line down between blower and the burner doesn't effect anything you might just as well save money and buy your final burner nozzle diameter all the way. A blower as drawn is a "Transparent" compressor, meaning  blocking input or output doesn't make the motor stall, heck they're not moving air, they actually speed up. You can blow straight through the blower without inhibiting the flow. It's fluid flow transparent. 

The only thing I worry about with increasing the diameter of the nozzle is blowback. There has to be sufficient gas velocity to overcome the flame front. I turn my flow way down when the forge gets hot, which also decreases the velocity. I've had blowback issues in the past under these conditions when I had too many ports in the burner and not enough velocity. Something to consider anyway. 

Share this post


Link to post
Share on other sites

He's running a gun burner Ted, WAY below the blower's capacity it's not going to blow back returning to the main duct size. The blower doesn't produce enough static pressure to accelerate the stream significantly with the reduction shown. Take it from the legend eh? 

OI VEI! When they decide the date of my holiday we'll talk about legend. :rolleyes:

Frosty The Lucky.

Share this post


Link to post
Share on other sites

I know, I run the same type. I have it 90 percent choked off at start up and decrease it as the forge heats up. This design needs very little air to get quite hot. I have more trouble keeping the heat down than anything else. This means choking to 95+ percent resulting in a pressure / velocity loss at the nozzles. I've plugged up all but 5 nozzles and that's about right for my rig. I've also noticed that the more nozzles I plug, the higher the efficiency of the forge.

At a high amount of choke, there is relatively little gas velocity in the bigger pipes. It's only when the diameter is reduced sufficiently that the gas velocity surpasses the flame front speed. 

Nevertheless, if you have both ends of the combustion chamber wide open and flames shooting out everywhere this is of little concern. You could probably have a 2" nozzle and get away with it.

I look at my forge more as an oven, where there are no flames exiting anywhere, thick doors on the front and a small exhaust hole in the back. I do everything I can to keep the heat inside and it has paid off. At 95% choke I can have a bright yellow/white combustion chamber which reheats most work in 15 to 20 seconds. 

Share this post


Link to post
Share on other sites

We're playing in the same puddle Ted, I'd be tuning for max whatever I needed. You have to balance everything and one of the real advantages of a gun is being able to close up the furnace almost completely.

One of the guys in the club has a commercially made gun burner that are unfortunately unavailable now. It takes a moment to tune it but it has no trouble bringing a brick pile forge to bright yellow and holding it there after being turned down. The darned thing is little more than a small blower with a fitting for propane and a needle valve. 

Pat used to use it for moderate sized bronze melts but mostly uses one of his home built melters now, he casts commercially and teaches so the little burner isn't used much. If I could buy one I'd be experimenting with a recuperative wall forge. Not recuperative by preheating the the burner output, recuperative by heating the flame face of the furnace chamber from both sides. Basically circulate the exhaust through a space between the inner flame face liner and the outer insulating layer. 

Gotta have a gun though.

Frosty The Lucky.

Share this post


Link to post
Share on other sites

Hey Mikey98118, you can see the forge running at about 1.5 psi towards the end of the video (10:00). Much of the video I have the forge barley running... in an attempt to keep the temp below 1600F. 

 

Have a great weekend!  :D

Share this post


Link to post
Share on other sites

I did see your video and liked your forge. I meant to wheedle Frosty into giving us more information about his friend's burner. I don't think we feature gun burners near enough on this forum.

Share this post


Link to post
Share on other sites
22 hours ago, Mikey98118 said:

How about a photo of his burner running?

Don't have one, I'll try to remember at the next meeting. If I get by Pat's sooner I'll get a couple pics of the burner and placard. 

Frosty The Lucky.

Share this post


Link to post
Share on other sites

Greet. Frosty. I think gun burners are only going to increase in importance because of the whole ribbon burner thing :)

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.