First post and looking for Blown Burner Advice

[gofast]

Hi All,

 

Absolutely new to the forum.  I've been fooling with metal for years and have many tools for smithing including two anvils, post vise, swage block, and an assortment of tongs and hammers.  I also have a pile of high carbon steel and have booked myself into a few classes.  I've taken a few lessons too.

I'm pretty much set on building my own forge and would like to go with a blown burner.

 

Search hasn't netted me results yet other than this link http://www.iforgeiron.com/topic/19623-forced-air-burner-design/#comment-202388  many other links appear to be broken.

 

I'm building a Peot style forge  http://www.spaco.org/Blacksmithing/PipeForge/PipeForgeAndPropane.htm

 

Any advise on threads to read or things to avoid would be really welcome.  I'm trying to figure out what parts to find for my burner including the parts needed for hook up to a tank.

Here's a drawing of the forge design I'm considering:

 

Thanks,

 

John

[Frosty]

Welcome aboard John, glad to have you. There isn't a lot of difference in the forge itself between naturally aspirated and gun (blown) burners. The basics of the drawings are fairly good for a forge. There is a LOT of recent discussion here about forge construction and kiln washes.

Probably the most relevant factor to consider is the furnace's volume and shape. A well tuned, 3/4" burner (determined by the nozzle diameter) is generally good to bring 300-350 cu/in to welding temperature, say 2,300f. It doesn't matter if it's a gun or NA what makes heat if putting X amount of burning fuel air in the chamber per second. PERIOD.

Building a gun burner is much easier than a NA it doesn't require the metal shop skills as they're don't require precise work. That just is, no reflection on anybody. I can't tell you what volume or pressure a blower needs to output to work well but more than you need is much better than less. It's easy to gate the blower and reduce it, heck you'll be doing that to keep it tuned in operation anyway.

Frosty The Lucky.

[gofast]

1 hour ago, Frosty said:

Welcome aboard John, glad to have you. There isn't a lot of difference in the forge itself between naturally aspirated and gun (blown) burners. The basics of the drawings are fairly good for a forge. There is a LOT of recent discussion here about forge construction and kiln washes.

Probably the most relevant factor to consider is the furnace's volume and shape. A well tuned, 3/4" burner (determined by the nozzle diameter) is generally good to bring 300-350 cu/in to welding temperature, say 2,300f. It doesn't matter if it's a gun or NA what makes heat if putting X amount of burning fuel air in the chamber per second. PERIOD.

Building a gun burner is much easier than a NA it doesn't require the metal shop skills as they're don't require precise work. That just is, no reflection on anybody. I can't tell you what volume or pressure a blower needs to output to work well but more than you need is much better than less. It's easy to gate the blower and reduce it, heck you'll be doing that to keep it tuned in operation anyway.

Frosty The Lucky.

Thanks Frosty!  I think I got most of it down and you've confirmed for me the lack of precision needed with a blown SYSTEM which if I'm learning might just be what the Smith ordered.

 

Seems that you're suggesting the 3/4 will work for the burner nozzle for a blown system? And this would be wide open? not the typical 1/4 npt nipple with mig tip? 

If so that's really easy to make!

 

[Frosty]

The 3/4" number is the diameter of the burner nozzle into the furnace chamber. The gas is fed through a "jet". The larger the jet diameter the lower the pressure for the same volume. I wouldn't use the same size jets and pressures as a naturally aspirated burner of the same size. It's unnecessary as the burner doesn't need the velocity to furnish the power to intake air. Larger lower pressure gas jets allow you to place them creatively.

With gun burners, especially home made ones it's a good idea to have the flow turn a corner after the gas is introduced. It really helps mix it and if there's a back fire corners will really blunt the pressure wave if not stop it. Blowers don't like explosive backfires.

My favorite jet placement is at the blower intake port so the impeller can mix the fuel air AND you can just clamp it on rather than drill, tap and clamp or whatever to put it somewhere in the middle of the burner tube.

More efficient  and easier is my kind of device.

Frosty The Lucky.

[WayneCoeArtistBlacksmith]

For  a blown burner I like the Ribbon Burner.  Go to www.WayneCoeArtistBlacksmith.com Forge Supplies page.  There are two attachments there, one Build a Gas Forge and the other is titled Ribbon Burner.

Let me know if I can help you.

[gofast]

14 hours ago, WayneCoeArtistBlacksmith.c said:

For  a blown burner I like the Ribbon Burner.  Go to www.WayneCoeArtistBlacksmith.com Forge Supplies page.  There are two attachments there, one Build a Gas Forge and the other is titled Ribbon Burner.

Let me know if I can help you.

Thanks Wayne the article on the burner is exactly what I need.  I might even try making the ribbon burner.  

[Mikey98118]

If you're going to rigidize the ceramic fiber, forget the inconel studs. they are a complete waste of time and money, in return for nothing but creating a bunch of heat sinks, with which to siphon off internal heat.

I don't think you'll be very happy with a ribbon burner operating in such a confined space.

[gofast]

On 1/20/2016 at 11:28 AM, Mikey98118 said:

If you're going to rigidize the ceramic fiber, forget the inconel studs. they are a complete waste of time and money, in return for nothing but creating a bunch of heat sinks, with which to siphon off internal heat.

I don't think you'll be very happy with a ribbon burner operating in such a confined space.

Hey Mikey,

https://www.abana.org/downloads/pipeforge_plans.pdf

Finally found this after looking for a blower info - shows a simple forge design with plans to build the blower.  I'll think I just use firebrick on each end of the forge.  When I start learning to heat treat I might buy an oven specific for it.

 

 

[Frosty]

It's a good basic design but old in '92 when ABANA published it. No need to use "pipe" for the body, even Ron and Hans were using old propane and helium tanks by time this was published. All the outer shell needs do is contain the refractory, provide enough strength for attachments, (burner, lets, etc.) and support the work. Unless you're going to be putting pieces weighing over 100lbs. even stove pipe works just fine.

The flame orientation is good, it's been proven good for well more than a century.

A good door design is a track you can slide the closures horizontally. It's more convenient than just stacking bricks and a nice open track doesn't suffer warpage too badly. Either works just fine.

Frosty The Lucky.