Burner angle

[DirtyDusty]

Been looking over multiple threads and I think I am more confused than when I started.  If I understand Mr. Porters advice, in other threads, I need to come down 2” from top dead center and angle it so that the burner hits the floor directly under it, but slightly angling towards the opposite side.  The pic I attached is my interpretation of it, does it look correct?  Wouldn’t this create a direct hot spot on the piece in the forge?  

 I have looked at quite a bit of pics that have the burner down lower, and pointing at the opposite corner of the floor.  

I plan on lining the forge with Satanite on the sides and ceiling, and using mizzou for the floor.  Intended use would be for forging and heat treating knives.  

[Mikey98118]

Yes; your interpretation is correct so far. The idea is to aim the burner so that the flame impinges close to the near edge of the floor area, missing the wall and the work, but still angling enough to encourage swirl. The key thought here is to encourage flame swirl; not try to create as much as much swirl as possible.

[DirtyDusty]

How far back should the burner be, for a single burner forge?  Dead center, more toward the front, but angled back, or in the back angled slightly forward?

Also, I was reading your book on building a 3/4" burner, and it said to make four slots for the air intake.  I thought I had read on a post, here at IFI, where you said the updated version needs 3 slots.  I can't find that post anymore, is that correct, or am I confusing it with another thread?

[Mikey98118]

For a single burner, in the middle is standard. If I were going to tweak that some, I would move it toward the back a little; NEVER toward the front. Or to be more specific; never closer to the main exhaust opening. You want to gain hang time for the flame; not lose it.

[DirtyDusty]

Started assembling my burner.  I used 3/4” blank iron for the main body, 1”schedule 40 for the spacer ring sing 1 1/4” stainless schedule 40 for the flame nozzle.  The 3/4” to 1” was a good tight fit.  The 1” - 1 1/4” has gap around it.  Will this be detrimental to the performance?

[Mikey98118]

That is a little larger gap than I would feel comfortable with, BUT, try the burner and see if the design will tolerate it; if not you can stuff some ceramic fiber around the back part of the nozzle to seal the gap (to keep it from inducing to much air), wihile you search for an additional spacer ring.

[Mikey98118]

How did my answer work out for you, Dusty?

[DirtyDusty]

On 12/1/2018 at 9:08 PM, Mikey98118 said:

How did my answer work out for you, Dusty?

I just got it finished, I think. I started with a .023 mig tip, but I was having to close the choke almost all the way to stop the flame from blowing out.  Ran it from 5-15 psi.  Next I switched to a .030 tip, I can open the choke between 1/4- 1/2 way open and see the flame shorten and lengthen. The air openings are @5/8” wide and there are three.  Not sure if I should try a .035 or leave it be.  Put it in the forge and fired it up until it got red hot inside, put it together with an idler circuit. 

Angle seemed ok, I set the burner edge, to the back side of the center line of the forge.  It gives a hotter area in the back, so I angled slightly forward with the adjustment screws.  I have to get some baffles set up for the front and back.  

The video shows the burner going from idle to full fire at 15psi.

 

Tried adding video, it wouldn’t load right  

 

 

[Mikey98118]

16 minutes ago, DirtyDusty said:

I just got it finished, I think. I started with a .023 mig tip, but I was having to close the choke almost all the way to stop the flame from blowing out.  Ran it from 5-15 psi.  Next I switched to a .030 tip, I can open the choke between 1/4- 1/2 way open and see the flame shorten and lengthen.

First off, congratulations; you have achieved the magic flame.

It is possible but unlikely that you will want to change out that .030" MIG contact tip for a .035" tip. It is far more likely that you will want to use a set of torch tip cleaners to enlarge the .030" MIG tip to around .041" diameter. The actual orifice diameter of a .030" MIG tip is .038" and the actual orifice diameter of a .035" MIG tip is .044". MIG conatact tips are listed for the welding wire diameter they are meant to handle; not their orifice size.

Of course hand filing a contact tip's orifice a few thousandths large with torch tip cleaners isn't a fast and easy task ( about half an hour of cautious work), so if you can buy the larger tip and try it out, without much hassle first, that is what I would try. What I think you will end up with for a flame from the larger tip will be quite hot but ever so slightly reducing. Most blacksmiths would up for such a flame, but a picky butt like myself could never trade in perfection for advantage \

If you are anything like me, the gap in your retention nozzle will bug you. Since you have digital calipers, you can check the inside and outside diameters of thin wall  tube like copper water pipe and electrical conduit for a more satisfactory solution.

'

[VainEnd84]

3 hours ago, DirtyDusty said:

Tried adding video, it wouldn’t load right  

I've had the same issue, as have others. You can always upload the video to youtube and then post the link.

[DirtyDusty]

One thing I may have going on is, I wasn’t sure if I needed the end of the tip past the air openings, into the tube, or a 1/4” back from the edge of the openings.  For now, I put a little Satanite on the back end of outside, of the nozzle. 

[DirtyDusty]

Definitely have a hot spot in the back. Hoping once I restrict the openings it will do better. 

[Mikey98118]

I'm looking at a very hot forge; especially considering that one end of it is running wide open so that you can photograph its inside. Well done

[DirtyDusty]

How much open area would it normally require, on each end, to still allow the burner to run efficiently?  

[Mikey98118]

As always, the answer is it depends. The back opening is normally only used for longer than usual objects, which means that yours is a little on the large size for that purpose. Since the back opening is seldom used, some builders keep it closed, when not needed, with a flap or plug; this also ends the need to resize your back opening.

The best opening size for the front of a forge is...wait for it...variable; for this and other good reasons, a baffle wall just in front of that opening trumps trying to come up with just the right sized opening on the forge. Usually a few bricks (no, they don't have to be insulated) are placed in front of the opening at a very short distance; this allows the middle layer of bricks to have convenient gaps between them. I strongly recommend that bricks be used first; at least long enough for you to familiarize yourself with various aspects of baffle walls before attempting more sophisticated forms.

[DirtyDusty]

Well I had already cut out a shape of the door, from 1” insulboard. Coated it with sataniye and ITc 100. I was planning to make a hinged door similar to what was in the book.  As far as the back, I had put a shelf under the opening, and made 2 sliding baffles from insulboard for it. There is also a shelf in the front place to place bricks. 

 

What kind of psi psi will the burner run at?  I have only cranked it up to 15 so far. I had a piece of round did in there for a few minutes and it got almost to yellow heat. 

[Mikey98118]

Go ahead and install the insulboard; you don't want to waste anything that expensive; besides, the board's opening can always be cut larger if needed. And a baffle wall can still be used if the opening ends up being too large. You still gain an advantage from an overlarge opening around the exhaust area, in that it changes the exhast's direction, slowing it down before it leads the forge. Then a baffle wall will help speed the expended gases back up as they leave; a win-win situation. Plus you get the benefit of maximum retention of radiant energy. You should find the fron end almost matching the back end of the forge for heat level; a level that will itself rise.