283 posts in this topic

I deal with Zoro; they are pretty good. But Supplyhouse.com is a pleasant surprise; thanks for that.

If you read closely on his site, Larry said that his "Z" burner was hotter burning then his modified side-arm burner. It only takes changing out one fitting for another.

Most burners nowadays employ MIG contact tips as gas jets; they are cheap, powerful and easily found; but, as with most things,  they have irritating practical limits, which will sometimes force anyone who pursues maximum performance to go through some extra effort. The smallest contact tips are made for 023" welding wire; they have .031" orifice diameters, and are the best available tips for 1/2" burners. But .028" or .029" orifices would be better; you can only achieve that small an orifice by inserting a one inch long piece of capillary tube in the tip. For 3/4" burners, you have to choose between .023" and .030" MIG tips; one a little too small, and the other a little too large. I normally suggest purchasing the smaller tip, and enlarging it three or four thousandths of an inch with a set of torch tip cleaners. However, when used in a listless burner, the undersized tip can be just what the doctor ordered.

Learning how to "tweak" burner performance is just as valuable as building the right burner design exactly according to the inventor's instructions.

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Glad I could contribute! I currently have the .030 mig tip in my 3/4" burners and I based my build almost entirely from Ron Reil's pages and pictures of similar burners I could find from the Internet. I'll definitely be checking out Larry's "Z" burner as this is the first I've heard of a build of one. I've seen them for sale on his site (I also bought the flares for my burners from him) but I missed the plans for it.

On a side note I bought your book from Centaur Forge (it was over $100 on Amazon) but I got an email saying that the publisher was waiting on final edits from the author before it went back into print. Any idea on when it'll be available? I'm trying to soak up as much knowledge as I can find!

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Well; I guess I'll have to get back with the publisher! In the meantime, anyone can download a pirated PDF of the book for zero dollars.

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1 hour ago, Mikey98118 said:

In the meantime, anyone can download a pirated PDF of the book for zero dollars.

I have enough information on these pages to keep me occupied until it gets here, lol. Plus, I do better with hard copies of books than digital versions.

I misspoke yesterday, by the way. The jet tip I have in my burners now is a .035 Tweco tip. I'm not sure where I saw that size recommended but I'm sure it was from an out-of-date page. I ordered the .023 tips this morning and I'll be swapping them out whenever they get here. In the mean time, I'm off to research the "Z" burner and the "Mikey" burner!!

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So after looking at the "Z" burner on Larry's website it looks like the only thing that he changed in the design is that instead of using a reducing tee fitting he uses a sort of Y fitting instead. After reading all the info in here about the swirl of air and gas in the mixing tube I would assume that this gives as much of the attributes of a linear burner that you can get with a side-arm set up. Brilliant! I might have to see if I can find some of those fittings and do some "tinkering" as Frosty would say.

I also found where I got the .035 orifice suggestion from. It's on Larry's page in the side-arm section; he recommends a .035 or a .045 mig tip for the 3/4" burner and a .023 for the 1/2" burner. I'll try and post some pictures of my progress for other FNGs like myself.

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I have preferred orifice sizes for my burner designs, and others have different preferences for theirs; its all good.

 

Making gas jets from capillary tube & MIG contact tips

Employing reusable dispensers needles in Luer lock adapters as gas jets on small burner are pretty straight forward, and the small amount of care needed to cut them to length and clean out internal burrs afterward are the same as are needed for heavy wall capillary tube.

    I recommend using a Tweco plain series 14 MIG contact tip, for .052” welding wire (which actually has a .064” orifice), to closely match with the outside diameter of heavy wall stainless steel capillary tube, which mostly comes in 1/16”, .0625”, or .064” outside diameters. You can choose to swage the capillary tube in place within a MIG tip; or you can employ a series 14T (tapered) MIG tip, if you are going to silver braze the capillary tube in place. These tips are 1/4” diameter and 1-1/2” long (excluding their threaded portion); their thread is 1/4-28. Miller also makes a series of contact tips that are 1/4” diameter by 1-1/2” long (excluding their threaded portion, which is also is 1/4-28), but they are not tapered. Because stainless steel capillary tube comes in vary limited diameters, other heavy wall brass or even copper tubing, normally employed as electronic discharge machining (EDM) tubes, are also used as gas jets. Even thin wall hypodermic can be used, so long as both its inside and outside diameters are listed; it is available as dispenser needles, and as 3’ to 5’ lengths.

   MIG contact tips come in limited diameters, as do capillary and hypodemic tubing. You must begin your search with a tube with the desired orifice size (inside diameter). Next, you try to find a MIG tip with as close a match to its outside diameter as possible. If the tip’s diameter is within .0005” oversize to the tip, it is easily swaged down to trap the tube in it.

    You merely have to drill a 1/4” diameter hole in a short piece of 1/2” x 1” bar. Begin by scribing a line on the 1” face of the bar, somewhere near its center, using a combination square. Then scribe a second line from it, over the a 1/2” face. Use the square to find the center of the line on the 1/2” face, scribe a cross mark, and center punch it; drill the 1/4” hole completely through the bar. Use a thin cutoff disc to cut completely through the bar at the first line, and clean off all burrs.

    Place the desired length of capillary tube into the MIG tip, and place them within your new swaging die; Hit its top sharply with a hammer. Cut off the excess tube within a 1/8” beyond the die, and hand sand it back even with the tip’s face. Then clean out any internal burrs, with torch tip cleaners.

    If the MIG tip’s orifice is too small for the capillary tube to fit in, Use torch tip cleaners to enlarge it a few thousandths of an inch. You will find one round file in the kit to be small enough to push back and forth within the MIG tip, while turning it slowly. Every few minutes, you need to check the hole against the capillary tube, as it gradually enlarges. The new orifice will not be parallel, but end up slightly tapered; probably by less than one thousandths of an inch all around the periphery of the capillary tube. If, you are committed to silver brazing you tube in place, continue filing until it will slide into the tip to its desired length; its end will stop against the wall of the tapered MIG tip’s orifice; helping to stop the filler alloy from plugging up the capillary tube.

    If you would rather avoid silver brazing, stop 3/16” short of the desired length, and cutoff the capillary tube 5/16” overlong. Place the tube in the MIG tip, and screw the tip into place in the burner, or within a part that will end up in the burner (or within a threaded hole in a block of steel; whatever). Tap the whole assembly against a metal surface, or tap a hammer against the excess tube, until it comes within 1/8” of the MIG tip’s front face. Use a circular motion on very fine sandpaper (at least #300 grit or finer) to reduce it down to even with the tip’s face; use the torch tip cleaners to remove the tube’s internal burr.

    Wire gauge drill bits can be hand spun in a pin vice to enlarge holes in MIG tips to within a couple of thousandths of an inch of your capillary tube, so that hand filing an available MIG tip orifice to the right inside diameter never needs to become tedious.

    It is important for the MIG contact tip in most burner sizes to be tapered for proper air flow from the air intakes as it passes by the gas jet on its way into the mixing tube, or the mixing area in tube burners. How important? How small is you burner? The smaller the burner the more important it becomes. 

  

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Silver brazing capillary tube

    While there are a variety of sources for capillary tube, the easiest way to find any particular orifice size you need, still remains blunt end dispenser needles; all of which are stainless steel. Most easily available capillary and hypodermic tubes, are stainless steel; Stainless steels require the use of brazing alloys that contain 50% or higher silver content (the higher the better), and flux that is rated for use with stainless steel; most of these are black flux. I recommend Harris white flux for use on thin wall stainless tubing, rather than black flux, which is likely to be too aggressive.

    Just before brazing, use fine grit sandpaper to break up surface oxide, and to scratch up the tube’s smooth surface, wherever you want the silver braze alloy to adhere. Equally as important is to keep the flux well away from areas you don’t want the filler alloy to overrun, like the end of the capillary tube.

Harris white flux for stainless steel (#348-SSWF7POP): https://www.amazon.com/J-W-Harris-348-SSWF7POP-Brazing-Paste%252c/dp/B00PB9WJZ4/ref=sr_1_2?ie=UTF8&qid=1467760440&sr=8-2&keywords=harris+stainless+steel+flux  

Rio Grande 65% silver content brazing alloy #3101100, which is excellent and inexpensive; it is especially recommended for small pieces, such as stainless needles and capillary tube: https://www.riogrande.com/Product/silver-wire-solder-20-ga/101100

 

It is best to push an oversize length of tube into the tip, add flux to the tube, and draw it back into the hole, leaving excess tubing protruding from the end of the gas jet; and then cut, sand, and deburr the tube to fit, after brazing.

    Brass or copper EDM tubing can also be used to provide the right size gas orifices, by combining them with MIG contact tip holders of other sizes.

    Heavy wall nickel and stainless steel capillary tubing can be hard to find in desired orifice sizes, but are still available from Small Parts, which is now owned by Amazon.com: https://www.amazon.com/s/ref=nb_sb_noss?url=srs%3D3041233011%26search-alias%3Dspecialty-aps&field-keywords=capillary+tube  

If you have the choice, I recommend heavy wall capillary tube (AKA gauge tubes) over thin wall hypodermic tube, if you can find them in the orifice diameters desired (as they are far less inclined to be partially dissolved by the flux, should you be a little too slow with your braze work): http://ziggystubesandwires.com/Capillary-Tubing   

Various heavy wall stainless steel capillary tubes are also available from: https://microgroup.com/store/fractional-stainless-tubing.html  

1/16” (.0625”) O.D. in various inside diameters are available from Lab Express: https://www.labemco.com/capillary-tubing.html

Stainless heavy all capillary tube is available from Rapid Tube: http://cadenceinc.com/catalog/product-group/type-316-ss-capillary-tubing-cut-to-length/   

Stainless thin wall hypodermic capillary tubing are available in various orifice sizes from Rapid Tube & Wire: http://cadenceinc.com/catalog/product-group/type-316-stainless-steel-tubing/  

 

Various diameters of stainless steel cleaning wire are also available from Rapid Tube & Wire: http://cadenceinc.com/catalog/product-group/304-stainless-steel-wire/  

 

 

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Mberghorn said,

"I misspoke yesterday, by the way. The jet tip I have in my burners now is a .035 Tweco tip. I'm not sure where I saw that size recommended but I'm sure it was from an out-of-date page. I ordered the .023 tips this morning and I'll be swapping them out whenever they get here. In the mean time, I'm off to research the "Z" burner and the "Mikey" burner!!"

In that case, dropping down to the .030" tip might help you burner's performance.

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