Propane-Air brazing torches

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cyberbadger
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Re: Propane-Air brazing torches

Post by cyberbadger » Mon Jun 05, 2017 7:06 pm

DetroiTug wrote:If you plan on doing the steam hobby, I would use the funds intended for an alternative and just spring for the Oxy/Acet setup. You'll be glad you did.
I second this.

I oxy/acet weld, can't stand electric. They are very versatile rigs from welding, brazing, cutting etc. Mostly I've done mild steel welding, but I'm just waiting for the first little job to get into brazing.

-CB
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Re: Propane-Air brazing torches

Post by Lopez Mike » Mon Jun 05, 2017 7:27 pm

Don't get me wrong. I use my oxy/acet gear regularly for concentrated heat and, given my ineptness with my Mig, for light gauge work. I've built about a zillion two stroke exhaust systems with no serious problems. The sort of thing where I do a very exact fit and then don't need filler. And it is indispensable for getting frozen nuts off and, of course, cutting steel.

The horrible economic truth is that you end up needing it all. I am holding off on TiG for mostly economic reasons.
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Re: Propane-Air brazing torches

Post by Mike Rometer » Mon Jun 05, 2017 7:57 pm

Whilst all that has truth and merit, here in the UK we have to pay a rather exhoritant annual rental on Ocy/Acet bottles, which take it out of reach except for heavy use. I've got by for more years than I can remember with the Propane torch for heat, MiG, and more recently a plasma cutter. It is a wonderous tool that will cut up to 1/2" plate and has earned it's meager cost several times over.
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Re: Propane-Air brazing torches

Post by cyberbadger » Tue Jun 06, 2017 12:38 am

Mike Rometer wrote:Whilst all that has truth and merit, here in the UK we have to pay a rather exhoritant annual rental on Ocy/Acet bottles, which take it out of reach except for heavy use.
Live rent free!

http://www.sgsgases.co.uk/

-CB
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Re: Propane-Air brazing torches

Post by Mike Rometer » Tue Jun 06, 2017 7:27 am

cyberbadger wrote:
Mike Rometer wrote:Whilst all that has truth and merit, here in the UK we have to pay a rather exhoritant annual rental on Ocy/Acet bottles, which take it out of reach except for heavy use.
Live rent free!

http://www.sgsgases.co.uk/

-CB
Great in theory, but our local SGS distributer holds no stock, a three day turn round minimum.
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Re: Propane-Air brazing torches

Post by DetroiTug » Tue Jun 06, 2017 9:44 pm

Quote: "I am holding off on TiG"

That is really the do-all welding machine. Can weld from paper thin steel to an inch thick (arc), weld aluminum, stainless, bronze etc. Hang a set of arc leads on it and arc weld. The electronics of a TIG mirror high end arc welders so they are very well suited for that. A much steeper learning curve than MIG/wire feeder, but if I could only have one welding machine, it would be a TIG. Gases are a bit more expensive than MIG, need argon for steel and light aluminum and Helium/Argon for heavier aluminum, or faster work with light aluminum. Developed for aircraft use welding aluminum with helium, hence the term "heli-arc". The Helium makes it much hotter and it is the most expensive gas. MIG is much faster for production welding. Aluminum and stainless can be ran with a MIG ($poolgun), but it is much harder to control those two mediums vs the TIG machine.

I use the TIG with arc leads to weld up boiler components. With a high quality 7018 rod, it runs smooth as silk. As the weld cools the slag just curls right up off the weld.

-Ron
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Re: Propane-Air brazing torches

Post by Lopez Mike » Tue Jun 06, 2017 10:50 pm

If I were to weld up a boiler I would be recruited by ISIS for bomb making! Totally not in the books.

My small locomotive boiler was done my a certified pressure vessel and pipeline welder who wanted to trade some machine work for the job. It was interesting to watch how he went about it.

First the sections were already beveled as they were things like a 10" to 12" offset reducer and I had already prepped the other joints. He spaced the joints apart by the thickness of a 1/8" stick welding rod. Then he went at it with his TiG machine. Tacks welds then short (2") runs spaced around the circumference with care to grind out the starts and stops as if it were 7018. When that root weld was done he did the rest with a plain old stick machine and 7018. Also grinding out the starts and stops.

I have a book about locomotive boiler explosions and when it is late on a stormy night and I want to scare my self silly I get it out and reflect.
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Re: Propane-Air brazing torches

Post by barts » Wed Jun 07, 2017 3:07 am

Lopez Mike wrote:If I were to weld up a boiler I would be recruited by ISIS for bomb making! Totally not in the books.

My small locomotive boiler was done my a certified pressure vessel and pipeline welder who wanted to trade some machine work for the job. It was interesting to watch how he went about it.

First the sections were already beveled as they were things like a 10" to 12" offset reducer and I had already prepped the other joints. He spaced the joints apart by the thickness of a 1/8" stick welding rod. Then he went at it with his TiG machine. Tacks welds then short (2") runs spaced around the circumference with care to grind out the starts and stops as if it were 7018. When that root weld was done he did the rest with a plain old stick machine and 7018. Also grinding out the starts and stops.

I have a book about locomotive boiler explosions and when it is late on a stormy night and I want to scare my self silly I get it out and reflect.
If you don't have a TIG welder, the root pass starts and stops and infill can be done w/ 6010. Grinding to smooth clean metal is critical after each pass. 7018 w/ electrode positive is awesome for welds on clean material; one gets a beautiful weld bead and very even penetration. A friend who used to be a Navy certified welder explained the process, and it worked like a charm.

I welded Otter's boiler 21 years ago - also her trailer. I found the trailer harder; the boiler was easy to position so as to do all downhand, the trailer not so much :).

Water tube boilers (and fire tube boilers using seamless or factory welded pipe as appropriate) are not unreasonable projects for a experienced welder who's willing to take their time and do it by the book. Of course, in certain areas this may not be permitted by the authorities.

Note that those boiler explosions were typically due to an overheated crown sheet rather than defects in construction.

- Bart
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Bart Smaalders http://smaalders.net/barts Lopez Island, WA
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Re: Propane-Air brazing torches

Post by Lopez Mike » Wed Jun 07, 2017 3:17 am

Oh, yes. Very few locomotive explosions were due to bad design and/or materials. As you say, let a large surface supported by stay bolts get dry and things start to go downhill rapidly.

It's not obvious until you look at the drawings how little water is on top of a crown sheet. A combination of climbing a steep grade, foaming of the water in the glass and inattention led to many a blowup.

I look to the historical record more for reminders of the consequences than for design inspiration.

The first impression is to fear a high pressure boiler over a lower rated one. But some of the most violent disasters were with very low pressures. Stern wheelers with surprisingly low pressures and ordinary steam heating systems hold an amazing amount of energy. Examination of steam tables is worth while.
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Re: Propane-Air brazing torches

Post by DetroiTug » Wed Jun 07, 2017 12:11 pm

Quote: "It's not obvious until you look at the drawings how little water is on top of a crown sheet."

I've noticed that and have always wondered why there hasn't been more failures considering their widespread use in traction engines. Looking at the design and considering an engine going down a steep grade for a considerable amount of time seems that it would have resulted in the loss of the fusible plug at least. Coupled with fired boiler under very little load going down hill, would have ran the pressure higher, all adds up to high probability of a mishap.

The more I learn about steam, that greater distance I keep myself away from traction engines. :) I was at one antique tractor show and they were having a parade, and an old not-too-well-maintained looking Case engine waiting in the line popped off and shot steam 50 feet in the air for a good five minutes, while the operator was beating on the relief valve trying to get it to reseat. If the relief valve is like that, what else is and may be even worse.

A good consideration regarding the possible state of some of those antique boilers, steel applied in similar duty more less deteriorates at the same rate over time, the Medina, Ohio engine had deteriorated to total failure almost 20 years ago.

-Ron
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