Copper Boiler Design

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Marty_Knox
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Re: Copper Boiler Design

Post by Marty_Knox » Tue Jan 23, 2018 1:41 pm

redneckalbertan wrote:
Sun Dec 23, 2012 11:47 pm
Marty_Knox wrote:I needed the high amps to start the arc, but couldn't back off enough to keep from melting the copper once it heated up.
What do you have for a TIG machine?
It is Miller Dialarc HF, 300 amps max.

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Marty_Knox
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Re: Copper Boiler Design

Post by Marty_Knox » Tue Jan 23, 2018 1:41 pm

Marty_Knox wrote:
Tue Jan 23, 2018 1:41 pm
redneckalbertan wrote:
Sun Dec 23, 2012 11:47 pm
Marty_Knox wrote:I needed the high amps to start the arc, but couldn't back off enough to keep from melting the copper once it heated up.
What do you have for a TIG machine?
It is a Miller Dialarc HF, 300 amps max.

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jschoenly
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Re: Copper Boiler Design

Post by jschoenly » Tue Jan 23, 2018 2:13 pm

Bill,

I actually don't have much of a plan, but was more inquiring. It seems like the original builder that started the boiler was planning on using the 3/8" thickness as the "flange" for enough solder on the lap. It seems there going to be pockets milled into the plates to make them more like flanged sheets. I don't think you need the extra solder line on the tubes so it's an interesting way they were going.

I'm debating between staying copper or going with a steel boiler for the loco, but if I stay copper I may very likely go with a more standard flanged construction on it. We'll see. I certainly would not roll copper in copper, but I was curious how the thick plats compared to older cast boiler components for construction. Thanks!
Jared Schoenly

Cabin Fever Expo
Model Engineering of all sorts.....

rkcarguy
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Re: Copper Boiler Design

Post by rkcarguy » Tue Jan 23, 2018 2:24 pm

Having worked at a marine cooling shop in the past, I've done a lot of repairs and TIG welding on some of the oddest things. You can braze with a TIG welder, we preferred it when repairing a leaky tube because the heat was more focused than a torch instead of affecting nearby tubes. In an environment where you have a bunch of brazing to do, it doesn't work well for exactly that reason....the heat needs to be pulled way back and unless you have a tiny head your TIG it's probably won't work. I know when brazing with a torch, once I've got the material flowing I pull the torch way back and stuff the filler in there pretty fast, if it starts to feel "stiff" and flow slower, time to bring the torch in closer again. It's quite an art.

Back to the TIG, what amp torch are you running on it? I have an old 1960's Miller 430A from a shipyard, and it will melt holes though 1/2" aluminum plate. It also requires 125 amps of 220 Volt power. I used to have to make sure no one was vacuuming, using the oven, dryer, or any other items in the house when I used it on high. Anyway, I have two torch setups, and will change to the smaller 180 amp? torch with an 1/16" tungsten and a tiny cup if I'm doing thin stainless or other intricate work. Using that setup, I was able to TIG "braze" another fitting onto an exchanger without affecting the soft soldered thermostat housing, bolt up flange, and filler neck that were already on it.

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Bill Shields
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Re: Copper Boiler Design

Post by Bill Shields » Tue Jan 23, 2018 3:51 pm

steel boilers on smaller locos don't have a lot of 'corrosion allowance'....copper is (in reality) a longer-term solution.

Roll the copper...heck no - get the tube from Reeves....

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Builder01
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Re: Copper Boiler Design

Post by Builder01 » Tue Jan 23, 2018 8:02 pm

Typical copper plate thickness for 1" scale locomotives is 1/8". I saw the "kit" of parts I think you have found at "Cabin Fever". I cannot imagine exactly what the 3/8" copper plate was intended for. That piece of copper could probably cost new for $300. As for milling pockets to make a "flanged plate", this would involve much more time and energy than making a traditional flanged plate. Proper flanged copper plates are easy to make. On my 1" scale loco with a copper boiler, there is only 3/8" between the plates in the water legs of the firebox. If this were done in steel, the grate would be pretty small.

David

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