Silver soldering stainless steel hot end

Discussion on Stirling or "hot air" engines (all types)
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Wellington
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Silver soldering stainless steel hot end

Post by Wellington » Fri Jan 05, 2018 9:39 am

It would seem it is impossible to buy stainless steel tubing in uk that has one end of the tube sealed or seamless to save money on buying expensive glass syringes. Im considering silver soldering plate stainless steel onto the end of some stainless tube. Does anyone know if the join will hold up under the heat of a meth flame?
Thanks

Alfista
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Re: Silver soldering stainless steel hot end

Post by Alfista » Fri Jan 05, 2018 7:35 pm


Wellington, in my opinion it should. I also assume that you intend a silver brazing wire like Harris Safety Silv 45 or something similar. In operation, you should not allow the engine to stall indefinitely under high heat.

Ian S C
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Location: New Zealand

Re: Silver soldering stainless steel hot end

Post by Ian S C » Sat Jan 06, 2018 2:36 am

Yes it should be ok, if you want it to really hold together under higher temperatures, find a TIGGER, and get it TIG welded, that's what I do, I would prefer a pressed cup, but can't usually find one. If your into making a mess, and you have an old, dead NiCad battery of the right size, the steel case of one of these works well. Don't do as one person did, he went out and bought a new one, and while digging the insides out things got fairly hot, and there was a bit of smoke involved. The hot cap on my little beam engine is made from a AA size NiCad.
Ian S C
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Wellington
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Re: Silver soldering stainless steel hot end

Post by Wellington » Sat Jan 06, 2018 12:36 pm

Ian S C wrote:The hot cap on my little beam engine is made from a AA size NiCad.....]
Oh yes. batteries. I tried emptying one the other day but had little success as the icky chemicals were stuck hard to the casing. Any idea how to empty a battery easily cleanly and safely?

wellington

Wellington
Posts: 143
Joined: Mon Apr 18, 2016 4:02 am

Re: Silver soldering stainless steel hot end

Post by Wellington » Sat Jan 06, 2018 12:37 pm

Wellington wrote:
Ian S C wrote:The hot cap on my little beam engine is made from a AA size NiCad.....]
Oh yes. batteries. I tried emptying one the other day but had little success as the icky chemicals were stuck hard to the casing. Any idea how to empty a battery easily cleanly and safely?

wellington

Wellington
Posts: 143
Joined: Mon Apr 18, 2016 4:02 am

Re: Silver soldering stainless steel hot end

Post by Wellington » Sat Jan 06, 2018 12:40 pm

Alfista wrote:
Wellington, in my opinion it should. I also assume that you intend a silver brazing wire like Harris Safety Silv 45 or something similar. In operation, you should not allow the engine to stall indefinitely under high heat.
have you ever known a stirling engine to explode? Thinking about it i guess they can be dangerous like steam engines. Never thought about stirlings like that. I guess i should be equally cautious like with steam engines. Just been running my mamod steam engine. They are such a joy to run.
Wellington

cbstirling2
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Re: Silver soldering stainless steel hot end

Post by cbstirling2 » Sat Jan 06, 2018 6:59 pm

So NiCd batteries are in a stainless cup?
So to be safe, one must drain the battery?
What happens if one tries to burn the other parts out by tossing them into a campfire?
CBStirling2

cbstirling2
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Re: Silver soldering stainless steel hot end

Post by cbstirling2 » Sat Jan 06, 2018 7:03 pm

Oops, the cadium is tocic. I'd steer clear from them.
CBStirling2

Ian S C
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Re: Silver soldering stainless steel hot end

Post by Ian S C » Sun Jan 07, 2018 2:18 am

I cut off the + end with a thin wheel on the Dremmel tool, as near the end as I can, then use a screw driver to dig out the innards, you can do it without getting your fingers dirty. If you don't want to dig out the cadmium, you can use an alkaline battery, but the + tit is on the bottom of the main case on these(no real problem). In the top photo: L rear is the case from an alkaline battery, and next to it a NiCad case, next two are a AA, and AAA NiCad battery. In front is the hot cap from the little beam engine.
The bottom photo shows what happens to a aluminium displacer.
Ian S C
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Wellington
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Re: Silver soldering stainless steel hot end

Post by Wellington » Sun Jan 07, 2018 2:20 pm

Ian S C wrote:I cut off the + end with a thin wheel on the Dremmel tool......
Thanks Ian. Your always very helpful. Takes a bit of time to get all the innards out i guess. Any idea if the casings are regular mild steel or some other special alloy?

Wellington

Ian S C
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Re: Silver soldering stainless steel hot end

Post by Ian S C » Mon Jan 08, 2018 1:48 am

Sorry don't know what they are made of, they don't seem to rust, the silver solder, or braze easily, I actually use brass, usually brass sheet cut in thin strips. Materials (for me) is a case of what I can find, I do buy some bits of aluminium off cuts. The only bought in piece in the photo of the little beam engine is the cheap micrometer you can see the barrel of, I bought that somewhere about 1962/63, every thing else was found around the workshop.
Ian S C

Alfista
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Re: Silver soldering stainless steel hot end

Post by Alfista » Mon Jan 08, 2018 8:16 am

Wellington wrote: have you ever known a stirling engine to explode? Thinking about it i guess they can be dangerous like steam engines. Never thought about stirlings like that. I guess i should be equally cautious like with steam engines. Just been running my mamod steam engine. They are such a joy to run.
Wellington
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Wellington, I have never had a Stirling engine explode nor would I worry about it. I have read one caution in some book but I cannot provide a reference. The caution had to do with oil. The notion was that an excess amount of oil might vaporize and explode. :shock:

My caution about avoiding prolonged exposure of the engine to the fire while the engine has stopped has to do with melting something in the hot end. As the engine is running it cools the hot end, including the welds :big smile:



Ian S C
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Re: Silver soldering stainless steel hot end

Post by Ian S C » Tue Jan 09, 2018 3:00 am

I think the reported explosion was in a development engine at Philips in Holland. It was a pressurized motor, and it got oil in the wrong place, oil, heat, high pressure, Bang, just look at a diesel engine, that's how it works. I think someone was killed in that case. You are more likely to hurt your self by dropping the motor on your foot.
Ian S C

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