silver soldering preperation

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JohnR
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silver soldering preperation

Post by JohnR »

Getting ready to silver solder my shay engine .
I have fabricated a fixture to hold the assembly during soldering.
The assembly will be held to the fixture by several 10 x 24
cap screws threaded into the assembly.
Is there anything I can do to prevent the possibility
of solder going into thread interface ?
Is there a coating ican put on the screw to prevent this ?
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Bill Shields
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Re: silver soldering preperation

Post by Bill Shields »

No way to prevent it that may not also interfere with the soldering process.

Use brass screws and plan on cutting through and filing flush
Too many things going on to bother listing them.
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Harold_V
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Re: silver soldering preperation

Post by Harold_V »

I question the use of brass screws. Wouldn't bronze be a better choice? Not only stronger, but resistant to leaching of zinc, which they don't contain.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
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Bill Shields
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Re: silver soldering preperation

Post by Bill Shields »

If structural I would not disagree...I never use brass on a boiler for assembly.

If they are only for mounting to fixtures...what does it really matter? They just become blind hole plugs anyway.

Brass is cheaper..
Too many things going on to bother listing them.
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Harold_V
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Re: silver soldering preperation

Post by Harold_V »

Got it! Thanks, Bill.

H
Wise people talk because they have something to say. Fools talk because they have to say something.
Wolfgang
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Re: silver soldering preperation

Post by Wolfgang »

If it is a boiler you are soldering, use copper or tin bronze screws.
As stated above, brass and related "bronzes" are subject to dezincification which leaves a porous, leaky, mess.
Considering the money spent on material and time to fabricate what is probably an heirloom artifact, it is false economy to save a few dollars on the fasteners.
Several years ago I was one of a two man team that assembled and silver soldered a 1" scale copper boiler. The barrel was 6" dia. with 5/32" wall thickness.
My friend and I made all the fasteners from 1/4" square copper bar.
With a square collet or, a 4 jaw self centering chuck (our tool) and a tailstock die holder, it didn't take that long to make the required quantity.
pete
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Re: silver soldering preperation

Post by pete »

Most of the better recommendations I've seen while fabricating and soldering any complex assembly together almost always mention pinning the parts first as a mechanical means of maintaining the correct part alignment. Depending on screw threads for exact part alignment is usually considered poor practice. Custom machined aluminum bolts, studs, nuts would work except it's almost for sure they can't take the heat produced during hard soldering.
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