Silver soldering

This topic has 9 replies, 7 voices, and was last updated 9 January 2013 at 20:10 by George Scollay.

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8 January 2013 at 14:44 #108206
George Scollay
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@georgescollay44108
Hi, This could be a stupid question to ask some of you but as i have never done it before, I am going to silver solder a cast sleeve to a steel water jacket must i heat up the cast first or can i just start and solder it

The reason i am asking is that i thought that the cast would crack if not heated up The water jacket is 50mm x 50mm x 60mm long and the cast sleeve is 38 mm outside and 30mm inside and 65mm long, Many thanks for any help
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8 January 2013 at 14:44 #6508
George Scollay
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@georgescollay44108
8 January 2013 at 17:52 #108223
Speedy Builder5
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@speedybuilder5
Sorry – Can't help, but want to follow this thread.
8 January 2013 at 18:59 #108228
KWIL
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@kwil
Cast, what metal?
8 January 2013 at 19:26 #108230
George Scollay
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@georgescollay44108
Hi, The cast is cast iron (ex window weight, carron) and going to be soldered to steel box iron which will be the water jacket, Thanks
8 January 2013 at 19:42 #108235
Jeff Dayman
Participant
@jeffdayman43397
All parts of the assy will need to be at full dull red soldering temperature if a good joint is to be made. I would suggest applying heat to the heavier of the two parts first, working the whole part up to temp. You will probably find that the smaller part is at the correct temp by this point, from heat conducted from the bigger part. You can then add flux if required (some may have burned away during the heating of the bigger part) and then start adding silver solder.

JD
8 January 2013 at 19:53 #108236
JasonB
Moderator
@jasonb
I've used this method to drive off the carbon in the CI which makes it easier to get a decent joint
8 January 2013 at 21:32 #108243
Sub Mandrel
Participant
@submandrel
I tried silver soldering cast iron to see what happened, and to my surprise, it worked.

The two parts would each be about the same bulk as yourcast sleeve, and I just made sure it was a freshly machined (filed) surface, clean of any trace of oil. I used easyflo and easyflo flux IIRC.

Neil
9 January 2013 at 09:19 #108263
CuP Alloys
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@cupalloys
Hi George,

Heat the cast iron to red heat in air – no flux – to burn off surface carbon. Allow to cool. Then take a stiff wire brush to remove surface oxide/scale. Do not use a grit or emery cloth as these can leave a deposit that can lead to voids.

Set the joint horizontal by laying it on a lightweight refractory brick (not from a storage heater!) or blanket.

Flux with a long life flux eg HT5.

Cut a piece of low melting point silver solder rod, say 455, with a melting temperature 630 – 660 deg C.

Suggest 1.0mm dia as you will get the alloy in close proximity to the joint and use less alloy.

Do not heat the alloy but heat the joint from the other side with a propane torch using a Sievert 2941 7 kw burner. Let the alloy get its heat from the joint. When the joint is hot enough, the alloy melts and it will draw through towards the heat and create the joint.

regards

keith
9 January 2013 at 20:10 #108319
George Scollay
Participant
@georgescollay44108
Hi, Many thanks for all the replies, tried this today and it appears to have worked,once everything was up to heat it seemed to just flow together, As i have never tried this sort of work before i thought it was worth asking on here first knowing some people would come up with answers, Thanks everyone
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