Author Topic: Silver solder question  (Read 9121 times)

Offline AdeV

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Silver solder question
« on: October 26, 2010, 04:08:28 PM »
I've machined up a couple of parts which I will need to silver solder together, albeit not quite yet. Please excuse the obvious tool crash on the right-hand part  :zap:



When put together, they look like this:



Is that gap big enough for silver solder to wick into? For reference, the outside diameter of the large part is 1.5", the OD of the inner part is approx. 0.98"

I'm asking now because I don't want to ruin the concentricity of the setup, if I have to make the gap slightly wider.

Thanks in advance!  :nrocks:
Cheers!
Ade.
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Offline John Hill

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Re: Silver solder question
« Reply #1 on: October 26, 2010, 04:39:41 PM »
I believe a slide fit is plenty enough clearance.
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Offline Bogstandard

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Re: Silver solder question
« Reply #2 on: October 26, 2010, 05:17:33 PM »
Ade,

0.002" is perfect for the solder to wick into.


Bogs
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Offline wongster

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Re: Silver solder question
« Reply #3 on: October 26, 2010, 09:18:33 PM »
Hi AdeV,

Are you able to take pics showing the process of silver soldering? I bought a Proxxon torch but yet to find the other stuff for this.  Don't need to silver solder anytime soon though.

Regards,
Wong

Offline AdeV

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Re: Silver solder question
« Reply #4 on: October 27, 2010, 04:58:51 AM »
Thanks John & John, most reassuring. I think that's about a 2 thou gap, but being as it's not a straight line, I'm not sure how to accurately measure it...

Wong - Absolutely, I will document it. It'll be the first thing I've silver soldered, so I'll probably do a practice piece first, just to make sure I'm up for it. I need to get some firebrick from somewhere as well...

One more question.... (always 1 more): What do people recommend I pickle it in after I do the silver soldering? Both parts are regular brass (can't remember the code, it's the easy-machining one).
Cheers!
Ade.
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Offline ozzie46

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Re: Silver solder question
« Reply #5 on: October 27, 2010, 06:33:27 AM »


  I just use white vinegar. It's cheap and easy to get.


  Ron

Offline cidrontmg

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Re: Silver solder question
« Reply #6 on: October 27, 2010, 07:08:35 AM »

  I just use white vinegar. It's cheap and easy to get.

  Ron

Likewise. Iīve also used hydrochloric acid (aka muriatic acid), also cheap and easy to get. Itīs used in cleaning masonry, swimming pool walls, floor tiling, etc. It acts faster than vinegar.
« Last Edit: October 27, 2010, 08:24:22 AM by cidrontmg »
Olli
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Offline AdeV

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Re: Silver solder question
« Reply #7 on: October 27, 2010, 07:28:38 AM »
Excellent, thanks for the quick replies; I have some brown (malt) vinegar, but white vinegar should be just as cheap if the brown is no good...

 :nrocks:
Cheers!
Ade.
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Offline Ned Ludd

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Re: Silver solder question
« Reply #8 on: October 28, 2010, 06:45:18 AM »
Hi AdeV,
As you are new to silver soldering have you heard of silver solder paste? The advantage if it is you can put it where you want it ie in the joint, before heating, and not have to worry about it wicking in from the outside.

Again as a beginner to silver soldering, one major tip to give is to get the work hot enough before adding solder, which can take longer than you might think. If working outside, as some would recommend, make sure you have no drafts or you might not have enough heat to get the work hot enough. 1.5" is a fair lump of brass if you don't have a good sized torch, a little torch as favoured by cooks for glazing creme brulee is just not big enough.
Ned
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Offline No1_sonuk

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Re: Silver solder question
« Reply #9 on: October 28, 2010, 07:38:58 AM »
Excellent, thanks for the quick replies; I have some brown (malt) vinegar, but white vinegar should be just as cheap if the brown is no good...
Wouldn't the brown stuff be likely to stain the metal?

Offline AdeV

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Re: Silver solder question
« Reply #10 on: October 29, 2010, 01:15:22 PM »
Ned - I've heard of it, but don't have any (& I do have some s/s rods now). I have a decend sized MAPP-style torch (one with a drop, split, kaboom bottle on it), I do have oxyacetylene facilities too, not that I've ever used them...

I believe the flux behaviour (Tenacity 5) gives one a good clue as to when the temperature is about right? Plus, I do plan to practice first...

No1-son - good question.... I don't know. I'll try it out on a practice piece & let you all know :)

Cheers!
Ade.
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Offline Divided he ad

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Re: Silver solder question
« Reply #11 on: October 29, 2010, 01:35:52 PM »
When do you need the fire bricks for Ade?

I got some here that can be cut with a hand saw (blunts it mind) I'm sure we could get you enough to make a reasonable hearth?  The blocks are approx 8x4x3 inch.

This silver soldering lark ain't that easy.... I've tried it about 10 times now and had 3 good results! (full fillets with little run off) It certainly takes practice!



Pickle... Chemist "citric acid" little boxes for about 80p each, dilute in warm water and drop your part in to get it cleaned (ooh err!) check on it every now and again. I personally agitate using a paint brush.... Cause I am impatient  :ddb:




Ralph.

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Offline AdeV

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Re: Silver solder question
« Reply #12 on: October 29, 2010, 01:43:01 PM »
Ralph - I was planning to s/s probably next weekend (not this). If you want, bring whole bricks over, I've got a bandsaw with a near-knackered blade that would probably do the job well enough; I've got a knackered blade for the Manchester Rapidor as well, in case the bandsaw's not up to the job.


Hey, why do it by hand when there's machines around?  :)

I'm also impatient, that's why none of my parts end up highly polished.... too lazy!
Cheers!
Ade.
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Offline Bogstandard

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Re: Silver solder question
« Reply #13 on: October 29, 2010, 02:57:23 PM »
Ade,

If you are using Tenacity 5, then you will have very little trouble.

Mix it up with a few drops of water and the tiniest drop of washing up liquid, after getting it to a mixture like pouring cream, paint it on to and into the areas to be joined. Don't go mad, the more you put on, the more you have to get off. Just use a thin layer on each.

Assemble the two parts together and stand it up on your firebricks.

Now form a ring of silver solder that is the same size as the circular joint, and place it on top of the joint, onto the flux gathered around the joint.

Now heat up the job from the outside, starting roughly where the depth of the joint finishes and upwards. When everything gets to melt temperature, the silver solder will melt and by caplliary action will form the joint. DO NOT point the flame at the silver solder, only onto the outside of the job. Unless all the silver solder you have put onto the joint is wicked in, you shouldn't need to feed any in from a rod. If the joint still requires a bit more solder, then still keeping the job hot by heating around the outside, feed in a bit more rod until the joint is full. The solder should start to flow when the parent metal reaches a very dull red colour, any hotter, and you are liable to cook things a little too much.

Be very careful when you first start to heat the job up. Because the two parts resemble a piston in a cylinder, the evaporating water in the joint might try to push the inner part out. Just hold it down with a bit of metal rod until all the steam has gone from the joint.

A lot of people struggle with silver soldering, but if you have the correct solder, flux and heat in the right place, then it is in fact difficult not to form a good joint.

There are lots of my posts showing how I do it.


John
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