Author Topic: How to recover this silver solder operation?  (Read 2660 times)

Offline matthew-s

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How to recover this silver solder operation?
« on: March 18, 2021, 01:46:30 PM »
Hi - continue to chip away at my 3/4" scale A3.

I'm soldering up the steam "T" and as you can see, there is a gap at the bottom that I cannot fill. I am concerned it will result in a leak, as I will be boring steam passages through this solder line. What would the more experienced folks suggest I do?  The options I've come up with:

1. Do nothing - the solder is there ... somewhere.
2. Clamp the parts, and reheat - squeeze them together - maybe put flux along joints?
3. Heat it up, separate the parts, clean it up, and start over.

I doubt I need to scrap this, so I did not bother making that #4!

Thank you in advance



 

Offline crueby

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Re: How to recover this silver solder operation?
« Reply #1 on: March 18, 2021, 02:48:39 PM »
If you try the reheat, it needs to be as clean as possible, good long soak in the pickle. Add more flux and put another chunk of solder along that little gap to flood it. If you have it, use an 'easier' grade of the silver solder which will melt at a lower temp and flow in. Will need to heat it well, best to heat from the back side to draw the solder in, it will want to wick into the joint as long as the metal is hot, don't play the flame on the new solder or it wont flow in.

Offline john mills

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Re: How to recover this silver solder operation?
« Reply #2 on: March 18, 2021, 09:20:15 PM »
I would clean it as much as you can then cover with flux  ad more silver solder as it comes to temperature
you should see the solder become shinny and  flash around the joint if you touch with a piece of solder it should melt and run into the joint it should form a filet around the sharp corner .Have enough heat so you don't take to long heating .add enough solder with flux and it should flow.
    John
   

Offline matthew-s

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Re: How to recover this silver solder operation?
« Reply #3 on: March 18, 2021, 10:07:41 PM »
Thank you both. Should I clamp the part together?
I do think I may have put the heat too close to the solder last time. I should be a little more patient.

Offline crueby

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Re: How to recover this silver solder operation?
« Reply #4 on: March 18, 2021, 10:11:45 PM »
If its possible for the parts to move when the solder reflows, then by all means put a clamp or something on it to keep the parts in place. I like to put a small brass screw on brass parts to hold them together - does not add much mass that would draw off heat, and it can be filed off flush easily afterwards so it does not show. A C-clamp or that sort of thing will work, but will draw off heat, and you can ruin a good clamp too.

Offline john mills

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Re: How to recover this silver solder operation?
« Reply #5 on: March 18, 2021, 10:44:44 PM »
Don't clamp too tightly it needs space for the solder to fill  i usually find if the parts can be placed where they tend to fall together and position with a bit of wire, if parts want to move just as the solder sets as it cools.
John

Offline matthew-s

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Re: How to recover this silver solder operation?
« Reply #6 on: March 19, 2021, 01:05:36 AM »
The parts actually fit together fairly snugly. Those gaps you see are probably no more than 0.005", so I suppose it's just as well there is some room for the solder no? Maybe I'll pass on the clamping idea.


The good news is this is one good size chunk of brass (roughly 3/4" x1") and the joint is not bearing from what I can see - so it's really about a steam-tight join than massive strength.

I hope to give it another heat this weekend - I'll set folks now how it goes!

Offline Bearcar1

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Re: How to recover this silver solder operation?
« Reply #7 on: March 19, 2021, 04:59:39 AM »
I would as others have said, flux the crap out of it and reheat the joint. Apply a bit more solder to ensure it flows into the joint. Either by pillion application or wire fed manually.


BC1
Jim

Offline derekwarner

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Re: How to recover this silver solder operation?
« Reply #8 on: March 19, 2021, 06:38:57 AM »
Just a little off line, but any generic TYPEX ....the liquid writing correction fluid as painted as a line, can be used as a barrier to   :Mad: inhibit the flow of flux & hence the actual flow of the silver solder

However, "cleanliness is next to Godliness" in any soldering process

Derek
Derek L Warner - Honorary Secretary [Retired]
Illawarra Live Steamers Co-op - Australia
www.ils.org.au

Offline gbritnell

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Re: How to recover this silver solder operation?
« Reply #9 on: March 19, 2021, 11:30:46 AM »
It looks to me like the 2 pieces were not at the same temperature.  The smaller piece was at the correct temperature as can be seen by the flowing of the solder but the larger piece wasn't.  It's best to start heating the larger piece away from the joint and then work the heat toward the smaller piece. The question is did the solder wick into the joint from the first attempt? If not then it needs to be taken apart and redone.  There should always be a tiny gap between the two pieces for the solder to flow into.
gbritnell
Talent unshared is talent wasted.

Offline matthew-s

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Re: How to recover this silver solder operation?
« Reply #10 on: March 19, 2021, 07:06:00 PM »
The solder did wick into that gap the first attempt - it did not seem to fill it.

On the second attempt, I did put solder and flux right on the gap - but I think you are right - I probably heated the narrower (vertical) part more than the bottom.

I've let it pickle all day today - I rinsed it mid-day and scratched around the joints a bit, and dripped it back in the pickle.

I guess I'll try at least one more heat, being more carful to event heat away from the joint, and see what happens? If that fails, maybe it's time to disassemble, clean the parts separately, and try again?

Offline Barneydog

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Re: How to recover this silver solder operation?
« Reply #11 on: March 19, 2021, 09:12:58 PM »
Hi Matt.

Heat the large first then add solder when it has all reached the same temp both sides of the joint. If your new solder flows away from the joint the opposite side is not yet hot enough. If you get it all equally hot this will fill easily. Plenty flux and very clean. If it  doesn't work go again. It's a heat problem. If you clamp too tightly the brass will expand and damage itself. I often solder upright with a lump of brass sat on top to add weight to hold it in place.

Cheers

Julian

Offline Don1966

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Re: How to recover this silver solder operation?
« Reply #12 on: March 20, 2021, 04:12:08 PM »
It looks to me like the 2 pieces were not at the same temperature.  The smaller piece was at the correct temperature as can be seen by the flowing of the solder but the larger piece wasn't.  It's best to start heating the larger piece away from the joint and then work the heat toward the smaller piece. The question is did the solder wick into the joint from the first attempt? If not then it needs to be taken apart and redone.  There should always be a tiny gap between the two pieces for the solder to flow into.
gbritnell
Agree with george on this... my input you could tint one piece clean then flux and clamp together and the pressure will make the two pieces joint together if ypur able to clamp them, with proper heat and flux. My two cents.

Don

Offline matthew-s

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Re: How to recover this silver solder operation?
« Reply #13 on: March 20, 2021, 06:45:48 PM »
Well, the second time was better.
I pickled it and mechanically cleaned it. Plenty of flux and solder. Lots of heat working from the edges of the part inward to the best of my ability.

There are very small pores still. Is this typical or 3rd time the charm?


Offline rklopp

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Re: How to recover this silver solder operation?
« Reply #14 on: March 21, 2021, 02:25:01 AM »
Hopefully not typical, now that you have some practice. Practice makes perfect, same as any “sport.”


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