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Small "Mill Engine Plant" (Display)
Stilldrillin:
--- Quote from: bogstandard on August 23, 2009, 02:56:22 PM ---Lads, you have to be very careful when buying silver solder paste, it has a very short shelf life, sometimes as little as 6 months, depending on the grade, and there is no rescue procedure, once the time is up, the whole lot becomes no good.
It is very good if you have a use for it all in the short term, but if you are only going to use a little bit every now and again, it can get very expensive. If you do buy some, check the dates very carefully, and make sure you only buy very fresh stock.
I used to nearly cry, when in industry, when we found our 1000 squid a tub had gone out of date, and it was only good enough to throw in the bin. I even brought some home to try out, and a couple of months out of date and it was useless.
Bogs
--- End quote ---
Thanks John,
Not much good for me then........ ::)
David D
klank:
Thanks for the warning Bogs - you got me worried with that timely warning.
As there was no "use-by" date on the goop I bought, I telephoned the manufacturer (Cup Alloys) to find out what the shelf life of it might be. I have bought a small syringe of the stuff, containing 10g of 842 paste, which (I quote!!) "is a mixture of powdered 42% silver, cadmium bearing alloy, with EF flux and held together in suspension by an organic binder." !!! Cost £8. (It looks like brown sticky toffee pudding!)
The syringe has a metal push-in plug-cap in its nozzle.
I was told by Cup Alloys that provided the plug-cap was kept in the nozzle (to keep the air out of contact with the goo), the syringe contents should last for a long time. They have a demo syringe they take to exhibitions, which has been capped but used at all of them - lasted 18months so far and still going strong. Keep the cap in and you should be ok for at least that time was their advice.
If you have it in a tub though (like your example Bogs), then its lifespan may only be 6 months before it dries out, as air is always in contact with it.
I think my litttle syringe of the stuff should be ok for a while, and at £8 - provided I keep the cap in the end - shouldn't owe me too much when it finally goes off, possibly in a couple of years or so. Despite the cost, I think its still worth having at this small 10g amount (ready fluxed), as it does do really neat small silver solder jobs. A metre of 0.7mm silver solder wire (from them) costs the same, and I'm pretty sure I would use that up in the same time span, and probably waste a bit of it.
I hope this helps.
Peter
bogstandard:
Peter,
I wasn't trying to put people off at all, but just to be aware that it does have a limited lifespan.
You will find that certain retailers do give a warning about it's limited life.
I fact we didn't throw our tubs in the bin, but had the silver recycled from it by the people who recycled the gold off our scrap circuit boards, so all was not wasted, just about 80% of the cost.
Bogs
klank:
Thanks John - you are right about the warning notice (or lack of!!) Certainly on this syringe there was no warning at all - not even "keep the cap on".
Those scrap - cost figures look dreadful - what a waste of resource!
Peter
CrewCab:
Can I refer you gentlemen to "This" suggestion
I have a lot of respect for the guy who posted it & it sounds quite feasible but, ............. is there any real advantage over using a small piece of Silver Solder wire :scratch:
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