Multicore RA Solder Cream on Ebay

[JimG]

Having read the message on the "Flux and Solder " thread last week

http://www.westernthunder.co.uk/index.php?threads/flux-and-solder.1250/page-2#post-78824

...I thought it worth a pop at £3.95 to see how good or bad it was. It turned up on Monday but the coupling rods for the pug got in the way so I didn't get a good chance to try it out until this morning.

I dug around on Google for information and it is a "No Clean" solder cream for use on printed circuit board assembly. It is basically a ~60/40 tin lead solder with 2% silver added, so it should flow well. I couldn't find any details about its melting temperature that I could apply to our modelling work - it all related to production line PCB soldering.

So I did a quick trial this morning with my soldering iron and my RSU. I set the iron to 350F and tried two joints - sticking thin, brass strip to a heavier brass strip - and it melted and flowed very well along the joint. I then tried the same operation with my Graskop RSU on the BC setting (second lowest) and it worked quickly and well.

The "Best By" date on the syringe is March 2013 and the maker states that the recommended shelf life is six months, so it is getting a bit far away from ideal, but I found the cream still quite usable and had no problems applying it with a cocktail stick (no needle supplied with the syringe). In fact I found that I was tending to apply too much and my joints would have required cleaning off on a model. I made no attempt to clean or polish the brass and there was slight oxidisation on both parts, but the flux worked well and the joints were made quite easily.



The syringe as supplied with the small test piece to the left. Some may recognise an RS catalogue number code - it is, and it looks as though they might be clearing out old stock.

But I think it is well worth the money at £3.95 as long as I use it fairly quickly before it goes solid - the full price as almost £18 in the RS catalogue and there is still VAT to go on -.

Jim.

 

[SteveO]

Thanks for doing this Jim, I got my syringe Monday too but I won't be able to test it until Sunday. It will be interesting to find out how long this lasts. Did you get a green cap too? Do you know what the two caps are for? The green one is longer but looks sealed. Any ideas on how to prolong its life?

 

[Steph Dale]

Any ideas on how to prolong its life?

Steve,
I doubt you can in a meaningful way, the shelf life will relate to the reactivity of the flux, drying or perhaps surface reactions of the metal particulates in the suspension.
However, the date will relate to wetting and reflow of the solder under production conditions for electrical work. You're not going to be worried about the ability to create a lasting electrical joint so will be able to use it well beyond the life date. As long as you continue to get a usable joint, keep using it!
Steph

 

[SteveO]

Cheers Steph, will do!

 

[ZiderHead]

0.5mm Multicore SN62 is what Ive always used for electronics and beats anything else Ive tried hands down, its quality stuff (but not cheap!) quick and clean to work with, and seems to work well for brass too.

Melt point is 179deg and its much narrower melting range than normal 188deg 60/40 so it "sets" quicker meaning you get nice shiny clean joins. Never tried the paste though.

Edit: BTW Ive always set irons to 370deg for it.

 

[JimG]

Did you get a green cap too? Do you know what the two caps are for? The green one is longer but looks sealed. Any ideas on how to prolong its life?

Steve,

I only received one, red cap so I'm not sure what the green one would do. It looks as though the red cap I have could be opened and have a hypodermic needle inserted, but I reckon I will stick with my cocktail stick. I do remember getting a hypodermic needle from Brian Lewis to use with the C&L paste I got some years ago but that got difficult to use as the cream dried out.

I'm not sure about prolonging its life. I would assume that you could add a solvent of some type but it would have to be carefully chosen so that the flux still worked and didn't cause oxidation after use.

I did read that it should be stored at 5C - 10C, in a refrigerator so that my be the way to keep its life extended.

Jim.

 

[Steph Dale]

Jim,
Yep, just found the manufacturers data sheet. Shelf life relates to the resin binder in the flux, so store air-tight at 5-10ºC. Out of life will just mean that the paste becomes too stiff to use.
Remember again that this is associated with industrial process (screen printing directly on to PECs), and our use will be much less critical. So use it until it stops doing what you need it to!
Steph