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This is NOT a "game changer?" like the mosquito, RIIG or Grid tie inverter For the community it's just helpful.
During the course of development we dealt with smd components for prototypes, a lot o them, obviously we need solder paste, Not a lot in quantity but a lot of times There are some notations:
They are expensive and offered for sale by gram (like gold?)
Unopened, they have relatively short shelf life.
Once opened they turn rock- like very quick, in days.
It took us days for new orders to arrive., or weeks if they were from overseas.
On the net there are instructions for DIY. We followed them (any we could find at the time), they were either impractical or simply did not work.
Like coke, we could not find a publicly available formula, it's understandable, no one wants to share others their bread and butter ingredients
After trials on error these are things we have to have on-hand. (As in the attached picture)
Solder Powder. You may need to order from overseas
Water soluble Flux
Rosin flux - In paste form. Somehow liquid rosin flux doesn't help the final paste to work in reflow oven
Instructions:
Mix the solder power and the Water soluble flux to the desired viscosity.
After that, add a tiny part of Rosin paste. then mix again.
We did not really pay attention to the mixing ratio, just eyeballed.
You will have the solder paste at the time you need.
The step 2 of the above instructions makes it to have a few months shelf life, you can reverse the step only until needed.
I see no mention of refrigerating the paste when not in use and then letting it warm to room temperature before using. Ours lasted for months that way and we had to buy in quantities. They were always shipped in boxes with packages of frozen liquid to keep the paste cold.
Paul
Paul_KD7HB:
I see no mention of refrigerating the paste when not in use and then letting it warm to room temperature before using. Ours lasted for months that way and we had to buy in quantities. They were always shipped in boxes with packages of frozen liquid to keep the paste cold.
Paul
We did their too both in refrigerator and in freezer. Ours So cheap! We don't really care. just mix new one. I forget. how much our initial investment 3 dozen? It lasts us for more then 10 years to spend about 10% of it.
ephitran:
We did their too both in refrigerator and in freezer. Ours So cheap! We don't really care. just mix new one. I forget. how much our initial investment 3 dozen? It lasts us for more then 10 years to spend about 10% of it.
Ours had to be certified as to alloy and flux, so quite a difference in the work.
Paul
Example: From Amazon
Same 63/37 the most common alloy, with certification?
I just share my experience on our in-house work, That's it B/C I think it's helpful.
If people are able to DIY price will go down, it is the community who get the benefit at last.
I've been happily using Kester EP256 for 10 years no with no issues.
Keep it sealed and refrigerated between builds of boards.
I buy it in 250g tubs.
Bought a 500g tub that lasted quite a while too.
Reflows nicely - preheat to 150C and wait 90 seconds, heat to 190C and wait 90 seconds. Let cool.
If there are a lot of components on the boards, then holding for 2 minutes might be needed.
I had never tried that brands. Our developments were self funded with no foreseeable ending time thus we used those much less expensive in small blue vials., how small? I forgot.
Yours are better b/c it's NO_CLEAN. The ingredient I suggest requires some residue cleaning, not a lot but some.
Lately we use T-962, cheap, China made reflow oven option 1. and it worked.
Please disregard if you don't think it's helpful.
ephitran:
Example: From Amazon
Same 63/37 the most common alloy, with certification?
I just share my experience on our in-house work, That's it B/C I think it's helpful.
If people are able to DIY price will go down, it is the community who get the benefit at last.
ephitran:
I had never tried that brands. Our developments were self funded with no foreseeable ending time thus we used those much less expensive in small blue vials., how small? I forgot.
Yours are better b/c it's NO_CLEAN. The ingredient I suggest requires some residue cleaning, not a lot but some.
Lately we use T-962, cheap, China made reflow oven option 1. and it worked.
Please disregard if you don't think it's helpful.
Could there be other options than the T-692 reflow Owen?
If you mention it..it would be helpful
ameliacris:
Could there be other options than the T-692 reflow Owen?
If you mention it..it would be helpful
At the time T-962 is the cheapest one I can find. It uses open-source, by look at the temperature curve it's (almost) identical to those of DIY.
Good Luck!
Modified £20 sandwich toaster worked well for me. Viewing window allows you to cut the heat at the
precise moment everything has reflowed, which means you can get away with primitive temperature
control: soak for 3 mins at 150C, turn up heat, watch, kill heat when paste flows. Simple
