Solder Paste
Mike Huselton
Posts: 746
I need to get some experience using solder paste. Is it true that due to transport restrictions, refrigerated trucks must be used for shipment? I live in Austin.
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JMH
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JMH
Comments
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It's Only A Stupid Question If You Have Not Googled It First!!
That seems like a low-cost and low-risk method to me. Can you remember the email of the vendor?
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JMH
Dave
Did you notice any refrigerated trucks roaming the neighborhood?
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JMH
You can look at: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=SMD291SNL-ND
You look at handling says to store at 42 - 47 but higher temps will shorten life. Guess 2 days doesn't hurt that much - would not order it this week with the temps in Austin
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JMH
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My new unsecure propmod both 1x1 and full size arriving soon.
-Phil
I bet this thing about refrigeration is just for long term storage or for those with special equipment that require a certian viscosity.
Digikey made me pay for overnight shipping, but I think it would only make a difference in the middle of summer...
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My Prop Info&Apps: ·http://www.rayslogic.com/propeller/propeller.htm
My understanding of solder paste is from many solder paste manufacturers and distributors. The reason solder paste has an expiration date:
Solder paste in a dry form only contains metal. The metals can be of different alloys, which make leaded and unleaded solder pastes.
When the flux is added, there is a chemical reaction which is started, and will continue to happen. If the paste is cooled (refrigerated) the reaction slows significantly. If left at room temperature the reaction within the paste is always on going and will eventually cause the paste to not "flow/wet" properly. Some pastes will sometimes get thick because of this reaction, but some pastes do not.
There are other things which happen to solder paste, like settling, and separating.
I however do not make any of the above claims, they are from various solder paste reps.
James L
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James L
Partner/Designer
Lil Brother SMT Assembly Services
I guess keeping it in the fridge IS needed afterall.
www.amtechsolder.com/pdf/Procedures-5Fsolder-5Fpaste.pdf
"Refrigerated storage is not required but highly recommended (1°C to 10°C), as it prolongs the shelf life of the solder paste."
John
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Whistler: I want peace on earth and goodwill toward men.
Bernard Abbott: We are the United States Government! We don't do that sort of thing.
Sneakers (1992)
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JMH
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Tracy Allen
www.emesystems.com
Well, I'm sold! I've got another half-full 35cc syringe of Kester solder from DigiKey that's gone bad. 10cc is much more reasonable, as are Zephyrtronics' prices. Thanks for the link!
-Phil
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My new unsecure propmod both 1x1 and full size arriving soon.
Their solder paste is very sensitive to humidity. If you are in a humid area, use the solder paste quickly after it is exposed to air.
I had problems with their solder paste when I bought it, but to give them some slack, I was exposing it to the open air for a long period of time (about 3 hours). I'm in the deep south, so humidity is a major problem.
If you are in a humid area, I suggest a no-clean solder from Amtech (Solder and More is a dealer). We only use their solder pastes. I do not recommend the 4300 (water soluble) variety for anyone in a humid area.
Kester is also a good solder, but hard to find for a reasonable price in small quantities.
James L
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James L
Partner/Designer
Lil Brother SMT Assembly Services
Were you using Zephyr's paste from a syringe or from an open can or jar? I live in a humid area, too (Pacific NW), and am now thinking that a syringe would protect the bulk of its contents against external influences.
-Phil
Phil,
I was using the paste in the syringe. I do not ever use any water soluble in a "jar". We do however use no-clean SAC305 in a "jar".
Yes, the syringe will protect the solder paste in the tube itself. It is only after it is squeezed out of the tube, the clock starts.
Also, make absolutely sure the solder paste is at room temp. If you squeeze it out cold, it will condense the humidity in the air.
We do not use syringe solder paste much. The solids percentage is lower in a syringe, unless special ordered. Jars have 88% or higher, and syringes typically have 86-87% solids.
When using a stencil, care must be taken with the syringe paste. It will tend to "run" under the stencil, and cause bridges.
Probably more solder paste education than most need, but I had to learn all of it, I figured others may benefit from the knowledge.
James L
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James L
Partner/Designer
Lil Brother SMT Assembly Services
-Phil
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My new unsecure propmod both 1x1 and full size arriving soon.
http://www.amtechsolder.com/syntechlf.html
Ordered a 35g syringe from Celeritious, but won't be using it for a couple of weeks:
http://www.celeritous.com/estore/index.php?main_page=product_info&products_id=47
Not real cheap @ $28 (plus $23 shipping to Calgary), but you get a kit with a plunger and 6 tips. Lead-free also available.
-Dave
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Brian
uController.com - home of SpinStudio - the modular Development system for the Propeller
PropNIC - Add ethernet ability to your Propeller! PropJoy - Plug in a joystick and play some games!
SD card Adapter - mass storage for the masses Audio/Video adapter add composite video and sound to your Proto Board
You should try:
www.solderandmore.com/servlet/the-No-dsh-Clean-Solder-Paste/Categories
Their prices are real good, and their service is outstanding. You get more paste for just a little more money.
I haven't ever tried SRA solder.
James L
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James L
Partner/Designer
Lil Brother SMT Assembly Services
By the way I am in calgary also
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My new unsecure propmod both 1x1 and full size arriving soon.