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When do you use Tin/Lead/Silver paste ?

#18929

When do you use Tin/Lead/Silver paste ? | 20 February, 2002

When do you use Tin/Lead/Silver paste ? What is the advantage of using Tin/Lead/Silver paste comparing to Tin/Lead? Do you have to use Tin/Lead/Silver paste only if the components are made from Tin/Lead/Silver ? I would appreciate your quick response on that since the customer have to fill out a report on this issue.

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#18930

When do you use Tin/Lead/Silver paste ? | 20 February, 2002

Search the fine SMTnet Archives on � Sn62 � 62Sn � 2% Ag � 2% silver � 2Ag � etc

re: "Do you have to use Tin/Lead/Silver paste only if the components are made from Tin/Lead/Silver ?"

No

Several points are: * Component leads with silver in the solderability protection are fairly rare. * If you have leads with silver in the solderability protection, you can use solders with formulation that do not include silver. * Components do not have a uniform solderability protection. Every day we see components with tin/lead, palladium mixes, high tin mixes, and other no-lead coatings on the same board.

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JAX

#18931

When do you use Tin/Lead/Silver paste ? | 20 February, 2002

Silver in paste is usually employed to prevent scavenging of silver from silver plated surfaces, BUT Dave's right. I wouldn't think Components are uniform enough to base a process change on. See how it goes with what you have. You will probably find that it's "A"o.k. That's just my opinion, I could be wrong!

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#18932

When do you use Tin/Lead/Silver paste ? | 20 February, 2002

Paste w/ 2% silver has a eutectic temp of 179deg.C vs. 183deg.C for std. 63/37. The 2% can give better wetting in some applications.

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#18953

When do you use Tin/Lead/Silver paste ? | 22 February, 2002

Thanks for the input.

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