[Elecraft] Solder Question

Wed May 28 15:32:00 2003

YAWN! hihi
----- Original Message -----
From: "Rich Lentz" <[email protected]>
To: "Elecraft Reflector" <[email protected]>
Sent: Wednesday, May 28, 2003 12:10 PM
Subject: [Elecraft] Solder Question

From a Navy Training publication for electronic Technicians:

"Solder is a metal alloy used to join two or more metals with a metallic
bond. The bonding occurs when molten solder dissolves a small amount of the
metals and then cools to form a solid connection. The solder most commonly
used in electronic assemblies is an alloy of tin and lead. Tin-lead alloys
are identified by their percentage in the solder; the tin content is given
first. Solder marked 60/40 is an alloy of 60 percent tin and 40 percent
lead. The two most common alloys used in electronics are 60/40 and 63/37.

The melting temperature of tin-lead solder varies depending on the
percentage of each metal. Lead melts at a temperature of 621 degrees
Fahrenheit, and tin melts at 450 degrees Fahrenheit. Combinations of the two
metals melt into a liquid at different temperatures. The 63/37 combination
melts into a liquid at 361 degrees Fahrenheit. At this temperature, the
alloy changes from a solid directly to a liquid with no plastic or
semiliquid state. An alloy with such a sharp changing point is called a
EUTECTIC ALLOY.

As the percentages of tin and lead are varied, the melting temperature
increases. Alloy of 60/40 melts at 370 degrees Fahrenheit, and alloy of
70/30 melts at approximately 380 degrees Fahrenheit. Alloys, other than
eutectic, go through a plastic or semiliquid state in their heating and
cooling stages. Solder joints that are disturbed (moved) during the plastic
state will result in damaged connections. For this reason, 63/37 solder is
the best alloy for electronic work. Solder with 60/40 alloy is also
acceptable, but it goes into a plastic state between 361 and 370 degrees
Fahrenheit. When soldering joints with 60/40 alloy, you must exercise
extreme care to prevent movement of the component during cooling. "

A search on the WEB  for the words eutectic and solder provides a wealth of
information on this topic.

Rich
KE0X

_______________________________________________
Elecraft mailing list: [email protected]
You must be a list member to post to the list.
Postings must be plain text (no HTML or attachments).
See: http://mailman.qth.net/mailman/listinfo/elecraft
Elecraft Web Page: http://www.elecraft.com

---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.481 / Virus Database: 277 - Release Date: 5/13/2003