>1) Can I get your thoughts on my delimma? Have any of
>you runned into this problem in the past?
>2) Since I'm building boards for a space application,
>I want to make sure that I have backing when someone
>asks me about my soldering temperature. Also, if the
>EE guy is wrong with his established soldering-temperature
>standard, I would like to make sure that I am not acting
>on a hutch either. Does anyone know of mil-spec standards
>that specify what the tip temperature of the soldering
>iron should be for hand-soldered joints?

Right, I can speak from a position of authority on this one. I am an ESA 
qualified soldering inspector, for PCBs that get used in space flight 
instrumentation.

>From ESA PSS-01-738 Issue 1 "High-reliability soldering for surface mount 
and mixed technology printed circuit boards", the relevant section is 
section 3.5.7. For 'standard' tin/lead solder the soldering bit temperature 
of 280C is recommended, but not to exceed 320C. Now 280C = 536F and normally 
one would use a 600F tip (when I used to use a Weller temp controlled iron, 
I always used a tip with a '6' stamped on the magnet, as that is the 600F 
selection. 600F = 315.5C, so is within the maximum allowed.

ESA standards are very closely related to NASA standards, and my 
qualification under ESA rules allows me to inspect items being used on NASA 
projects.

Certainly using an iron at only 420F will take an age to melt the solder, 
and most likely leave a pasty joint that will create all sorts of problems. 
It certainly will not create the nice bright surface that indicates a well 
tinned and flowed joint.

Feel free to print this off and wave it under his nose.

Thank you

Alan B. Pearce
Space Science and Technology Department
R25 Rm 1-122
Rutherford Appleton Laboratory
Harwell Science & Innovation Campus
Chilton
Didcot
OXON OX11 OQX
United Kingdom

Tel +44 1235 44 6532
Fax +44 1235 44 5848 

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist