You're right about the propensity of wave solder metal parts to dissolve
in tin. However, the best protection has always been a thorough coating
of oxide before the parts are put into use. Excessive cleaning of solder
machines (and the use of metal tools for scraping surfaces) actually
reduces the life of the machines by breaking through the protective
oxide coating. Introducing higher percentages of tin should not affect
the machine life from a purely metallurgical standpoint. (Premature
aging due to higher temperatures is a separate issue.)

Jim Smith
Managing Director
Cambridge Management Sciences, Inc.
4285 45th St. S.
St. Petersburg, FL 33711-4431
Tel: (727)866-6502 ext. 21
Fax: (727)867-7890
eMail: [log in to unmask]

Christopher Jorgensen wrote:
>
> The following is a question from Frank Coultard, PCIF. His contact information is included at the end of the message.
>
> ++++++++++++++++++++++++++++++++++++++++
> It has been brought to my attention that due to the high corrosivity of
> molten Sn, wave solder Pumps, Flow Ducts and Nozzles should be treated with
> a protective coating to ensure long term service with Sn-0.3Cu lead-free
> solder .  Malonite (sp?) is one recommended protective coating.  It is
> apparently also the case that one should not apply, at least the Malonite
> coating, to these items if they have previously been exposed to conventional
> SnPb solder.  Does anyone have any experience converting existing wave
> solder equipment to lead-free service or have other information to share on
> this subject?
>
> Best regards
>
> Frank Coultard
> Director
> PCIF
> Beaufort Court,  #45, Admirals Way
> London E14 9XL
> England
> W: 011 44 1715151166, F: 011 44 1715151188
> [log in to unmask]
>
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