Yes Graham, there are washable spacers available from several sources.
We used them extensively in the past with mixed results. I will point
out the problems I have experienced with them:

The ones we used were brittle and occasionally broke prior to wave
soldering. This resulted in unnecessary rework and a tendancy for
operators to over-inspect boards prior to wave.

They are tiny and a pain to put on the leads. Way to much labor
involved.

They washed off in the in-line cleaner, resulting in increased waste and
maintenance on the cleaner.

I would really suggest you consider setting up a component forming
operation to handle this. Most parts commonly requiring standoff can be
formed using a couple of relatively inexpensive machines. You might also
consider revisiting lead to hole diameters from a PCB design
perspective. Also recheck the packages available on your parts, many
styles are available with standoffs built into them. Finally, I would
ask just why a component needs to standoff the board. You may find a lot
of "because thats the way we've always done it."

                                                Best of luck.
                                                                Steve Tucker
                                                                AlliedSignal Aerospace
                                                                (785) 838-5116

>----------
>From:  COLLINS, GRAHAM[SMTP:[log in to unmask]]
>Sent:  Monday, November 03, 1997 12:03 PM
>To:    [log in to unmask]
>Subject:       Mechanical standoff
>
>Good Day Technet!
>In wavesolder attachment of some through hole components, we have to provide
>a temporary standoff to keep the part off the board surface.  Currently we
>are doing this with bits of wire or other mechanical means, which are then
>removed after wavesolder.  Some components we keep off the board with a
>washable solder masking material, but this is not a precise or quick method.
>Is there such a thing as a preformed standoff that will dissolve when the
>assembly is washed, that would be put on the lead before insertion into the
>board?
>
>Thanks!
>
>Graham Collins
>Process Engineer,
>Litton Systems Limited, Atlantic Division
>(902) 873-2000 ext 215
>
>

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