[Elecraft] Mineral spirits OK for cleaning boards?

Wed Jun 18 21:32:01 2003

Hi

Not all that many years ago boards were cleaned with vapor degreasers these 
were refrigerator type affairs that heated the solvent on the bottom and 
cooled it on the top forming a valor cloud in between. When the board was 
placed in the cloud the solvent would condense on the board and run off into 
the pool below taking all the flux and grease with it. The solvent was Freon 
or a mixture of Freon and isopropyl alcohol (Freon TF). The EPA outlawed 
Freon to "save the ozone layer" so these machines were scrapped. About 10 
years ago you could buy them for about $20 at a lot of surplus houses around 
Dallas. TI and Rockwell (Collins) must have dumped them. If you are thinking 
why not use alcohol in them, all you need is a nice flammable vapor cloud 
waiting for a spark. Freon and Freon TF are not flammable. Yes MIL spec 
boards are cleaned but most likely with alcohol now.

BTY when I worked at Tektronix we cleaned scopes with soap and water. We 
used a special electronic soap called Allied Kelite Spraywhite E in a turbo 
washer gun followed with deionized water. They were then placed in a large 
oven and heated overnight at 150 degrees F. We never had any electrical 
problems washing the equipment this way.

Most board houses now use water soluble flux so the boards are cleaned in 
hot water in machines much like large dishwashers. Don't try to use water 
soluble flux solder on your K2 it is about as bad as acid core solder if it 
is not removed properly.

Don Brown
KD5NDB

----- Original Message ----- 
From: "Dave Hottell" <[email protected]>
To: "elecraft" <[email protected]>
Sent: Wednesday, June 18, 2003 7:45 PM
Subject: Re: [Elecraft] Mineral spirits OK for cleaning boards?

SNIP

>
> Also, FWIW, when I worked at North American Rockwell years ago all boards
> were 100% cleaned before being potted with a sealant.  Not sure now what
> they used - this was 30+ years ago - may have been alcohol.   But mil-spec
> boards were cleaned with no apparent damage.  Indeed, I believe the
> mil-spec required it.
>
>
> 73 de Dave
> ab9ca/4
>
>
>
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