Homebrew PCBs

--- Adam Seychell <adam_seychell@...> wrote:
> Hello,
> I'm wondering it its possible to seal the shaft from
> a very low RPM (< 20 RPM) electric motor (stepper
> maybe), enough so its protected from splashes of
> etchant.

Yes:

2.) 60+ minute polyester resin, which is also known as
epoxy, is both water, gasoline, fecl and hcl proof
(Just to name a few). I've used this in many
applications as a chemical barrier. It's effective,
cheap and lasts longer than anything else I've found.
I have appliations where it has literally lasted 10
years. This soltion is great for metal, plastic or
anything else you can think of. This is a high
friction solution.  

It's done like this:

A.) Clean the area to be protected with 0000 steel
wool and Ajax or comet. Wipe this stuff off really
well with a rag and some h20. 

B.) Dry with 100% denatured alcohol and a clean paper
towl. Be sure the area is TOTALLY clean. This is
vitally important.

C.) Protect the area you do NOT want any epoxy or
lagur with petroleum jelly.

D.) Apply 3 coats in very thin layers with a bush. Let
each coat dry over night (24 hours at least) before
applying the next coat. Rough each coat up with 0000
steel wool (Clean again with denatured alcohol and
leave no debre) before applying the next coat.
Anything over three coats will not provide additional
protection and could mechanically bind whatever your
protecting if you apply too much.

E.)  If a sleave or anything else is going to be in
contact with the area you have applied the protective
coat, and this sleave or whatever it is will be
subject to friction, apply a liberal coat of petroleum
jelly between the area you protected and the sleave. 


This is a well known, tried and true solution for
protection from chemicals in industrial, military and
aviation enviroments

Best regards

Marvin Dickens
Alpharetta, Georgia

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