Apple IIGS sheet metal cleanup

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Last seen: 9 months 4 days ago
Joined: Jan 22 2012 - 21:38
Posts: 4
Apple IIGS sheet metal cleanup

I did try to search on this but I may be having a senior moment and not finding it.  Is there a technique or guide on a proper way to clean and restore (light rust) the metal inside the IIGS case?  



Last seen: 6 hours 32 min ago
Joined: Feb 27 2021 - 18:59
Posts: 214
heat staked

This kind of heat-staked metal insert is difficult to restore because it can't be effectively removed without a ton of headaches.

Because of this, you can't use wet methods of rust removal because there's no way to rinse and dry behind the insert. The best you can do, I think, is to use a buffing wheel on a Dremel or Foredom to polish away light surface rust. Regular buffing compound (rouge wax) should do it.

Another place that heat-staking shows its ugly head is in some keyboard assemblies. The Digital LK-201 key assy is heat-staked to a steel stiffening plate and is effectively impossible to clean or repair.

An experiment I won't try is to use a rust removal solution containing sodium thioglycolate (hair perm salt). This is sold as a rust remover in Japan and appears to be non-acidic with a pH around 8. It may be possible to wipe the insert with a shop towel wetted with the solution and then "rinsed" with a clean damp towel. With luck, residue that migrates around the heat stakes onto the inside won't cause future rust, but I can't say for sure. Just the presence of water in this kind of closed assembly is a rust hazard, so a drying step in a 150°F oven may also be advisable. As long as the temperature is held below 150°F, the ABS plastic won't be affected.

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