Cosmetic replicas

Jules Richardson julesrichardsonuk at yahoo.co.uk
Thu Apr 20 22:00:18 CDT 2006


William Donzelli wrote:
>> In some cases museum practice seems a little odd, though. I remember
>> discussing our ICL mainframe with others at Bletchley a little while
>> ago - some of the cabinets are pretty scratched and rusted up. It
>> seems that London Science Museum policy as part of restoration is not
>> to repaint anything, and I still can't quite get my head around that.
> 
> That same kid might do his doctorate on computer cabinet paint.

Yep - hence the reason for keeping samples of the original paint, though. I 
can see that someone in the future might be interested in the original paint 
used (although doesn't that in itself open a whole can of worms in terms of UV 
exposure and the like?).

I just wouldn't like the future possibility of a handful of people being 
interested in the paintwork compromising the preservation of an item in the 
medium term (and the same goes for other components)

> To be proper, the over the top method used by NASM is to coat the original
> paint and finish with a non-reactive wax, then new paint is applied over
> the wax. 

Well, I suppose it's not *that* over the top - providing that it's a 
*certainty* that the wax is non-reactive over time :-)

Mind you, experience of old cars is that moisture often gets beneath the 
paintwork and attacks the metal, causing rust, which then only starts showing 
through to the surface and becoming visible once it's taken a good hold 
beneath. I doubt that computer cabinets are any different - so that wax 
coating better be darn good if it's going to stop further deterioration 
beneath the new coat of paint...

> This is not as nuts as it seems. To all those that ask about curing
> yellowing plastic, do something much the same - a thin coat of latex paint
> will work fine.

In the case of plastic, isn't it UV exposure that causes the yellowing? So 
yep, that certainly makes sense as the paint coat should both improve the look 
of the item and stop the plastic itself from breaking down further. Of course, 
I'm not sure how someone would remove the paint at some future date without 
whatever method used (chemical or blasting) also damaging the plastic itself...

cheers

Jules



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