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Retr0Bright: Does re-yellowing occur even in the absence of

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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by Corestore » Sun Jan 27, 2013 6:34 pm

machinecoder wrote:clear acrylic laquers are subject to fairly rapid "oxygen-attack" and are brittle, 2-K is far more flexible and will last a lot longer, I used to be an automotive refinisher and ALL paints have a certain amount of porousness.


Excellent! A professional paint guy! Hopefully you can give a pointer on something that affects several jobs I've had outstanding for a while.

Many computers, especially larger ones - DEC pdp and IBM mainframe systems - which have painted metal panels or skins have a paint finish that is NOT smooth; it's rough on a fine scale, like a textured or very fine-grained orange-peel finish.

How was that generally achieved? I'm presuming they were sprayed, was it a particular type of nozzle? A particular type of paint? Texturing material or filler added to the paint? Paint thinned to a specific viscosity? Something that's not too hard to recreate?

Any help would be appreciated, I have a bunch of old IBM mainframes with varying degrees of rust and denting, I want them to look new again :-)

Thanks

Mike
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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by Corestore » Sun Jan 27, 2013 11:23 pm

Thanks, some great thoughts there.

Here's a close-up of the kind of thing I mean:

Image

The area shown is about 2cm square. That's the kind of texture I'm going to have to recreate. What do you reckon?

I'm in Welly, and I'd seriously consider getting a pro to do at least some of this stuff - or, perhaps best (given the sheer number of panels I'll ultimately be refinishing), work out a repeatably technique and teach it to me! I do have a large workshop compressor with a big reservoir which should be adequate for most paint jobs, with the right paint gun on the end of it?

Cheers

Mike
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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by SpidersWeb » Mon Jan 28, 2013 8:55 am

I have the same issue with my IBM PC and PC-XT cases, so am interested in this also.
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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by Gibsaw » Mon Jan 28, 2013 1:17 pm

Kitch wrote:Would that mean once all the Bromide had degraded the case would now be flammable?

The case is pretty flammable anyway. The brominated plastic is flame retardant, not flame proof.
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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by Corestore » Mon Jan 28, 2013 3:15 pm

Machinecoder, a few more pics for your professional opinion! :)

About the worst of the panels. Was originally smooth semi-gloss black:

Image


A more typical panel, some rust spots and scratches, textured or 'spattered' blue:

Image


Closeup of texture on blue panel, with scale:

Image


What do you reckon? How would you restore that? Just FYI, the *average* size of the panels is probably about 1m x 1m (many smaller, many larger), and there are probably the equivalent of about 60-80 panels I would ultimately want to restore.

Thanks!

Mike
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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by Carcenomy » Mon Jan 28, 2013 6:39 pm

Capri eh?
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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by Carcenomy » Mon Jan 28, 2013 7:15 pm

That's badass :)

Sorry, I'll stop derailing now!
Just the local Commodore hobo and middle-aged PC hoarder.
eisa on Trademe. A lasting reminder of a Compaq fetish when I was younger.
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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by Corestore » Mon Jan 28, 2013 8:35 pm

Thanks a bunch machinecoder, that's given me a lot to ponder.

I'm sure I'll pop up some questions, but frankly I think I'm going to throw some panels in the car, along with my chequebook, and head for Christchurch! If a picture tells a thousand words, a demonstration tells a million :-)

I do recall hearing a lot of Dire Warnings about 2K paint, and health effects; if I do get into that I'll treat it with appropriate respect.

Tergo & scraper to remove old paint?

Mike
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Re: Retr0Bright: Does re-yellowing occur even in the absence of

by Corestore » Mon Jan 28, 2013 11:05 pm

Thanks for that, one quickie. There are various Iwata 400 models, which would you suggest? The LVB?

Mike
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