Painted chassis (was: Re: Removing duct tape residue.)

From: Tothwolf <tothwolf_at_concentric.net>
Date: Mon May 19 10:35:00 2003

On Sat, 17 May 2003, Joe wrote:
> At 10:01 PM 5/16/03 -0500, you wrote:
>
> > I guess you could say these have a pebble finish. The texture is
> > pretty fine and you don't notice it right away. I have a bead blasting
> > cabinet, but the metal underneath the paint is smooth. I guess the
> > texture is only part of the paint.
>
> Correct. They call it splatter paint or something like that. It has
> lumps in it and you spray it on that way. I guess the size of the lumps
> control the size of the bumps in the finish. I used to work in a paint
> and body shop and we used the stuff to re-pain the insides of trunks of
> 60s and 70s cars that had that finish. The stuff they used left a
> greyish finish with large spots and streaks of very dark color.
>
> You can sandblast or bead plastic the base material (metal or plastic)
> and then paint over it and get a rough finish but it will have holes and
> dips in it instead of bumps (pebbles) so it's not the same.

It sounds like the best thing I can do for now is leave it alone until I
can find out what kind of paint to use. I wouldn't mind repainting it, but
I don't want to mess it up. I have a number of these units, and would like
to preserve a consistent look.

Since the thread is already on the subject of paints...

How difficult would it be to touch up scratch damage on a painted metal
chassis? Specifically, I'd like to repair some transit damage on a SGI
IRIS 1400, which has an off-white lightly textured paint. The paint
differs from the drive chassis that has sharpie marks, in that the paint
on the SGI is very hard (and easier to chip/scratch) and the texture is
much more coarse. Also like the drive chassis, the texture appears to be
part of the paint and not the metal.

I also have a rack-mount device that was originally painted with a rubber
like paint that got "sticky" and made a mess. I've been trying to strip it
off of all the metal surfaces so I can repaint it with some regular
spray-on paint, but some of the metal is textured. What would be the best
way to get that nasty rubberized paint off the metal? The paint came right
off the non-textured metal with some paint stripper and a plastic scraper.

> > > I see on TV that they now have lasers that can burn off dark spots
> > > like freckles and tatoos without burning the lighter color skin
> > > around them. I wonder if something like that could be used to burn
> > > off dark marker stains without damaging the lighter surrounding
> > > area. Yeah I know that kind of equipment is expensive but I wonder
> > > if it would work. If so there are some of us that could build their
> > > own lasers or modify existing ones. Just an idea.
> >
> > Thats an idea. That type of equipment turns up at local auctions every
> > year or two too. The last time that kind of gear turned up, one guy
> > picked up all 3 laser units for a total of $5.00 simply because no one
> > else wanted to haul them off. They do tend to be kind of bulky. He
> > later told me they worked fine, though one needs a supply of liquid
> > helium or liquid nitrogen to operate. Oh, and they use *lots* of
> > electricity...
>
> I've never seen any of that stuff close up. What's the liguid mitrogen
> for?

These units were all cart-like and had wheels. They were of course older
units, and were not very small. I think they averaged about 1-1/2 to 2ft
square and about 3ft high. The liquid helium or liquid nitrogen was needed
by one of the units to cool part of the laser. The laser levels could be
adjusted for different things, and the guy who bought them told me he had
no trouble cutting 1/2" steel plate with one of them. Other than that, I
don't know too much more about them, but I wish I would have had room so I
could have bought them myself ;)

-Toth
Received on Mon May 19 2003 - 10:35:00 BST