Removing Pitting and Rust From an Enclosure

Doug Ingraham dpi at dustyoldcomputers.com
Thu Jul 20 10:13:34 CDT 2017


On Wed, Jul 19, 2017 at 1:52 PM, Rob Jarratt via cctalk <
cctalk at classiccmp.org> wrote:

> The TURBOchannel extender I got has a bit of rust and quite a lot of dark
> pitting on the steel surfaces. I am not sure what the finish is, whether it
> is anodized or galvanized. In any case, does anyone have recommendations
> for
> how to remove the unsightly pitting? Bear in mind that I am in the UK, so
> brands available in the US may not be available here and it may be more
> useful to know what the active ingredients are.
>

I have restored a couple of racks that have been shall we say mistreated.
The
approaches you can use are the same ones that automobile restoration people
use.

Remove the scale.  Steel brush works for this.
Fill the pits.  This might be something as simple as a sandable primer.
Prime.
Paint.

You want to use a primer and paint that is compatible.  If all you are
doing is gloss
black then there is nothing wrong with the Rustoleum product line.  The pro
version
seems to have a little better spray pattern.

There is a point beyond which the only solution is to replace or augment
the material.
You can cut out the sheet metal and weld in a new piece or you can
reinforce with
a fiberglass band aid in some cases.

If the surface is not normally visible you can remove the scale and then use
one of the rust converting primers.  A flat black topcoat will hide almost
anything
that is not directly visible.  Of course this does not apply if you are
trying to do a
museum quality restoration.

Look into restoration videos on youtube for detailed techniques.

-- 
Doug Ingraham
PDP-8 SN 1175


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