RE: Removing Pitting and Rust From an Enclosure

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis
> via cctalk
> Sent: 20 July 2017 14:43
> To: Brent Hilpert via cctalk <cctalk@classiccmp.org>
> Subject: Re: Removing Pitting and Rust From an Enclosure
> 
> On 07/20/2017 12:02 AM, Brent Hilpert via cctalk wrote:
> 
> > A copper layer can perform some filling and smoothing function in a plating
> job.
> > Its perhaps more significant purpose however (as I understand it in my
> limited experience with having plating done*), is to provide an oxygen barrier
> for the steel substrate.
> 
> You can plate copper on steel to substantial thicknesses--it's often used as a
> filler material--plate more than you need, machine it to spec, then plate over
> with something durable (nickel is very common).
> 
> It's not cheap and probably not a do-it-yourself affair.   I don't know
> how OCD you want to get over this, but it'll be expensive.
> 
> You might also check out the finishing.com forum and caswellplating.com for
> alternative approaches.
> 
> --Chuck


I suppose really I want to stop any further corrosion and make it look at least 
presentable. I don't want to paint it, the finish is the usual silvery type 
finish (which I assume to be nickel) and I want to keep that. The biggest 
problem is the honeycomb grill on one side, that seems to be a bit corroded 
too, cleaning the rust off that with any kind of hand held abrasive is going to 
be pretty hard. I suspect the honeycomb may need to be sandblasted to get rid 
of the rust before electroplating. I will enquire with local companies about 
doing this work for me.

Thanks

Rob

RE: Removing Pitting and Rust From an Enclosure

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul
Koning
> via cctalk
> Sent: 20 July 2017 15:18
> To: Brent Hilpert <bhilp...@shaw.ca>; General Discussion: On-Topic and
Off-
> Topic Posts <cctalk@classiccmp.org>
> Subject: Re: Removing Pitting and Rust From an Enclosure
> 
> 
> > On Jul 20, 2017, at 3:02 AM, Brent Hilpert via cctalk
<cctalk@classiccmp.org>
> wrote:
> >
> >> ...
> >
> > The yellowish plating is probably chromate conversion:
> > https://en.wikipedia.org/wiki/Chromate_conversion_coating
> 
> That sounds familiar from vague DEC memories.
> 
> As for those galvanized iron pieces attached to the cover, I have never
seen
> anything like that.  They are very unlikely to be original.  For one
thing, the
> mismatch in finish says so; for another, the fact they serve no clear
purpose
> and look like they were attached with no skill.
> 

I'll get rid of those horrible "feet", they actually prevent the machine
being moved around on a smooth surface, I will have to add rubber feet where
they are missing though.

Thanks

Rob

Re: Removing Pitting and Rust From an Enclosure

[Doug Ingraham via cctalk]

On Wed, Jul 19, 2017 at 1:52 PM, Rob Jarratt via cctalk <
cctalk@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

Re: Removing Pitting and Rust From an Enclosure

[Paul Koning via cctalk]

> On Jul 20, 2017, at 3:02 AM, Brent Hilpert via cctalk  
> wrote:
> 
>> ...
> 
> The yellowish plating is probably chromate conversion:
>   https://en.wikipedia.org/wiki/Chromate_conversion_coating

That sounds familiar from vague DEC memories.

As for those galvanized iron pieces attached to the cover, I have never seen 
anything like that.  They are very unlikely to be original.  For one thing, the 
mismatch in finish says so; for another, the fact they serve no clear purpose 
and look like they were attached with no skill.

paul

Re: Removing Pitting and Rust From an Enclosure

[Chuck Guzis via cctalk]

On 07/20/2017 12:02 AM, Brent Hilpert via cctalk wrote:

> A copper layer can perform some filling and smoothing function in a plating 
> job.
> Its perhaps more significant purpose however (as I understand it in my 
> limited experience with having plating done*), is to provide an oxygen 
> barrier for the steel substrate.

You can plate copper on steel to substantial thicknesses--it's often
used as a filler material--plate more than you need, machine it to spec,
then plate over with something durable (nickel is very common).

It's not cheap and probably not a do-it-yourself affair.   I don't know
how OCD you want to get over this, but it'll be expensive.

You might also check out the finishing.com forum and caswellplating.com
for alternative approaches.

--Chuck

Re: Removing Pitting and Rust From an Enclosure

[TeoZ via cctalk]

It depends on what the object in question is for (decoration or durability) 
and what time period it was done.


Way back in the early 90's when I worked at a plating facility for the 
printing industry (Tide soap boxes, Marlboro cigarette boxes as an example) 
they used to copper plate  large and heavy steel (or aluminum which needed 
another step) cylinders. The copper layer was then diamond engraved with the 
design for each color  and then a heavy chrome plating was done for wear to 
keep the design from getting damaged from printing rolls of paper or what 
have you. No nickel plating at all back then. A final QC test was spinning 
the cylinder and running sandpaper over it to spot imperfections (shiny 
spots that show indentations where no design was) that would show up during 
printing , if it passed it went to the onsite printer for a proof print 
otherwise acid bath to remove the chrome then the lathe to cut off the 
designs and back to copper plating again. The chrome plating was pretty 
thick.


-Original Message- 
From: Brent Hilpert via cctalk

Sent: Thursday, July 20, 2017 3:02 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Removing Pitting and Rust From an Enclosure

A copper layer can perform some filling and smoothing function in a plating 
job.
Its perhaps more significant purpose however (as I understand it in my 
limited experience with having plating done*), is to provide an oxygen 
barrier for the steel substrate.


(* OT, FWIW: I once went through the trial, albeit educational, of having a 
chrome Scott radio chassis replated. Longer tale.
A proper chrome plate job is not chrome on steel, it's copper on the steel, 
then nickel, and finished with a few atoms of chrome.) 



---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

Re: Removing Pitting and Rust From an Enclosure

[Brent Hilpert via cctalk]

On 2017-Jul-19, at 11:37 PM, Rob Jarratt via cctalk wrote:
>> -Original Message-
>> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis
>> via cctalk
>> Sent: 20 July 2017 03:34
>> To: Fred Cisin via cctalk <cctalk@classiccmp.org>
>> Subject: Re: Removing Pitting and Rust From an Enclosure
>> 
>> On 07/19/2017 07:13 PM, Fred Cisin via cctalk wrote:
>> 
>>> In most places other than the south and Chicago, Coke and Pepsi are what
>>> is used.   I don't think that SNL (Saturday Night Live) ever did a "No
>>> Coke; RC" skit.
>> 
>> There's also some stuff called "Naval Jelly"
>> 
>> http://www.loctiteproducts.com/p/s_trmt_naval/overview/Loctite-Naval-Jelly-
>> Rust-Dissolver.htm
>> 
>> I was going to suggest leveling with Bondo, but that seemed the cheap way to
>> go.
>> 
>> I've used Bondo many times to fill missing bits of broken plastic
>> faceplates.   A little sanding and a coat of paint and it looks
>> downright presentable.
>> 
>> Machine tools (particularly Chinese ones) that use gray iron castings are 
>> often
>> smoothed with a Bondo-like putty before being painted.
>> (They're not very pretty under the putty).
>> 
>> If you were really serious about this, you could plate a generous coat
>> of copper, sand it smooth, then plate a layer of nickel.   But if you've
>> never done electroplating, it's probably not a good idea to start with 
>> something
>> valuable.
> 
> 
> Well I could always see if I can get electroplating done professionally 
> without spending a fortune, although trying myself with something unimportant 
> is also an option. But first I would need to know what the finish actually 
> is. There seem to be two common finishes to the metal used in MicroVAXen, 
> DECstations and the like, one is a sort of subtle yellow, the other is a 
> silvery finish. In this case it is a silvery finish. Can anyone tell me what 
> those two finished actually are? I am guessing it is nickel. If that is the 
> case, why the copper plating first?

The yellowish plating is probably chromate conversion:
https://en.wikipedia.org/wiki/Chromate_conversion_coating

A copper layer can perform some filling and smoothing function in a plating job.
Its perhaps more significant purpose however (as I understand it in my limited 
experience with having plating done*), is to provide an oxygen barrier for the 
steel substrate.

(* OT, FWIW: I once went through the trial, albeit educational, of having a 
chrome Scott radio chassis replated. Longer tale.
A proper chrome plate job is not chrome on steel, it's copper on the steel, 
then nickel, and finished with a few atoms of chrome.)

RE: Removing Pitting and Rust From an Enclosure

[Rob Jarratt via cctalk]

> -Original Message-
> From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Chuck Guzis
> via cctalk
> Sent: 20 July 2017 03:34
> To: Fred Cisin via cctalk <cctalk@classiccmp.org>
> Subject: Re: Removing Pitting and Rust From an Enclosure
> 
> On 07/19/2017 07:13 PM, Fred Cisin via cctalk wrote:
> 
> > In most places other than the south and Chicago, Coke and Pepsi are what
> > is used.   I don't think that SNL (Saturday Night Live) ever did a "No
> > Coke; RC" skit.
> 
> There's also some stuff called "Naval Jelly"
> 
> http://www.loctiteproducts.com/p/s_trmt_naval/overview/Loctite-Naval-Jelly-
> Rust-Dissolver.htm
> 
> I was going to suggest leveling with Bondo, but that seemed the cheap way to
> go.
> 
> I've used Bondo many times to fill missing bits of broken plastic
> faceplates.   A little sanding and a coat of paint and it looks
> downright presentable.
> 
> Machine tools (particularly Chinese ones) that use gray iron castings are 
> often
> smoothed with a Bondo-like putty before being painted.
> (They're not very pretty under the putty).
> 
> If you were really serious about this, you could plate a generous coat
> of copper, sand it smooth, then plate a layer of nickel.   But if you've
> never done electroplating, it's probably not a good idea to start with 
> something
> valuable.


Well I could always see if I can get electroplating done professionally without 
spending a fortune, although trying myself with something unimportant is also 
an option. But first I would need to know what the finish actually is. There 
seem to be two common finishes to the metal used in MicroVAXen, DECstations and 
the like, one is a sort of subtle yellow, the other is a silvery finish. In 
this case it is a silvery finish. Can anyone tell me what those two finished 
actually are? I am guessing it is nickel. If that is the case, why the copper 
plating first?

Regards

Rob

Re: Removing Pitting and Rust From an Enclosure

[Chuck Guzis via cctalk]

On 07/19/2017 07:13 PM, Fred Cisin via cctalk wrote:

> In most places other than the south and Chicago, Coke and Pepsi are what
> is used.   I don't think that SNL (Saturday Night Live) ever did a "No
> Coke; RC" skit.

There's also some stuff called "Naval Jelly"

http://www.loctiteproducts.com/p/s_trmt_naval/overview/Loctite-Naval-Jelly-Rust-Dissolver.htm

I was going to suggest leveling with Bondo, but that seemed the cheap
way to go.

I've used Bondo many times to fill missing bits of broken plastic
faceplates.   A little sanding and a coat of paint and it looks
downright presentable.

Machine tools (particularly Chinese ones) that use gray iron castings
are often smoothed with a Bondo-like putty before being painted.
(They're not very pretty under the putty).

If you were really serious about this, you could plate a generous coat
of copper, sand it smooth, then plate a layer of nickel.   But if you've
never done electroplating, it's probably not a good idea to start with
something valuable.

--Chuck

Re: Removing Pitting and Rust From an Enclosure

[Fred Cisin via cctalk]

On Wed, 19 Jul 2017, drlegendre . via cctalk wrote:

Chuck is right, but pits can also be filled.. JB Weld is one suggestion. It
can be sanded perfectly smooth & painted over. You can also try using some
auto-body spot filler, though I don't know how tough that is.


tough enough that it is sometimes used for auto-body spot filler!
Bondo is durable.
Fenders lead a rough life.

But, the purists insist that all auto-body spot filler should be done 
with lead.  Very similar to the way that some of us insist that any 
replacement parts of a classic somputer should be exactly the same as the 
original, perhaps down to with period appropriate date codes.


Painted over?
On something that was originally bare anodized or galvanized?
I like the "crackle-coat" paint,
but you could paint it pink and purple, like a "repurposed art" 026.



If the rust pits are deep, you can use muriatic acid to clean the rust out
of the pitting before you fill & coat. Make sure to follow-up any muriatic
use with some phosphoric acid.. else it's going to flash-rust like mad. If
you don't have a bottle of it, RC Cola is a cheap & available source of
phosphoric.. yes, it's low concentration, but it's enough to do the job.


In most places other than the south and Chicago, Coke and Pepsi are what 
is used.   I don't think that SNL (Saturday Night Live) ever did a "No 
Coke; RC" skit.

Re: Removing Pitting and Rust From an Enclosure

[drlegendre . via cctalk]

Chuck is right, but pits can also be filled.. JB Weld is one suggestion. It
can be sanded perfectly smooth & painted over. You can also try using some
auto-body spot filler, though I don't know how tough that is.

If the rust pits are deep, you can use muriatic acid to clean the rust out
of the pitting before you fill & coat. Make sure to follow-up any muriatic
use with some phosphoric acid.. else it's going to flash-rust like mad. If
you don't have a bottle of it, RC Cola is a cheap & available source of
phosphoric.. yes, it's low concentration, but it's enough to do the job.

On Wed, Jul 19, 2017 at 5:53 PM, Chuck Guzis via cctalk <
cctalk@classiccmp.org> wrote:

> On 07/19/2017 03:13 PM, Fred Cisin via cctalk wrote:
>
> > To get rid of the pitting, you would have to grind, brush, or mill
> > down to below the depths of the pits. Or fill them in (bondo?) and
> > paint over. Maybe paint it like an 026 punch?
>
> Crackle-coat paint looks very nice.
>
> Removing pits by sanding is laborious and probably not worth the effort.
>
> --Chuck
>
>
>
>

Re: Removing Pitting and Rust From an Enclosure

[Chuck Guzis via cctalk]

On 07/19/2017 03:13 PM, Fred Cisin via cctalk wrote:

> To get rid of the pitting, you would have to grind, brush, or mill
> down to below the depths of the pits. Or fill them in (bondo?) and
> paint over. Maybe paint it like an 026 punch?

Crackle-coat paint looks very nice.

Removing pits by sanding is laborious and probably not worth the effort.

--Chuck

RE: Removing Pitting and Rust From an Enclosure

[Fred Cisin via cctalk]

> You can't remove pitting. You mean remove the dark oxide?

On Wed, 19 Jul 2017, Rob Jarratt via cctalk wrote:

Well yes, I suppose so, and anything that can be done to make the result
look a bit better after removing the dark oxide.


maybe steel wool?
or try a wire brush that is softer than the material (such as brass)

To get rid of the pitting, you would have to grind, brush, or mill down to 
below the depths of the pits.

Or fill them in (bondo?) and paint over.
Maybe paint it like an 026 punch?

RE: Removing Pitting and Rust From an Enclosure

[Rob Jarratt via cctalk]

Well yes, I suppose so, and anything that can be done to make the result
look a bit better after removing the dark oxide.

 

Regards

 

Rob

 

From: dwight [mailto:dkel...@hotmail.com] 
Sent: 19 July 2017 22:16
To: r...@jarratt.me.uk; Rob Jarratt <robert.jarr...@ntlworld.com>; General
Discussion: On-Topic and Off-Topic Posts <cctalk@classiccmp.org>
Subject: Re: Removing Pitting and Rust From an Enclosure

 

You can't remove pitting. You mean remove the dark oxide?

Dwight

 

  _  

From: cctalk <cctalk-boun...@classiccmp.org
<mailto:cctalk-boun...@classiccmp.org> > on behalf of Rob Jarratt via cctalk
<cctalk@classiccmp.org <mailto:cctalk@classiccmp.org> >
Sent: Wednesday, July 19, 2017 12:52:44 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Removing Pitting and Rust From an Enclosure 

 

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.

 

Also, the case has some very annoying metal "fins". They don't look original
to me, but can anyone tell me if they are? Here is a picture of the feet:
https://rjarratt.files.wordpress.com/2017/07/turbochannel-extender-base.jpg

 

Thanks

 

Rob

Re: Removing Pitting and Rust From an Enclosure

[dwight via cctalk]

You can't remove pitting. You mean remove the dark oxide?

Dwight



From: cctalk  on behalf of Rob Jarratt via 
cctalk 
Sent: Wednesday, July 19, 2017 12:52:44 PM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Removing Pitting and Rust From an Enclosure

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.



Also, the case has some very annoying metal "fins". They don't look original
to me, but can anyone tell me if they are? Here is a picture of the feet:
https://rjarratt.files.wordpress.com/2017/07/turbochannel-extender-base.jpg



Thanks



Rob