12 Jul
2013
12 Jul
'13
4:17 p.m.
My PDP-8/L arrived this afternoon (in one piece and without any damage)
and I'll be going over it and cleaning it up over the next few days.
Looks like it won't take much more than elbow grease to make most of it
look nice again,but there's a big piece of masking tape stuck right
above the switches. Age has more or less permanently affixed this to
the front panel -- any recommendations as to how to remove this without
damaging the front panel?
Thanks,
Josh
12 Jul
12 Jul
5:23 p.m.
I use googone. Do test it on a location
that doesn't show first.
It slowly cuts plastic but I've found it is useful to remove
old oxidized surfaces and polish it. It uses orange oil
and acetone as far as I know.
Dwight
Date: Fri, 12 Jul 2013 16:17:43 -0700
From: derschjo at gmail.com
To:
Subject: Solvents for removing very old masking tape from front panels?
My PDP-8/L arrived this afternoon (in one piece and without any damage)
and I'll be going over it and cleaning it up over the next few days.
Looks like it won't take much more than elbow grease to make most of it
look nice again,but there's a big piece of masking tape stuck right
above the switches. Age has more or less permanently affixed this to
the front panel -- any recommendations as to how to remove this without
damaging the front panel?
Thanks,
Josh
5:53 p.m.
On Fri, 13 Jul 2013, dwight elvey wrote:
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
I use googone. Do test it on a location
that doesn't show first.
It slowly cuts plastic but I've found it is useful to remove
old oxidized surfaces and polish it. It uses orange oil
and acetone as far as I know.
Dwight
I generally use rubbing alcohol + manual scrubbing. ;)
Date: Fri, 12 Jul 2013 16:17:43 -0700
From: derschjo at gmail.com
To:
Subject: Solvents for removing very old masking tape from front panels?
My PDP-8/L arrived this afternoon (in one piece and without any damage)
and I'll be going over it and cleaning it up over the next few days.
Looks like it won't take much more than elbow grease to make most of it
look nice again,but there's a big piece of masking tape stuck right
above the switches. Age has more or less permanently affixed this to
the front panel -- any recommendations as to how to remove this without
damaging the front panel?
Thanks,
Josh
6:14 p.m.
White paper masking tape contains some kind of organic acid that actually
does "eat" into not only paint, but other finished surfaces.. even anodized
aluminum under the right conditions.
We've all had this experience, more than once. You pick up some little gem
at a yard sale or thrift.. but for some unexplained and inexplicable
reason, there's a big old piece of tape on it. Just stuck right on the
cabinet or panel, not doing anything or bearing any information - just a
piece of tape, or what originally was tape - and it is NOT coming off.
There is a vernacular term for this.. the item is said to be "F_cked up
with tape!". As in, "Wow, I just got the sweetest old Superman lunchbox,
but some jackass totally f_cked it up with tape!".
DO NOT PUT TAPE ON YOUR TREASURED GOODS.
On Fri, Jul 12, 2013 at 7:53 PM, Cory Smelosky <b4 at gewt.net> wrote:
On Fri, 13 Jul 2013, dwight elvey wrote:
I use googone. Do test it on a location
that doesn't show first.
It slowly cuts plastic but I've found it is useful to remove
old oxidized surfaces and polish it. It uses orange oil
and acetone as far as I know.
Dwight
I generally use rubbing alcohol + manual scrubbing. ;)
Date: Fri, 12 Jul 2013 16:17:43 -0700
--
Cory Smelosky
http://gewt.net Personal stuff
http://gimme-sympathy.org Projects
From: derschjo at gmail.com
To:
Subject: Solvents for removing very old masking tape from front panels?
My PDP-8/L arrived this afternoon (in one piece and without any damage)
and I'll be going over it and cleaning it up over the next few days.
Looks like it won't take much more than elbow grease to make most of it
look nice again,but there's a big piece of masking tape stuck right
above the switches. Age has more or less permanently affixed this to
the front panel -- any recommendations as to how to remove this without
damaging the front panel?
Thanks,
Josh
6:02 p.m.
I believe the GooGone uses acetone. ?Be very careful of using acetone around plexiglas
(perspex).
I believe it will dissolve the plastic quite?easily (though I may be thinking of MEK).
I can't speak from experience with respect to masking tape, but I removed a large area
of sticky residue
(likely left by some sort of tape or adhesive overlay) from a PDP/8 front panel simply by
rolling it up
mechanically with my fingers. ?It was tedious, and I got a few blisters from doing it,
however. ? Little
specks remaining can be cleaned up by dabbing with the adhesive side of cellophane packing
tape.
The paint on the 8/E front panel (at least the one I was working with -- don't assume
they are all the same!)
is somewhat soluble in IPA, but applied very sparingly, it cleaned up the panel nicely and
removed some
dullness without apparent damage, though doubtless taking off a bit of paint on the
surface. ? If you do this, however,
be *very* careful, as the black paint on the back is highly soluble, to the extent that
you can feel the tackiness
with your fingers if slightly moist with IPA.
BTW, the PDP8 panels are covered with a urethane (?) clear-coat layer that absorbs water
and takes on a milky cast.
I suspect there is no harm in dusting a panel with a slighly damp cloth, but scrubbing the
panel with soap and
water (or, heaven forfend, soaking it) is not a good idea, despite the fact that water and
mild soap are so frequently
recommended as the safest way to clean plastics. ? For this reason I used *anhydrous*
(technical grade) IPA for
the cleaning exercise mentioned above, and would recommend steering clear of the drugstore
stuff, which is
anywhere from 10% to 30% water.
--Bill
________________________________
From: dwight elvey <dkelvey at hotmail.com>
To: General Discussion: On-Topic and Off-Topic Posts <cctalk at classiccmp.org>
Sent: Friday, July 12, 2013 5:23 PM
Subject: RE: Solvents for removing very old masking tape from front panels?
I use googone. Do test it on a location
that doesn't show first.
It slowly cuts plastic but I've found it is useful to remove
old oxidized surfaces and polish it. It uses orange oil
and acetone as far as I know.
Dwight
Date: Fri, 12 Jul 2013 16:17:43 -0700
From: derschjo at gmail.com
To:
Subject: Solvents for removing very old masking tape from front panels?
My PDP-8/L arrived this afternoon (in one piece and without any damage)
and I'll be going over it and cleaning it up over the next few days.?
Looks like it won't take much more than elbow grease to make most of it
look nice again,but there's a big piece of masking tape stuck right
above the switches.? Age has more or less permanently affixed this to
the front panel -- any recommendations as to how to remove this without
damaging the front panel?
Thanks,
Josh
6:08 p.m.
I believe the GooGone uses acetone.
D'oh! ?I meant to say naptha here.
Be *very, very* careful using any kind of solvent on the panel, and test an inconspicuous
area
with a slightly damp cloth before applying it any any significant quantity. ? I suspect
the black
paint on the back of the panel is soluable in more than IPA, too. ? Best to keep the panel
on a
padded flat surface and not pick it up and hold it while working.
--Bill
11:44 p.m.
On Fri, 12 Jul 2013, William Maddox wrote:
On Fri, 12 Jul 2013, dwight elvey wrote:
None of the Goo Gone products that I'm aware of contain acetone. There are
a lot of different products under the Goo Gone brand but the one I use is
the original "citrus formula".
http://googone.com/c.983960/site/gg/MSDS/GZ92-Goo_Gone_Pro_Power.pdf
http://googone.com/GooGone-MSDS
According to the MSDS, it contains:
Ingredients Percent CAS #
Distillates (petroleum), hydrotreated light < 95 64742-47-8
Tripropylene glycol methyl ether 1 ? 10 25498-49-1
Citrus extracts blend 1 ? 10 94266-47-4 / 8028-48-6
64742-47-8 - low odor paraffinic solvent (dearomatized kerosine)
25498-49-1 - methyl ethoxy propanol [organic solvent]
94266-47-4 - orange terpenes (orange oil)
8028-48-6 - orange terpenes (orange oil)
One of the main ingredients in WD-40 just so happens to be dearomatized
kerosine, CAS # 64742-47-8.
http://www.wd40company.com/files/pdf/msds-wd494716385.pdf
I find isopropyl alcohol (2-propanol) plus a lot of scrubbing with a rag
to work better for dissolving stubborn dried tape and sticker adhesive on
plastic and some painted surfaces, but 'Goo Gone' (or WD-40) work well
when the adhesive is still sticky and active. You still have to remove any
residue from either Goo Gone or WD-40 with something like isopropyl
alcohol too.
If the paint on a PDP-8 is soluble with isopropyl, my normal technique for
dried adhesive removal wouldn't be well advised at all though.
On Fri, 12 Jul 2013, Josh Dersch wrote:
I believe the GooGone uses acetone. ?Be very careful of using acetone
around plexiglas (perspex). I believe it will dissolve the plastic
quite?easily (though I may be thinking of MEK).
I can't speak from experience with respect to masking tape, but I
removed a large area of sticky residue (likely left by some sort of tape
or adhesive overlay) from a PDP/8 front panel simply by rolling it up
mechanically with my fingers. ?It was tedious, and I got a few blisters
from doing it, however. ? Little specks remaining can be cleaned up by
dabbing with the adhesive side of cellophane packing tape.
The paint on the 8/E front panel (at least the one I was working with --
don't assume they are all the same!) is somewhat soluble in IPA, but
applied very sparingly, it cleaned up the panel nicely and removed some
dullness without apparent damage, though doubtless taking off a bit of
paint on the surface. ? If you do this, however, be *very* careful, as
the black paint on the back is highly soluble, to the extent that you
can feel the tackiness with your fingers if slightly moist with IPA.
BTW, the PDP8 panels are covered with a urethane (?) clear-coat layer
that absorbs water and takes on a milky cast. I suspect there is no harm
in dusting a panel with a slighly damp cloth, but scrubbing the panel
with soap and water (or, heaven forfend, soaking it) is not a good idea,
despite the fact that water and mild soap are so frequently recommended
as the safest way to clean plastics. ? For this reason I used
*anhydrous* (technical grade) IPA for the cleaning exercise mentioned
above, and would recommend steering clear of the drugstore stuff, which
is anywhere from 10% to 30% water. My PDP-8/L arrived this afternoon (in one piece
and without any
damage) and I'll be going over it and cleaning it up over the next few
days. Looks like it won't take much more than elbow grease to make
most of it look nice again,but there's a big piece of masking tape
stuck right above the switches. Age has more or less permanently
affixed this to the front panel -- any recommendations as to how to
remove this without damaging the front panel?
I use googone. Do test it on a location that doesn't show first. It
slowly cuts plastic but I've found it is useful to remove old oxidized
surfaces and polish it. It uses orange oil and acetone as far as I
know. 
13 Jul
13 Jul
12:28 a.m.
On Sat, 13 Jul 2013, Tothwolf wrote:
I find isopropyl alcohol (2-propanol) plus a lot of
scrubbing with a rag to
work better for dissolving stubborn dried tape and sticker adhesive on
plastic and some painted surfaces, but 'Goo Gone' (or WD-40) work well when
the adhesive is still sticky and active. You still have to remove any residue
from either Goo Gone or WD-40 with something like isopropyl alcohol too.
If the paint on a PDP-8 is soluble with isopropyl, my normal technique for
dried adhesive removal wouldn't be well advised at all though.
I'd be wary of using any sort of alcohol on acrylic/plexiglas/perspex --
it rapidly causes cracks and brittleness. See this:
http://www.youtube.com/watch?v=cU9Ty0L0g7E
Toothpaste and peanut butter might be helpful. The abrasives in
toothpaste are mild, but can frost glossy-smooth surfaces. Peanut butter
shouldn't do that. It might actually polish surfaces. In any case,
peanut butter is a handy way of applying oil and making it stay put.
--
David Griffith
dgriffi at cs.csubak.edu
2:40 a.m.
On Sat, 13 Jul 2013, David Griffith wrote:
On Sat, 13 Jul 2013, Tothwolf wrote:
Yikes. The youtube video bothers me in that the acrylic sheet was already
under tremendous stress from the bungee cord before anything was done to
it though. Acrylic (unlike polycarbonate) is very brittle. Curved the way
it was in the video, it was likely already growing microfractures in the
surface, and probably would have eventually broken even just sitting there
with the bungee cord on it.
While they look similar, there is a chemical difference between
polycarbonate (lexan) and acrylic [or more appropriately, poly(methyl
methacrylate), aka PMMA] (lucite, perspex, plexiglas, etc). I've had no
issues cleaning polycarbonate with isopropyl, and manufacturers
specifically recommend alcohols such as isopropyl, ethanol, etc for
cleaning. On the other hand, ammonia based cleaners (such as Windex)
/will/ damage polycarbonate (and PC-ABS plastic blends), often causing
stress fractures later.
This /does/ help explain some of the cracked and crazed modular connectors
[http://en.wikipedia.org/wiki/Modular_connector] I've seen over the years
that had been cleaned with alcohols though. While the standards call for
polycarbonate, those plugs must have been molded with less expensive
acrylic instead of polycarbonate. This is something to keep in mind for
later too since companies keep trying to phase out polycarbonate due to
the fears over the Bisphenol A content. For that fact, I should see about
taking microphotographs of some of those plugs that are still in my scrap
bin...
I guess this is yet another reason for me to avoid acrylic and stick with
time-tested polycarbonate and also always check chemical compatibility.
I find isopropyl alcohol (2-propanol) plus a lot
of scrubbing with a
rag to work better for dissolving stubborn dried tape and sticker
adhesive on plastic and some painted surfaces, but 'Goo Gone' (or
WD-40) work well when the adhesive is still sticky and active. You
still have to remove any residue from either Goo Gone or WD-40 with
something like isopropyl alcohol too.
If the paint on a PDP-8 is soluble with isopropyl, my normal technique
for dried adhesive removal wouldn't be well advised at all though.
I'd be wary of using any sort of alcohol on acrylic/plexiglas/perspex --
it rapidly causes cracks and brittleness. See this:
http://www.youtube.com/watch?v=cU9Ty0L0g7E
Toothpaste and peanut butter might be helpful. The abrasives in
toothpaste are mild, but can frost glossy-smooth surfaces. Peanut
butter shouldn't do that. It might actually polish surfaces. In any
case, peanut butter is a handy way of applying oil and making it stay
put. 
12 Jul
12 Jul
5:53 p.m.
I use something available in the UK called sticky stuff remover seems
to be citric acid based.
I rub it on the label and allow it to soak for a bit, hopefully that
softens the sticky enough to pull the paper off (very slowly)
probably needs more than one/many applications to soften if very hard.
Also WD40 softens the sticky and a few other solvents,
I have recently tried
http://consumables.com/Products/Sealants_2/Pvcu-Solvent-Cleaner.html
(safety sheet on that page with its makeup)
which also works but has some noxious fumes.
as always test on a small area if the plastic/paint will affected by
the solvent.
After softening I try to use nothing harder than finger nails to
remove the labels, can be painful and take a long time but the panel
matters the nails can grow back the panel cannot.
Then a final washing (rubbing with a paper towel dipped in solvent)
with the solvent in use to get the remainder off.
Note you need to be careful at this stage because the rag/paper can
polish the surface of the paint/plastic surface.
Dave Caroline
17 Jul
17 Jul
12:38 a.m.
Thanks to all for all of the varied suggestions (which I will definitely
keep in mind for future projects). WD-40 did the trick here; letting
the tape soak for 2-3 hours loosened things up enough so that the "tape"
portion came right off, leaving behind the dried adhesive. Soaking that
for another couple of hours softened it to the point where it scraped
off easily with just a fingernail.
This also worked on the three panel switches that had masking tape
applied, however the adhesive appears to have marred the surface of
these switches a bit (not so much that it's really that noticeable, though.)
Now that it's all cleaned up, it looks very very nice. I'll take some
pictures tomorrow.
- Josh
11:40 p.m.
Just a quick update; I put a few pics of the 8/L's front panel post
cleanup (amongst other things) here:
http://rottedbits.blogspot.com/2013/07/8l-exterior-cleanup.html
- Josh
On 7/17/2013 12:38 AM, Josh Dersch wrote:
Thanks to all for all of the varied suggestions (which
I will
definitely keep in mind for future projects). WD-40 did the trick
here; letting the tape soak for 2-3 hours loosened things up enough so
that the "tape" portion came right off, leaving behind the dried
adhesive. Soaking that for another couple of hours softened it to the
point where it scraped off easily with just a fingernail.
This also worked on the three panel switches that had masking tape
applied, however the adhesive appears to have marred the surface of
these switches a bit (not so much that it's really that noticeable,
though.)
Now that it's all cleaned up, it looks very very nice. I'll take some
pictures tomorrow.
- Josh
18 Jul
18 Jul
9:43 a.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Josh Dersch
Sent: 18 July 2013 07:40
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Solvents for removing very old masking tape from front
panels?
Just a quick update; I put a few pics of the 8/L's front panel post
cleanup
(amongst other things) here:
http://rottedbits.blogspot.com/2013/07/8l-exterior-cleanup.html
- Josh
On 7/17/2013 12:38 AM, Josh Dersch wrote:
> Thanks to all for all of the varied suggestions (which I will
> definitely keep in mind for future projects). WD-40 did the trick
> here; letting the tape soak for 2-3 hours loosened things up enough so
> that the "tape" portion came right off, leaving behind the dried
> adhesive. Soaking that for another couple of hours softened it to the
> point where it scraped off easily with just a fingernail.
>
> This also worked on the three panel switches that had masking tape
> applied, however the adhesive appears to have marred the surface of
> these switches a bit (not so much that it's really that noticeable,
> though.)
>
> Now that it's all cleaned up, it looks very very nice. I'll take some
> pictures tomorrow.
>
> - Josh
Just one more thing regarding the Teletype, can't remember if this was
mentioned.
Check the rubber on the print hammer that hits the typewheel. This turns to
goo, and if this has happened you will end up quickly ruining the typewheel.
The advice I have had is to use a length of vinyl tubing (Outer diameter
7/16", inner diameter 5/16") and fit it over the arm of the hammer. Mine is
just starting to go and I will have to do this before using the Teletype
again.
Regards
Rob
11:30 a.m.
On Thu, Jul 18, 2013 at 9:43 AM, Robert Jarratt <robert.jarratt at ntlworld.com
wrote:
Just one more thing regarding the Teletype, can't remember if this was
mentioned.
Check the rubber on the print hammer that hits the typewheel. This turns to
goo, and if this has happened you will end up quickly ruining the
typewheel.
The advice I have had is to use a length of vinyl tubing (Outer diameter
7/16", inner diameter 5/16") and fit it over the arm of the hammer. Mine is
just starting to go and I will have to do this before using the Teletype
again.
Thanks -- I'll check that. I'm curious, though -- how does the goo ruin
the typewheel? I can see it covering it with tar and making it really
sticky, but that'll clean off, right?
Thanks,
Josh
Regards
Rob
11:54 a.m.
Check the
rubber on the print hammer that hits the typewheel. This turns to
goo, and if this has happened you will end up quickly ruining the
typewheel.
The advice I have had is to use a length of vinyl tubing (Outer diameter
7/16", inner diameter 5/16") and fit it over the arm of the hammer. Mine is
just starting to go and I will have to do this before using the Teletype
again.
Thanks -- I'll check that. I'm curious, though -- how does the goo ruin
the typewheel? I can see it covering it with tar and making it really
sticky, but that'll clean off, right?
2:18 p.m.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-
bounces at classiccmp.org] On Behalf Of Josh Dersch
Sent: 18 July 2013 19:30
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: Solvents for removing very old masking tape from front
panels?
On Thu, Jul 18, 2013 at 9:43 AM, Robert Jarratt
<robert.jarratt at ntlworld.com
wrote:
Just one more thing regarding the Teletype, can't remember if this was
mentioned.
Check the rubber on the print hammer that hits the typewheel. This
turns to goo, and if this has happened you will end up quickly ruining
the typewheel.
The advice I have had is to use a length of vinyl tubing (Outer
diameter 7/16", inner diameter 5/16") and fit it over the arm of the
hammer. Mine is just starting to go and I will have to do this before
using the Teletype again.
Thanks -- I'll check that. I'm curious, though -- how does the goo ruin
typewheel? I can see it covering it with tar and
making it really sticky,
but
that'll clean off, right?
Thanks,
Josh
>
> Regards
>
> Rob
>
>
It is that the rubber hammer turns to goo and comes away, leaving the metal
behind to smash into the letters on the typewheel and, presumably, flatten
them.
Regards
Rob
12 Jul
12 Jul
6:10 p.m.
On 07/12/2013 04:17 PM, Josh Dersch wrote:
My PDP-8/L arrived this afternoon (in one piece and
without any damage)
and I'll be going over it and cleaning it up over the next few days.
Looks like it won't take much more than elbow grease to make most of it
look nice again,but there's a big piece of masking tape stuck right
above the switches. Age has more or less permanently affixed this to
the front panel -- any recommendations as to how to remove this without
damaging the front panel?
I've had a fair amount of success using lamp oil (light kerosene), but
it works v-e-r-y s-l-o-w-l-y. I soak a small piece of folded up paper
towel with it and let it sit on the spot for a day or so. The result is
usually very easy to wipe off and plastic remains unaffected.
--Chuck
13 Jul
13 Jul
3:03 p.m.
One method I haven't seen discussed is to use a steam cleaner. I did
this to successfully remove masking tape residue, but it was fairly
time consuming. However, it had the advantage that it didn't involve
any solvents. Obviously, significant heat and moisture can be applied
when cleaning with steam, so that is something to consider. I removed
metal covers from a Tektronix terminal cabinet in order to clean them
with the steam cleaner. I also used it to clean a CDC display console
cabinet.
--
"The Direct3D Graphics Pipeline" free book
<http://tinyurl.com/d3d-pipeline>
The Computer Graphics Museum <http://computergraphicsmuseum.org>
The Terminals Wiki <http://terminals.classiccmp.org>
Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>
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17 comments
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