1960s-1970s Telephone Repair

On Mon, 11 Apr 2016 11:48:37 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Mon, 11 Apr 2016 09:51:46 -0700, etpm@whidbey.com wrote:

I don't know what kind of plastic your part is but there is a two part
plastic cement that bonds well to many of the plastics that are hard
to glue. I don't remember the name but I think it is made by Loctite

http://www.loctiteproducts.com/p/sg_plstc/overview/Loctite-Plastics-Bonding-System.htm

Cyanoacrylate resin and MEK as "activator". Works quickly and great
for most plastics. However, the MEK tends to dry out prematurely in
the bottle. Have some extra MEK handy if you're going to use it.
Also, make sure everything is free of grease or it won't stick.

Greetings Jeff,
The stuff I'm talking about is not a cyanoacrylate resin and activator
system. It is two parts that must be mixed and then applied. This is
the stuff. I think. See the link:
http://www.homedepot.com/p/Loctite-0-85-fl-oz-Plastic-Epoxy-1360788/100371824

Eric

 

On Mon, 11 Apr 2016 09:06:48 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Mon, 11 Apr 2016 07:23:49 -0400, "J. B. Wood"
john.wood@nrl.navy.mil> wrote:

On 04/10/2016 04:42 PM, Jeff Liebermann wrote:

Are you sure about the model number? The SC number was SC-554 while
the WE number was 2554.

SC-554:
https://www.youtube.com/watch?v=cDP6I8bEP8o

WE 2554:
https://www.youtube.com/watch?v=VedsBJfsLlo

Thanks for the response, Jeff. The number stamped on the back of the
instrument is S-C 2554BPM. Perhaps the "2" designated a DTMF type dial?
Sincerely,

Ah, that's a better number. There's one for sale on eBay if you need
parts:
www.ebay.com/itm/STROMBERG-CARLSON-2554-BPM-Wall-Mounted-Single-Line-Corded-Phone-/281979044418

It's impossible to get into a discussion on adhesives without everyone
recommending their favorite potions, concoctions, and methods. I'll
just make things worse.

My guess(tm) is that the plastic in the phone is probably ABS (acrylic
butyl styrene) which will weld nicely with acetone solvent. There are
overpriced potions available that are mostly acetone, but might
include other solvents (MEK, toluene, etc).
http://nerfhaven.com/forums/topic/18527-intro-to-solvent-welding-plastic/

Superglue (cyanoacrylate) is too brittle and mutilates acrylics.
http://info.craftechind.com/blog/bid/323475/Stick-to-it-A-Guide-to-the-Best-Glue-for-Plastic

Urethane adhesives, such as Gorilla Glue, don't do well with many
plastics because they do NOT contain any solvents. Fortunately, the
phone switch insulator (or whatever it's called) sees force in only
one direction, so marginal adhesives will probably work, for a while.

Just to muddy the waters, I've been learning plastic welding using
some home made brass nozzles attached to my SMT desoldering station
hot air gun. When it works, it works great. When I do something
wrong, it destroys the part. Plastic welding works best for me on
large plastic parts, and not so good on small plastic parts.

I'm also a fan of hot melt glue, but that's not appropriate for this
job. However, if you do decide to try hot melt glue, be sure to get
the correct type of adhesive stick:
https://en.wikipedia.org/wiki/Hot-melt_adhesive

Good luck.
ABS=Acrylonitrile butadiene styrene.

 

[Jeff Liebermann]

On Mon, 11 Apr 2016 12:09:30 -0700, etpm@whidbey.com wrote:

On Mon, 11 Apr 2016 09:06:48 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:
My guess(tm) is that the plastic in the phone is probably ABS (acrylic
butyl styrene) which will weld nicely with acetone solvent.

ABS=Acrylonitrile butadiene styrene.

Sigh. I stand corrected (again). Thanks.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Mon, 11 Apr 2016 12:07:15 -0700, etpm@whidbey.com wrote:

On Mon, 11 Apr 2016 11:48:37 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

On Mon, 11 Apr 2016 09:51:46 -0700, etpm@whidbey.com wrote:

I don't know what kind of plastic your part is but there is a two part
plastic cement that bonds well to many of the plastics that are hard
to glue. I don't remember the name but I think it is made by Loctite

http://www.loctiteproducts.com/p/sg_plstc/overview/Loctite-Plastics-Bonding-System.htm

Cyanoacrylate resin and MEK as "activator". Works quickly and great
for most plastics. However, the MEK tends to dry out prematurely in
the bottle. Have some extra MEK handy if you're going to use it.
Also, make sure everything is free of grease or it won't stick.

Greetings Jeff,
The stuff I'm talking about is not a cyanoacrylate resin and activator
system. It is two parts that must be mixed and then applied. This is
the stuff. I think. See the link:
http://www.homedepot.com/p/Loctite-0-85-fl-oz-Plastic-Epoxy-1360788/100371824
Eric

Do you recall if the goo you used took 5 min or 20 min to set?

The Home Despot ad above shows "Epoxy Plastic" with a 5 minute time to
set. However, I couldn't find that on the Loctite web pile, but found
this instead:
<http://www.loctiteproducts.com/p/epxy_plstc_s/overview/Loctite-Epoxy-Plastic-Bonder.htm>
which is a "Plastic Epoxy Bonder" with a 20 minute time to set. I
prefer the longer setting times and overnight hardening, so I'll start
with the 20 min flavor.

The Plastic Epoxy Bonder stuff is NOT an epoxy. Epoxy is a
thermosetting plastic. The Plastic Epoxy Bonder is an acrylic, which
is thermoplastic. See first question at:
<http://juxtamorph.com/difference-between-polyester-acrylic-and-epoxy-resins/>
That's fine because an acrylic based glue is what you want for ABS
anyway.

I suspect it also has some sort of solvent to soften the base plastic.
Looks like the formulation has changed slightly:
<http://henkelconsumerinfo.com/products/henkel.datasheets.DownPdf.pdf?BUSAREA=0006&VKORG=3450&MATNR=1442491&RECNDH=20257403&ACTNDH=0&LANG=EN&COUNTRY=US>
<http://www.menards.com/msds/107040_001.pdf> (older)
Yep, 1% carbon tetrachloride solvent, which should do nicely for
softening plastics. Three different forms of methyl methacrylate
(MMA). Incidentally, MMA was once used for fake finger nails, but was
banned for some reason:
<http://www.hooked-on-nails.com/mmaandyou.html>
I'm not sure what the other stuff does and am too lazy to dig it out.

So, what you have here is an acrylic plastic glue, with some rubber
compound added to make it a little flexible, no epoxy resin anywhere
in sight, and a bit of solvent to soften the base plastic.
Also see the data sheet at:
<http://www.loctiteproducts.com/tds/EPXY_PLSTC_S_tds.pdf>

The 5 min "Epoxy Plastic" MSDS is rather cryptic:
<http://henkelconsumerinfo.com/products/henkel.datasheets.DownPdf.pdf?BUSAREA=0006&VKORG=3450&MATNR=1071291&RECNDH=20924077&ACTNDH=0&LANG=EN&COUNTRY=US>
<http://henkelconsumerinfo.com/products/henkel.datasheets.DownPdf.pdf?BUSAREA=0006&VKORG=3450&MATNR=1071250&RECNDH=21213716&ACTNDH=0&LANG=EN&COUNTRY=US>
and only shows "epoxy resin, proprietary". The hardener is listed as
"tertiary amine" which is an epoxy resin curing agent.

I would go for the 20 minute flavor.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

On Mon, 11 Apr 2016 15:28:32 -0700, Jeff Liebermann <jeffl@cruzio.com>
wrote:

On Mon, 11 Apr 2016 12:07:15 -0700, etpm@whidbey.com wrote:

On Mon, 11 Apr 2016 11:48:37 -0700, Jeff Liebermann <jeffl@cruzio.com
wrote:

On Mon, 11 Apr 2016 09:51:46 -0700, etpm@whidbey.com wrote:

I don't know what kind of plastic your part is but there is a two part
plastic cement that bonds well to many of the plastics that are hard
to glue. I don't remember the name but I think it is made by Loctite

http://www.loctiteproducts.com/p/sg_plstc/overview/Loctite-Plastics-Bonding-System.htm

Cyanoacrylate resin and MEK as "activator". Works quickly and great
for most plastics. However, the MEK tends to dry out prematurely in
the bottle. Have some extra MEK handy if you're going to use it.
Also, make sure everything is free of grease or it won't stick.

Greetings Jeff,
The stuff I'm talking about is not a cyanoacrylate resin and activator
system. It is two parts that must be mixed and then applied. This is
the stuff. I think. See the link:
http://www.homedepot.com/p/Loctite-0-85-fl-oz-Plastic-Epoxy-1360788/100371824
Eric

Do you recall if the goo you used took 5 min or 20 min to set?

The Home Despot ad above shows "Epoxy Plastic" with a 5 minute time to
set. However, I couldn't find that on the Loctite web pile, but found
this instead:
http://www.loctiteproducts.com/p/epxy_plstc_s/overview/Loctite-Epoxy-Plastic-Bonder.htm
which is a "Plastic Epoxy Bonder" with a 20 minute time to set. I
prefer the longer setting times and overnight hardening, so I'll start
with the 20 min flavor.

The Plastic Epoxy Bonder stuff is NOT an epoxy. Epoxy is a
thermosetting plastic. The Plastic Epoxy Bonder is an acrylic, which
is thermoplastic. See first question at:
http://juxtamorph.com/difference-between-polyester-acrylic-and-epoxy-resins/
That's fine because an acrylic based glue is what you want for ABS
anyway.

I suspect it also has some sort of solvent to soften the base plastic.
Looks like the formulation has changed slightly:
http://henkelconsumerinfo.com/products/henkel.datasheets.DownPdf.pdf?BUSAREA=0006&VKORG=3450&MATNR=1442491&RECNDH=20257403&ACTNDH=0&LANG=EN&COUNTRY=US
http://www.menards.com/msds/107040_001.pdf> (older)
Yep, 1% carbon tetrachloride solvent, which should do nicely for
softening plastics. Three different forms of methyl methacrylate
(MMA). Incidentally, MMA was once used for fake finger nails, but was
banned for some reason:
http://www.hooked-on-nails.com/mmaandyou.html
I'm not sure what the other stuff does and am too lazy to dig it out.

So, what you have here is an acrylic plastic glue, with some rubber
compound added to make it a little flexible, no epoxy resin anywhere
in sight, and a bit of solvent to soften the base plastic.
Also see the data sheet at:
http://www.loctiteproducts.com/tds/EPXY_PLSTC_S_tds.pdf

The 5 min "Epoxy Plastic" MSDS is rather cryptic:
http://henkelconsumerinfo.com/products/henkel.datasheets.DownPdf.pdf?BUSAREA=0006&VKORG=3450&MATNR=1071291&RECNDH=20924077&ACTNDH=0&LANG=EN&COUNTRY=US
http://henkelconsumerinfo.com/products/henkel.datasheets.DownPdf.pdf?BUSAREA=0006&VKORG=3450&MATNR=1071250&RECNDH=21213716&ACTNDH=0&LANG=EN&COUNTRY=US
and only shows "epoxy resin, proprietary". The hardener is listed as
"tertiary amine" which is an epoxy resin curing agent.

I would go for the 20 minute flavor.

I don't remember if the stuff was 5 or 20 minutes but I suspect it was
the 5 minute variety. I wondered about that epoxy name. Looking at the
ingredients made me think it wasn't an epoxy but I don't know enough
about epoxies to tell. I do know that there are some pretty damn good
acrylic based adhesives though. I suspect that the adhesive backed
aluminum tape made for ductwork (not duct tape!) uses an acrylic based
adhesive. That stuff sticks remarkably well and does so for years.
Eric

 

[Bennett]

While it admits to not addressing the fine points of gluing all the
different sorts of plastics, this web site is often really handy:
www.thistothat.com


On 4/10/2016 1:12 PM, J. B. Wood wrote:

Hello, all, especially those with familiarity with subject. I've got a
decades-old Stromberg-Carlson SC-2554 wall mount phone. It's still in
great shape except recently a small white piece of plastic on the
make/break hook switch broke rendering the rest of the cradle mechanism
inoperative. The plastic piece finally broke from the tension from the
return spring. It's a clean break but I'm afraid that even if I can
glue the pieces back together it will most likely fail again in short
order. Thanks for your time and your comment is most appreciated.
Sincerely,

 

[DaveC]

I don't know what kind of plastic your part is but there is a two part
plastic cement that bonds well to many of the plastics that are hard
to glue. I don't remember the name

I’ve had great success mending most plastics of all kinds (varying degrees
with poly-types) using Devcon Plastic Welder:

http://www.amazon.com/Devcon-22045-Plastic-Welder-Dev-Tube/dp/B003NUGL9S

It’s my go-to solution when fixing anything plastic.

Cool phone. Brings back memories. Ours was (at different times, replacements
installed after family of 6 abused it) red, yellow, black, white. With
extra-long handset cord, of course.

Good luck.

 

[DaveC]

History of the development of the Model 500 phone:

https://en.wikipedia.org/wiki/Model_500_telephone

Fascinating...

 

[Jeff Liebermann]

On Mon, 11 Apr 2016 23:05:33 -0700, DaveC <not@home.cow> wrote:

I don't know what kind of plastic your part is but there is a two part
plastic cement that bonds well to many of the plastics that are hard
to glue. I don't remember the name

I’ve had great success mending most plastics of all kinds (varying degrees
with poly-types) using Devcon Plastic Welder:

http://www.amazon.com/Devcon-22045-Plastic-Welder-Dev-Tube/dp/B003NUGL9S

It’s my go-to solution when fixing anything plastic.

Well, at least Devcon doesn't claim that it's an epoxy. From the MSDS
sheet at:
<http://www.itwconsumer.com/userfiles/files/msds/DV-MSDS/22045.pdf>
it appears to be similar to the MMA based Loctite Plastic Epoxy Bonder
but without the carbon tetrachloride solvent to soften the base
plastic.

Data sheet:
<http://www.itwconsumer.com/userfiles/files/techdata-sheet/DV%20Tech%20Data/22045%20TDS.pdf>
"Not recommended for use on copper or brass"

Cool phone. Brings back memories. Ours was (at different times, replacements
installed after family of 6 abused it) red, yellow, black, white. With
extra-long handset cord, of course.

Same here, but with fewer phones and colors. In college, I helped
build a private exchange, complete with direct dialing and rotary
steppers, in the dorms. Everything was "donated", which translated
from student slang meant stolen. This was approximately when we first
walked on the moon, so the administration was tolerant of anything
that might be considered science and resisted the temptation to throw
all us phone phreaks out of skool. Yep, fond memories.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[J.B. Wood]

On 04/10/2016 04:12 PM, J. B. Wood wrote:

Hello, all, especially those with familiarity with subject. I've got a
decades-old Stromberg-Carlson SC-2554 wall mount phone. It's still in
great shape except recently a small white piece of plastic on the
make/break hook switch broke rendering the rest of the cradle mechanism
inoperative. The plastic piece finally broke from the tension from the
return spring. It's a clean break but I'm afraid that even if I can
glue the pieces back together it will most likely fail again in short
order. Thanks for your time and your comment is most appreciated.
Sincerely,

Hello again, everyone and many thanks to all the timely responses from
Jeff L. and others. Just one additional comment: When that plastic hook
switch part breaks the phone will be permanently off-hook even with the
handset parked in the cradle. Also, while many usenet groups have
become silent, s.e.r is most certainly a notable exception! VTY,

--
J. B. Wood e-mail: arl_123234@hotmail.com

 

[Michael A. Terrell]

"J. B. Wood" wrote:

On 04/11/2016 07:13 AM, Don Y wrote:

Your description is vague.

Is the plastic piece part of the housing? Or, a mechanical actuator that
conveys the hookswitch's state to the actual switch?

Said another way, does the phone *appear* (visually) to be intact -- but,
some INTERNAL mechanism is broken that allows it to FUNCTION as it should?

(Could you, perhaps, post a picture on a hosting site with a link, here?)

Hello, and yeah, I kind of figured that might be a problem. It's just a
small piece of plastic that separates the electrical contacts on the
hook switch. A small shaft which passes through the plastic piece upon
which a spring-loaded bracket pivots. This bracket makes contact with
the arm that determines whether the handset is on or off the cradle.
The plastic split right where that small shaft passes. Sincerely,
--
J. B. Wood e-mail: arl_123234@hotmail.com

Here is a brand new phone in that style for $33

http://www.ebay.com/itm/Scitec-Single-Line-Corded-Wall-Mount-Phone-Ash-2554W/301751024095

I had some of those, but no one wanted them. They ended up being
scrapped. I have a pile of WE & SC Touchtone keypads from several
hundred old 1A2 business phones that I scrapped, as well. I have a large
box of 400 series KTU cards, as well.

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

 

[J.B. Wood]

On 04/18/2016 02:03 PM, Michael A. Terrell wrote:

Here is a brand new phone in that style for $33

http://www.ebay.com/itm/Scitec-Single-Line-Corded-Wall-Mount-Phone-Ash-2554W/301751024095

I had some of those, but no one wanted them. They ended up being
scrapped. I have a pile of WE & SC Touchtone keypads from several
hundred old 1A2 business phones that I scrapped, as well. I have a large
box of 400 series KTU cards, as well.

Hello, and while I'm certainly grateful for all the responses to my OP
I'm sort of thinking that whatever adhesive I might use to glue that
plastic (nylon?) piece back together is at best short term. Trying to
staple the pieces together might work if the staples don't get in the
way of the contacts. Still kind of kludgy, though. And then there's
the prospect of reassembling all those hook switch contacts properly and
with the insulating spacers where they need to be. Once that cradle
return spring is put back into position it will most likely cause a
stress break in the same area again. The proper repair solution would
be to replace the entire switch hook assembly but that would entail
drilling out the rivets that mount it to the phone base plate and
attaching an identical (NOS ideally) replacement if I could obtain one.
Sincerely,


--
J. B. Wood e-mail: arl_123234@hotmail.com

 

[whit3rd]

On Monday, April 18, 2016 at 12:12:00 PM UTC-7, J.B. Wood wrote:

Hello, and while I'm certainly grateful for all the responses to my OP
I'm sort of thinking that whatever adhesive I might use to glue that
plastic (nylon?) piece back together is at best short term.

Whatever made it come apart the first time, could just happen again.
Nylon doesn't glue well.
Maybe you could paint over the glued part with latex (available at
plastics suppliers as mold-making material), and use the mold
to make an epoxy duplicate?

 

[Heisenberg]

On Mon, 18 Apr 2016 21:11:05 -0700 (PDT), whit3rd <whit3rd@gmail.com>
wrote:

On Monday, April 18, 2016 at 12:12:00 PM UTC-7, J.B. Wood wrote:

Hello, and while I'm certainly grateful for all the responses to my OP
I'm sort of thinking that whatever adhesive I might use to glue that
plastic (nylon?) piece back together is at best short term.

Whatever made it come apart the first time, could just happen again.
Nylon doesn't glue well.
Maybe you could paint over the glued part with latex (available at
plastics suppliers as mold-making material), and use the mold
to make an epoxy duplicate?

I worked for Telecom Australia in the 1970s.

=-=-
"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville
(*Diagnostic and Statistical Manual of Mental Disorders)