MDS case material

[Paul Birkel]

Does anyone know what material is used in the MDS case?  It’s somewhat granular when it breaks.

 

I’m reassembling my MDS-230 using epoxy.  One wonders whether it  was assembled using a solvent rather than a glue.

 

-----

[Jack Mcmullen]

I would guess mold injected with a colored epoxy resin 

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[Al Kossow]

On 4/27/21 11:42 AM, 'Jack Mcmullen' via intel-devsys wrote:
> mold injected
expansion foam, same as an Apple II

[Paul Birkel]

Epoxy ... expansion foam?

IAW https://www.landsnail.com/apple/local/design/apple2.html the Apple II was "reaction-injection molding" and "polyurethane"; later "ABS (acrylonitrile-butadiene-styrene) plastic".

Found this article on "Structural Foam ABS": https://journals.sagepub.com/doi/pdf/10.1177/0021955X7100700604

This page shows a cross-section: https://neaforma.com/technieken/thermoplastisch-schuimgieten-tsg-sfi/

I see no evidence of any internal cellular structure in my various MDS case fractures. It's quite dense and solid.

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[Paul Birkel]

Alright, I withdraw my comment about "solid". Some of the small parts used to assemble the card-cage do have that foamy-interior with a hard shell look. The case itself looks pretty dense throughout, but there are occasional small bubbles to be found. I suppose that I _could_ use an ABS cement to put Humpty-Dumpty back together again. But I'm a bit leery about that ....

-----Original Message-----
From: Paul Birkel [mailto:pbi...@gmail.com]
Sent: Tuesday, April 27, 2021 4:00 PM
To: intel-...@googlegroups.com
Subject: RE: intel-devsys MDS case material

Epoxy ... expansion foam?

IAW https://www.landsnail.com/apple/local/design/apple2.html the Apple II was "reaction-injection molding" and "polyurethane"; later "ABS (acrylonitrile-butadiene-styrene) plastic".

Found this article on "Structural Foam ABS": https://journals.sagepub.com/doi/pdf/10.1177/0021955X7100700604

This page shows a cross-section: https://neaforma.com/technieken/thermoplastisch-schuimgieten-tsg-sfi/

I see no evidence of any internal cellular structure in my various MDS case fractures. It's quite dense and solid.

-----Original Message-----
From: intel-...@googlegroups.com [mailto:intel-...@googlegroups.com] On Behalf Of Al Kossow
Sent: Tuesday, April 27, 2021 3:08 PM
To: 'Jack Mcmullen' via intel-devsys
Subject: Re: intel-devsys MDS case material

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[forjack842]

Look for epoxy  used in/on aircraft structures...you'd be surprised on how strong they can be

Sent via the Samsung Galaxy A11, an AT&T 4G LTE smartphone

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[Paul Birkel]

Not surprised :->.  I’ve tried the usual 2-part epoxy on a couple of small breaks and am satisfied with the bonding.  If this box ever “flies” off the benchtop it will undoubtedly experience a harder landing than “nature intended” … and we’ll have a test case for whether the epoxied breaks open up before something else does.  But not interested in experiencing any test-to-destruction scenarios :-}!

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[forjack842]

I've used JB Weld many many times fill in missing small parts, and join semi porous material.  Great epoxy

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[Herb Johnson]

So on a related topic of materials and gluing. There's a number of
times, when I find myself with a backplane with broken PC board edge
connector sockets. Often the "ears" break off at the very end and expose
a socket pin or two. Sometimes there's a chip along the length, same
exposure. Repair of these connectors in place, would be preferable to
removing tens of pins on a PC board.(68 on multibus, 100 on S-100, etc).

I can provide photos and brand/models if this is confusing. These are
materials of the same 1980's age as the Intel cabinets. But they are of
a harder, more brittle material, which has pores but I'd not call it
"porous". This is just outside my knowledge of industrial materials.

Can anyone shed light on the material these are made from, and recommend
repair materials. "JB Weld" is a plausible product line of many kinds of
epoxies, so some specific choices would be helpful.

Regards, Herb

On 4/28/2021 1:15 PM, 'forjack842'

> I've used JB Weld many many times fill in missing small parts, and join
> semi porous material.  Great epoxy
>

> -------- Original message --------
> From: Paul Birkel <pbi...@gmail.com>
> Date: 4/28/21 1:58 AM (GMT-08:00)
>

> Not surprised :->.  I’ve tried the usual 2-part epoxy on a couple of
> small breaks and am satisfied with the bonding.
>

> *From:*'forjack842'
> *Sent:* Tuesday, April 27, 2021 5:33 PM

>
> Look for epoxy  used in/on aircraft structures...you'd be surprised on
> how strong they can be

> -----Original Message-----
> From: Paul Birkel
> Sent: Tuesday, April 27, 2021 4:00 PM
>

> Epoxy ... expansion foam?
>
> IAW https://www.landsnail.com/apple/local/design/apple2.html the Apple
> II was "reaction-injection molding" and "polyurethane"; later "ABS
> (acrylonitrile-butadiene-styrene) plastic".
>
> Found this article on "Structural Foam ABS":
> https://journals.sagepub.com/doi/pdf/10.1177/0021955X7100700604
>
> This page shows a cross-section:
> https://neaforma.com/technieken/thermoplastisch-schuimgieten-tsg-sfi/
>
> I see no evidence of any internal cellular structure in my various MDS
> case fractures.  It's quite dense and solid.
>

--

Herbert R. Johnson, New Jersey in the USA
http://www.retrotechnology.com OR .net
preserve, recover, restore 1970's computing
email: hjohnson AT retrotechnology DOT com
or try later herbjohnson AT comcast DOT net

[forjack842]

Herb et al, I guess my reference of porous I meant not glass smooth surface, something for the epoxy to fill in and grab on too.

Now I have used an adhesive which is part of Click Bond faster line of products. They provide a "Nut Plate" that their adhesive bonds the nut plate to an aircraft or like structure allowing a threaded attachment. I've used this adhesive on aircraft and other stress joining and it is amazingly strong and long lived. 

JB Weld is a great adhesive also. I use the quick cure for making pot metal patches and anything that needs "body" that can be molded and filed as a filler/adhesive. Auto Bondo is a great filler as anyone doing auto restoration knows not much of a joining adhesive Then there's Super Glue. Stuff is amazing rock solid joints, best on smooth surfaces, can replace screw threads, etc. 

Sent via the Samsung Galaxy A11, an AT&T 4G LTE smartphone

-------- Original message --------

From: Herb Johnson <hjoh...@retrotechnology.com>

Date: 4/28/21 12:22 PM (GMT-08:00)

To: intel-...@googlegroups.com

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