RE: [AH] Damn sticky plastic...

From Lorne Hammond
Sent Sat, Feb 3rd 2018, 19:17

chemically all plastic are unstable. I am not an object conservator but =
it was explained to me about our plastics that they are all stable until =
the last 10-5% of their life and then break down quickly. Some will off =
gas and the gas will cause a red rust on nearby metals.
PVC plastics like tb-303 cases, will show breakdown first by becoming =
oily.  Freezing plastics slows down but does not stop the plastic =
deterioration.  All plastics are a complex chemical stew and there are =
no easy rules like 1910 "French ivory" goes first then 1950s then 1970s. =
It is not about chronology but about chemical bonds at the molecular =
level. Professional conservators know about this but it is not easily =
understood especially because the makers of things use plastics provided =
by other companies with proprietary (secret) formulas. At work we have =
stable plastics from the 1910-1920s, but all our drafting triangles =
crumbled around the same time.

1) Don't store your tb-303 in the bag. Keep off gassing risks to a =
minimum.  Put the case in a zip lock bag with a little nylon sack of =
fish tank charcoal to absorb off gas, place in cool storage.
2) Rubber going from black to red or hard and curly is not collectable, =
has no sonic qualities and is not reversible. Replace it.
3) Black foam in road cases. Scrap it out, replace it. It will powder =
down into your keyboard mechanism. If so vacuum it out.  A foam shop can =
do a better job cutting (their saw is a hot wire and they have masks and =
air systems for this and for the glues. Road cases were $600 new, pay =
some bucks to have it redone correctly.
4) Moog cables.  Yes, heat shrink (it shrinks right?) is not so stable, =
cut it off from around the wire and redo it.
5) audio cables will get brittle over time. The chance of a short caused =
by a break is there. Replace.
6) Button contact strips in late 1980s and 1990 synths will go. If you =
can get new replacements or NOS (same problem) you may get extra shelf =
life.
7) Plastic panels sometimes show crackling. Its there in my tt-303. So =
far its just an aesthetic issue.
8) No sign of knobs going, say Minimoog 1975 seems stable as are the =
blue early Buchla knobs.

Lorne




-----Original Message-----
From: Fernando Zarone [mailto:xxxxxxxxxxxxxx@xxx.xxx]=20
Sent: February-03-18 9:24 AM
To: AH send <xxxxxxxx@xxxxxxxxx.xxx>
Subject: [AH] Damn sticky plastic...

Hi all
after moving to my new house (more than 1 year) finally I am cleaning / =
recalibrating / overhauling my machines in order to tweak their knobs =
again=E2=80=A6
I have noticed that some stuff, after more than 40 years, is going to =
age, as I am   :-(
In particular, plastic and rubber  seem to be very prone to some =
problems:=20
- the soft original case of my TB303 has an oily, somewhat sticky =
surface, although maintaining its colors and shape.=20
- some of my Moog modulars=E2=80=99 cables (the original s-trigger ones) =
have a short collar of black rubber around the cable at the level of the =
metal screwed =E2=80=9Ctie=E2=80=9D locking it to the Chinch Jones Jack. =
Such collars are melting, leaving a black sticky stain that is very hard =
to remove Any suggestion?

Ciao

Fernando=20