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