The phenomenon of cable-shaped indents within the plastic circumstances of retro methods is one which’s in all probability painfully acquainted to many a collector of such methods. Though in these conditions neither aspect bought scorching sufficient to trigger any melting – particularly whereas disconnected in storage – it nonetheless has that very same melted look. The actual trigger right here isn’t warmth, however plasticizer migration, as detailed in a current video by [Run Stop Restored] over on YouTube.
Plasticizers are an additive to many plastics that intention to make it extra versatile (‘plastic’), in addition to enhance different traits of the bottom materials, with PVC specifically counting on plasticizers to present it its desired properties for functions the place PVC must be versatile. Right here the versatile cable insulation of those units usually makes use of PVC, which over time can migrate to different polymers when introduced into shut contact for prolonged durations of time.
The – often ABS – enclosures of e.g. Commodore tape drives as on this video demonstration thus get correspondingly inundated with the identical kind of plasticizers that ABS can also be extremely vulnerable to. Since in storage the cables are typically wrapped – tightly – across the system they’re connected to, this ends in a strong contact which thus permits this gradual course of to work its magic, whether or not it’s a Commodore datasette or an influence provide brick.
Correspondingly the PVC insulation turns into brittle because it loses its plasticizer, with the method sped up by increased environmental temperatures. To forestall this, by no means wrap a PVC cable round a tool, and preserve it bodily separated from vulnerable plastics like ABS as a lot as moderately doable. Together with a cool atmosphere this could forestall plasticizer migration from ruining what was once a pristine case.
This downside is especially important for retro gear from the Eighties and thereabouts, earlier than phthalate-free plasticizer options had been developed, together with different modifications reminiscent of extra secure formulations that forestall this migration course of. Including a coating may assist, particularly for shielding older gear, however versatile PVC specifically needs to be considered with suspicion and handled fastidiously.
