All this chatter and no one has yet to answer the actual question....do commercial sources of low quantity custom O rings simply glue strip stock or somehow mold all new rings ? Doesn't matter really, but curious if there is a way to create all new O rings in small quanties without glue involved ? Seems like at the low prices it would be a money loser either way.
Surely it is a money-loser as onsies. Multi-cavity molds can do MANY at a go, and it is not a SLOW go. "Somebody" may fab them and "weld" them on bespoke machinery, too.
Person could go a loooooong way as a "custom fab" just by being better able to read more catalogs. Be happy our Finnish friend gave that a miss!
If you want to be ABLE to make onesies to save time or in emergencies? Army uses RTV for lots of stuff it isn't expected to last very long.
Many of the more serious elastomers can be had as two-part pourables. "Silicone rubbers" were ones I had used extensively at one time. Be aware that among other things (expensive!), they have finite shelf lives. Not talking RTV or bathtub caulk here.
Others can be had as reels of round stock, heat-joinable or ultrasound weldable. How many diameters would you care to stock? Extrude though a sized nozzle onto a turntable? Now we are talking. But which elastomer, and will it do for YOUR job?
We made our own molds to make similar elastomeric goods in MANY experimental materials and carefully controlled durometers as part of ongoing research over fifty-plus years to fight feedback in hearing-aids. Microphones and reproducers had to live in close proximity and up to 135 dBA of audio gain. Until the "electret" microphone arrived, they were devilishly sensitive to shock as well.
Top of the market goods, if only because the founder, his sons, grandson, and somewhere between 1/3 and 2/3 (over time) of the staff were also hard-of-hearing and had need of the best as could be had of our own best efforts.
We didn't break-out that minutia from the overall R&D budget, but most went through a 24 hour cure to stabilize, then off for a week, minimum, of artificial environmental stress testing to simulate age effects and exposure to chemicals (human perspiration and body oils, organic acids, etc.)
Commercial "O" rings have all those R&D efforts and field history behind them w/r fluids and gases and such. Air conditioning systems over time have needed three different elastomers for O rings as the refrigerant gas brew and compatible lubes morphed and the earlier elastomers were no longer compatible.
You'd be wise to test a DIY, even if using what you BELIEVE is the same elastomer and process as the ready-mades. And of course WHICH of those ready-mades suits the need, and did your brew match it?
And there goes the budget.
Fully-burdened costs, and what did PM turn up?
30 cents US for a stock item, 30 pounds, Sterling for custom. Trust this - it isn't the cost of the elastomer. Somebody has Day Jobs on payroll and rent to pay.
Or - when WE got it wrong, as we did do, Model 990 - the need to supply two units under warranty for every ONE sold new as three successive revisions of elastomers failed us due to stiffening "too fast" once in the field. ELSE turning into MUSH!
Cheap-ass bottle jacks have been known to leak, too, yah?
20CW
