Plastic DIN cap warning

[jonnythan]

Delrin isn't plastic it's an engineered polymer. Theres a big difference. If you have any factual information to post please feel free to post it. Otherwise, try harder keeping to yourself jonny.

That's kinda funny, because DuPont - the creator and manufacturer of Delrin - refers to it as a durable, low friction plastic. See http://heritage.dupont.com/floater/fl_delrin/floater.shtml as well as just about any other site that has information about it. For instance, http://www.interstateplastics.com/meta/fmdel.htm refers to Delrin as "an outstanding general purpose plastic."

Plastics by design are engineered polymers. I'm not sure what you're trying to say, but Delrin is most definitely plastic. The ~ 1 square inch of surface area on a plastic DIN plug will experience an outward force of almost 2 tons and it's no surprise that the thing broke apart under that kind of pressure.

Anyway, back to the topic at hand.....

Hope your finger heals up well, Alan.

 

[TomvdH]

Alan,

Your post is one of those that I look for. My hats off to anyone who will come forward and tell it like it is, in the interest of hopefully saving someone else 7 stitches or maybe worse.

Sorry about the pain, but thanks for sharing the information.

 

[TCDiver1]

Not to hijack the thread, but what is the distinction between a plastic and a polymer?

None, plastic is a type of polymer. The point i was trying to make is there is a big difference between what is typically called plastic (mattel toy) and delrin.

So Steve, you have seen the delrin plugs explode?

 

[biggsy]

The K200-Bar DIN / Yoke (K) valves have a release hole on the side of the valve that allows pressure to escape if you accidentally turn the valve on. These are the valves that come with the PST cylinders and having a din plug is not an issue with these types of valves.

Good info, hope your hand heals up better than it was before!

 

[Alan Owens]

Did these caps have gas release holes in them? or were they solid caps?

No gas release holes.

 

[Alan Owens]

I've seen the plastic/delrin ones with the holes in them fire the retaining bead that holds the loop of string across a room at a truly amazing velocity. If you're going to use DIN plugs (not caps - those go on regulators) they need to be made of brass or stainless steel. No vent holes will mean you'll need a wrench to loosen them but they will save your gas if the valve is accidentally opened.

Not to hijack the thread, but what is the distinction between a plastic and a polymer?

Yes they were the plugs, not the caps

 

[SDAnderson]

None, plastic is a type of polymer. The point i was trying to make is there is a big difference between what is typically called plastic (mattel toy) and delrin.

So Steve, you have seen the delrin plugs explode?

The only ones I've seen pop off were what I would have called delrin. The plug itself remained intact but the gas escaping through the vent took the little (delrin?) bead that the string is attached to with it. A dive shop isn't normally somewhere you expect to see little black bullets doing the ricochet thing. My primary motive in using the plugs is to avoid accidentally losing an expensive trimix fill or have high O2 mixes blasting around the back end of the truck, so I use the ventless SS variety and carry a big wrench.

 

[Alan Owens]

Thanks to all for the well wishes.

 

[Scubaroo]

I swear I'm not following you around Alan

Here's a picture of a Delrin plug that HAD a vent hole. Note the lack of, well, most of the plug.

 

[biggsy]

Let me just state this is my observation and there is no scientific facts backing what I said earlier. I dont know what kind of valve that was plugged into Scubaroo, but that does look very good. The K valves on the PST seemed to be alright, but a stainless steel plug would probably work better