CTI 75mm O-Ring Source

[cerving]

Anybody know a good place to get silicone #228 and #230 o-rings for CTI 75mm hardware? I used to get them from McMaster, but they apparently don't carry them anymore. I do a lot of AT-to-CTI crossloads, the AT propellant kits come with two #230's but not the #228 for the CTI nozzle holder. Thanks!

Eggtimer Cris

 

[tfish]

Anybody know a good place to get silicone #228 and #230 o-rings for CTI 75mm hardware? I used to get them from McMaster, but they apparently don't carry them anymore. I do a lot of AT-to-CTI crossloads, the AT propellant kits come with two #230's but not the #228 for the CTI nozzle holder. Thanks!

Eggtimer Cris

The Oring store https://www.theoringstore.com/store/

Tony

 

[cerving]

Thanks! I forgot how expensive the red silicone ones were... almost $4 each. Is there a cheaper acceptable compound? I think AT ships butyl or buna o-rings... they're black, not red.

 

[mikec]

You might ask local people who go in the opposite direction and don't use the one that comes in a CTI reload. I've got at least one, I'll bring it to the next TRA-SD launch.

Also, the last CTI kit I got had black BUNA rings, not red, I believe.

 

[cerving]

You might ask local people who go in the opposite direction and don't use the one that comes in a CTI reload. I've got at least one, I'll bring it to the next TRA-SD launch.

Also, the last CTI kit I got had black BUNA rings, not red, I believe.

Thanks. I have four of the #228 red silicone ones left... trying to be proactive so I don't run out. Honestly, every time I remove them they look new... they could probably be reused, since they're the inside nozzle holder o-rings and (theoretically) shouldn't be subject to any hot gas exposure. I throw them away anyway...

 

[TBob]

Are these what you're looking for? May be a better price if the same. That's an amazon short link, btw.

https://a.co/d/9qGwmkE

 

[cerving]

Yup... Amazon Prime next-day shipping too. Thanks!

 

[Maxwelljets]

I've found that Grainger has decent prices on silicone o-rings. $12.17 for 25 -228 o-rings, and $16.41 for 25 -230 o-rings. Plus, there's a local pickup spot pretty close to me so I don't have to pay shipping.

 

[Dennis Schmaltz]

Hercules Sealing Company

https://www.herculesus.com/index.php

 

[Jowayen]

McMaster carries 228's and 230's in high-temp silicone

 

[jd2cylman]

I’ll dig around. I’m sure I have set or two.

 

[Rocketjunkie]

Why use silicone. You only use them once so just use buna. The only time I've needed silicone was for the nozzle of a snap ring case.

 

[Conway Stevens]

Why use silicone. You only use them once so just use buna. The only time I've needed silicone was for the nozzle of a snap ring case.

Agreed. Only time I use a silicone high temp is on a graphite nozzle snap ring case. Forward closure Buna N is plenty. I use

Orings and more

https://www.oringsandmore.com/
The oring store

https://www.theoringstore.com/store/