QDV Orings Mcmaster

[clemsonguy1125]

Ive been planning a 2 inch QDV using a 2 inch tee. The housing will also be 2 inch with a single rectangular port. The piston will be made from a piece of 1.25 inch pipe with pieces of coupler glued on to make the grooves. Ive check Mcmaster but am having issues finding the perfect size orings. Does anyone have a suggestion or link to which orings to use. Heres the stats about the piston.
Pipe size-1-1/4"
O.D-1.660"
ID-1.364"
Pipe Size-2"
O.D-2.375"
ID-2.049"
Thanks

[mark.f]

For 1-1/4" pipe and fittings, I use 2" OD x 3/16" wall o-rings. I have been able to find them at Ace Hardware as well. You may need to wrap some teflon tape in the bottom of your O-ring grooves to get a satisfactory seal.

EDIT: here's an example. Sealed 100% airtight before the addition of an equalization hole.

Click for larger image

[clemsonguy1125]

Thanks, I think I have a Ace about an half hour away so it should be worth the trip.

[Gun Freak]

I also got mine at Ace. A buck each. But when they rang them up at the register they put 0.18 instead of 1.18 LOL I should have got more than 2!

[Gaderelguitarist]

I had the same problem looking on mcmaster for o-rings. Best bet would be take a chunk of the pipe with you to Ace and fit the o-ring to the pipe.

[Gun Freak]

I had the same problem looking on mcmaster for o-rings. Best bet would be take a chunk of the pipe with you to Ace and fit the o-ring to the pipe.

Or just use some of the short pieces they have there. That's what I do.

[Gaderelguitarist]

I hadn't thought of that, but yes thats a good idea. I just like walking in with my own reference material. That way, when an employee asks me if I need any help finding anything, I can reply, "I know this store better than you know your family."

[clemsonguy1125]

Thanks ill make a trip there as soon as I get a chance to start the gun.

[Gun Freak]

I'd make the grooves floating too, just for a better seal...

[clemsonguy1125]

What do you meean floating grooves?

[Gun Freak]

Make the grooves wider than the o-rings. The pipe OD might not allow it though. O-rings at that size are pretty thick so if you use pipe for a piston I don't know if there is enough room for floating o-rings...

[Fnord]

If you are careful about it, you can chop up orings and glue them back together with super glue, with no compromise in the seal. That's why you can buy rolls of oring round stock.

You may want to invest in a big box o' o-rings from harbor freight. Last I checked they cost about $20 and you get a couple hundred ranging from 1/8th to 2".

[Technician1002]

What do you meean floating grooves?

See this page in the Wiki;
http://www.spudfiles.com/spud_wiki/inde ... ston_valve

Scroll down to the bottom of the page to show the dimensions of the o ring gland (groove) in relation to the size of the o ring for a floating o ring.

Floating o rings..

[clemsonguy1125]

Thanks, I understood floating orings, I just didnt know what he meant by floating grooves. I just checked out the page, I was talking to the guy who just built one(forget his username, and he said on his it orings were flat against the inside of the groove. Will this weaken the performance.

[Gun Freak]

There should be room under the o-ring for the air to get in and push the o-ring against the wall of the cylinder.