O-ring Materials..

[willydiver]

I'm gathering materials for a DPV project and have found that o-rings come in about 10 different kinds of materials (Viton, silicone, EPDM, neoprene, etc.). I just need them to seal a cannister lid. I guess I'll use EPDM, as it has about the same hardness as the neoprenes and is more abrasion resistant than silicone.

Any suggestions on what kind of o-ring material is suggested?

Thanks,
WD

 

[ShakaZulu]

Please let us know how this project turns out...........are you using a aluminum extrution for the barrel???

 

[willydiver]

Please let us know how this project turns out...........are you using a aluminum extrution for the barrel???

I'm using 6" Schedule 80 PVC for the cannister and 1" acrylic for the lid. I found a used 52# thrust trolling motor that I butchered for the motor. I'm rebuilding the seals in the motor casing with better orings to be safe.

I've already worked out the electrical side. I found 12volt/12ampHr SLA batteries that fit great inside the cannister. Two of them in parallel give me the full 24ampHr that most commercial DPVs have. They turn the motor great through a switch and relay.

My CAD drawing looks like a torpedo. I don't want to divulge TOO much before I actually get into the assembly stage. This thing is still in design, although it's looking very good. I'll machine the cannister and lid during the holidays. Thanks for the interest.

WD

 

[dlndavid]

I'm gathering materials for a DPV project and have found that o-rings come in about 10 different kinds of materials (Viton, silicone, EPDM, neoprene, etc.). I just need them to seal a cannister lid. I guess I'll use EPDM, as it has about the same hardness as the neoprenes and is more abrasion resistant than silicone.

Any suggestions on what kind of o-ring material is suggested?

Thanks,
WD

Since I work for Parker Haniffin I would suggest Parker O-Rings
Here is a great breakdown of o-ring mat'ls and their use. There also more in depth material/fluid compatibility charts availlable.

http://www.parker.com/sg/parker.pdf

 

[willydiver]

Since I work for Parker Haniffin I would suggest Parker O-Rings
Here is a great breakdown of o-ring mat'ls and their use. There also more in depth material/fluid compatibility charts availlable.

http://www.parker.com/sg/parker.pdf

dlndavid,

Man, you guys sure know seals. Thanks for the great info.

WD

 

[DiverMo]

Just curious as to what you decided on material wise. I am researching the same subject for building a video housing. I was thinking epdm based on resistance to sunlight and weathering and ozone, and it has a good compression set resistance, plus it is relatively inexpensive to some of the other choices.

 

[wedivebc]

Just curious as to what you decided on material wise. I am researching the same subject for building a video housing. I was thinking epdm based on resistance to sunlight and weathering and ozone, and it has a good compression set resistance, plus it is relatively inexpensive to some of the other choices.

I believe most O-rings in the scuba industry, not being used in an O2 rich environment are made from buna-n

 

[willydiver]

Just curious as to what you decided on material wise. I am researching the same subject for building a video housing. I was thinking epdm based on resistance to sunlight and weathering and ozone, and it has a good compression set resistance, plus it is relatively inexpensive to some of the other choices.

DiverMo,

I ended up ordering EPDM from McMaster. Both they and allorings.com listed EPDM, silicone, and neoprene as having a durometer hardness of D-70. I wanted to get the softest ones I could find. EPDM seemed to have the best all-around weather, water, and abrasion resistance. They seemed like the cheapest to me, too.

One thing you may want to consider, I ordered 1/4" thickness orings for the DPV cannister. Before drilling the holes for the latches, I checked the compression force needed to seal the oring between the PVC cannister and the acrylic lid. The force needed to create a positive seal seemed excessive for the latch attachment points, so I decided to go with 3/16" thickness orings. I've got them on order. Be sure your sealing surfaces are very smooth and lube the orings up with a good, but not excessive, film of silicone grease. A good source of 100% silicone grease is the local auto parts store. They sell it in the electrical or glue section for use as an electrical contact grease.

WD

 

[DiverMo]

DiverMo,


One thing you may want to consider, I ordered 1/4" thickness orings for the DPV cannister. Before drilling the holes for the latches, I checked the compression force needed to seal the oring between the PVC cannister and the acrylic lid. The force needed to create a positive seal seemed excessive for the latch attachment points, so I decided to go with 3/16" thickness orings.
WD

I'm glad you mentioned that, cuz I was just looking at the o-ring selection and trying to decide what thickness I was going to use. I'm following someone elses plan, and they used 1/4" o-rings but I was thinking 3/16" or even 1/8". I will probably split the difference and go with the 3/16". Also, I was wondering about what type of grease to use. You mention silicone. I know that the different camera and video housing manufacturers specify that you must use proprietary or different types of grease for their respective o-rings. Would you happen to know if it is because of different materials, or maybe just marketing? I guess it doesn't matter as long as the silicone grease worked for you. Anyhowz, thanks for you input - gets me one step closer!

 

[willydiver]

I'm glad you mentioned that, cuz I was just looking at the o-ring selection and trying to decide what thickness I was going to use. I'm following someone elses plan, and they used 1/4" o-rings but I was thinking 3/16" or even 1/8". I will probably split the difference and go with the 3/16". Also, I was wondering about what type of grease to use. You mention silicone. I know that the different camera and video housing manufacturers specify that you must use proprietary or different types of grease for their respective o-rings. Would you happen to know if it is because of different materials, or maybe just marketing? I guess it doesn't matter as long as the silicone grease worked for you. Anyhowz, thanks for you input - gets me one step closer!

Glad to be of some help. I think you'll be fine using the silicone grease. I would suspect that the manufacturer recommended/required greases are more for marketing reasons. EPDM is shown to have good resistance to silicone products, so silicone grease shouldn't deteriorate the material.

If you don't mind, post a pic of your housing when you get it finished.

WD