I'm trying to buy, in the US, new O-Rings for my Retra Pro X strobes. 

 

The Retra website has them for sale but shipping is something like $32 to the US which is crazy given the cost of the o-rings themselves.

 

The Retra website says "you can buy them at your local o-ring store" (40 x 2.5mm EPDM 70) but I'm a bit wary of doing that and when I checked www.theoringstore.com, the minimum buy quantity (believe it or not), it was 273. I don't need 273 of them. 🙂

 

Backscatter only seems to have o-rings for the first gen strobe (or my searches are just ineffective).

 

I can't believe that it should be this hard to get o-rings. Any ideas?

 

Thanks,

 

- brett

 

Check Ebay.  Sellers there are more likely to sell in smaller quantities.

 

Searching is a bit overwhelming at first, but some sellers let you pick the size/diameter desired.

42 minutes ago, mcgowman said:

Check Ebay.  Sellers there are more likely to sell in smaller quantities.

 

Searching is a bit overwhelming at first, but some sellers let you pick the size/diameter desired.

 

Thanks. I'm a bit leery ordering o-rings off EBay, especially with two expensive strobes at risk.

 

I found another o-ring store, but it lists the dimensions of a "040 x 2.5mm" o-ring as "4mm ID x 45mm OD x 2.5mm C/S" and I just want to make sure that is the correct o-ring.

 

It seems very strange that the actual dimensions don't match. I guess the "40" refers to the ID while the 45mm OD is the sum of the ID + the 2 x 2.5mm measurements.

 

Confusing at best. It is hard to believe that US Retra dealers don't just stock the Retra o-rings. Maybe my search kung-fu is just really limited.

 

- brett

 

 

 

On Monday I would call Backscatter direct as they may have them but not listed yet.

 

Another option would be Reef Photo.

1 hour ago, Jay-11 said:

On Monday I would call Backscatter direct as they may have them but not listed yet.

 

Another option would be Reef Photo.

 

Yep. I sent an email to Backscatter but will call them in the AM.

 

Thanks,

 

- brett

 

I just now looked up the O-Ring Store with Google and the price is $0.17 per 2.5 x 4O ring, an acceptable price.

https://www.theoringstore.com/store/index.php?main_page=product_info&products_id=2032

 

You might want to use another search engine, or give more practice to your O-ring searches, your search Kung-Fu as you call it. 

 

Hi, regarding the dimensions: All dimensions on our website are in millimeters and follow this format: (internal diameter of the O-ring) X (thickness of the O-ring). The material of the O-ring should always be "EPDM 70".

 

If you can't find any suitable O-rings locally please write to us: [email protected]

15 hours ago, Kraken de Mabini said:

I just now looked up the O-Ring Store with Google and the price is $0.17 per 2.5 x 4O ring, an acceptable price.

https://www.theoringstore.com/store/index.php?main_page=product_info&products_id=2032

 

You might want to use another search engine, or give more practice to your O-ring searches, your search Kung-Fu as you call it. 

 

 

Thanks! Very strange. That is the exact place I checked over the weekend and, at that time, the minimum quantity was 273 and now it looks like it is twenty. Odd.

 

In the meantime, I had found another on-line store that had lower minimum quantities so I bought them. 

 

Thanks,

 

- brett

 

3 hours ago, Oskar - Retra UWT said:

Hi, regarding the dimensions: All dimensions on our website are in millimeters and follow this format: (internal diameter of the O-ring) X (thickness of the O-ring). The material of the O-ring should always be "EPDM 70".

 

If you can't find any suitable O-rings locally please write to us: [email protected]

 

Thanks, Oskar!

 

- brett

 

15 hours ago, Kraken de Mabini said:

I just now looked up the O-Ring Store with Google and the price is $0.17 per 2.5 x 4O ring, an acceptable price.

https://www.theoringstore.com/store/index.php?main_page=product_info&products_id=2032

 

You might want to use another search engine, or give more practice to your O-ring searches, your search Kung-Fu as you call it. 

 

 

I figured out the difference. 

 

Retra recommends EPDM 70 O-Rings (not Buna-N 70 Duro) and I'm not even sure what the difference is?

 

When you look up the EPDM 70 version of the O-Rings on the website, the minimum buy quantity is 273:

 

https://www.theoringstore.com/store/index.php?main_page=product_info&cPath=368_2278_2284&products_id=46227

 

Again, I don't know the technical difference between EPDM 70 and Buna-N 70, but if Retra says EPDM, then I'm going to do my best to buy that kind.

 

IMHO, it would be much, much easier and foolproof to just have a place in the US that sold the Retra O-Ring kits.

 

Regards,

 

- brett

 

EPDM is a bit more resistant to sunlight and ozone than is Buna. Otherwise in terms of mechanical properties (compression set, and durometer they are nearly identical and a very large fraction of your scuba o-rings are likely Buna-N.  Call the O-ring guys and tell them you need only 10 of epdm that has worked for me

Bill

 

As a quick follow-up, Backscatter does stock them, they just don't appear to be on their website. For reference, the part number they use is

 

"rt-pro-o-ring   Retra Spare O-ring for the Pro / Prime Strobe - EPDM70 Ø40x2,5mm"

 

Regards,

 

- brett

 

 

I am not sure from your specs if the 40 mm is the ID or the OD, but here's a source as well:

 

https://www.mcmaster.com/products/o-rings/system-of-measurement~metric/cross-section-shape~round/id~40-000-mm/material~viton-fluoroelastomer/?s=o-ring+40+x+2.5mm+epdm+70