Based on all the EK barb endorsements I've seen around here, I ordered 6 for my water blocks (Apogee, MCW60, MCW30). I'm a bit confused now why everyone is endorsing these barbs.
Pics attached.
Here's some facts:
1. Flange size: The nut flange on the EK barbs is bigger(18mm wrench size) and the rubber o-ring is counter-sunk into a groove on the underside of the flange. This is only a problem when trying to thread the fitting into a Swiftech block... At least on the MCW30 and MCW60 I have, the flange will make contact with the rim of the block opening before the rubber o-ring makes contact with the seat. Are people actually using EK barbs in Swiftech blocks and getting water tight seals?
With the DD barbs, the flange is smaller (16mm wrench size), and will not make contact with the rim of the block as the fitting is threaded in. The o-ring is not counter-sunk into the flange, allowing the o-ring to make good contact with the seat on the block.
2. Thread length: There are four threads on the EK vs. 3 on the DD. The actual length of the threaded area below the flange is identical, the difference being that EK threaded one additional turn vs. DD. While this was touted as an advantage with the EK in other posts, the problem from #1 means the EK barb cannot engage any more thread than the DD on a Swiftech block since the EK flange will hit the block rim before all the threads can be engaged. The added thread on the EK can only be helpful when not using a Swiftech block where the mating surface does not have a rim.
3. Thread cut: Some people touted the EK barbs as having a rounded thread vs the sharp threads on the DD barbs. This is totally false. The two barbs have equally sharp threads. There is zero difference between the thread cut on these two barbs.
4. O-ring: As mentioned, the EK barbs use an o-ring that is slightly counter-sunk into the flange. The EK o-ring is larger... in fact, it is the same size as the o-rings included with the Swiftech plastic barbs. DD uses a smaller o-ring that is not counter-sunk. I don't think either design is better than the other except that the DD o-rings can be used with other G1/4 fittings and are therefore more universal - if you need to steal an o-ring for some kind of G1/4 adapter for example.
5. ID: The DD barb has a minutely larger ID than the EK barb. Not enough to be a consideration, I'm sure, but if you are looking for the least turbulence at the inlet to the block, DD is your choice because the lip at the end of the barb is thinner.
So given all this, and especially problem #1, I'm not sure why people recommend these barbs... especially for Swiftech blocks where a water tight seal would seem very unreliable.
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