Info Technical Discussion | HOTDIVE Diving Equipment Development

[HotDive(Hide In Ocean)]

I’ve long thought SCUBA gear would be better off using only PFPE grease. Personally, I’m not the biggest fan of Christolube 111; there are better, if sometimes more expensive, alternatives. Wouldn’t it make sense to drop silicone grease completely from the line-up, even if cost is a factor? I think your gear would benefit from it.

I made a simple translation mistake here. We use fully fluorinated grease thickened with PTFE, so please disregard the mention of silicone.
You mentioned that PFPE grease might be more suitable for scuba equipment than Christolube 111, and we fully agree on the importance of continuously optimising lubrication solutions. Could you share some specific suggestions or recommendations? For example, in different application scenarios—such as high-pressure environments, low temperatures, or oxygen compatibility—which types of grease would you consider most appropriate? Or are there approaches you would recommend for balancing performance and cost? We would greatly appreciate your professional insights and hope to use these valuable suggestions to continuously improve our equipment, providing users with safer and more reliable products.

 

[HotDive(Hide In Ocean)]

May I ask what exactly you did for thermal conductivity optimisation? I don’t see fins or other obvious surface enlargements that would improve heat exchange.

For the T4 2nd stage, our design integrates a heat exchanger concept. By extending the connection between the 2nd stage and the hose interface, we incorporated a heat exchanger structure that increases the contact area with water, thereby enhancing heat dissipation and improving overall performance.

 

[HotDive(Hide In Ocean)]

Lubrication: We use CHRISTO-LUBE® MCG111, a fully fluorinated grease thickened with PTFE, capable of operating under extreme temperatures with excellent oxygen compatibility. It is highly compatible with metals, plastics, and elastomers. This medium-consistency fluorinated lubricant is particularly suitable for valves and regulator components. CHRISTO-LUBE® MCG111 meets MIL-PRF-27617G Types I, II, and III, and is NSF H-1 registered, meaning it can be used in or around food processing equipment. NSN: 9150-01-441-9016. MCG111 silicone grease has extremely low vapor pressure and excellent thermal stability, preventing decomposition or combustion in high-pressure oxygen environments. It is mainly used on regulator O-rings, valve stems, and threads to reduce friction and avoid mechanical ignition.

 

[HotDive(Hide In Ocean)]

On hyperbaric oxygen chambers, I can’t fully agree either. From what I know and have worked with, most valves are brass, though you are right that most fittings are stainless steel, the pipes included.


There’s no question that 316L can be used in oxygen systems. My question is more whether it’s the best choice for SCUBA. I would argue brass is still the clear winner in terms of oxygen suitability.


I certainly enjoy the photos and videos you share from production, please keep them coming.


On the cold-water discussion: there is no shame in stating that the S1 is not a cold-water regulator. While a few unbalanced pistons have been adapted for cold conditions, most are not.


For the S3, I don’t doubt your customers have had success even in the Arctic Circle. First stages with environmental sealing are very difficult to ice up externally; the second diaphragm is too far from where ice forms. Getting the second stage to cooperate in those conditions is much more challenging, kudos for that.
May I ask what exactly you did for thermal conductivity optimisation? I don’t see fins or other obvious surface enlargements that would improve heat exchange.


That is excellent news.


Then you’re clearly more adept than I am! I’ve never had much success cleaning filters: disc, conical, sintered, or mesh. That is probably a "me" problem.


I don't think I can entirely agree. While the efficiency doesn't differ with brand new filters, disc shaped filters undeniably clog up faster than conical ones. That is the entire point of the conical shape, enlarged surface area. That's one of the reasons that most companies moved on from disc filters.


While we may not agree on everything, I appreciate the civil discussion and your openness in sharing details. Thank you!

Hello, Mr. Tanks A Lot,

Through our conversations, I can truly sense your deep understanding and unique insights into the diving industry, and I greatly admire this spirit of professional knowledge.

In the future, if you are interested in developing your own products, we would be more than happy to explore potential cooperation with you. At the same time, we sincerely welcome all friends who are interested in our products or services to stay in touch with us, share ideas, and explore opportunities for collaboration.

 

[Tanks A Lot]

Thank you so much for your detailed reply, I truly appreciate it.

I do have to correct you on one thing straight away:

Hello, Mr. Tanks A Lot,

[...]your deep understanding and unique insights into the diving industry, and I greatly admire this spirit of professional knowledge.[...]

I understand there is a language barrier at play (mine included), but I'm certainly no Mr., nor do I have any special insights into the industry. I'm in no position to develop any regulators, as I lack the expertise and knowledge that engineers possess. I'm just some random guy with a keen interest in the technical side who ran a workshop for a while. If you want to call me something, I love Mr. "Numbnuts"!

Once again, I appreciate the different viewpoints. While I'm still not convinced that stainless steel is a good option for oxygen use, I can certainly see the appeal for "regular" air usage. Stainless steel brings a lot to the table in that context.

I do hear you on the O-rings. For a project a while ago, I looked into the prices of different O-ring materials. The O-ring in question was a BS1806-214 (standard cylinder neck O-ring). When ordering a few hundred, NBR came in at 0.003€ per piece, FKM (Viton) at 0.33€ per piece, and FFKM-----wait for it-----31.38€ per piece.

To my shame, I have never handled an FFKM O-ring or a gas appliance that used them. I would love to see how they perform!

As far as lubrication goes, there is nothing inherently wrong with Christolube 111. In fact, it is a great grease. The only thing I dislike about it is that the grease separates from the carrier over time. This is very noticeable on packed piston first stages, where the oil slowly oozes away from the grease. The same can be observed in a package of Christolube 111 that has sat unused for a prolonged period.

I do like Tribolube 71, Krytox 206, or Gleitmo 599. The PFPE lubricant market is fairly large, there really is a lot of choice. SCUBA is a tiny industry, so getting proper recommendations from the grease manufacturers is difficult. When I asked, I usually did so sneakily, under the guise of some HPP (high pressure food processing) application. That seems to have worked great so far for me.
The recommended grease is obviously food safe and can handle large pressures. For oxygen use, I stated right off the bat what the actual usage is. Unfortunately many manufacturers then don't even bother replying...

I hope that HotDive keeps being this open about their products. This is definitely a boon to the interested crowd, such as myself. Now, if you were to open up service manuals, schematics, and spare parts as well, that would take things to a whole new level for the DIY crowd.

 

[tursiops]

My antivirus says fix your infected website. You might find that a more productive use of your time than this thread.

Seriously who cares about your stupid equipement? I would never ever buy anything from a company so useless it cannot correct an infected website even when it has been pointed out to them.

I am not angry - I am laughing at you. You really think you stand a chance as a business when you can't run a website?

Best of luck with the kit - you will need it.

I have four different virus/website checkers in use constantly. I see no problem with hotdivescuba.com.
Why are you so sure there is a problem?

 

[BoltSnap]

four different virus/website checkers

What are you using?

 

[BoltSnap]

I see no problem with hotdivescuba.com.
Why are you so sure there is a problem?

I think that he is referring to another site with .cn extension.

He's rude anyways

 

[tursiops]

What are you using?

Bitdefender, Malwarebytes, SuperAntiVirus, and Microsoft Defender.

 

[HotDive(Hide In Ocean)]

I think that he is referring to another site with .cn extension.

He's rude anyways

Yes, before that we had shut down the server for www.hotdive.cn. But now we have reopened the .cn site. We are currently preparing www.hotdivescuba.com, which will be a platform where products can be added to the shopping cart and purchased.