Talc on duckbills

[duckbill]

I think most of us here are well aware of the benefits of dusting rubber parts like our duckbills with talc to aid in preservation during storage; but, is there any benefit to dusting latex duckbills as well? I would think that the talc would help to keep the insides from sticking together, but what about actual preservation? Any harm in it?
Thanks in advance.

[YankDownUnder]

Talcum powder used in the preservation of rubber products is the non-scented type, so don't use baby powder or anything sold as a bath powder. You can order pure talcum from pharmacies or chemical supply companies.

I have found hoses and other rubber products that were in 'like new' condition and made 40 or 50 years earlier, which were covered in pure talc. Obviously it works. It can't hurt the duckbill valves, but might just be washed away. A silicon or other preservative spray, like Armoral, might last longer. Duckbill valves should be replaced annually if the regulator is used a lot. In anycase, they should be inspected regularly. You should keep several on hand in your spares box. Remember, that hose and valve are contaminated by your own body's fluids (saliva is a digestive juice).

Duckbills tend to break down in the exhaust can and stick closed. It may be because divers really do not clean their gear properly. The best way to clean your gear is to soak it over night in fresh clean water, and let it dry in the shade or indoors and away from heat. The exhaust hose should be flooded. Rinsing it off is not enough. Once it is completely dry, you can blow talc down the exhaust hose. If you are going to store the regulator, take the hoses off and talc all surfaces, inside and out. Never store them in a seal plastic bag as they will never dry.

There are two problems, one is the electrolysis of dissimilar metals in salt water, or any water which is not pure. That is what causes corrosion and the oxidation of other materials. The second problem it not chemical, but physical. Micro salt crystals form and tend to work like a grinding compound on the surfaces as they move.

In the final analysis, the materials used in production, and the way they are used and maintained by the diver are the keys to longevity. Exhalation effort goes up as the duckbill deteriorates, and can make exhalation impossible. You may want to look at installing another valve type, as some vintage divers are working on at the moment. One idea is to put a mushroom valve cage in the exhaust horn. Another idea is to make a tube which is inserted in the exhaust tube on one end and blocked and flattened on the other, with a mushroom valve installed on the flattened end. The British Heinke MkIII regulator featured a mushroom valve cage in the ehaust hose, about two coils from the horn. I have one and it works flawlessly, although, I have no idea how it is inserted.

If you try any modifications, you should couch breathe it for some time. That is a trick used by rebreather divers who modify their units. If they pass out, it is just in front of a Mike Nelson episode, not in Davey Jones' locker.

[duckbill]

Thanks for the reply.
My question has more to do with talc on latex versus rubber. Dan here at DSS is selling latex duckbills. That's why I was asking if there is the same benefit of using talc on them as on the rubber ones.

As a side note, and touching on what you said concerning using mushroom valves for the exhaust (I'm following that thread too), I have found all duckbills to leak to some degree. Try taking a 1" section of 3/4" PVC pipe and install a duckbill onto it just as you would on the exhaust horn of your regulator. Then, submerge the duckbill portion but keep the open end out above the surface of the water so you can look into it and see how the water seeps up into it. I got so tired of getting water in my mouthpiece that I finally did this with all of my duckbills (I have several- two in latex and several more in rubber) until I fould the ONE that had the least seepage (turned out to be one of the latex ones). I was able to then enjoy a dry dive without having to do the purge twist every several minutes. In fact, you don't even have to submerge the duckbill- Just try sucking air through it.
I like to dive my USD regulators as original as possible, but don't really enjoy water in the mouthpiece. I'm extremely happy that duckbills are currently available and hope that they always will be (seepy or not), but I can't help but think that the original factory made ones must not have been as leaky. Even though this thread is about talc on latex, I'm curious what the older divers having experience with the original duckbills have to say about water seepage.

[Deleted]

Terry

I've never noticed seepage thru the exhaust back into the mouthpiece, even when I picked up my RAM in 69, but then again, I hold my mouthpiece so lightly that I get occasional seepage around my gums so I probably would not notice exhaust seepage........I just blow it out......

From a manufactureing point of view, one duckbill would be less expensive to make than a two or three part mushroom valve assembly......might explain why the design is the way it is.....

I have wondered why the duckbill does not have a hard internal frame to lay against like the mushroom valves........would stop the seepage you indicate.......hummmm, that gives me an idea......

Later..........

[nemrod]

I have some NOS duckbills installed in two of my regulators. Sorry, I just installed my last one. They are thinner and more pliable than the duckbills I have seen from current sources. They exhaust easier and they don't leak--BUT---I am entirely happy with both the VSS and VDH duckbills. I have not found leakage to be a problem and they are much less likely to reverse due to their stiffer body section and heavier contruction. They also are more rugged and seem to last longer. Sometimes leakage back into the moutpiece is due to a faulty exhaust side cage valve. The neoprene or rubber ones teend to curl up over time. I just had this happen--it was a new valve installed last summer from one of the current sources and I started geting leakage. Checked the valve and it had curled--replaced with a new one and problem solved. Also, some mouthpieces leak at the seam unless you use an Xacto to remove the flashing/seam.
James

[SeaRat]

Everyone has things to say about duckbills. The original ones, on the DA Aqualung and Overpressure Breathing regs, were probably the best, as they simply fit over the metal tube. I've found that the new one by Dan works extremely well, but as it is made of latex, it needs to be cared for to prevent deterioration (as do all the duckbills, whatever the material).

Using a mushroom valve in the exhaust hose is problematic. First, the mushroom way up there allows some water up the hose, which must be blown clear each breath in some positions. Second, for a finely-tuned regulator, in some positions they will leak air with a mushroom in the hose rather than a duckbill over the diaphragm. Finally, in the hose they tend to be either smaller, and cause more exhalation resistance, or larger, and stick open by having the hose corrugations interfere with the mushroom valve.

The way to get over this is the way Healthways did their mushroom valve on the SCUBA Deluxe, Gold Label edition. They had the mushroom in the housing (like the Snark III), with the diaphragm right against it in the first (blue label) SCUBA Deluxe, and the diaphragm interfered with it. In the Gold Label edition, they placed a small metal tab on the exhaust area to keep the diaphragm from impinging on the mushroom valve (as I recall--I haven't had that regulator since the late 1980s).

But a good-functioning duckbill valve is very difficult to beat for an exhaust. The one (shorter mushroom valve) on my Trieste II works wonderfully, and I believe that one was manufactured by Bryan. It sits right down on the diaphragm, and is in just the right position not to allow air to leak through. The longer ones Dan now has do the same for the USD Mistral and Aquamaster series regs.

John

John

[william]

Hi You really need to be carefull what you use on Rubber Valves other than Talc. I used some Armor All on 3 different sets of brand New Cage Valves in 3 different mouthpieces and they distorterd Badly, rendering them ( totally Not functioning correctly )when I checked them a month later. I do not know how long it took the Armor All to ruin them. I do know that they are totally unusable and ruined. I will be buying and installing the Clear Silicone Rubber mouthpiece cage valves soon as I can. I am replaceing the duckbill Valves with Dan's new and better Duckbill Valves too. I will be useing nothing but talc on them. William

[duckbill]

Thanks for the responses. Sometimes I think that my breathing technique has a lot to do with water getting into the mouthpiece. I breathe deeply and exhale as slowly as possible. This may allow more water to get by the force of the exhaled air. But, this doesn't discount the fact that I was unable to find even one which didn't readily seep during static testing as described.

I also got to thinking today about how latex gloves are usually packaged with a dusting of something on them. I assume it is talc and, if so, would show that talc at least doesn't harm latex. I don't know if it aids in preserving latex. I think they do this to keep the sides of the glove from sticking together and to aid in donning them.

searat said:

I've found that the new one by Dan works extremely well, but as it is made of latex, it needs to be cared for to prevent deterioration (as do all the duckbills, whatever the material).
John

John, what specific measures do you use to care for your latex duckbills to "prevent deterioration"? Same as for rubber ones?

[duckbill]

william said:

I will be buying and installing the Clear Silicone Rubber mouthpiece cage valves soon as I can.William

That is what I have in mine. As far as my set go there is quite a difference between the two silicone mushrooms. One is noticeably harder to breathe through. Not really difficult, but just noticeably so. I previously had the stiffer one on the exhale side because I usually exhale slowly. Well, last weekend I decided to try switching them to see if the lighter one might seal better to keep water out of the mouthpiece. I have never experienced a hard breathing regulator before (except for a marginal one- one of the earliest Voit MR12s with the original fabric diaphragm. Yea, I know. The MR12 is a great regulator, but that diaphragm leaves a LOT to be desired. No wonder they changed to the neoprene ones!), but that was quite an experience. After two dives my chest was very sore. Needless to say, I switched them back around. Yes, it did stay dry, but those were also the dives where I installed the duckbill showing the least amount of seepage.

Anyway, my two silicone valves even look different from eachother. I guess they were from different batches or something. Silicone is great, but in this case I would say that the stiffer silicone valve was stiffer than a standard neoprene one.

[SeaRat]

The old MR-12 regulator diaphragms, when in like-new condition, were very good. But what happened is that, over time, they would harden. I have one which is almost inflexible, and I have another which is like-new and very flexible. In a like-new state, they were hard to beat. I think it has to do with exposure to air-borne substances that hardened them; my guess is ozone.

John

[crimediver]

Ozone is a factor on rubber. But I had an incident diving in contaminated water at a marina fire that consumed 80 vessels. I dove for one hour, got out and was decontaminated. My dive gear was a Viking 1050 vulcanized suit and had double exhaust for contaminated water. All my latex and silicone items were carefully decontaminated at the scene and I went back over the gear at the hotel that night with a dishwashing soap and totally broke down all my gear for an ovehaul. Everything looked good and all rubber was supple. I was amazed about 2 days later to find all my rubber gear on the regs to be stiff, brittle and had the consistancy of newspaper. I feel like some of the contaminants we unknowingly dive in may play a role in aging our gear and result in diaphrams getting stiff. Not very scientific but I am extrapolating from some incidents I have observed. My 2 cents worth. Sure was glad I only swallowed abount a quart of that water.

[stuart]

Natural rubber is degraded by copper ( this is information I got from the rubber company when I had my flapper valves made), so copper alloys, ie the reg box will melt the valve over a period of time, but only where it is in contact. Remove it if you're not going to be diving for long periods of time, or just leave it there and when it shows signs of aging throw it out and get a new one. for goodness sake we're talking about an item that is no longer hard to replace and is only a few dollars. I was also told that a smear of silicone grease is all that is required to prevent it sticking shut, much better than taking everything apart to dry and talc. A lot of the valves myself and Dan sold were chlorinated which prevented them from sticking shut, and they last much longer than the originals.
As for the leaking flapper valves, and the need to install a secondary valve is a load of nonsense. This is a simple and efficient valve that was good enough for thirty years , and now people are fault finding. Yes, most flapper valves you can draw air back through when sucking on it, but when you have it installed the ambient pressure in the hose assembly keeps any water out as the valve under normal diving positions is at the lowest point of the now buoyant hose . The only time a small amount Of water might flow back up the hose is long periods of standing on ones head. By the way the flapper valves sold by myself through Dan with the slit ends instead of the chopped ends are 100% watertight.
I don't want to offend anyone, but sometimes , with some of the subjects talked about , I feel there are some armchair vintage divers using this site who would be better off buying a modern regulator.

[sea.explorer]

I have not experienced the leaky duckbills as some have reported. The only time I have had significant water in the hose is when I did not have the hose clamps tight enough. If this is the problem you can see bubbles coming out when the reg is submerged. Duckbills are a simple and effective valve. The slit style is going to provide a slightly better seal than a chopped seal. Even if you are getting some water past the duckbill it would have to flow uphill through the hose (in most diving positions) and then pass through the mushroom valve at the mouthpiece. This means that the mushroom valve is equally at fault for water in the mouthpiece. The only advantage I see to a mushroom exhaust would be possible decreased resistance on exhalation and slightly increased longevity. There is a difference between testing a duckbill on a piece of hose and on a regulator. The regulator by definition equalizes the air pressure to the water pressure. and keep in mind as the pressure drops in the hose there is is more water pressure holding the duckbill closed. This has been my experience. -Ryan

[SeaRat]

Because of the pressure of the water acting at 90 degrees to the duckbill's opening, the waterpressure should seal these shut when not exhaling through them during normal diving conditions.

What can happen though, is that when installing the duckbill, the person installing them can get the valve twisted inside the case. This twist can artificially hold the valve open, and water can therefore enter. In our U.S. Navy School for Underwater Swimmers training (1967 in Key West, FL), we were taught to use a pencil (eraser side) to push the duckbill through the opening. Fold the duckbill out over the horn, and look inside. If there is a fold that can be seen, then hold it up to a light and look through the small holes in the bottom box. If it is twisted, it will be apparent as a large blob of material; if it is not, then you should see the valve in profile, going to a small slot. This is how it should be, and how it functions so well. It should lay directly over the diaphragm, in line with it, and completely flat against the diaphragm. Once it is in place, I usually try to inhale against it directly--it should seal and not allow any air through.

Now, once it is in place, you need to carefully put the hose on the regulator boxes. On the exhalation side, you need to ensure that the hose doesn't twist the duckbill. Once the hose is in place and clamped, again look through the bottom box's holes to ensure that the orientation remains flat. If it is twisted, you need to release the clamp and turn the hose to "untwist" the duckbill, then clamp it up again. You will now probably have to make the same turn of the hose on the mouthpiece, as this may off-balance the mouthpiece.

I hope this helps.

John

[duckbill]

It was never my intent to offend anyone either, Stuart. In fact, leakage really had nothing to do with my original question.
My leakage experience is apparently mine alone. I appreciate that the duckbills are available, but also realize that they may not always be around in the distant future. That is why I asked the question about the preservative effects of talc on latex duckbills (as opposed to butyl or neoprene or whatever material the other ones are). The reason for my question is because I would like to know if talc would help preserve latex for long term storage (as in years). Obviously, I do like your duckbills.

I realize that I got my own thread off track, so to get back on track:

duckbill said:

I think most of us here are well aware of the benefits of dusting rubber parts like our duckbills with talc to aid in preservation during storage; but, is there any benefit to dusting latex duckbills as well? I would think that the talc would help to keep the insides from sticking together, but what about actual preservation? Any harm in it?
Thanks in advance.