RCABS custom bladder

[adriaticsea]

Hi everyone,

I'm fitting the RCABS in my 1/96 Thor Permit, and I noticed that, due to the most unique configuration of my WTC, a commercial bladder will not be under the boat's projected waterline, and thus much of its volume will be wasted and will produce no lift to the boat.
I'm quite experienced in repairing bicycle inner tubes and thought that maybe I can build some custom made bladders tailored to the exact spatial configuration and volume I want.
I'm going to cut off the valve section of a inner tube and clamp its ends in order to seal them with rubber vulcanizing product.
Then real problem is how to have two openings in the bladder to le enter the two air tubes. One of the opening is pre-made (I'll use the valve itself without the closing mechanism) but I don't know how to do the other hole. I was thinking of cutting another valve from a different inner tube and glue it on the bladder, but I'm not very sure of sealing & strenght under pressure.
Does anyone have any thoughts on a possible solution?
Thanks in advance,
BEST REGARDS MAURO



Edited By AdriaticSea on 1147542593

[Guest]

Mauro,
I folded the cut ends

Mauro,
I folded the cut ends of the inner tube, and glued and clamped them, with metal bent over the glued ends. If you don't want to use a second tube with its valve body, you could seal one end the same way, and glue in a rubber laboratory cork (with a hole for a glass tube built in it) in the other end. Then just glue a brass tube in the hole in the cork. It should hold well.
Or, the original oversized bladder could be considered as having reserve buoyancy and allowed to remain, or you might want to replace it with an infant sized bladder.



Edited By Art Broder on 1147546526

[crazy ivan]

Mauro,

One thing to know about

[color=#000000]Mauro,

One thing to know about RCABS (or Reverse RCABS for that matter) is that the bladder is not really under much pressure relative to the outside environment, unless you inflate it to the point where it stretches (which should not really be necessary). So the bladder does not need to be extremely robust or elastic. With this in mind, I have been making my own custom bladders for the past year. Here's how]



Edited By Crazy Ivan on 1147564993

[adriaticsea]

Hi Crazy Ivan and Art,

thanks

Hi Crazy Ivan and Art,

thanks very much for the answers, I find them really useful to solve a problem that was becoming really upsetting for me.
Crazy, I like your idea, but I don't fully understand the material you are using to realize the bladder. From what I have in my kitchen, I found that something similar to a sturdy clear bag is the one we use to seal food that is to be put into the freezer. Perhaps this will work? What is the plastic bag form a box of wine?
Thanks in advance,
MAURO

[tmsmalley]

In North America, Spain, Italy,

In North America, Spain, Italy, and Australia several wineries sell wine in cardboard boxes.

The boxes are lined with a sturdy plastic bag with an on / off valve to dispense the beverage. The bag collapses as the wine is dispensed which keeps air from oxidizing and ruining the wine when it is stored over a period of time.

This plastic bag material is what Crazy Ivan is talking about.

See the following website for a list of wine brands that might be available in your home area.

Boxed Wine Website

[crazy ivan]

Thanks for the clarification, Tim.

Thanks for the clarification, Tim. Although I personally prefer the 5 liter size (bigger bladders, better unit pricing, longer lasting satisfaction) Maybe we should ship Mauro a case (unopened, of course).

Mauro, your freezer bag may work. The only way to know for sure is to give it a try. If it fails, your only loss is just a few minutes of your time.



Edited By Crazy Ivan on 1147617171

[adriaticsea]

Hi Crazy and Tim,

thanks very

[color=#000000]Hi Crazy and Tim,

thanks very much for the information, now I understand very well what you're taking about. I didn't know that there was a plastic bag inside those dispensers, though.
I browsed the site that Tim linked and I found that sometimes the bags appear to be covered by a silver-like outer skin. Is this kind of material fusable?
And, Crazy Ivan]

[Guest]

Mauro,
Just wish her a happy

Mauro,
Just wish her a happy Mother's Day, let her drink the wine, and she won't mind if you ruin the iron!
These guys know they can use a bicycle tire inner tube. They just need an excuse to empty the plastic bag in the box of wine.

[crazy ivan]

Art, Art, Art! Your insight

Art, Art, Art! Your insight is sometimes frightening!

Mauro, yes, contact and pressure are necessary to fuse a good seam. I also use a firm base, like a wood board, to work on. A regular ironing board is too soft to get proper pressure. I use just the edge of the iron, and keep the iron moving. So far I have not had the bag melt to the iron. I don't have experience with the silvered material. I use the clear type. As a bonus, this allows you to see if any water has leaked into the system when you use it.

[Guest]

One ingenious soultion I once

One ingenious soultion I once observed for a custom bladder, was a bag made from a piece of net curtain soaked in latex rubber.

Looked ever so ornate, and worked rather well.

Just don't cut a hole in the lounge curtains!

Andy

[adriaticsea]

Hi everyone,

Art, I'd like to

Hi everyone,

Art, I'd like to see some pictures of how you realized your custom bladders from bicycle inner tube...it would be useful for me to see how you clamped the end and how you bent the metal around the clamped ends.
Thanks in advance for the courtesy,
BEST REGARDS MAURO



Edited By AdriaticSea on 1148321725

[Guest]

Hi Mauro,
This site will not

Hi Mauro,
This site will not accept my post with a picture.
I cut the inner tube to the desired length including the valve. I then put rubber cement inside the cut ends, folded them over once and glued the folded ends down. Then I bent a piece of aluminum bar around the ends to further secure them. See photo on my web site- last photo in RCABS pictures folder. http://groups.msn.com/ArtBrodersmodels/ ... hotoID=298My]http://groups.msn.com/ArtBrod....=298]My Webpage[/URL]

[adriaticsea]

Hi Art,
thanks very much for

Hi Art,
thanks very much for the answer, the picture si very celar and explains well how to do the custom bladder. One doubt though-I see you use only one valve to inflate/delfate the air chamber...how can you use it as a 2 way valve? Using this system (three custom bladders with three valves connected to asingle tube) would greatly simplify the fabrication of the bladder and would eliminate the risk of leaks from another additional valve.
I guess you use a "Tee" fitting, but I can't find them in Italy, can you pleas explain me what they really are(and where I can find them?)
Thanks,
BEST REGARDS MAURO

[Guest]

Mauro,
In the past, I got

Mauro,
In the past, I got "T" fittings from an aquarium shop, (used on aeration lines). Now I get fittings from automotive supply stores. They are used to connect windshield washer hoses.

I use the "T" fitting inside the WTC to connect to the pump and to the air release valve. I use the "T" outside the WTC to send the air to multiple bladders,(2 in my Flying Sub). That way, there is only one penetration needed through the end cap.



Edited By Art Broder on 1148341160

[tmsmalley]

Here's Art's photo of his

Here's Art's photo of his bike tube bladder. I downloaded it from Art's site, put it on my SC webpage and linked it to this reply.