Topic: ballast bladder (Read 7124 times)

nautilus · « **on:** October 27, 2018, 01:10:36 pm »

hi all
im after a 800ml/1000ml rubber bladder one tube version if possible
anybody know where I can get one or similar
in the uk?
many thx

pettyofficernick · « **Reply #1 on:** October 27, 2018, 10:19:46 pm »

I was about to ask the same question.

Fred Ellis · « **Reply #2 on:** October 28, 2018, 08:31:40 am »

Hi

Try a child swimming arm bands.

thegrimreaper · « **Reply #3 on:** October 28, 2018, 10:55:19 am »

try a blood monitor cuff chemists sell the cuff seperately

Mark

nautilus · « **Reply #4 on:** October 28, 2018, 11:01:19 am »

Quote from: thegrimreaper on October 28, 2018, 10:55:19 am

try a blood monitor cuff chemists sell the cuff seperately

Mark

hi mate thanks will try that
cheers

pettyofficernick · « **Reply #5 on:** October 28, 2018, 12:24:17 pm »

Good call Mark! I will be visiting Daughter in hospital this afternoon...Hmmmmmmmmm

Fred Ellis · « **Reply #6 on:** October 28, 2018, 06:40:17 pm »

Hi

I recall one of the members of the AMS made one from some tights wrapped around a milk bottle and liquid Latex.

Pull one of the tights leg over the bottle, then paint the latex onto the covered bottle, twist the leg and pull back over the bottle and paint more latex onto the bottle twist again, do this until you have a few more layers, leave until dry, after a few days drying cut the end off and remove the bottle now make an end cap, you now have a flexible contain that will always return back to it's originally shape.

Have fun trying

Fred

Paxton · « **Reply #7 on:** October 29, 2018, 08:12:35 am »

Have you considered an intravenous saline bag? Your local NHS establishment may be able to help you out with that. I think they have 500 and 1000 cc bags. A windscreen washer pump works well with them.

Fred Ellis · « **Reply #8 on:** October 29, 2018, 04:45:59 pm »

S.H.G. did them they may still have some,

Tel 01785 840308
Email info@shgmodels.com

Fred

pettyofficernick · « **Reply #9 on:** October 29, 2018, 06:19:45 pm »

many thanks...

Fred Ellis · « **Reply #10 on:** October 29, 2018, 06:36:32 pm »

Hi

Sorry if I have missed just why you need them.

Would you be using them as part of the ballast system as used in the old Darnell type system?

Fred

pettyofficernick · « **Reply #11 on:** October 29, 2018, 07:55:27 pm »

Basically yes. Not got funds for piston tanks and all the other fancy stuff. I needed smelling salts after I looked at Engels website!

Fred Ellis · « **Reply #12 on:** October 30, 2018, 08:57:30 am »

Hi P.O nick

have sent you a P/M

Fred

Subculture · « **Reply #13 on:** October 30, 2018, 06:22:29 pm »

If you make a hard tank, you can create any volume you choose, and you don't have to worry about them splitting.

Martin (Admin) · « **Reply #14 on:** October 30, 2018, 07:42:36 pm »

What about something like this?

https://www.ebay.co.uk/itm/Horobin-Drain-Air-Bag-Canvas-4-6-9in-Options-Inflatable-Pipe-Blocking-Bung/251992980321?hash=item3aabf3bb61:m:m4o76S7uXCblEab-ugc759A:rk:1:pf:0

https://www.ebay.co.uk/itm/Horobin-Drain-Air-Bag-Canvas-4-6-9in-Options-Inflatable-Pipe-Blocking-Bung-/251992980321?var=

Subculture · « **Reply #15 on:** October 30, 2018, 08:14:26 pm »

Bags can be a pain in the ar5e, you're really better off avoiding them if possible. Some boats are difficult to avoid using one without significant modification- the Thunder Tiger Neptune is one that springs to mind, but if you're building something up from scratch, do yourself a favour and make a hard tank.

pettyofficernick · « **Reply #16 on:** October 30, 2018, 09:53:45 pm »

Drain bung looks good, thanks Martin.

How does a hard tank work> Is it a sort of free flooding tank that air is pumped in to for buoyancy, similar to the real thing?

I have a 1 meter length of 90.. acrylic tube, I was going to chop it in to 3 pieces, forward one for pump, bow planes radio etc. Middle one as a ballast tank with the air bag inside to control buoyancy and the rear one housing motors, battery rudder and rear plane servos. I intend 3D printing end caps and equipment trays in ABS.

Subculture · « **Reply #17 on:** October 30, 2018, 10:11:17 pm »

Pretty much. There are various ways of implementing a ballast system. You can pump air or pump water- each method has its own pros and cons. Some systems compress air inside the tank or inside the module at various different pressures, others vent to the atmosphere through a vent or snorkel mast, once again there are pros and cons to each.

Davy1 · « **Reply #18 on:** October 31, 2018, 09:02:53 am »

Hi All,

All systems have good and bad points (cost, complexity etc.) There is a good review (link below) which gives the + and - :

http://associationofmodelsubmariners.com/pages/Divingsystems.html

David

Subculture · « **Reply #19 on:** November 02, 2018, 11:13:18 am »

Many of the descriptions refer to systems from twenty years ago, and things have moved on. Some of the descriptions are misleading e.g. vented tank systems need larger hydroplanes and can use more power? Apparently compressed air ballast systems have expensive parts, not these days with mass produced pumps available from about £1.50p.

pettyofficernick · « **Reply #20 on:** November 03, 2018, 12:28:24 pm »

So, here is the ballast tank. I will probably go for a pumped water type system using a windscreen washer pump, solenoid operated valve.

TomHugill · « **Reply #21 on:** November 03, 2018, 12:53:28 pm »

Quote from: pettyofficernick on November 03, 2018, 12:28:24 pm

So, here is the ballast tank. I will probably go for a pumped water type system using a windscreen washer pump, solenoid operated valve.

What's the tank originally? It sounds like your going for a high pressure system so I needs to be robust enough to take the pressure. Are you bonding the end on? What baffles are you using? That's a big tank and without them the sloshing effect will be terrible.

pettyofficernick · « **Reply #22 on:** November 03, 2018, 01:24:38 pm »

The tank is 90mm acrylic tube with a 3 mm wall thickness. End caps are 3D printed in ABS and will have neoprene gaskets and M3 tie rods holding it all together. Baffles will be made the same way as end caps.

pettyofficernick · « **Reply #23 on:** November 03, 2018, 01:58:41 pm »

I seem to have posted 3 photos of the same thing. Could an admin please remove?

thegrimreaper · « **Reply #24 on:** November 03, 2018, 02:15:22 pm »

I don`t think the OP is using the whole tube as a ballast tank Tom I read that he is going to cut it into 3 pieces so there will be slosh but will be easier to control with a couple of baffles.

Mark

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Author Topic: ballast bladder (Read 7124 times)