Banner Ad 1

Has anyone tried this? - Water-proof test method

Post your favorite modeling 'tips' and 'tricks'

Postby Captain Nemo12 » Fri Mar 04, 2005 11:28 pm

Hello all,

After reading Helmut Berghaus' website (chap who built a Krick U-25), I found out about his method of testing the water-proofness of his sub's hull (I assume the Krick kit doesn't not have a wtc, the hull is a dry compartment; dryhull) he did this by installing a syringe on top of the wtc cover and a bike valve on another side of the wtc. By using a bike pump and pumping air into the wtc through the bike valve, the air fills up the compartment and eventually builds up pressure to push the syringe piston outward, indicating that there is no air escaping out. However, if the the opposite happens, it means that air can escape out. My thinking:

Air can't go in, water can't go in, air goes in, sub is doomed! :D

Wonder if anyone has ever tried this and proven that it is useful. I have a 4 ft long u-boat to be tested and a bathtub might be too small to test it in. I just want to know if this is useful in testing the wtc on dry land, without getting your feet wet (I like getting my feet wet, this is an exception... nearest lake or pond is 4 miles away from my house :( )

Thanks for any help! :)

Link to Helmut Berghaus's website:http://home.wxs.nl/~bergh601/submarine/index-en.html
280 meters.... and she's still in one piece!
-Jurgen Prochnow, Das Boot.

http://eisernwolf.blog.com
User avatar
Captain Nemo12
Registered User
 
Posts: 293
Joined: Sun Sep 14, 2003 3:56 pm

Postby TMSmalley » Fri Mar 04, 2005 11:54 pm

Air leaking slowly out of a pressurized WTC doesn't necessarily prove it will leak water.

On an RC submarine, the pressure is on the outside not the inside. In fact some watertight compartments (most?) need the pressure of the water pressing on the top plate forcing it down onto the gasket to create the seal.
Tim Smalley
User avatar
TMSmalley
SubCommittee Member
 
Posts: 2487
Joined: Fri Feb 21, 2003 8:58 am
Location: Edina, Minnesota USA

Postby Bob the Builder » Sat Mar 05, 2005 1:37 am

I suppose it would be more effective to suck the air out of the WTC to create a vacuum inside the WTC. That's what I did to test my WTC after I got a small leak at one of the power terminals. I sucked the air out through my antenna tube, and then quickly plugged it off again. I'm not sure what the vacuum registered at, but it was pretty significant. I then stuck it underwater for an hour or so to check if it leaked. It did, and I could see the droplet trail leading right to the culprit.
Bob Martin,
RCSub homepage: http://www.rc-sub.com
User avatar
Bob the Builder
SubCommittee Member
 
Posts: 782
Joined: Fri Feb 21, 2003 9:40 am
Location: Naples, FL

Postby Captain Nemo12 » Sat Mar 05, 2005 12:12 pm

Thanks for that advice guys, sometimes air can go through spaces water cannot penetrate in, I figured that if one could do his best to seal the wtc from air getting in/out, water would have a much less chance of getting through. But could this method still be trusted in testing the wtc?
280 meters.... and she's still in one piece!
-Jurgen Prochnow, Das Boot.

http://eisernwolf.blog.com
User avatar
Captain Nemo12
Registered User
 
Posts: 293
Joined: Sun Sep 14, 2003 3:56 pm

Postby Carcharadon » Thu Mar 10, 2005 8:21 pm

I use watertight chambers made of PVC pipe. There are only wires going into and out of it. Whenever I work on the components I check to see if there are any leaks by pressurizing the watertight chamber and looking for leaks by putting it in the bathtub. There are actually bubbles coming through the insulation over the wires. I generally put a drop of superglue over the ends of the exposed wire. I have installed a valve stem from an automotive tire. I use a bicycle pump to pump it up a couple of times. Probably 25 psi. If there are no leaks it goes back in the sub. Method works good, subs have been deep (30ft) no leaks.



Edited By Carcharadon on 1110500733
User avatar
Carcharadon
Registered User
 
Posts: 300
Joined: Fri Feb 21, 2003 9:10 am
Location: Savannah GA


Return to Modeling Tips and Tricks

Who is online

Users browsing this forum: No registered users