Afloat at last

periscope · 23-01-2006

Got my Seawolf set up in the test tank today - there's a total of 2lbs weight to ballast it. Glad you told me about the air valve Chris - I've had quite a job getting a good seal at the rear of the test tank - the air valve was ideal for blowing into while the sub was afloat, then I could spot where the air bubbles were from. The gasket on the WTC seems a bit of a tight fit and a lot of the elasticity has gone out of it due to stretching tight over the rim - I found that by adding a couple of thin rubber bands with the gasket really made things airtight (and more important watertight) I seem to remember some time ago reading on one of the forums that someone changed to a 90mm gasket instead of the 85mm supplied - I wonder if that worked better -

Anyway tomorrow I've just got to add the fins on the sail then I'll have to think about a colour scheme. Many thanks to all those who helped with tips and advice - much appreciated.

Ian.

ajg141 · 24-01-2006

Good to see the finished product Ian. I usually put a smear of vaseline round the O-ring before tightening everything up. It's managed to keep the water out so far! Also just a little air should go in through the valve - the first time I tried it I used a bicycle pump and blew the O-ring out! I have disconnected the front plane dive mechanism to test out the theories we discussed earlier but the weather (and a holiday) have prevented any tests so far. Hopefully I'll be able to se what happens this coming weekend. Report to follow.

Andrew

adzam · 24-01-2006

looks good ian.

glad you`ve not had many problems with the build and i`m looking forward to the finnished product.

i would take andrews advice and just apply a small smear of grease, but make sure it`s rubber friendly . a good idea is too have a couple of spare seals and bellows just in case, they`re obtainable drirectly from robbe.

Mankster · 24-01-2006

Don't use Vasline on the orings, it usually destroys them over time. Silicone grease is the prefered choice for this.

periscope · 24-01-2006

Hi All - thanks for the replies - afraid I hit a snag this morning - I filled the bath again and tried the sub again but couldn't totally get rid of the air leak - I tried various combinations of rubber bands and I was tempted to use some vaseline or similar - but decided to not use any grease until I heard from you experts... anyway after about six attempts I managed to strip the thread on the front of the tray....... so I decided that I would do what I heard of a few months ago and fit a larger sized bolt with a washer and wingnut, and do away with the long rod. I've managed to get the old bolt out by drilling a series of 1mm holes along the length of it then using a craft knife to saw through the lot. I've got a new bolt setting now in the gap so I'm on dry land again until I've finished all the glueing. While I've got the thing in bits again I've been checking to make sure that the tray goes in evenly into the WTC - it does because without the gasket the tray goes up to the front of the sub and the rear bung (with the tail section on) fits snug up to the WTC. When I get seaworthy again I'll just have to detach the bow section top to tighten the wing nut but that doesn't take too long (I'm a flippin' expert at that bit by now) and I did fit an on/off outer rod at the tail section so I'll put the battery in, tighten everything down at home and then switch the RX on when I get to the club pond. Anyway I've got Vaseline and Silicon grease so I'll give one of those a try - I'm relieved to hear that you guys use it as well, 'cos this means that it isn't as simple as Robbe make it sound to get the seal watertight. In the instructions they do say to make sure that there isn't an air leak but they don't suggest what to do if there is one..... I really do appreciate all your comments guys and I'll give you a report as soon as I get in the test tank again.

Thanks a lot.

Ian

ajg141 · 25-01-2006

Interesting info about the silicone grease. I've used white petroleum jelly for the life of the sub - since the kit was first introduced and that must be about 15 years ago I think. Haven't had a problem with the O-ring so far! Maybe I've just been lucky and it'll go next week. However I do refer to everyone's greater knowledge of these things. I'll change to silicone grease if & when this one goes!

Andrew

Mankster · 25-01-2006

There are specialist lubricants a plenty for O rings, depending on the what material your oring is made out of - Nitrile, polyurethane, PTFE, Silicone, etc. If its a radial or axial seal, and if its static (say a lid) or dynamic (say a pushrod seal). Also if your prime considerations are lubrication, seal itegrity, temperature range etc.. For our purposes Silicone grease is best bet (for non silicone orings - if its a black oring then its probably not silicon - silicone grease will cause silicone orings to swell). There are better ones but pricey and harder to come by. Remember the other material also that the grease comes into contact with. Petroleum based grease will craze and crack some plastics in no time, while silicone grease is pretty inert.

periscope · 26-01-2006

Hi Ramesh - Thanks for the info - I've got the sub back in the test tank and pleased to say that there are no apparent leaks. I must admit I had to use Vaseline this time just to experiment with, now I seem to have it cured I'll get my local model shop on the trail of a suitable grease. One of our club members ownes a model shop in Goole, I'm sure Andy will be able to get me something suitable - I've already ordered spare O rings from him. I'm going to leave the sub in the bath for about an hour to see if there's any ingress of water - if all is still OK then I'll be looking at some sort of paint job. Our club pond is about the size of a swimming pool but it's only 3 feet deep maximum and not too clear because it's topped up from the dockside. For this reason I'll be looking at something bright - I don't know if you saw the TV program about the Russian sub that was rescued recently but that sub was red and white vertical stripe bands in about 3 metre sections - I might go for something similar but red and yellow bands 7 inches wide.

Thanks again mate,

Ian

Mankster · 26-01-2006

IMHO I always felt the Seawolf in black made it look more like a real mordern nuclear sub. http://www.marinerc.net/submarines/seawolf.htm
You could always use a bright coloured aerial pipe as a scope to make it easier to spot under water, and remove it when the sub is on display.