Guest Joe90 Posted April 24, 2015 Share Posted April 24, 2015 Woke up to find water inside the van, it would appear the inboard ( good idea unless it leaks ) 120 litre fresh water tank has sprung a leak from somewhere, and it is definitely the tank , apparently a known issue with some Rapidos. So my question is has anyone successfully had a plastic tank of any kind welded, and if so by whom, thanks. Link to comment Share on other sites More sharing options...
lennyhb Posted April 24, 2015 Share Posted April 24, 2015 Search Google for "boat repair plastic welding", quite a few boat repairers can do it, or DIY kits available. Link to comment Share on other sites More sharing options...
Keithl Posted April 24, 2015 Share Posted April 24, 2015 Joe, Try CAK Tanks in Kenilworth. They make tanks for many manufacturers. http://www.caktanks.com/ Keith. Link to comment Share on other sites More sharing options...
Guest Joe90 Posted April 24, 2015 Share Posted April 24, 2015 Sadly not for Rapido, I spoke to them yesterday, and due to the complexity of the moulding sourcing one from Rapido seems the only option apart from a welding job that may or may not be possible, but thanks anyway Link to comment Share on other sites More sharing options...
Will86 Posted April 24, 2015 Share Posted April 24, 2015 Most plastics cannot be welded and unless they are attempted by someone specialising in it they would probably not be leak-proof. Vibration can cause fractures to a welded joint or repair. (Another of my past employment occupations making fume hoods for acid baths) It is / was carried out using a hot air gun by melting all parts at the same time and ... they often fractured later ! Try a glue but you would probably have to provided the type of plastic to achieve a result. Will PS It really depends on the leak, a simple hole is doubtful (use an old fashioned pot mender) or a crack (most likely unrepairable). Wear by rubbing unlikely also unrepairable. Link to comment Share on other sites More sharing options...
kevina Posted April 24, 2015 Share Posted April 24, 2015 I had to remove my Rapido tank in December and welded a repair before replacing it (posted on the MHFacts thread you have probably read). Since then we used it for 2 months skiing and all is well. The hairline crack on mine was at the bottom of the moulded in boss which takes the legs, so it was easily accessible to weld. I was expecting it to be in the top of the boss where the (very unevenly cut) top end off the leg finished. The tank now sits on some custom cut foam blocks; stress-free! I rotomould kayaks with the same materials and repair quite a few so am familiar with the work. I have a sequence of photos but don't have time to look them out until tomorrow. If you want to give it a go pm me for my phone number. Kev Link to comment Share on other sites More sharing options...
Guest Joe90 Posted April 24, 2015 Share Posted April 24, 2015 Kev that's very decent of you, I have literally spent all day stripping out the van just to get at the tank, a completely unbelievable job, they must have put the tank in first and built around it, the upside being it's a thoroughly well screwed together vehicle. :-S I've taken a good few pictures in case it is of help to anyone undertaking the same job if it should happen to others in the future, some below, the biggest problem being the double floor being slotted in to the "furniture" requiring it's complete removal, a nightmare, but on an older vehicle than yours I think, it is a 7087F model, 2005 vintage, although from looking at the tank ( now removed ) with some lengths of what looks like some old drain pipe for legs ( three of ) never come across a tank that has the filling point at the bottom, which is completely obscured from view when the tank is in situ, really scary stuff. It appears you need to subscribe to Mfacts but it looks an interesting forum, didn't know of it to be honest, happy to give it a go, but I would be very happy of you could tell me how you resolved your problem, or provide a link to your posts on facts, then I can register, what equipment you used and some pictures if it's not too much bother would be great, tearing my hair out at the moment, and I have very little left............ I've sent you a PM, very many thanks. ;-) Link to comment Share on other sites More sharing options...
kevina Posted April 24, 2015 Share Posted April 24, 2015 Link the the Motorhomefacts thread, early on there is a link to an earlier thread: http://forums.motorhomefacts.com/63-rapido-motorhomes/112238-water-tank-leak-7090-a.html Assuming your tank has the same leg support as mine, ie a bit of poorly cut plastic pipe shoved up into a moulded boss, this is what you may find. Although the top of the leg scored the inside of the boss I couldn't find the leak spot up there. What had happened is that 1) The boss moulding is too close to the outside wall (there should be a separation of 5x plastic thickness whereas it is only about 3x) leading to poor powder distribution in moulding and an inherent weakness. 2) the bottom of the leg (also poorly cut) embedded itself into the vinyl floor so when cornering/braking the tank had to flex at the weak point because the rest of the tank is free to move a bit. In preparation for applying an adhesive (will look up type) I "flamed" the inside of the boss to oxidise the polyethylene surface for better bonding, this glosses the plastic and makes it more transparent. Only then did I see the stress fracture that would seep water with load on the leg. (when I filled the tank on a bench (legs out) it didn't leak). You can see this in one of the photos. sorry, finished my cuppa have to get back to work. Kev Link to comment Share on other sites More sharing options...
Guest peter Posted April 24, 2015 Share Posted April 24, 2015 If it's high density polythene or polypropylene (most likely), it is possible to weld it. You cannot glue it at all or weld it yourself without the proper equipment. You need the welding rod the same as the parent material and preferably nitrogen gas instead of air to stop it oxidising. You can use air if gas not available. I have manufactured loads of tanks in a previous life as a fabricator. If you can find a plastics fabricator near you I would recommend you use them to do it. If you lived near me I could do it for you , as I still have my hot air gun. Do not try and glue it, it will not work. You may be able to melt it together using some strip of the same material and a clean soldering iron. Link to comment Share on other sites More sharing options...
kevina Posted April 24, 2015 Share Posted April 24, 2015 Hi Peter It is polyethylene, a standard tank grade and easy to weld. Since the crack was only hairline and would not be stressed again (with the new foam base) I used some ski repair strips. I use a gas pen with catalytic tip for welding, the hot gas exhaust doesn't contain much oxygen. The adhesive I mentioned is "Lexel", one of a few that will bond well to polyethylene. Kev Link to comment Share on other sites More sharing options...
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