Stuart As John says above, don't get conned into "sloshing" the leaky tanks, as that solution is temporary at best, as the resin used for sloshing will not bond to the tank due to dirt and contamination inside the tanks.
As Mike says opening the tank, cleaning and sealing the tank is the only correct method. One trick you can try on an Astir is to put a little pressure on the tank (125 mm water gauge, the same as AD 165) and use soapy water and try and find the leak, Astir tanks are not very long and I have found one leak on the end rib around the front drag pin mounting, which had become porous some how., or use the trick Mike suggests with the water and stethoscope , you can usually locate the area of the leak with in a 100 mm radius. If you manage to find the leak, open up the tank with a oval hole just big enough to get your hand in , clean the tank thoroughly with scrubbing brush, wire brush, or what ever it takes to clean the scale etc out, wipe thoroughly with acetone, stay away from any areas that have polystyrene though,(Astirs are OK, mainly cirrus.) with chemicals that might dissolve the Styrofoam as some manufactures use this in fillets etc. or on the leading edge as seal the wing halves before joining. then paint liberally with Duram 195<http://www.duram.com.au/productdetail_var11var21var33>- Liquid Polyurethane Waterproofing Membrane, as far as you can get around the opening , but keep a little area around the cut hole clean with masking tape so a joggle can be fitted after the sealer has set which takes a couple of days , don't forget to seal the back of the joggle with the Duram, glue in the joggle and conduct a standard repair and close up the wing. I have never failed to fix a tank by this method, but it is time consuming and messy, expensive if not a labour of love ! I fixed a standard Cirrus once that took 6 holes per wing as I sealed the whole tank, and there are baffles in the tank which means holes each side of the baffles ! Also the obvious must be said, that you are putting holes in the "D" box in the wing, which is a structural repair, and should only be tackled by a authorised repairer with a Major repair rating in FRP. Kind Regards Chris Runeckles On Mon, Oct 28, 2013 at 6:32 AM, John Orton <[email protected]> wrote: > Stuart et al, > > Mike is right. I have seen the inside of tanks where they tried to seal > them by pouring in a resin mix to coat the inside andget it to seal. It was > a mess with sheets of resin peeling away from the inside skin. > I have leak detected several tanks using the method Mike describes and > found that often the leak is in a corner at the end of the tank or where > there is a baffle attached to the skin i.e. at a discontinuity. > > Regards, > John Orton > > > > On 28 October 2013 06:04, Mike Borgelt <[email protected]>wrote: > >> Stuart, >> >> The only rally satisfactory way I have heard of is the method invented in >> WA many years ago. Put a little water in the tank, put a little suction on >> it and listen for the air bubbles with a stethoscope. You need to roll the >> wing around to to get the water over the leak. >> Then use a hole saw, cut a hole and do a standard repair. >> Nowadays you may be able to put a little camera in the tank with a light >> to see what needs doing through a smaller hole first. >> >> Mike >> >> >> >> >> >> At 09:12 PM 27/10/2013, you wrote: >> >> Hi all, >> >> Can anybody recommend a product and method to seal an integral wing tank >> in an Astir cs. >> >> Cheers >> Stuart >> _______________________________________________ >> Aus-soaring mailing list >> [email protected] >> To check or change subscription details, visit: >> http://lists.internode.on.net/mailman/listinfo/aus-soaring >> >> ** >> >> ** *Borgelt Instruments* - *design & manufacture of quality soaring >> instrumentation since 1978 >> * www.borgeltinstruments.com >> tel: 07 4635 5784** **overseas: int+61-7-4635 5784 >> mob: 042835 5784** **** **: int+61-42835 5784 >> P O Box 4607, Toowoomba East, QLD 4350, Australia >> >> _______________________________________________ >> Aus-soaring mailing list >> [email protected] >> To check or change subscription details, visit: >> http://lists.internode.on.net/mailman/listinfo/aus-soaring >> > > > _______________________________________________ > Aus-soaring mailing list > [email protected] > To check or change subscription details, visit: > http://lists.internode.on.net/mailman/listinfo/aus-soaring >
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