fuel tank mounting

[maru222]

i have a 80 lt s/s underfloor petrol tank which needs re-installing into bottom of my f/glass boat.it was just sitting on the bare f/glass skin (same shape) and secured with ply and f/glass batons.
i would like to see it 5mm off floor to allow water to pass by and run away too bungs
silcon beads f/glass strips, strips of rubber, marine ply ????

any ideas would be great

regards davo

[bigjimg]

Get a cheap cutting board,nylon one,use a holesaw around the 50mm size to cut out some discs.Space these out inside your fuel tank space and use the hole in the center of the disc to fix down on a bed of sikaflex.Make sure that the screws are countersunk so not to rub a hole in the tank.Jim

[Goochi]

I had my alloy 150 lt under floor tank out to check it out. It's been there for 25yrs. It was just bedded down on some large blobs of silicon that were about 5-7mm thick. I put it back the same way. I've tried rubber matting before but it moves around and nothing I know of really sticks to it to permanetly hold it in place.

[deckie]

Only problem with the cutting board material mounts and sika is that sika wont glue it...very little apart from the specialist stuff will glue polyethylene to anything, let alone strong enough to be a fastener mount. All it will effectively act as is a caulking and not as a fastener base. If u have a large surface area in contact it might hold tho. Prob more secure to just sika the tank down, good stuff to have in contact with the metal tank if u can use it as some sort of a liner material on any mount used. From what i understand some of the silicones over time can cause corrosion with metal too...but just a matter of getting one of the right ones i guess.

[deckie]

How about some nitrile rubber maybe ?? ..then strap it down again.

[Hagar]

G'day Davo

I had the same issue with my new alloy tank that went in . I ended up going to the big local bakery and bought for next to nothing ( think it went to the Xmas party fund ) some damaged plastic bread trays and used the bottoms secured in with Sika . Seems to drain OK and no probs so far .

Chris

[bigjimg]

Only problem with the cutting board material mounts and sika is that sika wont glue it...very little apart from the specialist stuff will glue polyethylene to anything, let alone strong enough to be a fastener mount. All it will effectively act as is a caulking and not as a fastener base. If u have a large surface area in contact it might hold tho. Prob more secure to just sika the tank down, good stuff to have in contact with the metal tank if u can use it as some sort of a liner material on any mount used. From what i understand some of the silicones over time can cause corrosion with metal too...but just a matter of getting one of the right ones i guess.Deckie the Sika is purely a gasket seal for the screw and bedding medium for any lumpy bits in the glass,Not much will stick to any plastic material as most is self lubricating.Jim

[maru222]

i am heading towards silcon shaped blobs ,so they will not hold water. maybe the aquarium silcon (it is pretty damp under my floor,condension ,cold nights/hot days is keeping it wet )alot of silcons dont like continuous wet damp
will then batten down with Nema polymer board
thanks for your input guys, hope to make little video on my boat project at some stage, will put links up at later stage
regards davo