fuel tank replacement

[greenpearl]

my 43t is in need of new fuel tanks since the aluminum ones which where new 10 years ago have corroded due to being installed in foam inside the original tanks. i am considering biulding fiberglass tanks so that they can be custom built in place to maximize size. does anyone have any experience with fiberglass tanks?
greenpearl

[mike]

Hi,

Yes I've built tanks for both water and diesel out of GRP, I recall there's a flow coat resin that is more resistant to diesel than standard polyester. I made ours by laminating GRP using a mixture of chop strand and what they call 'needle mat' her in the uk, the needle mat is basically a bulking type mat that produces quite a thick laminate by absorbing resin into its core but it does require bonding between conventional matt. I laminated the grp to an approx shape for each piece onto melamine faced chip board using a conventional release agent, then cut the panels to shape and bonded the corners internally and externally. Baffles were fitted then the tank was flow coated out with gelcoat. The top was made in 2 pieces, a rebated section the shape of the top of the tank about 3" wide all round the tank with the rebate the same depth as the lid, this lip was laminated into place then the top dropped into the rebate with gelcoat applied between the mating surfaces, the top then had a couple of layers of chop strand. Inspection ports were cut into the top an lids made from GRP fitted in place with hex head machine screws up through tapped threaded holes on the perimeter of each hatch the lid was made secure with an oil resistant gasket dropped over the studs and secured with nut/washers, you could use 'Henderson' water tight screw hatches instead. The secret is to post cure the tanks especially if using for drinking water, elevate the temperature in the tank with a couple of light bulbs to get it hot was a few days, this prevent any chance of styrene release into the fluid. I used the inside of the hull as the bottom of our water tanks, and included moulded in bilge drains running through the tanks.

If you send me your e-mail I'll post you an article with pics from PBO magazine showing the construction.

Mike

[greenpearl]

Thanks this is very helpful. I would like to read the articles you have. My e-mail is svgreenpearl@yahoo.ca

[mike]

Hi Greepearl, did you receive the pictures/article I sent you?

Mike

[greenpearl]

Thank you very much. I found the material very helpful. The suppliers here in Canada are hesitant to recommend their products for use on a diesel tank. West System recommends using epoxy but does not guarantee it will work. Another supplier recommended using vinyl ester resin instead of polyester, so I found it interesting that you used gelcoat to seal your tanks. The other problem I am facing is the issue of insurance. I haven't contacted a surveyor yet but the boat yard I inquired at said they didn't think home made GRP tanks would pass a survey. I will need to do more research before making a decision. Thanks again for taking the time to send those e mails.
Mike greenpearlū

[mike]

Yes I would agree with using vinylester resin,at the time I built our HC tanks which were for water vinylester was still hard to get in smaller quantities. I have made earlier tanks by using a ply carcass and glassing inside and out but regard solid GRP as better. Regarding insurance, my old yard successfully makes diesel tanks out of welded together polypropylene sheet using a Lester Hot air gun with a filler rod to weld the tanks together, the process doesn't seem too hard to do, this could be another alternative.

mike