Need some help with repair of my gas tank on my 1939 P8 Business coupe. I had it boiled out and welded recently to patch leaks, but it still leaks profusely. I am thinking about fiberglassing the lower half or just replacing it by buying a new one. Would appreciate some suggestions from someone who has gone through this before. If I can salvage the old one by fiberglassing it, I would like to, but I don't know if patching it that way is safe or smart. Please reply.
1939P8
There are several different brands of gas tank sealer that you can get fairly resonable. I used POR 15 gas tank sealer and am very pleased with the results. It also had leaks after being repaired. As for Fiberglassing it, I would recommend using POR 15 sealer. It's easier to do and it is designed for that purpose. I also coated the outside. It states on the can it will seal small holes. Fiberglass may be okay, but it your leaks aren't that bad, I would just order sealer and do it that way. Otherwise you could take it to a place that does that and have them just put in the sealer. It could get a little pricey though.
http://por15.com/PRODUCTS/FUELSYSTEMRESTORATION/USSTANDARDFUELTANKSEALER/tabid/112/Default.aspx
1939.....I'd like to 'strongly' suggest that you take the tank to a local radiator shop for repair, as they......if you can find a good one......will have the correct tools and know-how to make a proper repair of your tank.
If you really wish to do it yourself, the correct repair is to use sheet metal of the same thickness as the tank, either brass or steel, and solder patches where appropriate.
******Fill the tank full with water before using heat on a fuel tank. Even tho a tank may be empty and have been blown out completely dry with air, there will be hydrocarbons sticking to the walls of the tank interior which will be driven off by heat, and will.....believe this or don't......form an explosive mixture with the ambient air in the tank.......this is no joke. Fill the tank with water, plug the filler, and rotate the tank to bring the working area upright******
Fibre-glass and 'gas tank sealers' are a bad idea......sometimes you can 'get lucky' in repairing small leaks with fibre-glass, but thats purely a gamble.....sometimes the fibre-glass adheres well, sometimes not. The 'gas tank sealer' products are basically a scam......sometimes they will adhere for a long time, sometimes they flake off and clog up the fuel line.....again a gamble, but your fuel tank doesn't really need to be 'sealed'.......if its rusty inside, shake it with sand inside to remove the rust, or send it to a specialist firm who can use a phosphate dip system.........or get some 'metal-prep', a phosphate material, mix it with water, and leave the mix in the tank awhile to chemically neutralise the rust.....if you use sand or metal-prep, wash the tank out thoroly before re-fitting it.
As a generality, tho, its really best just to send the tank to a reliable radiator shop to be tank-cleaned, pressure-tested, and any pinholes properly repaired with soldered patches....its 'cheap at the price', really, to have proper repairs made by someone who knows the work.
cheers
Carla