Aluminium diesel tank sealant

[webcraft]

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My (old) aluminium diesel tank was leaking from three pinholes along a weld at the bottom. The affected section was cut out and new material welded in, and the tank was cleaned out. I then painted it (aluminium primer plus Rustoleum) and was going to put it back in the boat.

However, a friend who restores vintage m/cs has advised that using one of those slosh-about tank sealants as a belt and braces solution might be a very good idea.

Has anyone on here used one of these products (Flowlinter, POR-15, Slosh etc) on an aluminium diesel tank, and what sort of a result did you get?

- W

[Pete7]

Using it in an old petrol motor bike tank is one thing, but a used aluminium diesel tank? how are you going to get it clean enough to stick if the tank has previously had diesel in it?

I have previously recovered an old aluminium jet drive by sticking it in a bucket of diesel and leaving it submerged for the winter. The diesel did an excellent job of working its way into all the fittings.

If the chemical stuff doesn't adhere and comes away will it clog the pick up pipe and filters?

Pete

[model 10]

If it were a gas tank it would be easier but with diesel I would only use an aircraft sealant suitable for jet fuel.

[webcraft]

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Why is it so much harder to clean out a diesel tank than a petrol tank?

[model 10]

It's not so much the cleaning. Fuels like diesel and jet will leak past almost anything. The sealant needs to be pretty good and made for that purpose.

[Fuss]

then put the sealant on the outside

[Pete7]

Just pressure test the tank and see what happens, either it will leak or hold a pressure. If it leaks then more repairs or call it a day and scrap it.

Pete

[a64pilot]

If you want or need or seal a fuel tank, then for goodness sake use a fuel tank sealant, aircraft Jet fuel is very close to Diesel and these products are used to seal new and used aircraft fuel tanks, many aircraft wings are actually the fuel tank, and hundreds of rivet holes etc need to be sealed, it is messy and not inexpensive but it works.
http://www.aircraftspruce.com/menus/...ksealants.html.

As a general rule there are two types, type A is thinner and like 5200, type B is thicker like silicone caulk.
Type A is thinner and will run into a crack say but won’t stay on the side of a tank, type B is thicker, doesn’t run and has a tendency to stay put better, it’s about like peanut butter.
Then there is a number that corresponds to the working time, usually from 1/2 to 2 meaning 1/2 hour or 2 hour.
Likely 90% of what is used is B2.

[P3sailor]

I believe A64 is speaking about a product similar to PR1422A or B. Don't get the 1422A 1/2 or B 1/2 unless you feel the job will be under 1/2 hour. Once the stuff starts to set up it's almost impossible to apply. Clean the areas thoroughly with MEK prior to applying, if you opt to go with B you can use a little MEK to thin the product but use it sparingly.

If the facility doesn't have PR, they may carry Pro-Seal which is a similar product. Wear gloves when working with this stuff, it can get messy and is difficult to remove from the skin.

As with anything, prepping the surface is important, if not, the stuff may not adhere or seal your tank.

[P3sailor]

To add to this PR 1422 is a two part sealant, no need to mix it all at once, but make sure you get the ratios fairly close to what is recommended.
Also, 1422B is pretty "stiff", more so than peanut butter, "A" has the consistency of honey or molasses.
Tape off the areas you want to seal and apply with a tongue depressor.

[model 10]

Also the catalyst is a carcinogen and I challenge anyone to use this sealant and not get some on your fingers.

[Pete7]

Surely this is just sticking plasters on a wound. Its a small aluminium tank that needed repair so probably at the end of life if it still leaks. The simple and cheap option is just to put a poly tank in place and be done with it. £60 and an afternoons work.

Pete

[tkeithlu]

In response to the forgotten question above "Why is it more difficult to clean diesel tanks than gasoline tanks (or similarly worded)." Diesel has a flashpoint (the temperature at which it gives off a flammable gas) of about 150 F, while gasoline's flashpoint is about -40 F or C (being the same). Therefore the remaining diesel in the tank after you have scrubbed it out is not going to evaporate, unless you heat it above 150 F, which could create a whole new set of problems.... Diesel is going to hide in the very crevices you are trying to clean. This is the same reason that the ABYC rules on diesel are so much easier than for gasoline -- a drip, drip, drip of gasoline in your bilge can create an explosive mixture. Following a bit of creative idiocy on my own part my wife and I pumped, filtered, and returned to the tanks about 100 gallons of spilt diesel from our engine room.

[johnrid123]

we have same issue, cleaned with usual detergent then dried and abraded, then used garage floor sealer paint, 2 pack, resistant to all petro chemical types, still, ok after 8 years,

[johnrid123]

had to make access though, large square holes and fabricated sealing lids which bolted back in place, allowing opportunity to get in to clean and then paint all round etc