Fuel tank patch

[pfhoeycfi]

I accidentally drilled into my tank between the fuel fill and vent...about a 1/2 from the edge of the vent fitting. The drill did not go thru but went about an 1/8 inch into the tank material. Is there any type of fill or epoxy that I can use on the "hole" just in case? Or should I just get a new tank?

Peter

[Chigbee]

I recently had a similar experience where I drilled through the tank when routing some wires.

I am told one could weld the tank. Here's one resource:
https://www.polyvance.com/fenderwelder.php#:~:text=Polyethylene%20is%20a%20%22thermoplastic%22%2C,rod%20and%20base%20material%20together.&text=Because%20of%20this%2C%20our%20PE,any%20color%20of%20base%20material.

Because I drilled through my tank I decided to buy a replacement; I wasn't positive I could make a good enough weld through the thickness. I'm going to try the repair just as a learning experience. HarborFreight sells a plastic welding kit, it gets mixed reviews though. I plan on using a simple soldering iron.

In your position I think it'd be worth a try. If you spend a few minutes on youtube looking up plastic kayak repairs you'll get the idea pretty quick. Let me know what you end up trying. I'll let you know how my repair attempt goes.

Chris

[peter anson]

Fuel tank sealants such as Desoto PR1422 and Proseal adhere quite well to the plastic fuel tanks. It would probably be best to roughen the surface slightly using abrasive paper so that it can key in. I successfully patched a leak from one of the fuel tan fittings 7 years ago using PR1422. I have heard of Proseal being used successfully too. The PR1422 is described as a "sulphide curing rubber" so any of those sorts of sealants should work.

Peter

[pappas]

If you pressure test the tank to no more than 5 psi and the partial hole you drilled does not fail, you are probably ok leaving it alone. Your tank is vented and it is unlikely that you would ever build enough pressure in it to make the spot fail.

If you are uncomfortable with it and just can't leave it alone, you could install an oops fitting from Sonex and simply cap the thing off. I added one to the aft, upper, starboard of my Waiex B tank. I installed the oops fitting and an AN elbow with a cap. The purpose was to have a transfer port pre-installed in the event I ever added a supplementary fuel tank. The oops fittings work well and I have not seen any leaks.

If it passed the 5psi test, I would likely leave it alone.

[pfhoeycfi]

I will research the welding but I'm likely to make a mess of that. I'll also take a look at the sealant Peter recommends. I thought of the Oops fitting but the spot is very close to the vent oops. I would need one smaller than the vent size...they'd be sitting side by side. I will def do the pressure test.

Does sonex make the oops or do they source them?Perhaps I could find one similar but smaller...
This is def one of my biggest blunders to date...
Thanks...

Peter

[Bryan Cotton]

An oops fitting is a large head hollow bolt with threads inside. Rather than use an oops fitting, an option would be to grind flats on a bolt, and use it to seal the hole with a gasket inside. Potential pitfalls are the same as the oops fitting - you need a flat sealing surface else it will leak.

I'd pressure test it and let it go if it passed. I thought nothing adhered to the tank but if pro-seal or a similar product actually works, as reported, that is a good option. I'd use it to glue on a circular patch of aluminum to give the adhesive more surface area.

[DCASonex]

As others have said, if it does not leak with moderate pressure, leave it alone or simply fill the hole with one of the sealants mentioned. Assuming it is a small 1/8" hole, it should not be subject to any stress in that area.

If it does leak or you just want to do something with it, make your own "oops" fitting. Drill the hole the rest of the way through. Put an O-ring under the head of a small bolt and pass it through from the inside then put a nut and washer on it. If you use a #10 (3/6") or larger, bolt, take one about 3/4" long, and grind flats on two sides of the last 1/4" of the threaded part, then drill small one through that flat. You can then thread a string (fishing line works well for this) down through your hole in the tank, draw it out through the fuel fill, tie it through the hole in your bolt, and pull the bolt (with O-ring) up through the hole in the tank. Install the washer and nut and tighten using the flat on your bolt to keep it from turning as you tighten the nut. That would allow you to use an elastic stop nut, or a castellated nut and cotter pin, but probably will have to take your bolt back out to drill the hole for the cotter pin once you have determined the proper location for it.

David A.

[pfhoeycfi]

If it does leak or you just want to do something with it, make your own "oops" fitting.

Good idea. I'll do the pressure test and if need be do the bolt oops. Would a std cad AN bolt work or should it be stainless or other?
I'll look around for some fuel rated o rings I'm sure spruce has them.

thanks

peter

[DCASonex]

Stainless steel would be best, considering that the location in question is near top of tank, it will be mostly out of the fuel and thus subject to rust.

David A.