Patching a hole above the waterline

[DianneB]

My 21' Sylvan was a fishing boat with a factory-installed live-well which I removed. It drained through a plastic fitting mounted in the hull just above the waterline. Removing the fitting will leave about a 1-1/2" diameter hole that I want to close up.

I am thinking the best patch would be to rivet another piece of aluminium to the inside with Permatex #2 as a gasket/seal.

Is there a better way?

(My background is in steel but I am not up to welding aluminium!)

Thanks guys (and gals).

Dianne, that will certainly work but so would simply capping the fitting that's there now. You can't find another use for that hole? If not, my vote is for welding but we have a density of aluminum welders here - it may not be the same there but if I trailered the boat to a welder, I'd be out of his shop for 25bucks.

[Fanie]

Alu welding is an art to do. Spend the couple of bucks to get it fixed professionaly, it will be worth it.

[DianneB]

I have a friend a few miles away who is an accomplished welder - the only one I have ever seen who can cut an aluminum beer can in two and then weld it back together - but it isn't worth the hassle. I think I will just cap it and leave it for the time being. Maybe do a permanent plug when I am ready to repaint the hull in a couple of years.

(I have built/rebuilt/repaired just about everything over the years, from airplanes to bulldozers - and steel boats - but this is my first aluminum can LOL!)

[alan white]

Alternative--- get some JB WELD epoxy (auto parts). Make a disc to fit in the hole (pilot-less hole saw using wood block with hole to guide/clamps) and a larger square backing plate to put behind the hole, of same weight aluminum (sheet metal shop) as boat.
The backing plate can be nice and large (3x3 inches). Sand all gluing surfaces with 50 grit paper. Glue on the backing plate. Afterwards, glue in the disc (for cosmetics), Sand (thru several grits 100-1000 then buffthe outside.
Welding is great too, but it requires boat be moved twice, a good welder, and some distortion can possibly occur. I'd guess welding would cost $25 to $40 depending on location. JB WELD repair would cost under $10.
What is seen is a gray ring, barely noticable