Qestion on pre-treating this hole in the aluinium transom?

[Expidia]

So I have this hole for the past few seasons which is at least way above the water line and now I'm seeing probably the wood of the transom through it. So I'd like to finally address it.
I bought this expensive stuff (like $92 for a 1.8 lb can from my boat dealer) called Gluvit. It's a 2 part waterproof epoxy resin sealer. Designed specifically to seal leaky aluminium seams.

My rig is a 2007 Lund which I bought new and it's now 17 years old. Past few seasons I'm pumping out a gallon or so of water from the bilge pump over the course of a days outing, especially when just sitting around in a cove for a few hours.

I've filled the boat 1/2 way with a garden hose last season and found several places where it's slightly dripping out.

It's dripping at two places along the seam where the transom meets the bottom of the boat and one where an aluminium cap from the bow join cap that runs to the back of the boat. I asked my welder if he could run a bead of weld along that transom edge leak and seal it. He said he can't because Lund uses a rubber gasket in that area and welding will melt it.
He recommended using 3M Urethane Seam Sealer. This stuff actully worked pretty good for a few seasons. He said it does not harden, so it last a long time.

But I'm going to scrape it off, sand it and try this Gluvit that my boat shop swears by.
But in reading the instructions on the can and thinking I can patch that hole in the aluminium too . . . the first thing it says is to fill any holes with Marine-Tex.

I don't mind picking up some Marine-Tex but my concern is if I just fill it in won't there be continuing galvanic corrosion going on under the patch deepening the hole further?
Is there some type of pre-treatment that I might swap into the pictured hole before I apply Marine-Tex?

Thanks

 

[racerone]

Need to do more than a little patch on that hole..---Make a plate about 1 foot wide to cover the rotten aluminum.

 

[Expidia]

Need to do more than a little patch on that hole..---Make a plate about 1 foot wide to cover the rotten aluminum.

Before I would do that I'd bring it to a body shop and see if they can replace the back of the transom. This is the only place on the boat that has a few spots where the paint is bubbling. My guess is it's due to some type of galvanic action?

It's also around any of the hardware like the transom hold down hooks etc.

 

[Expidia]

Title reposted with spelling corrections (thx a lot Siri) Question on pre-treating this hole in the aluminium transom . . .
Looks like this forum only allows edits for a brief time period???

So I have this hole for the past few seasons which is at least way above the water line and now I'm seeing probably the wood of the transom through it. So I'd like to finally address it.
I bought this expensive stuff (like $92 for a 1.8 lb can from my boat dealer) called Gluvit. It's a 2 part waterproof epoxy resin sealer. Designed specifically to seal leaky aluminium seams.

My rig is a 2007 Lund which I bought new and it's now 17 years old. Past few seasons I'm pumping out a gallon or so of water from the bilge pump over the course of a days outing, especially when just sitting around in a cove for a few hours.

I've filled the boat 1/2 way with a garden hose last season and found several places where it's slightly dripping out.

It's dripping at two places along the seam where the transom meets the bottom of the boat and one where an aluminium cap from the bow join a cap that runs to the back of the boat. I asked my welder if he could run a bead of weld along that transom edge leak and seal it. He said he can't because Lund uses a rubber gasket in that area and welding will melt it.
He recommended using 3M Urethane Seam Sealer. This stuff actully worked pretty good for a few seasons. He said it does not harden, so it last a long time.

But I'm going to scrape it off, sand it and try this Gluvit that my boat shop swears by.
But in reading the instructions on the can and thinking I can patch that hole in the aluminium too . . . the first thing it says is to fill any holes with Marine-Tex.

I don't mind picking up some Marine-Tex but my concern is if I just fill it in won't there be continuing galvanic corrosion going on under the patch deepening and widening the hole further?
Is there some type of pre-treatment that I might swap into the pictured hole above before I apply Marine-Tex?

Thanks

 

[airshot]

Years back I picked up an old leaky Jon boat in a field. Ribs were worn thru and numerous leaky rivets and some corrosion pin holes. Did some searching and found a product called " leak stopper" available thru home depot and tractor supply. It is a clear roofing sealer that is fairly thick but remains plyable after curing. It is brushable and dries clear. I put a good heavy coat in each rib followed by a couple heavy coats on the outside. No leaks to this day and it gets dragged over a sand and stone beach. I painted over with rustoleum enamal , have had no issues in over 8-9 years. No signs of any corrosion and no signs of lifting or peeling. Just some food for thought here !!