How to fill small hole in back of transom?

I'm planning to replace the transom wood on my 12 ft boat at the end of this season. While I was taking measurements, I noticed a small hole in the aluminum on the very back of the boat. How can I repair this?

A temporary fix might be a machine screw, nylon lock nut, and a rubber-bonded washer. Washer on the outside with the rubber to the aluminum, lock nut inside, with an appropriate size fender washer under it.

Roger

Bubble gum works great. However, should that fail, you might want to try something like these offerings from Amazon.
https://www.amazon.com/s?k=hy-poxy+...ir+Kit,aps,1597&ref=nb_sb_ss_pltr-xclick_1_55

Nut and a bolt or a rivet would do just fine.

Sand it clean around the hole, then use JB Weld to fill the hole and feather it out around the edges.

That hole looks like corrosion, I'd want to get a better look at the inside of that transom to see how bad its corroded. Now is the time to stop it before its too far gone.
3M 5200 urethane sealer will seal that up too but its hard to get off for a more permanent repair later.
Be ready to deal with more of that sort of corrosion when you replace the transom wood.
Usually we see that on Lowe and OMC built boats of the late 80's and 90's due to the use of pressure treated wood in their transoms. Grumman, Sea Nymph, Lowe, and a few others were notorious for galvanic corrosion due to the copper content in the pressure treated wood then.

Nut and bolt with a rubber gasket/O-ring/4200.
Stuff a little ball of Water Weld epoxy in the hole and press it in until tight with only a little extra on the outside
Solid rivet
Blob of silicone.

Given it is all coming apart at the end of the season, just a dab of 4200 and an SS screw similar to one in the picture will prevent any more water intrusion. If it is above the waterline, just the 4200 will do on such a small hole. When you dis-assemble at the end of the season, will need to evaluate if it is corrosion and how ad the inside surface is.

mirrocraft16 said:

Sand it clean around the hole, then use JB Weld to fill the hole and feather it out around the edges.

That hole looks like corrosion, I'd want to get a better look at the inside of that transom to see how bad its corroded. Now is the time to stop it before its too far gone.
3M 5200 urethane sealer will seal that up too but its hard to get off for a more permanent repair later.
Be ready to deal with more of that sort of corrosion when you replace the transom wood.
Usually we see that on Lowe and OMC built boats of the late 80's and 90's due to the use of pressure treated wood in their transoms. Grumman, Sea Nymph, Lowe, and a few others were notorious for galvanic corrosion due to the copper content in the pressure treated wood then.

Click to expand...

My boat was made in the mid 90s, so I would not be surprised if the original transom wood is pressure treated. I'm doing research now, hopefully to be completely prepared and make the transom replacement easier. What do you think worst case scenario would be once I remove the old transom wood?

FuzzyGrub said:

Given it is all coming apart at the end of the season, just a dab of 4200 and an SS screw similar to one in the picture will prevent any more water intrusion. If it is above the waterline, just the 4200 will do on such a small hole. When you dis-assemble at the end of the season, will need to evaluate if it is corrosion and how ad the inside surface is.

Click to expand...

FuzzyGrub said:

Given it is all coming apart at the end of the season, just a dab of 4200 and an SS screw similar to one in the picture will prevent any more water intrusion. If it is above the waterline, just the 4200 will do on such a small hole. When you dis-assemble at the end of the season, will need to evaluate if it is corrosion and how ad the inside surface is.

Click to expand...

What do you think worst case scenario would be once the the transom wood is removed?

bikerider said:

What do you think worst case scenario would be once the the transom wood is removed?

Click to expand...

I don't see much use in speculating vs examining at the end of the season. Worse case is that there is allot of corrosion and it would need to be re-skinned. If you only have the one hole, think that is highly unlikely, though. The hole might not be corrosion or there is minimal corrosion that can be cleaned up and resealed.

bikerider said:

My boat was made in the mid 90s, so I would not be surprised if the original transom wood is pressure treated. I'm doing research now, hopefully to be completely prepared and make the transom replacement easier. What do you think worst case scenario would be once I remove the old transom wood?

Click to expand...

Depending on mfgr and quality of boat you have, there may not be any wood in the transom. My '92 Sylvan has an all aluminum transom. Smaller boats that use clampon motors often still have wood to give a better clamping surface.

mirrocraft16 said:

Sand it clean around the hole, then use JB Weld to fill the hole and feather it out around the edges.

That hole looks like corrosion, I'd want to get a better look at the inside of that transom to see how bad its corroded. Now is the time to stop it before its too far gone.
3M 5200 urethane sealer will seal that up too but its hard to get off for a more permanent repair later.
Be ready to deal with more of that sort of corrosion when you replace the transom wood.
Usually we see that on Lowe and OMC built boats of the late 80's and 90's due to the use of pressure treated wood in their transoms. Grumman, Sea Nymph, Lowe, and a few others were notorious for galvanic corrosion due to the copper content in the pressure treated wood then.

Click to expand...

I'm currently restoring my 1979 Lowe Lake Jon 1436. When I removed the old transom wood, I couldn't believe the galvanic corrosion that was there. The transom aluminum was full of holes and paper thin. I bought some 1/16" aluminum sheets and closed end aluminum pop rivets that I am going to sandwich the transom with. I also bought a piece of 3/4" white oak plywood for the transom replacement.

mirrocraft16 said:

Sand it clean around the hole, then use JB Weld to fill the hole and feather it out around the edges.

That hole looks like corrosion, I'd want to get a better look at the inside of that transom to see how bad its corroded. Now is the time to stop it before its too far gone.
3M 5200 urethane sealer will seal that up too but its hard to get off for a more permanent repair later.
Be ready to deal with more of that sort of corrosion when you replace the transom wood.
Usually we see that on Lowe and OMC built boats of the late 80's and 90's due to the use of pressure treated wood in their transoms. Grumman, Sea Nymph, Lowe, and a few others were notorious for galvanic corrosion due to the copper content in the pressure treated wood then.

Click to expand...

I'm currently restoring my 1979 Lowe Lake Jon 1436. When I removed the old transom wood, I couldn't believe the galvanic corrosion that was there. The transom aluminum was full of holes and paper thin. I bought some 1/16" aluminum sheets and closed end aluminum pop rivets that I am going to sandwich the transom with. I also bought a piece of 3/4" white oak plywood for the transom replacement.

FuzzyGrub said:

I don't see much use in speculating vs examining at the end of the season. Worse case is that there is allot of corrosion and it would need to be re-skinned. If you only have the one hole, think that is highly unlikely, though. The hole might not be corrosion or there is minimal corrosion that can be cleaned up and resealed.

Click to expand...

Yeah, true. I'll have to see how bad it is once the old wood's removed.

airshot said:

Depending on mfgr and quality of boat you have, there may not be any wood in the transom. My '92 Sylvan has an all aluminum transom. Smaller boats that use clampon motors often still have wood to give a better clamping surface.

Click to expand...

Interesting. I believe I saw a replacement aluminum transom for sale over on tiny boat nation.

Kim Taylor said:

I'm currently restoring my 1979 Lowe Lake Jon 1436. When I removed the old transom wood, I couldn't believe the galvanic corrosion that was there. The transom aluminum was full of holes and paper thin. I bought some 1/16" aluminum sheets and closed end aluminum pop rivets that I am going to sandwich the transom with. I also bought a piece of 3/4" white oak plywood for the transom replacement.

Click to expand...

That's a bummer. Are you worried about the structural integrity of the original aluminum, even after adding new aluminum around the new transom wood? I've seen several others talking about using white oak as their new transom wood. What are you planning to seal it with?

Kim Taylor said:

I'm currently restoring my 1979 Lowe Lake Jon 1436. When I removed the old transom wood, I couldn't believe the galvanic corrosion that was there. The transom aluminum was full of holes and paper thin. I bought some 1/16" aluminum sheets and closed end aluminum pop rivets that I am going to sandwich the transom with. I also bought a piece of 3/4" white oak plywood for the transom replacement.

Click to expand...

At least on most jon boats the transom wood doesn't cover the full transom, so structure wise its rarely an issue.
I'd have some concerns about doing the double panel type repair like that, water and contaminants can get trapped in between the old and new panels and cause corrosion as well.
Not only will salt corrode aluminum, but so will mineral deposits over time.
I'd use only buck type rivets and I'd bond the new metal over the old with an epoxy or some sort of metal adhesive The type that is often used to adhere auto body panels and door skins.
If all your dealing with is a narrow top transom panel, I'd likely just clean, sand or wire brush and then skim coat it with JB Weld or other suitable epoxy to seal and fill the pits, Epoxy needs to also be painted as most has little to no UV resistance.

Adding an unknown alloy reinforcement panel can also cause dissimilar metal issues and another source of galvanic corrosion. Some types of aluminum contain other metals in their alloy, which don't play well in corrosive or wet environments Various metals added to different alloys to ad rigidity can be a real issue when either in contact with other alloys.
Copper, magnesium, zinc, etc. are often what if found, ad in some saltwater and you create a crude battery of sorts.

Kim Taylor said:

I'm currently restoring my 1979 Lowe Lake Jon 1436. When I removed the old transom wood, I couldn't believe the galvanic corrosion that was there. The transom aluminum was full of holes and paper thin. I bought some 1/16" aluminum sheets and closed end aluminum pop rivets that I am going to sandwich the transom with. I also bought a piece of 3/4" white oak plywood for the transom replacement.

Click to expand...

Hey Kim Taylor, welcome to TinBoats. If you are going to skin over your compromised transom skin, the following link might be of interest:

https://www.tinboats.net/threads/tr...tarcraft-superfisherman-176.51160/post-508390

I hate to be a buzz kill -- Be careful if you are using cabinet grade white oak ply (which is the only oak ply I'm familiar with). It is great for cabinets, but not for exterior use. Better seal the heck out of it. Or, if not too late, return it in exchange for exterior grade ply (doesn't have to be hardwood).