Aluminum Boat Restoration

My dad has an old aluminum boat we use for duck hunting. Its from the early '80's, made by a Central California company called Valco, which is no longer around.

Its a great size - 12' long and over 50" wide. All the flat-bottom Jon boats made now in 12' are 32-36" wide, and really only good for 2 people and gear, while this one is stable with 3 and a dog, so its worth repairing.

Valco boats are like Grumman canoes: thick aluminum made to aircraft specs from when America was Great Before. I'd take a riveted Valco or Grumman over a modern "welded" boat made from recycled Bud cans any day.

Unfortunately, I don't have any 'before' pics of the whole boat, but from the detail shots it'll be clear it needed a thorough restoration.

This project started when my dad said, "The motor seems a little wobbly. Can you take a look?"

I figured the bolts that hold the motor to the transom (the stern, reinforced with wood, that outboards are clamped onto) were loose, or rusted, or even a little stripped.

"Sure, no problem. I'll drag it home where I've got my tools."

Turns out, the whole transom was rotten. Not just rotten, it was basically dust and splinters. I have no idea how the motor didn't fall into the water and sink.

As I started removing screws, something funny happened - none of the nuts turned, but ALL of the bolts snapped. Stainless steel rusts like anything else, when its embedded in rotten wood. So after breaking off all the machine screws and letting the splinters fall out, I knew it was in need of some major surgery.

With a closer look, it was clear the plywood seats had also eroded to where they were mostly just sitting on the floatation foam inside the thwarts. Those would also need to go. The hull was breached in one spot right above the waterline, and about 50% of the paint was gone leaving shiny aluminum, which isn't great camouflage.

These old boats had solid 2-side rivets on the major hull seams, and blind rivets for the corner plates. Almost all of the blind (pop) rivets were gone, or at least had lost their flanges and had to be punched through.

I replaced all that weren't sound with new 3/16" aluminum rivets. Had to do some clamping and straightening to get them to go into the holes, but didn't want to drill any new holes so it was worth it. Drift pins FTW!

I had to borrow a friend's pressure washer because I don't know where mine is. Probably lent it to someone else. There is probably exactly 1 fewer pressure washers in the world than people who need them, so they all just get passed in an enormous circle.

I cleaned the boat inside and out, and took some time spraying hard at the seams to look for leaks. Didn't find any, but the stern seams (that transom again!) seemed suspect. Since the boat's almost 40 years old, I decided to seal all the seams and rivets anyway.

You always want to seal watercraft on the outside. Anything floating is creating some water pressure with its displacement. So if you seal the seams and rivets from the outside, that pressure helps the seals stay on. If you seal the inside, water will still exist within the seams, and the pressure will always be working to push the seals out.

I used paint-on Flex Seal (as seen on TV!) because it really works. Paint doesn't stick to it all that well, but if it gets scratched and exposed, it'll just be more camouflage.

I did shoot the flex seal with some Krylon Plastic Primer. It was a guess, and it didn't do much. Probably wouldn't bother if I did it again.

I had to fix the breach with some JB Weld. Love that stuff.

I painted the shiny spots with metal primer.

And then I coated the whole bottom with some spray-on pickup truck bedliner. It'll provide some abrasion resistance and protection, and actually reduces drag by breaking up surface tension as the water runs along the hull. Think golf balls or shark skin. Faster!

I bought 2 sheets of 5/8" marine-glued plywood. I really only had the square-footage needs for one sheet, but since all 3 seats are 16" wide, and 50" long, it wouldn't have left me anything long enough for the 50" wide transom boards.

I made a cardboard template from the old transom. It'll be 2 layers, glued together with Titebond before primer & paint. I decided to make it 2" taller than the old one, to give more support to the stern end of the boat.

After cutting, I test-fit the seats so I could mark the holes for their new hardware. Didn't want to drill any new holes anywhere if I didn't have to.

I primed and painted both sides of all the pieces of wood, even the sides of the seats which will be hidden. Primer is actually designed to hold onto moisture, which is why it holds paint on. But primed and unpainted wood (or anything else) is actually worse than leaving it bare.

I got the transom bolted in through all the same old holes. Added some stainless fender washers to the middle holes, where the wobbling engine had made the old holes into ovals.

I noticed that the old seats had failed along their ends. The long dimensions rested on aluminum thwarts, but the ends were hung from aluminum flanges. Since we mostly step from the dock onto the ends of the seats, having them hung from thin flanges would lead to new failures, so I decided to reinforce the ends from below.

I cut the edge of a pressure-treated 2x6 to the right angle to support the seats, and screwed pieces of it in inside all the thwarts. I just evened it up with the long aluminum flanges. Its not in contact with the floor or the sides of the hull, and it'll be protected by the seats above, so I didn't paint it.

I had to shorten the EPS foam a little because of the new seat supports, but the high density stuff fit right underneath where it used to be.

The holes I'd drilled lined right up and the seats went in with their new hardware without any issues.

Each seat also had a pair of brackets to reinforce the rim of the hull and keep the boat from twisting under load. These are 1/4" thick aluminum, which over time had completely welded itself to the stainless screws that held it on. First I soaked them in some rust remover for a couple of days, but that had no effect.

I ended up putting them in a vice and using a sawzall to cut off the screw parts flush with the back of the brackets.

Then with a drill press and progressively larger bits, I took out the screw heads from the inside until I could crack off what was left with a large phillips screwdriver. Fortunately, this worked well and I didn't damage any of the brackets.

I'd also pre-drilled the seats for these holes (1/4"-20 instead of #10 like the other hardware) and they installed easliy.

Back to the Flex Seal. Everywhere a piece of stainless went through wood or through the hull, I wanted to seal it to prevent another round of rust and corrosion welding.

When painting camouflage, you need 1 main base color (Oregano for me), a couple more colors for major breakup (Nutmeg & Leafy Green), and then some accent colors to look like shadows, movement, and foliage. You don't want to overdo it on the darker ones (especially in a marsh) but you do need some. I like Espresso, Hunt Club Green (same as marine Sea Green) and some thin stripes of black.

Thanks for reading and I hope you liked my Instructable!

Its entered in the Outside contest, so if you think its worthy, please give me a vote. Thanks!