I've used the hell out of my 13' Sportspal square stern canoe since I first got it new in late July 2002, and it has been a fine craft. I use it a lot in the estuaries, and I have taken it into Puget Sound a couple of times.
If you are unfamiliar with Sportspal canoes, they are made of aircraft aluminum stretched over a form and then strengthened with extruded aluminum ribs. A 1/2" thick foam pad covers the inside of the hull, held in place by the 25 (on my 13' boat) ribs. The foam insulates, makes the hull quiet, and provides floatation.
I had coated the bottom with Gluvit so I could slide over the rocky riffle sections on streams in low water, as the aluminum hull was really "grippy" on the rocks.
Lately, I had noticed that the gluvit was getting bubbles of air pockets popping up randomly all over the hull. Were there tiny pinholes in the Gluvit, letting moisture in? I couldn't see any, so I chipped and sanded all the bubbles away, noticing that there were pinholes all the way thru the hull where the bubbles were.
Uhh-Oh! I deconstructed the boat, taking out the seats, ribs, and foam, and found what I had feared that I would. Sand, salt, and mud had worked its way under the foam and had become trapped down there. The hull was getting corroded thru from the inside. All that sand/salt/mud doesn't just wash out with a good hosing, as the ribs hold the foam tight against the inside of the hull, trapping all that bad stuff, which does its dirty work sight unseen, until it blossoms forth at an inopportune time. Now I am faced with a major repair job.
I washed and scraped most of the scale out, then polished the rest of the surface corrosion off with a wire brush on my electric drill. I'm over halfway done with this polishing phase. Took some time. There are a few hundred, maybe a thousand, small pits in the thin aluminum, but if I "etch" the aluminum with a mild acid solution (white vinegar) to clean the surface and the pits, patch the actual holes, and coat the inside with something to fill in all those pits, and then refinish the outer hull, I can probably still use this boat...in LAKES and FRESHWATER rivers.
I'm thinking of using "Coat-it" on the inside. Its what I'm using to refinish the outer hull as well.
I was wondering if there was some sort of polyurethane product which might work, as the stuff is tough and more flexible than Coat-it, but I dont know how well that would stay bonded to aluminum. That "hardened aircraft aluminum" doesn't like coatings. Anyone know anything about this kind of stuff?
If you use your Sportspal canoe in the salt, this may happen to yours as well. I don't know about you'all, but this sounds like work to me...work that cuts into one's water time. I won't be using this boat in the salt or brackish waters again, once I get it fixed.:beathead:
If you are unfamiliar with Sportspal canoes, they are made of aircraft aluminum stretched over a form and then strengthened with extruded aluminum ribs. A 1/2" thick foam pad covers the inside of the hull, held in place by the 25 (on my 13' boat) ribs. The foam insulates, makes the hull quiet, and provides floatation.
I had coated the bottom with Gluvit so I could slide over the rocky riffle sections on streams in low water, as the aluminum hull was really "grippy" on the rocks.
Lately, I had noticed that the gluvit was getting bubbles of air pockets popping up randomly all over the hull. Were there tiny pinholes in the Gluvit, letting moisture in? I couldn't see any, so I chipped and sanded all the bubbles away, noticing that there were pinholes all the way thru the hull where the bubbles were.
Uhh-Oh! I deconstructed the boat, taking out the seats, ribs, and foam, and found what I had feared that I would. Sand, salt, and mud had worked its way under the foam and had become trapped down there. The hull was getting corroded thru from the inside. All that sand/salt/mud doesn't just wash out with a good hosing, as the ribs hold the foam tight against the inside of the hull, trapping all that bad stuff, which does its dirty work sight unseen, until it blossoms forth at an inopportune time. Now I am faced with a major repair job.
I washed and scraped most of the scale out, then polished the rest of the surface corrosion off with a wire brush on my electric drill. I'm over halfway done with this polishing phase. Took some time. There are a few hundred, maybe a thousand, small pits in the thin aluminum, but if I "etch" the aluminum with a mild acid solution (white vinegar) to clean the surface and the pits, patch the actual holes, and coat the inside with something to fill in all those pits, and then refinish the outer hull, I can probably still use this boat...in LAKES and FRESHWATER rivers.
I'm thinking of using "Coat-it" on the inside. Its what I'm using to refinish the outer hull as well.
I was wondering if there was some sort of polyurethane product which might work, as the stuff is tough and more flexible than Coat-it, but I dont know how well that would stay bonded to aluminum. That "hardened aircraft aluminum" doesn't like coatings. Anyone know anything about this kind of stuff?
If you use your Sportspal canoe in the salt, this may happen to yours as well. I don't know about you'all, but this sounds like work to me...work that cuts into one's water time. I won't be using this boat in the salt or brackish waters again, once I get it fixed.:beathead: