In Search of a Gunnel Repair Solution

[Guest]

Willie, what material are the seat hangers? It is hard to tell in the photos if they are rusty or painted.

If they are steel or some ferrous metal and the pop rivets aluminum perhaps there is some galvanic corrosion going on, aided by a salt water environment.

Another possibility, perhaps Swift used steel pop rivets for the seat hanger attachments. A magnet test should provide the answer.

 

[Will Derness]

Willie, what material are the seat hangers? It is hard to tell in the photos if they are rusty or painted.

If they are steel or some ferrous metal and the pop rivets aluminum perhaps there is some galvanic corrosion going on, aided by a salt water environment.

Another possibility, perhaps Swift used steel pop rivets for the seat hanger attachments. A magnet test should provide the answer.

The hangers appear to be steel and the rivets aluminum. A vigorous wiggle of all the other stays revealed them all to be firmly secure.

One failed seat hanger rivet seemed to have discoloration like rust, the other was clean looking. Salt water for sure is very nearby and the hull bottom has some long linear scratches like maybe someone dragged it over an oyster bed.

I'm thinking one rivet failed due to corrosion/weight of the paddler and then the other failed due weight.

Fabric Issue -- Kevlar based upon the yellowish/honey color of the underlying cloth and the canoe weight (45 lbs on my scale). The serial number is all numeric, no K lettering in it.

Just finished putting on new handles, painters, tie off loops and lacing. Awaiting seats and yoke. Ready to paddle with ugly gunnels, seat, and yoke, but it does paddle, and quite nicely as a solo.

 

[Guest]

QUOTE=sailsman63;n33560]Not sure that that looks like anodized to me, either, though I am not an expert. I Believe that it is way to thick. (One aluminum finishing source I found on the web was quoting .0008" as a rather thick anodization.)

That being said, I have run across several references to anodization flaking, though no good photos. Most of these cases involve either overheating/stressing or 7000 series aluminum (high strength. Would seem to be a good candidate for gunwales. Also tends to corrode, and your bare aluminum is corroded a bit)
[/QUOTE]

I had a firsthand look at the Otter gunwales, which is always more revealing than guessing from photos.

They are not anodized. Way too thick

And the material doesn’t appear to be vinyl cladding. Too paper thin.

They appear to be painted. With some seriously tough paint. Willie ran an RO sander and 220 grit along the still intact painted sections without getting down to the bare aluminum. If it is paint I’d love to find out what; it is tenacious as heck and seems darned scrape proof.

Much as I hate to admit that Willie was right I think painting them is the way to go.

Which brings up what paint and primer?

I can see using aluminum primer on the bare, exposed sections of gunwale, but I’m not sure if etching primer is advisable atop the still painted sections.

The scrape proofieness of any paint on gunwales is another guestion. Spray Rustoleum is not very scrape resistant

I do have to say that the hull itself is nearly pristine. Nice boat.

 

[Jim Dodd]

I wonder if it might be powder coating ?

The High School shop teacher here, purchased a powder coating kit from Harbor Freight. I saw just a few things they did with it. Seems like it might have been a baked on finish.

Jim

 

[Guest]

I wonder if it might be powder coating ?

That may be the best guess yet and possibly explain how the coating could flake/peel off in some places and yet remain impervious to sanding in areas where it is still well adhered. MRC powder coats gunwales.

I know that powder coating can be removed with acetone or methyl chloride, but so can paint. I wonder if there is some evidentiary way to determine if something was powder coated?

 

[sailsman63]

I wonder if there is some evidentiary way to determine if something was powder coated?

A quick google returned this little article

Seems powder coating is usually thicker than paint, and the fact that this coating is smooth, rather than orange peeled suggests that t would be on the thicker end of a powder-coat finish. (source: wikipedia)

Removal in that case should be a standard paint stripper, left on for a longer time (binders in powder coat are more resistant to solvents, since they never had to be dissolved in one)

 

[Guest]

The first drop I grabbed to unscrew came away from the canoe and was just hanging in air supported by the other 3 drops. The two rivets holding that drop to the gunwale had sheared. Since I paddled the bow seat I hadn't noticed it either time.

Quick work to drill them out and install new rivets. Quick in my shop, another story on the river.

That would make me suspect of every other seat hanger rivet at the least

Willie should tell the rest of that (another) story on the river.

I will say that I wish that I had been there. I will also say “Moi?”. Not me, I’m too smart to….er….well…maybe not.

I was paddling a just completed refurbishment, a fiberglass MRC Explorer*. The wood frame seats were slightly bent from years of use and abuse, but I re-used them.

Sanded, revarnished, replaced the tattered cane with webbing. I had one seat clamped down to the bench, stretching the webbing taut, when I heard a short, sharp crack. There was no visible damage, so I finished the webbing and installed the seat.

That first trip out my companions were in playful mode. I had surreptitiously removed the drain plug from a friend’s kayak and was filling his boat with bailer water when he caught me and a chase began.

I was doing my best to escape when there was another sharp crack and I was suddenly on my back, legs in the air, looking at the sky.

The first shop crack was one biscuit on the old, bent seat frame joint breaking when I clamped it flat. The second crack was the other biscuit giving way as I tried to escape justice.

Having caught me helpless his revenge was sweet. Or at least very wet.

*That Explorer was a dumpster-ready freebie, an early glass boat from MRC Waitsfield. It is still going strong 20 years later as a friend’s thoroughly abused poling boat. Those glass boats from the original MRC were built tough.