A bit of background first on our Eureka. It was a rushed and rough build over 8 days for my son’s 13th birthday in Nov 2011, using whatever I could find from local hardware stores. Choice of materials was dictated by local availability of materials and time constraints rather than an attempt to save money. Though as I go about this refurb any previous savings are out the window. Lack of experience comes into play of course. Since this was my first boat build I made some poor choices against good advice or instructions and as I’ve stripped paint and epoxy back I’m left shaking my head at some of my handiwork, muttering to myself, “what the hell were you thinking”.
The need to refinish was brought about by cracks appearing on both sides of the hull, but particularly on the bottom panel and then bilge panels after a year of service. To my mind it’s directly the result of the use of inferior ply and poor application and choice of epoxy.
Firstly the ply was 3ply 4mm CD bracing ply instead of 5 or 6mm marine recommended. Apparently it does have an A type bond but didn’t last the boil test, a small piece delaminating within an hour from memory. Regardless of bond type, you can imagine that voids or defects in any of the plies reduces it’s thickness by a third and subsequently its strength. Although the canoe is solid, certain areas of the bilge and bottom panels in particular have been able to flex enough under stress to crack epoxy. Water has subsequently penetrated and contacted the ply
Secondly, the epoxy I used was the kind that requires a few drops of hardener for every 100mls rather than a 2:1 or 5:1 type epoxy system. My main issue with the former is it’s a pig to sand, clogging up any kind of abrasive I’ve tried to use on it. It also produces amine blush and the smell is overwhelming. The Mrs can’t stand it but I don’t mind it. Doesn’t make me dizzy but at the same time it makes you think it can’t be good for you. The BoteCote I bought is completely different. 2:1, no real smell, sands easily and cure time’s not so fast as the hardware store bought stuff. Really enjoyed using it.
Regarding improper application of the old epoxy – too thick on non glassed areas. I taped seams only and encapsulated bare wood with three coats, but my method of coating was like using pour-on-gloss. Even when spread about, the three coats ended up too thick compared to what one should do. At it’s thinnest it was 1mm, from a post from PAR some time ago, 0.5mm should be a maximum. After some early cracks appeared I rubbed back and applied some epoxy as repair and painted the external hull with a thick layer of external vinyl paint. But the cracks returned, showing up through the paint and water contacted the ply in a few spots.
Cracks showing through the paint
http://i1097.photobucket.com/albums/...ps76964ee2.jpg
http://i1097.photobucket.com/albums/...ps58a485c2.jpg
Gunwales have been knocked about a bit too from the oars and from being stored inverted. Just needing a sand and recoat, no real damage.
http://i1097.photobucket.com/albums/...psb3ad98c2.jpg
Just one of a few areas that've been affected by water ingress. No real damage apart from staining.
http://i1097.photobucket.com/albums/...ps7e413b1b.jpg