Tuesday, July 12, 2016

No Epoxy 3rd World Strip Planking for Low Budget Dummies

The decadent 1st world method.... with epoxy...

Ain't no epoxy to buy down here in Mexico. And I have looked thoroughly in two state capitals now (Tuxtla Gutierrez, Chiapas and Oaxaca city, Oaxaca). Of course, as a somewhat bumbling gringo, I might be overlooking some industrial suppliers.

Why even mess with it? 

Strip planking afficionados herald a good quality, clear stock core glued between strips with epoxy then a liberal coating with fiberglass cloth and epoxy. Or even a further layering up with wood veneer cold molding strips or even a few more layers of thin plywood.

George Buehlers take on cheap core strip planking

George Buehler suggested ripping 2X6s in half for the inner core of this 64 footer. No glue or bedding between strips but roofing tar between the outer plywood layers. Then a coating of cloth and epoxy.

But let's go back to the poor, hapless, somewhat idealistic and hopelessly romantic 3rd world builder who can't get epoxy. This marine construction sinner needs a frickin BREAK. He has access to great cedar stock locally and for way cheap too. He could do a Chris Morejohn type polyester outer coating but, once again, why? Why mess with all the goo in the first place?

One logical point made by a seasoned boatbuilder stuck with me: all this edge glued stock, of possibly different densities and porosity, expanding and contracting, with a hard glue trying to contain all this. Something is going to move and crack that hard glue. Heavy fabric and glass might do the trick to keep it all tamed, or layers of ply a la Buehler.

Then I came across a forum post from another fellow deluded marine architecture obsessed dullard who asked for opinions on going epoxy-less. And a old hand weighed in to suggest the TRADITIONAL way of strip planking: no epoxy, no fiberglass, no outer coverings. Just the strips, bedded in thickened paint or a good waterproof polyurethane compound (PL Premium, etc). Here's his exact reply:

#1- Have you gave any thought to planking the boat in the traditional strip planked fashion, instead of some form of sheet planking. Very solid and sound, simple to do, easy to get materials. You can use the P.L.Premium and ring shank boat nails either in bronze or 316 stainless.On the outside, sand it and give it a good coat of cuprinol, a few days to dry good and followed by several thin coats of a good oil based paint, like maybe kirby's. No epoxy and no fiberglass cloth.On the inside, clean it up and coat with cuprinol, thats it, install drain plugs and floor and sides, no need to do more.

Then other folks supplying stories of the longevity of similarly stripped craft with service lives well into three and four decades with no leaks, no separations, etc.. Just the occasional repainting with oil based paint. The wood strips are allowed to swell and move as they will but essentially are nailed with ring shank nails on 6" centers by staggering the nailing schedule and insuring nail lengths that go through 2.5 strips.

I would add that hard chine boats seem even better suited to such a method due to each strip seating essentially flat with the strip below it and thus sealing even better with whatever material is chosen between strips. And, overall, it is a ideal way for a single builder to work with relatively small pieces that won't herniate you like chuffling around 4X8 sheets of ply. Frames can exist on 2 to 3 foot centers thus quite economical of frame stock overall. Strips can be scarphed traditionally or even with a sufficiently deep birdsmouth joint:

I'd double plank the bottom and perhaps stagger the layers and maybe even go diagonally with a nice bedding of roofing tar between the bottom layers. But this might suffer on a really wide bottom, like a scow or a barge unless sufficient stringers were laid in.

Food for thought for those poor dough headed, 3rd world mired, hopelessly romantic boat builders who can't get epoxy locally and don't want to pay the astronomical freightage to get it south of the USSA. And who can take advantage of the fine, raw, local stock of quite nice wood. And are dunderheadedly oblivious to the ravages of marine borers.

It's always SOMETHING, aye?