Re: [bolger] More on Building a boat for the Navy in Gloucester
- Neal, I'll agree that all in all I'm not yet where I need to be. But inquiries and selling plans are part of 'the deal'.
I surely will breath easier when the boat-project is happily launched and working. Just a bit longer yet...
Then it will be on to designing in earnest again and the books.
In the mean-time, sharing processes, setbacks, successes remains the focus of this Forum.
Susanne Altenburger, PB&F----- Original Message -----From: philbolger@...Sent: Wednesday, April 25, 2012 4:41 PMSubject: [bolger] More on Building a boat for the Navy in GloucesterOn the Use of Epoxy
There may be different ways of using and applying epoxy to build up a decent thickness. We went with all WEST. Typically gravity-applied. No vacuum-bagging or other exotics.
We used 10oz glass-cloth over all outside surfaces, 2 and 3 layers of 10oz glass-cloth over all hull pieces below sheerline, with all episodes/pieces with the weave soaked level, not the glass sanded-down. Ergo most thickness per layer of glass. We sanded epoxy-ripples - not glass-cloth.
This was possible by building everything (!) from smallest to biggest panels in pieces on tables/across horses. Flat everything, and typically finished horizontally to at least a solid first coat of final paint. No drips or runs in paint or epoxy. Gravity as your friend. With epoxy leveling out to near perfection - but never without a few bubbles here or there; as Phil would say "the gods would be jealous..."
Heavy epoxy coat on all inside surfaces. Plus along much of her topsides closed-cell foam plus ply with epoxy in between everything.
We got better at wet-in-wet epoxy + glass + epoxy sequencing for a manic but single episode efforts to get the lamination down. Full-length hull-bottom in one shot was strenuous and required 3 folks plus 1 on the big-$$$ #309 5:1 gear-pump. No such work without the 309. Pays for itself as the sticker-shock wears off...
And no rollers, disposable or alu. A few 1" cheapo brushes for selected vertical and horizontal cleat-fastening during assembly into 3-D structure for applications. Ergo limited use of acetone for cleaning.
Average shop-conditions, limited budget, with reasonable 'back-up' provisions, such as the aforementioned double-skinning of all outer hull-surfaces against eventual dramatics, should glass-shredding gouges go unattended. Rot should at worst only travel half-depth. Taking out/grinding off damaged/rotting/offending patches/sections of the first layer would not be a terrible challenge to then re-laminate to re-establish full skin-thickness.
One way to do this. And it does indeed take a lot of epoxy.
But we traded 'costly' thickness built-up fast horizontally for costly man-hours doing 6 coats with its wiping and sanding regimes each time and 'hanging upside from the rafters' while likely eventually burning through the same epoxy-bill.
There sure seems no way to go 'green' boat-structurally here in the North-Eastern US while slicing tropical woods - whatever the pious 'sustainably-sourced' claims plus the inevitable carbon-footprint of transport. Lucky for folks in the Northwest of the US.
Eventually, New England will be doing its own regional marine-grade plywood again to avoid trans-continental ply-trucking/rail-voyage. There are decent tree-species hereabouts to do this with. But no remaining plywood-mill in the region for the moment, except for one in Quebec. But we'll get one yet.
Susanne Altenburger, PB&F