Author Topic: Radiata pine AC VC Exterior Phenolic glue  (Read 102 times)

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Sprig1

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Radiata pine AC VC Exterior Phenolic glue
« on: July 07, 2020, 03:56:21 PM »
I'm contemplating using Radiata pine AC Exterior plywood from Chesapeake Plywood for the hull. Brian do you have any thoughts. If you could check it out it would be great. It would save thousands. I have a friend that used it for a build and he sure liked it. I'll try to get a piece and do the boil test. 3/8th is $27.89, 1/2 $32.00, 3/4 $37.40 total $824.35. Okoume 3/8th $88.64, 1/2 $109.44, 3/4 $154.24 total $2961.44 that no extra. Hydrotec is $78.00 for 3/8 th a little cheaper than Okoume but not much. Thanks for your time.

Brian.Dixon

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Re: Radiata pine AC VC Exterior Phenolic glue
« Reply #1 on: July 08, 2020, 07:44:23 AM »
First, the Great Alaskan series of boats were designed to be overly-strong, even if built with just exterior grade softwood (read: fir plywood) plywoods.  That said, note that there are typically some trade-offs that I feel justify using something other than a softwood plywood ... you may well decide the trade-offs are OK with you ... you'll still get a fantastic boat in the end.  The Radiata Pine is definitely in the softwood plywood category.

Here's the trade-offs and thoughts that I have on plywood selection:
  • There is a fair amount of difference in hardness between softwood grain and the wood between .. sanding tends to highlight the grain, not hide it.  This has typically already happened to some degree right from the factory, so the boat will end up needing more fairing (time, cost) than if it were built from hardwood species (especially mahogany or pseudo-mahogany products)
  • Softwood ply is ... softer.  For at least the bottom panels and chine flats, I prefer a dense hardwood that is more resistant to impact damage.  If using softwood plywoods, I would suggest using them from the chines upward
  • Hard smooth hardwoods save labor and cost when it comes to fairing - Meranti, Okoume are good choices (but expensive)
  • I don't worry about the cost of the plywood, instead preferring to buy the best product available because as a percentage of the total cost of the boat project, the plywood is only 10-15 percent ... not enough to worry about.

I think that's about it, or close enough anyway.  Many have built Great Alaskans with good ol' fir plywood and been happy.  Perhaps the best money saving compromise is to go with a good mahogany type hardwood plywood for the bottom panels and chine flats, but use your pine plywood from the chine flats upward (and for decks, web stringers, superstructure etc).  If you want a yacht finish, it'll cost you time and effort in fairing later, but the level of finish is very individual choice ...

Brian

« Last Edit: July 08, 2020, 07:46:12 AM by Brian.Dixon »
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Sprig1

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Re: Radiata pine AC VC Exterior Phenolic glue
« Reply #2 on: July 08, 2020, 08:32:17 AM »
Thanks so much for your wisdom Brian! I know I was just trying to be cheap. I do a lot of building for other people.  I always  go top end on building materials for my jobs. This boats a luxury not a necessity. It's a toss up I'm 60 what hopefully I have ten years to enjoy it and two years to build it. Looking at it that way I might as well get my wheelchair now. 😀 Thanks again you have made some great plans!

Brian.Dixon

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Re: Radiata pine AC VC Exterior Phenolic glue
« Reply #3 on: July 08, 2020, 09:20:50 AM »

Just buy Hydrotech (Meranti) from Edensaw or someone for the bottom panels and chine flats, then your pine plywood for everything else.  I have proven (to myself) that a guy who's handy with even a 5" random orbital sander can do a pretty fine job of fairing without doing any long-boarding.  And, you only need to fair the outside of the boat from the waterline up to the roofs ... the profile view as the boat sits on the water.  It's entirely OK to see some wood grain and fiberglass lines inside the boat ... it gives the boat a nice 'charter boat ambiance' that I love... No need to do bristol work on every nook and cranny ...

Brian



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Jim_Hbar

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Re: Radiata pine AC VC Exterior Phenolic glue
« Reply #4 on: July 08, 2020, 12:51:15 PM »
I believe the Radiata Pine plywood referenced is an exterior grade of plywood, not marine grade - thus it's "cheap" price.

Marine plywoods are constructed with higher quality veneers in the core - with fewer and smaller core voids allowed, and possibly better glues..  They are also graded to higher standards.

Radiata Pine is a plantation grown crop that was/is planted in many regions of the world, such as Australia, New Zealand and Chile for pulp and lumber production.  The wood is similar to the SYP's, and isn't as strong as Douglas Fir.  IIRC, rot resistance is a little worse than Doug Fir.

It can also be quite resinous, so I would test it for epoxy adhesion.

Grady300

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Re: Radiata pine AC VC Exterior Phenolic glue
« Reply #5 on: July 08, 2020, 09:33:50 PM »
I agree with Brian, at least going with a good marine grade ply for the chines and bottom. Then from the chines up use your other ply. Very much like the foundation of a house needs to be strong and true.
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