Thoughts on Marine Tech Aquaply+

https://www.affiliatedresources.net/_files/ugd/4be681_8b0815cb613d46ca93ed90b7133a23bc.pdf

Does anyone have experience with this stuff?

I'm looking at some stitch and glue 15' skiff plans that call for 1/4" Okoume or Meranti for the hull and bulkheads, sheathed in FG and epoxy. The aquaply would save me around $450 at my local lumber yard. I cannot, however, find any testimonials online about its quality or suitability for boatbuilding.

 

I do not have any experience of this material, but the claims on the website are impressive.

They note that the laminates are bonded using "solid-content phenol formaldehyde exterior glue" and that it is "Completely bondable with all adhesives and resin systems".

Maybe you could buy a sheet, and cut off a few small pieces to use as test samples - you could give one piece a test in boiling water to see how it holds up (marine plywood has to be weather and boil proof - WBP).

They note that it is "Pressure-treated with AQUA SEAL® copper oxide formulated preservatives".
You could maybe try bonding a couple of samples together to form a T shape using an epoxy fillet on each side, and then walloping it to see how strong it is, I wonder if the epoxy would be affected by the copper oxide preservative?

 

I sent an email to the manufacturer asking if they could back up the claims in the data sheet, will post here if they get back to me.

Everything seems to check out from what I know about marine ply, but I'm wondering why it would not be more widely recommended for small boat building if it's comparable to a more expensive product. My big concerns are what their standards are for the inner plys as far as voids/knots, and, as you mentioned, if the preservative has any impact on resin bond strength.

If I can't get a clear answer from them or anyone who's used it I will probably just cough up for the known good product.

 

And where and how it fails. Most telling information.

 

$450 in savings sounds pretty stout. Does that include not using f/g epoxy covering on the aquaply?

 

1/4" Aquaply: $80/sheet
1/4" Okoume: $126/sheet

Plans call for 8 sheets, plus two sheets of 3/8" for decking.

 

This is what I received from the Aquatech sales rep:

 

I stand corrected; Noah's list 1/4" Okume at $159.26 a sheet. It's obvious I haven't built a quality plywood boat in a while ;-)

 

Why go all or nothing? Use the good stuff where it counts, and the cheaper where you think you can get away with it. It could be OK for bulkheads and scantlings etc. Then you can tell us about its qualities.

 

I had considered this, but the sales rep was not able to speak on whether or not their preservative treatment has any effect on epoxy bond strength. The plans I'm looking at call for the majority of bulkheads and stringers to be encapsulated by the glassed in deck, so if any delamination were to occur it would effectively total the boat. Without anyone able to share their experience with it I think I'll likely just play it safe and stick to something with a known reputation.

 

If you are encapsulating in epoxy the species of the plywood is not too important. Many successful boats have been built with balsa wood core. The boil test is an accelerated age test. It does not consider an encapsulated plywood. The bonding is a different issue. Do they say what the treatment product is?

 

The brochure says "Completely bondable with all adhesives and resin systems"; check with the supplier if your bonding scheme will be ok. If "yes" then go ahead.

 

A bond test is easy. A good bond will delaminate the wood.

 

I know it is sometimes criticised for being easy to fake paperwork but do bear in mind that BS1088 required veneers to be of durable species and the glue to conform to BS 1203 for resistance to boiling.Not many of us boil our boats but epoxy tends to fail at 95 deg C and I don't believe that fir core veneers would conform and the species that is known in the USA as Okoume is traditionally known in the UK as gaboon.Sheets of ply made of it may conform to the bonding standards of British marine ply,but they should carry a stamp that indicates that they are classed as BS1088 (gaboon) because the species isn't classed as durable.Thousands of Mirror dinghies have met their end because of rot from pooled water in the footwell overcoming the gaboon.So really,neither of the choices is ideal but if the bond is secure and the boat is kept sheltered from the extremes of weather,it may work out well enough.

 

The APA has a different set of standards for marine plywood. BS1088 is a good standard, but not the only one.