Plascore polypro honeycomb for cabintop core?

[Beausoleil]

I need to replace some of the pilothouse cabintop fiberglass core on our Formosa 51 due to leaks leading to rotting of the plywood core.

I was looking at either marine plywood ($237 for a 4'x8'x1" sheet at exoticlumber.com near Annapolis) or possibly even solid PVC sheet from most lumberyards, but then I saw this Plascore polypropylene honeycomb sheet from Fiberglass Supply Depot out of Michigan. A 2'x4'x1" sheet is available for $30 in quantities of 4 or more, equating to $136 for the equivalent to a 4x8 sheet. Even with shipping cost of $21, that's still less than marine ply and lighter as well.

A datasheet can be found here.

Has anyone worked with this stuff before? How does it compare to Divinycell, Airex, balsa or marine ply when it comes to cabintop/deck coring? Is it too good to be true?

[s/v Jedi]

Originally Posted by Beausoleil

I need to replace some of the pilothouse cabintop fiberglass core on our Formosa 51 due to leaks leading to rotting of the plywood core.

I was looking at either marine plywood ($237 for a 4'x8'x1" sheet at exoticlumber.com near Annapolis) or possibly even solid PVC sheet from most lumberyards, but then I saw this Plascore polypropylene honeycomb sheet from Fiberglass Supply Depot out of Michigan. A 2'x4'x1" sheet is available for $30 in quantities of 4 or more, equating to $136 for the equivalent to a 4x8 sheet. Even with shipping cost of $21, that's still less than marine ply and lighter as well.

A datasheet can be found here.

Has anyone worked with this stuff before? How does it compare to Divinycell, Airex, balsa or marine ply when it comes to cabintop/deck coring? Is it too good to be true?

Are you looking for cheapest or best or? What thickness, 1”? Is it flat or curved? Why not balsa?

[wingssail]

The plascore honeycomb appears to be "core only", no skins. You will need to consider how you will "skin" these boards since it is the skins which provide much of the rigidity and how you will adhere the skins to the core.

This seems like a boatbuilder's task than a DIY project.

[s/v Jedi]

You need skins. For this productI recommend Nidacore, like this: https://fiberglassflorida.com/nidaco...mb-sheets.html

You also have it in paper which works good but I can’t find it quick enough.

[Sailorman Ed]

I used Nidacore with the scrim skins for a large rigid bimini and was very please with it. I now have four 4x7 sheets of 20 mm in the shop to build a large bimini for the Gemini. I used 1 inch balsa for the large one and wasn't happy with the results, was heavier and required a more complex form. The Nidacore contours nicely. The cost was $67 a sheet in July from Boat Builders Supply in ft. Pierce. He did say he can cut with ship smaller pieces UPS.

Look on Utube for On Board Lifestyle, he made a huge bimini with this and detailed exactly how he did it.
Ed

[Scubaseas]

I've used carbon-core honeycomb 13mm before for hull and deck on 28' Carolina Skiffs.
https://www.lbifiberglass.com/produc...eycomb-panels/

It does not have skins on it but as long as you get it wet the surface with resin and pre-saturate your first layer the skins you make will stick fine. Excellent product that I use on dive boats that we do terrible things to like run over beaches and reefs etc. or smashing into the trailer. For a laminate schedule look at Gerr's "Boat strength..." Would work fine for your application.

[wingssail]

I finished the interior of my boat with Nomex (paper) honeycomb panels. Some were polyester skinned, others, where ultimate bending strength was required, carbon skins. All of the panels I used were 3/8 inch thick. For bare edges I crushed the honeycomb with a screw driver and and filled it with polyester filler, then sanded it smooth. Other exposed edges are finished with mahogany or teak edges, glued on. Much of our cabinetry is removable to allow access to tankage and other items beneath the soles. In these cases the panels are clamped. For the cabin sole I used 3/8" marine plywood with veneer, for impact resistance. I am not a boat builder or much of a craftsman actually but common sense led me along and the job got done. I probably used 2 dozen 4x8 panels. They are not cheap or easy to source.

The resulting structure is extremely light weight and rigid. The bulkheads foreward added significant stiffness to the boat and they have withstood considerable heavy weather (windward) work without flexing, cracking, or allowing the hull to deflect. The problems were fastening. Through bolting with fender washers worked OK, but for some permanent bulkheads I tabbed them together with epoxy and glass tabbing. The tabbing has held up well. You cannot use screws in honeycomb panels, nothing inside to bite into.

I would definitely do it again.

[thinwater]

[QUOTE=Beausoleil;3726452... How does it compare to Divinycell, Airex, balsa or marine ply when it comes to cabintop/deck coring? Is it too good to be true?[/QUOTE]


It is 4-10 times weaker in compression and shear than foam or balsa (I compared specs). Check the numbers and then look at the engineering loads for your project. It will certainly not hold screws or through-bolting loads, at all (it will crush).

[Beausoleil]

Originally Posted by s/v Jedi

You need skins. For this productI recommend Nidacore, like this: https://fiberglassflorida.com/nidaco...mb-sheets.html

You also have it in paper which works good but I can’t find it quick enough.

Yeah - I didn't notice until after I posted that it looks like the skinless version of Plascore was what I was looking at. And as pointed out in another response, the compression strength wasn't that great.

A cursory look at Nidacore looks pretty good though - I'll look into it

[Bill O]

Would check these guys out with many types of cores to choose from. Another good thing they are located not too far from you in Va or have a shipment charge of ~$150 if you wanted a bunch of 4x8 sheets.

Another possibility is Coosa from Harbor Sales (for us the price included delivery, not sure about Solomons). Easy to work with and will never rot.
Not certain how large of an area you need to replace, but you could laminate the 1/2" to the 1".

[Simi 60]

It's pretty good stuff, it does have its downsides like ALL construction materials.

I have seen a couple of large cats 40 to 55ft done in it before.
Some discussion here

https://www.cruisersforum.com/forums...am-106981.html

Google brings up more

https://www.google.com/search?q=cata...obile&ie=UTF-8

[Matt Johnson]

Carbon Core is 4' x 8' vs 4' x 7' for Nada. The extra 12" adds up if you're using enough.

There is a noticeable difference between our honeycomb and PVC foam panels. If I cut equal sized strips of each (5lb density) with 12oz biaxial on both sides, the honeycomb will fail much sooner than the foam. Not scientific, but matches the specs.

[clockwork orange]

I have used quite a bit of the stuff but only for select things like berth tops,
counter tops, things like that. i always make up my panels on a table with either epoxy or VE, double bias or 0/90 and always vacuum bag. I prefer foam but this stuff is a lot cheaper and readily available and is perfectly adequate for a lot of projects.

[Tupaia]

Originally Posted by thinwater

It is 4-10 times weaker in compression and shear than foam or balsa (I compared specs). Check the numbers and then look at the engineering loads for your project. It will certainly not hold screws or through-bolting loads, at all (it will crush).

Because the plastic honeycomb is flexible the panels are nowhere near as strong or stable as phenolic paper or aluminium hc.
Polycore will resist very light traffic but will not support being walked on. I know of a boat that used it for decking and it crushed so badly it became very bouncy due to internal delamination to the extent that the whole area was cut and filled, now very heavy.

It is ideal for non walked on biminis. I have a 5.2m x 2.2m bimini made of 16mm Polycore with epoxy skins. It was flexible enough to take a slight curve before being bolted down. It can be through bolted but you have to create epoxy plugs as with any honeycomb, using an Allen key to rip out the core, fill with epoxy and then redrill. The edges are trimmed with plastic table edging easy and robust. It is very light 19kg.

[Simi 60]

Originally Posted by Tupaia

Because the plastic honeycomb is flexible the panels are nowhere near as strong or stable as phenolic paper or aluminium hc.
Polycore will resist very light traffic but will not support being walked on. I know of a boat that used it for decking and it crushed so badly it became very bouncy due to internal delamination to the extent that the whole area was cut and filled, now very heavy.
.

Can't say I agree with you there.
I have made test panels and been involved with drop tests on various cores, cedar. Foam, duflex, Kiri and Polyvore stacks up well

See below vid, do you thing walking exerts the same loading as essentially sledge hammer blows?

Watch to end to see comparison against actual panels of other cores taken from other boats

https://youtu.be/hgrEjZqsKJY