lightweight core for low load area composite panels?

[CatBuilder]

SamSam: Thanks for the idea. That's exactly what I'm after... a cheap, common material that is light weight.

I built the inside of my RV out of furring strips (1"x2") and luan 3mm plywood. Basically, it's the cheapest stuff you can possibly buy and also happens to very - and I mean VERY light weight.

I used the furring strips as a frame for luan sheets.

The whole interior cost me maybe a couple hundred bucks. I'm well under the GVW. Similar "off the shelf" RVs such as Roadtreks have special part added to the suspension to handle the weight. Mine didn't need those parts since it weighs so much less. Another advantage was the higher fuel mileage I get.

I wanted to apply the same principles to the new catamaran.

I has made up a piece of foam insulation and cloth to show my wife what a laminate was like before starting this project. Sure seemed strong to me. It was a rock and very light weight. I assume it would fail over time with cyclical loading, but if there was no loading (like a dummy wall or a cabinet), you could save yourself a lot of time and money.

I'll make up some test panels as I get to the point of doing the interior... good idea.

[michael pierzga]

There are many different types of cored panel available for interior furniture work. Some cheap some expensive. Something to remember is the time required to structurally reinforce all the load points to enable mechanical fasteners for the hundreds of hardware bits inside your boat.

When you use cored panels you must carefully design these points and once built they are permanent...lightweight ply has a distinct advantage.

http://www.superhoneycomb.com/product_panels.html

http://www.mcgillcorp.com/products/catalog.html

[SamSam]

Originally Posted by Cretster

I'm not at all keen on sealing the deck in place by glassing it onto the edges of the hull etc because of the paranoia I've now got about water intrusion.

Glassing the floor to the hull around the edges adds a tremoundous amount of resistance to hull twisting and general beam type strength to the boat. The boat was designed to be built that way and any changes in construction may have bad results.

There are some foams used in commercial roofing that can be used in boatbuilding for a lot less than marine prices.

[CatBuilder]

Originally Posted by SamSam

There are some foams used in commercial roofing that can be used in boatbuilding for a lot less than marine prices.

Common brand names??

[Sand crab]

Back to a previous post about these guys that have a very unique wood cored honeycomb. Notice the doors and furniture and the fiberglass panels.
http://superhoneycomb.com/abouttheinventor.htm
Dow which makes Styrofoam brand has a very extensive line of foams. Some have densities as high as 100 PSI. I have wondered about glassing these for non structural panels. As the older thread talked about you would want to roughen up the surface first. I wonder if you took the standard 2" stuff which costs about $34 and glued luan on each side which is about $14. I would think that any of the construction type polyurethane glues would work. So for about $62 plus the cost of the glue you would have a 4'x8' panel.
http://msdssearch.dow.com/PublishedL...romPage=GetDoc
R-Control panels and their competitors brands are made in many, many locations locally and are commonly used in the building industry. These are engineered structural insulated panels commonly called SIPS. Basically they are plywood or OSB glued to one or both sides of foam. They become very stiff engineered panels. The R-Control guys have the materials and presses for this and are made on site at each plant and are affordable and local. I have seen some pretty thin plys attached to the foam for use as an architectural design element. You might want to try a test run of their thinnest foam laminated with thin ply. My local guys are very accomodating and so easy to work with. Did I mention that they are local? Who knows it might float your boat
http://www.r-control.com/
BOB

[sabahcat]

Originally Posted by Sand crab

Back to a previous post about these guys that have a very unique wood cored honeycomb. Notice the doors and furniture and the fiberglass panels.
http://superhoneycomb.com/abouttheinventor.htm

So what is it?
He doesnt say
But it looks to be end grain balsa

Sing honeycomb vs. wood, ------ Sing honeycomb only has 10% or less of wood and almost 90% of air. It is the strongest lightweight, renewable material made of vertical grain natural wood veneer fiber. Products made of Sing honeycomb core are the strongest lightweight renewable products available at a low cost.

[Sand crab]

Originally Posted by sabahcat

So what is it?
He doesnt say
But it looks to be end grain balsa

You got me. I sent them an email. I'll let you know. BOB

[SamSam]

Originally Posted by CatBuilder

Common brand names??

At commercial roofing supply places they'll have polyisocyanurate foam sheets in various thickness, densities, faced and unfaced. It's used a lot in hot mop roofs. It is dense enough to walk on and has a little fiberglass threads all mixed in the foam. Much better quality and much cheaper than Home Depot , Lowes, etc. Commercial places will usually sell to anyone. Sometimes they have leftovers, damaged, odd sizes real cheap.

[Sand crab]

I got this email from them
Thank you for your interest in our Sing Honeycomb Panels. The interior vertical grain wood grid system is a proprietary item and cannot discuss, but I can tell you that we can use any wood/formica/fiberglass/plastic on the outside of our panels that you wish.
I was wondering if it is Douglas Fir seeing as how they are in Washington State. I guess it doesn't matter. Hey Catbuilder the website says they may give you panels if it is for a new application. Maybe you can get some for free. BOB