Lighter weight boats ??

A toasted cheese sandwich is not floppy, Infact if you made a big one and ran a few layers of fibreglass round it it would make a good rudder.

 

Myself in into scrambled egs and one slice of toast !! so what does that do ??

 

A toasted cheese sandwich is welded round the edges. It is a perfect composite example.

As per Mr Watson was explaining. You need a toasted sandwich machine.

I don't think putting egg in it makes much difference.

If you balanced a piece of toast across say 2 jars of peanut butter it would not hold much weight but the toasted cheese sandwich would be much improved in weight carrying performance.

One layer of toast would be in compression and the other piece of toast in tension even with a soft centre of cheese.

Is that not what Mr Watson was explaining

 

Core Matt As A Core ???

ok we had the sandwich and we had toast so lets move on a little and venture into CORE MATT!!
TELL ME YOUR VEIWS ON THE CORE MATT THING !!!!

 

Ok keeping in the spirit of lighter weight, what would be wrong with using say 1/4" plywood for coring material like for a cabin structure on a steel hull/deck?

 

CAN USE YES BUT EPOXY RESIN TO STICK THE GLASS TO THE WOOD!! REMEMBER THE EPOXY WILL ONLY SOAK TO THE FIRST GLUE LINE OF THE PLY SO USE LESS PLYS AND GET THICKER VENEERS AND BETTER RESIN PENETRATION
POLY RESIN IS A WASTE OF TIME ! VINYLESTER SAME NOT RECOMENDED
OH SURE YOU WILL GET A INITAL STICK BUT WONT LAST !!
POINT TO REMEMBER THE WOOD IS THE INFERIOR MATERIAL THE GLASS AND EPOXY RESIN WILL WAY OUT LAST THE WOOD !!

 

Take Your CAPS LOCK OFF.

 

Tazman, the whole point of a sandwich build method is to separate the skins away from the center of gyration and of course, a light weight core. If the core isn't very thick, it's useless and if the core is heavy (like plywood) then you might as well just make it a single skin, solid laminate or a pure plywood structure.

Cheese is a pretty poor core material. It's not got the physical attributes you want. Composite structures need considerable understanding of the dynamics and physical properties in the materials employed, not to mention the engineering aspect of the assembled structure.

 

My only reason for the plywood would be more as a form using stitch and glue/origami method to build glassing the outside with a couple layers of biax then unbolt cabin and flip it over to glass the inside.
I would think if done right it would last just as long as anything else.
I gutted a Iona sailboat for a rebuild one time and the plywood they used as an inside liner/stiffener for the cabin/decks, even though some had dry rot and all of it stunk to high heaven from mold it was still stuck to glass quite well, what they had done was cut random slots in the plywood, looked like with a skill saw that gave the resins a better tooth to hold to

 

Thanks PAR
It would be a little simpler going thicker plywood with single skin, I'll have to do a couple test samples and see which I like better

 

Your idea isn't a sandwich construction, but a temporary mold, that happens to remain in the hull shell. Huge difference from and engineering point of view. You could do this with other, possably cheaper materials then plywood, though 1/4" lauan is pretty cheap.