ok i have a question for everyone and any one !! please enlighten me !!

[tunnels]

I have notices on more than one occasion recently and over quite a while that people re-coring there hulls with what ever sort of core and what ever thickness have this idea that a really light glass even just a chopped strand is all that's needed !!!

Why and where did this idea come from ????

Is it that the inside layer is just a cover for the core and does nothing else and is there to keep the water out ????

What am I missing ??? and has everyone forgotten the " I " beam principle that the core gives and that's why its used to make the hull bottom stiffer !!

It also took me a long time also come to grips with the thickness of some of the older cores as well ,they were Just 3/8" inch was one I saw !, now more recently 1/2" inch which sounds a little more realistic and there are stringers planted on top as well .

[XstreamVking]

All I know is what works. For example, my boat has 1/8'' of chop on the bottom, one layer of 1708 bi-ply running at 45 deg from the center line over that. For core, HS-80 1/2'' thick divinnycell bedded down. This is covered with 1708 bi-ply running the opposite 45 deg from the center line then covered with 1.5 oz of chop. 1 U shaped fiberglass stringer on the keel,1/2'' thick penske board, 12 lb density, for a floor with 1.5 oz matt covering that, tabbed to the hull with 1 layer 1708 at the floor edges. This tab pc is also covered in 1.5oz matt. What do you think of this layup? Just curious....

[powerabout]

remember when Cigarette started adding carbon it was the last layer inside the hull, so they knew.

[afr]

balsa makes up a end grain I beam
foam makes up a cell I beam
the thickness of the glass on both sides is set up with core thickness, for the loads your going to put the boat under during use
thats my 2 cents

[tunnels]

balsa makes up a end grain I beam
foam makes up a cell I beam
the thickness of the glass on both sides is set up with core thickness, for the loads your going to put the boat under during use
thats my 2 cents

You evaded the question !!Why are people just putting a very thin skin of glass over there new core
???
so the original skin that's on the out side is not mated by a equally as thick layer on the inside ???why ?????
what is the thinking behind this almost nothing skin inside ??

[tunnels]

remember when Cigarette started adding carbon it was the last layer inside the hull, so they knew.

so they knew what ??
Hypothetically carbon is completely the wrong choice !! can you tell me why ??

[tunnels]

[QUOTE=XstreamVking;2874482]All I know is what works. For example, my boat has 1/8'' of chop on the bottom, one layer of 1708 bi-ply running at 45 deg from the center line over that. For core, HS-80 1/2'' thick divinnycell bedded down. This is covered with 1708 bi-ply running the opposite 45 deg from the center line then covered with 1.5 oz of chop. 1 U shaped fiberglass stringer on the keel,1/2'' thick penske board, 12 lb density, for a floor with 1.5 oz matt covering that, tabbed to the hull with 1 layer 1708 at the floor edges. This tab pc is also covered in 1.5oz matt. What do you think of this layup? Just curious....[/QUOTE


Now that all makes sense !!!

[powerabout]

so they knew what ??
Hypothetically carbon is completely the wrong choice !! can you tell me why ??

if you want protection from something coming through use kevlar but its heavy
Yes carbon also works in compression

[powerabout]

[QUOTE=tunnels;2874807]

All I know is what works. For example, my boat has 1/8'' of chop on the bottom, one layer of 1708 bi-ply running at 45 deg from the center line over that. For core, HS-80 1/2'' thick divinnycell bedded down. This is covered with 1708 bi-ply running the opposite 45 deg from the center line then covered with 1.5 oz of chop. 1 U shaped fiberglass stringer on the keel,1/2'' thick penske board, 12 lb density, for a floor with 1.5 oz matt covering that, tabbed to the hull with 1 layer 1708 at the floor edges. This tab pc is also covered in 1.5oz matt. What do you think of this layup? Just curious....[/QUOTE


Now that all makes sense !!!

why would you ever use chopped if you are doing anything other than making it cheap?

[tunnels]

if you want protection from something coming through use kevlar but its heavy
Yes carbon also works in compression

that's A GOOD POINT !! BUT compression on the top of a inside of a panel? pretty unlikely!, the down side is carbon snaps like a carrot if iy get a crease of fold !, give me good old fashioned Glass any day over any thing made of carbon !

[tunnels]

[QUOTE=powerabout;2874810]

why would you ever use chopped if you are doing anything other than making it cheap?

Personal choice I guess ! but Id rather use something better that's for sure

[powerabout]

what is interesting in composite stuff is you measure the stretch/elongation properties of cloth and then all the various resins the industry hardly ever uses them correctly as they seem to always be a long way apart or should they?

[tunnels]

what is interesting in composite stuff is you measure the stretch/elongation properties of cloth and then all the various resins the industry hardly ever uses them correctly as they seem to always be a long way apart or should they?

You are right !! like one company I worked they used 2 layers of Carbon to strengthen the underside of a deck where it sat on a Bulk head !!BUT used polyester resin !! This was a very prominent boat company in nz that made 65 footers . When I saw it I laughed and the foreman asked me why and its what they had been using for a long time .
Not one person in the company could see anything wrong with it !! Its carbon !! its strong!! That's all they could think about the resin never even entered into the equation !


Theres some pretty strange things happen in some places !!

[tunnels]

Of the many and different companies I have worked over the years in different countries It has never ceased to amaze me how the factory managers , foremen , leading hands and team leaders in just about every company , how these people got there jobs !! because they know virtually nothing about what goes on before there very eyes ,every day of the working week !
How are young people going to learn to do there jobs and know what the products they use are really meant to be used if there superiors are as dumb as each other and know absolutely nothing ?? One thing I did discover in a lot of cases is if any one that knew a particular skill they guarded it and there was no shearing and helping any one else as they treated it as a closely guarded secret .
Last place I worked as a Quality controller I took photos and video of individuals regardless of the rank before saying anything and then lost my cool and exploded ! Even the company owner /manager saw nothing wrong with what was being done and classed himself as a composites expert and supposedly knew everything there was to know yet not one person in the whole establishment could recognize the incomparability of the mold release wax they were using !just one coat of a different wax and products simply pop off molds with ease .

[XstreamVking]

[QUOTE=powerabout;2874810]

why would you ever use chopped if you are doing anything other than making it cheap?

The hull was built with a chop matt from the factory. Removed the woven the factory had put down.( not even fully wet out or covered, This is why the core rotted) Covered this with the 1708, and the glass on top of the core mimicked the glass under the core to have an even lay-up on each side of the core. I used vinylester resin so mat is required under the woven glass. I also cover all woven matl with a layer of matt to seal it, and to also provide a surface to be ground upon without damaging the woven fibers underneath. I gelled the entire hull to make it waterproof. If your gonna gellcote something, you have to grind it 1st.