Core in a mould ?

[nevilleh]

Hi,

Just finally getting underway with our 35' workboat mould.

Wondering about cores. Most of mine have balsa. Has anyone any thoughts about using nidacore in a hull mould?

I was wondering about using 3/8" nidacore possibly vaccuum bagged on.

Hull has quite alot of fairly flat panels.


Any advice appreciated.


Neville, Scotland

[gonzo]

We are planning on using nidacore on some canoe bottoms. I think that you need to vac it on to get good adhesion and no voids.

[War Whoop]

Originally Posted by nevilleh

Hi,

Just finally getting underway with our 35' workboat mould.

Wondering about cores. Most of mine have balsa. Has anyone any thoughts about using nidacore in a hull mould?

I was wondering about using 3/8" nidacore possibly vaccuum bagged on.

Hull has quite alot of fairly flat panels.


Any advice appreciated.


Neville, Scotland

Building a Boat in the Mold or the Mold itself?

[nevilleh]

Its for bulding the mould itself. I have used it many times on boats typically on flat panels, but for a mould the panels have a slight bend so the only way I could see would be to use a vacuum bag system.

[War Whoop]

Originally Posted by nevilleh

Its for bulding the mould itself. I have used it many times on boats typically on flat panels, but for a mould the panels have a slight bend so the only way I could see would be to use a vacuum bag system.

I bag Sheet core into my Molds.

Here is the last little bit of 3/4" core going down on a 38' hull mold ,there are perforations
which allow the excess material out to the surface and maintain a consistent bond line this is bedded in ATC Corebond.

[jim lee]

We infuse our molds with core, glass and most of the framework in one shot. So yeah, core's good.

-jim lee

[War Whoop]

That would not work here, I use a lot of piping on the production molds.







And they have to be perfect, This one 38 ' is a inch thick solid glass ,nice pull here.

[jim lee]

Piping's not a problem. You can still add that after the mold is shot. We like infusing 'em 'cause you can build in more overall rigidity in the one shot. By using core and balsa ribbing. Once its shot, we'll add the final framework or what have you.

Granted our surface quality isn't perfect. But for what we do, its plenty good. What we really want is parts that are dimensionally accurate and infusing them has helped a lot in this respect.

-jim lee

[War Whoop]

I could have infused this as I have my own system ,KRYPTON which I have been working on for 20 + years.

But the all Molds here had to be first rate.

[Herman]

For cores in moulds, Nida would not be my first choice, for the relatively low shear modulus. For approx the same amount of money you have balsa, which gives a stiffer product.

On the other hand, if it is Nida that you have, go for it. It is not bad, just less "perfect", just "good".

[Coen]

Herman,
Why go with a balsa core? In my opinion I would always ago for a non-wood, closed cell core when possible.

If would look for a PVC or PET foam. I think Airex has both of these types of core.

Unfortunately, the youngs- and shear modulus will be significantly lower.

Cheers,

Coen

[Herman]

You are right, but not for the same money. Balsa still gives the highest shear modulus for the buck.

PET (Airex / A3 Composites T90 and T92 foams) is also an option indeed, but I would check where that ends up in the shear modulus / cost ladder.

[War Whoop]

Originally Posted by Herman

You are right, but not for the same money. Balsa still gives the highest shear modulus for the buck.

PET (Airex / A3 Composites T90 and T92 foams) is also an option indeed, but I would check where that ends up in the shear modulus / cost ladder.

OK by who's numbers??

[Herman]

I do not get the question.

[War Whoop]

You said balsa gives the highest sheer numbers and I asked by who's numbers?