Divinycell vs Core Cell

[AndrewK]

War Whoop; thanks for the information, unfortunately the 5-6% elongation is after 2hrs at 120'C post cure. Viscosity is also a bit on the high side.

Cat Builder; the hot box is a good idea but it does not help you much if you want to do your big laminating jobs during the night. Especially with full length (15m) strip of glass, it will be exposed to the high humidity for hours before you get to wet it out.
The link to the data sheet gives only one set of properties, but there are two hardeners. The properties will be different for each hardener.

rberrey; the 5-8% elongation is not exceptionally high and you e glass reinforecement most definitely will benefit from this. In my opinion the light weight S glass will only provide a marginal benefit and not worth the extra cost. While the ultimate strength of s glass is much higher than e glass you need to look at the strength versus strain curves. The s glass is only slightly stronger at low strain levels we are talking about in your typical marine laminates.

[War Whoop]

Originally Posted by AndrewK

War Whoop; thanks for the information, unfortunately the 5-6% elongation is after 2hrs at 120'C post cure. Viscosity is also a bit on the high side.

Cat Builder; the hot box is a good idea but it does not help you much if you want to do your big laminating jobs during the night. Especially with full length (15m) strip of glass, it will be exposed to the high humidity for hours before you get to wet it out.
The link to the data sheet gives only one set of properties, but there are two hardeners. The properties will be different for each hardener.

rberrey; the 5-8% elongation is not exceptionally high and you e glass reinforecement most definitely will benefit from this. In my opinion the light weight S glass will only provide a marginal benefit and not worth the extra cost. While the ultimate strength of s glass is much higher than e glass you need to look at the strength versus strain curves. The s glass is only slightly stronger at low strain levels we are talking about in your typical marine laminates.

There is a infusion version on the 411 also what are you talking about? 5-6 % elongation is plenty are you wrapping the glass around concrete ?This was a 488 KG 11 meter hull and deck before rigging and it seems just fine,The cure are you doing clear castings??

http://www.youtube.com/user/Cheetahc.../1/esxxtLg8qJ4

[AndrewK]

Originally Posted by War Whoop

There is a infusion version on the 411 also what are you talking about? 5-6 % elongation is plenty are you wrapping the glass around concrete

5% elongation is enough, I just dont want to heat it to 120'C to achieve that, I want it at ambient temperature cure.

I am more than happy with the epoxy that I am using as it gives me that. But if there was a VE resin that also provided these properties than I would use that too.

[War Whoop]

Originally Posted by AndrewK

5% elongation is enough, I just dont want to heat it to 120'C to achieve that, I want it at ambient temperature cure.

I am more than happy with the epoxy that I am using as it gives me that. But if there was a VE resin that also provided these properties than I would use that too.

Why would you have too, are you making a hot solvent tank and worried about the service life in the chemicals ? That cure is for a clear casting and Hot solvent!

[idkfa]

Comparison chart

[War Whoop]

Originally Posted by idkfa

Comparison chart

On the ductile cores normal test methods do not work as they indicate movement as failure,that is exactly what these materials are designed to do.

[AndrewK]

Originally Posted by War Whoop

Why would you have too, are you making a hot solvent tank and worried about the service life in the chemicals ? That cure is for a clear casting and Hot solvent!

Perhaps I am not making my self clear, the data sheet we are referring to only gives the properties for one cure condition. This is 24hr at ambient + 2hr at 120'C to achieve elongation 5-6%.
I dont know for sure but I am guessing that at ambient cure alone the elongation will be only around 3.5%. This is only an assumption based on other VE resin data sheets when I last looked into this.

[War Whoop]

Originally Posted by AndrewK

Perhaps I am not making my self clear, the data sheet we are referring to only gives the properties for one cure condition. This is 24hr at ambient + 2hr at 120'C to achieve elongation 5-6%.
I dont know for sure but I am guessing that at ambient cure alone the elongation will be only around 3.5%. This is only an assumption based on other VE resin data sheets when I last looked into this.

No at 24 hour ambient cure I would assume the elongation to be greater,think about that, What are you doing a clear casting or a laminate? a Clear casting will require the high post cure. the laminate something much less.

[AndrewK]

Originally Posted by War Whoop

No at 24 hour ambient cure I would assume the elongation to be greater,think about that, What are you doing a clear casting or a laminate? a Clear casting will require the high post cure. the laminate something much less.

Sorry I was not specific enough, I am looking for the 5% elongation after long term ambient cure.
Glass laminates, my own 12m catamaran and infused panels for other home builders.

[fcfc]

Originally Posted by idkfa

Comparison chart

Interesting charts.

I have nothing againt composite engineering, but may I remind the main issue of this thread was where do one get the products (availability), can one afford them (pricing) , and how long the offer can be valid (Can one get somewhat similar conditions within a year) ?

It is much more of a retailer problem (in homebuilding quantities/size) than an engineering problem.

I fear a chart showing what reseller sells what core foam at what price with what delivery delay would be much much much more interesting for CatBuilder.

[AndrewK]

CatBuilder has already purchased his foam, he got a great deal on the smaller sheets.

[CatBuilder]

I would also add that I didn't buy in "homebuilder" quantities or sizes.

I bought everything direct from the manufacturers of the materials because I am buying in the vicinity of $60K of materials for the hull alone. Same as any professional one off builder or possible more, if they had built a smaller boat.

My complaint was that Gurit kept doing a bait and switch on me, no matter if it was intentional or not.

I gave them my materials list for a quote and they came back with a certain price per square foot, saying they had tons in stock. Later, when they generated the SO, all of a sudden they only had about half of it and wanted to charge me $5.87/sqft for the remainder of the order. I had it out with them over the price hike and they refused to honor the original pricing.

So... I "fixed" it on my end. I ordered only the teaser amounts from them (enough for the hulls) and will do the other parts like the deckhouse and bridgedeck from Divinycell or another core priced more in line with sanity.

Their padding added over $10K to my order, sprung on me at the point of SO generation.

That was my actual experience. I did not care for the sales team over there, although the order fulfillment, warehouse and shipping people are quite nice.

I ordered all other materials direct from the manufacturer as well. I only picked up a few odds and ends at bateau.com other than my direct orders.

Anyway, the discussion thread here has been quite interesting, even though it has drifted a bit. Good thread to learn from.

[SandEngXp]

..... Looking at shear strength by arranging the foam according to shear specific strength, the H series is far stronger and appears at the top end of the scale.

Impact resistance is another story. Generally, the Balsa and Divinycell (group 1) are grouped together and the Corecell and Airex (group 2). Group 1 is on the poor end of impact resistance.

Attached comparison table.

This table is about 20 years old, and some of the data is older. I suggest getting updated information from DIAB and Corecell if you are going to design to this.... .... both products/companies have moved to a more middle ground or have grades for specific ends of the design spectrum now.

FYI

[rxcomposite]

Originally Posted by SandEngXp

This table is about 20 years old, and some of the data is older. I suggest getting updated information from DIAB and Corecell if you are going to design to this.... .... both products/companies have moved to a more middle ground or have grades for specific ends of the design spectrum now.

FYI

In the instructions posted somewhere, the user is advised to fill in whatever data they have on their foam core. Admittedlly, the Diab series was 4 years old as pointed by one of the members but the new DIAB data have a much better material properties. All other dats are new, recently downloaded from the net.

The data cells are not protected and can be changed at will.