|> Can a tube driver just change the properties of the core material in the software and see what happens?
|>
|​ What is a tube driver? Software works best if it is based on actual test results. And is not good at things like impact and fatigue.​

Sorry, a local dialect thing. A tube driver is slang for the cad operator who puts the info into the software, runs simulations, and generally can tell you what the software says.

He is probably part of the 'expensive and specific' bill from etamax.

They are, or used to be, common enough here that if one had an interesting enough question some one would ask a buddy to run a simulation at work to see what the software says.

|> what kind of margins a new core has?
|>
|​ Sure, costs about $1,700 per set of tests​ for flex, tension and compression to prove (usually)/disprove the manufacturers numbers... I do not know of any test regime for impact apart from hardness testing (depressing it with a ball and measuring the dent), resilience or fatigue although I am sure they exist.

Ya. You made that point (manufacture data lies, or, perhaps, differences, in the boat design thread too!

Perhaps we should look at this as a test of one composite sample vs another... If we have similar samples, one in H100, and in XPS 400 or 700. Then test them to destruction. Flex to fail. Smack and flex to failure. Whatever seems reasonable. Then we can probably get a PRACTICAL understanding of the differences of an actual laminate, vs data on paper of the cores.

You know boats and laminate. I imagine you got ideas of how you want the new stuff stressed to failure.

With the Rutan planes, when you had a hull you could put wheels on and mount the wings, guys would do a static load test. They would put a series of bags in proscribed positions along the wings from root to tip to see how the wing flexes. Then take pictures of wingtips deflected with some number of thousands of pounds on the wings. Quite dramatic. This right of passage let us check our work and prove to ourselves the thing could handle flying... They could also check control linkages moved freely when the wing flexed..

Here is a destructive test of an donated old plane.
http://www.cozybuilders.org/Canard_Pusher/RAF_LE-Structural-Test.pdf

I cannot think of an analog with boats. Can you? Boats don't generally see +/- 3 g's.

Perhaps think about a H100 vs XPS test that might convince you that XPS will cut it, or not. Then take that test to failure? I think you learn more when things break.

|> Is most composite engineering FEA simulation stuff or 'we know this works, because it worked lots of times before' engineering?
|>
|​Depends who you talk to. ;-)​

Ha!

Then let me ask you, when would you be comfortable telling others to build a boat out of it?

I asked about building with H60 vs H100 before. What are your thoughts on that? That seems similar to substituting XPS.

|> door mat for the home
|>
|​ditto, although it will probably be blown away the first windy day..​

I guess glue it to heavy things.

|> Why you doing 25mm pricing?
|>
|​I was not allowing for hot wiring, 25mm is the smallest they do. ​

Ah! I think the thinnest I have seen in XPS 700 is 1.5" (38? mm). 2" way more common. But I have just been checking availability, not asking if I could get a pallet cut to a specific thickness. Do you see a problem with hot wiring down to thickness? It seems to me having a thicker slab I can take cuts out of as needed is better than having different stacks of specific thickness. I would hate to have to order another 8mm sheet. Although I can see the value of a stack of factory cut perfection.

I guess once a builder got the machine working they might do a set of the thickness they will need all at once. So you probably still have different piles of foam around.

How do you think a builder will feel about this? A builder ordering a couple pallets may have an option to get it custom sliced.