On May 10, 2018 3:28:45 AM UTC, "StoneTool owly@ttc-cmc.net [harryproa]" <harryproa@yahoogroups.com.au> wrote:
>Hi:
>     I'm new to this forum, and it's rather interesting to me to find that the hot thread is exactly the same discussion I'm having on another forum.

I blame me.

> The use of XPS foam, the commonly available blue or pink 2 pound foam in foam sandwich construction for boats.   

If you had read the assigned material, you would know that we really are not talking about using that in boats. Although, I guess, you are, now.

>What is striking to me is how personal this quickly becomes, and how passionately people will argue against something, not from actual knowledge and experience, but quite the opposite. 

Right, because there's nothing objectional about the logical fallacies of appeal to authority, ad hominium, and , bah, screw it. I don't care

>There is an old saying about this, but I won't repeat it here, as it might  not be taken well.

No, teach us wise one. We await your lecture.

>One person wrote that he would not consider building a boat where XPS was used, or buying one, or sailing on one, or even setting foot on one.......

Different strokes. Would you believe some people post in threads without reading the thread? Imagine! Cads!

> XPS foam has been widely used in aircraft wing construction

You did read the thread, right?

>It has excellent properties

You did read the data sheets? Linked in this thread? For reference? I sure hope you dont start telling us what we already know...

>for foam sandwich with the exception of sharp impact, where it will crush and not rebound.......Hit it with a hammer......       That makes it unsuitable for core in areas subject to impact.  Hull sides, bottom, or anywhere where it will hit a dock or another boat.

Holy crap! Is that true! Imagine!

>The lower density as compared to H 80.... 2 pound versus 5 pound, and I use the 2 pound number because that is the commonly found foam, means that you can use thicker foam without additional weight,

Right, and get all the commonly available foams crappy performance as a bonus. It almost like its free. I think you should go read the sheets. And the linked threads.

>and with the same laminate on either side will bear far more load and be stiffer

That's literally, not how composites work. See the boatdesign.net thread.

>as a result.   I can see it in coach roofs and decks, bulkheads and beams, and interior furnishings.  It can ONLY be used with epoxy.

> The challenge is to determine where it is appropriate, and how best to use it.

Ha! You think that's the challenge. Why don't you write down your ideas about where we should use it in a data sheet. And we wont read it. For justice.

>At 1/8 the cost of Divinicell H 80 per sheet of the same thickness, or in reality 31% of the price per pound in the US,it's well worth considering when one considers it's pedigree in aviation.

A 1/2" 4x8 sheet of 25psi XPS foam, locally, is like 10$. Public net price FOR 1/2" H80 is like 150. That's like 1/15th

>If one is constructing using polyester resin, then one had better think things through a bit more carefully. 

>It's worth remembering that a thicker lower density core will yield a stronger stiffer more desirable structure which in many situations is desirable.

That is literally not true.

>It is said that when your only tool is a hammer, a hammer looks like the solution to every problem. 

That is not the saying.

>From "my" supplier, H-80 and H-100 Divinicell are the only core materials worth considering.

As mentioned in the thread prior.

>There have been concerns expressed about delamination,

Actually, they were actual observations.

>and I intend to play with it a bit, but based on what I've seen with aircraft, I don't think it's an issue.

Oh, so what Rob and Rick experienced didnt happen? You did read the thread?

>I happen to have a copy of Burt Rutan's "book" Moldless Composite Homebuilt Sandwich Aircraft Construction right here on my desk, copyright 1978..... I've owned it since about '81.

Neat?

>Dick Rutan and Jeana Yeager flew Burt's Voyager aircraft non stop without refueling around the world in December of '86.  Voyager had blue XPS foam core with carbon fiber over it on it's 110' 8" long wings.

Right. But do you know what GRADE of blue foam it was?

> All that said, I've considered delamination, as so many people seem to think it to be a potential problem

Actual problem. They actually experienced.

>.........  not from actual experience anybody had with delamination it would seem, but just because..............

Did you just call 2 prominent posters on this group liars?

Well nice to meat you StoneTool! Can't wait to see what you top this with.

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