There was discussion about replacement foam, and few went into aerogels, but then someone suggessted this: http://www.grantadesign.com/solutions/metalfoams.htm I was pretty intrigued . . . the site says its strong and stiff . . . but its metal so they can work it so it’s flexible (like damascus or spanish steel) And since its metal it can be shaped fairly easy, and can be strong. Anyone know anything about this? Or want to comment?
very high tech possibilities but checked one web site manufacture,price this is what they said,Pricing The price of Duocel foam varies tremendously depending on size, shape, complexity and quantity. For moderately sized items in simple shapes without much fabrication complexity such as heat treatment, anodizing, plating or brazing, the price can approach the raw material cost as noted below. However, for prototype quantities of complicated, high-precision parts with significant additional fabrication the price can rise to $200 per cubic inch or more. Most parts tend to fall in the $1 - $30 per cubic inch range however. The most best way to determine exact pricing for your application is to explain your specific configuration to our engineering staff so that we can provide you with a quotation.
If the aluminum foam is in something like an “0” condition it is soft and will probably require heat treat and age. Depends on what condition it would need to be in to work. If you have to heat treat it best to be done prior to shaping/machining to avoid distortion. The material designations (6101 I think ? at ERG) is unfamilar to me - sometimes certain material alloys require an entire furnace load dedicated to the material to HT or age - expensive if that’s the case! Not to mention you can’t get that stuff done just anywhere. Sounds like any of these would still need some kind of skin bonded on for comfort if nothing else. As for shaping, I’m thinking you would wind up having to machine the shapes, in which case the machined polyurethane blanks and end product boards would probably cost a fraction of a metal foam board. Still, interesting idea…
O-temper aluminum would be difficult to machine if you used traditional cutting tools such as a lathe, grinder, or planer. The soft material would gum up the blades. Apparently the metal foam is primarily used in sandwich type construction with an outer skin. It is also used in conjunction with foam as a stiffening agent. It looks to me like the biggest problem would be with corrosion resistance and sealing the final product. Saltwater is corrosive to most aluminum alloys. As pointed out, O or F temper material would need to be heat treated to get full material properties after shaping. Solution Heat treating usually occurs at temperatures just below melting point to help align the grain structure and give final strength properties to the finished product. This heat usually causes significant distortion and warping. You would not really be able to maintain rocker and twist through this process. High tolerance aluminum tubes are usually sent through a straightening and rounding process after heat treat. A lot of the heat treatment is determined by the type of alloy, 7005 which is used for many bike frames and such can be heat treated and aged in a big oven. 6061 usually needs a full solution HT to get to T6. It’s done in a salt bath that would cook your bones to jelly in minutes. Given these issues, I don’t think we’ll see much tinkering from the surf industry, we still think epoxy glassing is a black art.
An inventors axiom: new materials often require fresh paradigms, new tools and methods of fabrication. Just because the means of creating something must first be developed, doesnt mean the end result wont be cost effective, or without merit. Oftentimes the greatest barrier to thinking "outside the box" isnt a lack of ideas (there`s plenty of them around)… it has more to do with (1) money (2) a willingness to work, fail and persevere… than any other factors.
I say use it minimally if it’s so High tech,…perhaps as a high density foam stringer in an otherwise stringerless board, but then tooling might have to be changed. Or perhaps the foam could be used as the core of a fin. just an idea.