Old Airex Core

[SteveT44]

I'm going to have an initial look at a custom amateur one-off that was launched in 67. The current owner states that the hull is Airex cored with a ply cored deck. It's my thinking that the hull was probably built over a wood and batten plug in which the Airex was applied to that then the outer glass would have been applied to the foam wetting out with hand rollers. The inside would have been glassed similar once the hull was turned over. It's my thought that hand wetting-out of the glass to the foam would have established a fairly complete bond.

I was wondering if anyone could possibly comment on the quality of Airex and resin that the typical home builder would have had access to in the mid 60's? Also, if anyone could comment on the longevity of the resin/Airex bond after 40 years? The boat is Canadian built, one of the eastern provinces I think.

BTW, this is my first post on SailNet, hello everybody!

Steve

[sailingdog]

Welcome to Sailnet, Steve.

Airex was a pretty common foam core material for boats, and several production manufacturers used it. It is still in use today and is still one of the preferred foams, especially for the hulls of multihulls. CE Ryder used it in the Southern Cross series of boats, among others.

Bonding the foam to the glass skins is a bit of a problem in foam-core construction, since the foam doesn't wick resin up like end-grain balsa generally does. Usually a thickened paste or putty is used to help bind the foam to the glass laminate skin.

As for the quality of the airex and resin, it would really depend on the person doing the building... they could have gotten materials from any number of sources, some of which would be as good, if not better, than what production builders were using, and some of which were far less suitable. It is hard to say one way or another. The fact that the boat is 41 years old, and still floating says a good deal about it though IMHO.

I'd highly recommend you read the POST in my signature to help you get the most out of your time here. It has tips on searching sailnet, writing a good post, etc.. I'd also recommend you read the Boat Inspection Trip Tips thread I started.