AIREX Foam core

[Brad Seger]

I have a specification that calls for a 5 lb AIREX core that is 3.25" thick. How do I join sheets of AIREX together to get the thickness? I've only been able to find sheets that are less than an inch thick. They will be covered with fiberglass and used as engine stringers.

Thanks

[tonyw]

Originally Posted by Brad Seger

I have a specification that calls for a 5 lb AIREX core that is 3.25" thick. How do I join sheets of AIREX together to get the thickness? I've only been able to find sheets that are less than an inch thick. They will be covered with fiberglass and used as engine stringers.

Thanks

I have laminated sheets of Dininycell together when building Tornado catamaran hulls. Basically you can stick them together with resin, I use Vinylester for virtually everything else but I use unwaxed iso for laminating core. It is advantageous if you add a mix of Q-cell to the resin & make it pasty (this helps to fill the core & keeps weight down, although for stringers in a boat weight wouldn't be an issue). You have to perforate the core at regular intervals to allow the resin to spread & prevent air entrapment. This may also not be an issue for your application. You have to apply plenty of weight to the sheets (I use a vaccuum pump), but for what you are doing you can probably get away with Besa blocks or similar. The main thing is to get the pressure as constant as possible. Remember, you're not looking for super strength here, you just need to make the shape, & the laminate around the outside gives you your strength.

[War Whoop]

You can use B-70 Core Bond from ATC Chemical But if you like Epoxy then Spa Bond 740 From SP Systems.

[brian eiland]

Just make sure you are not bonding the sheets of core material together in such a manner that they will experience large shear forces in line with these bond lines. You want the forces to be perpendicular to these bond lines....and preferrable this bond line to exist on the neutral axis of the 'beam'. Even then, multiple layers of core material is not such a great idea.

And don't use poylester resin...the only thing it really likes to stick to is your shoes and your skin...it doesn't even like to stick to itself!