As above, I've used that to bond halves of wings together and not had a failure yet

I generally consider an adhesive to be something which adheres with a chemical bond, in this kind of setting. Hence I roughed the carbon with 240 grit and degreased the alloy in acetone. Using an adhesive that bonds, this should be sufficient. It would appear that the 515 adheres in the same manner that a silicone sealant does, and not with the tenacity of a cyanoacrylate or - even - the epoxy resin used with the carbon fibre which seems to actually adhere to aluminium pretty well.

Of all of the miles ridden on the framework built, the only failures I had were on joints where the ET515 was used, which I had to reinforce, en route, with garden wire (fancy).

What I learned is that carbon is a material that can be used for fabricated structures, however that any interfacing between it an another material is past what I can handle with my limited experience. ET515 is not the right adhesive, this is for sure. We traveled over 250 miles with 20+kg of luggage on carbon framed racks www.laureltache.tumblr.com

at over £30 when you include the syringe, nozzles and adhesive, ET515 is a very expensive mirror-tack.

If you are adhereing it to smooth (albeit degreased) aluminium then I would have expected the results you have had. This is why we advise keying BOTH surfaces.

We have had people use it for quite high loadings when joining tubes, certainly in the hundreds of kilos range on short tubes as well as additional shock and vibration.

Both the glue and resin are epoxy.  What i think has happened is the thinner epoxy resin mechanically bonded with the fine scratches on the surface of the aluminium, where as the more viscous epoxy based adhesive won't have flowed into the scratches as they are too fine.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

For future reference, I've just had confirmation from customer service at Permabond that the correct adhesive for structural bonds between, for example, metal and composites is their ES550 and ES558. They are described as: