Hi Ramrod, Ive never seen anything special about gluvit except that it is a little thinner than the average epoxy's and the price. All epoxy's stick to properly prepared aluminum and most all epoxy's are flexible at least to a an extent, there are epoxy's on the market witch are more flexible than most and are used mainly for repairing plastics. In the old days when we needed the epoxy to be a little more flexible we simply increased the hardener ratio. For instance one of the epoxy's we sell e-bond hardener ca370 for laminating is usually mixed 2 to 1, but as per the manufactures instructions can be mixed 50/50 for a more flexible required application. Stop-Rot is a thin epoxy like gluvit and can be used in other applications other than stopping rot but it is best suited for the purpose it was designed for. It gets very hot when mixed witch helps steam the moisture out of the wood while curing, there also is a chemical in the stop-rot that helps it cure even in a wet environment. Another plus is when mixed with a power mixer getting as much air blended in as possible, like making an omelet, when all the little air bubbles start to expand from the heat produced by the activating epoxy, it expands similarly to the expanding 2 part foams and subsequently fills the voids left by the rotting wood. PS always be careful when trying to seal seams with anything, because if there is dirt,mold, corrosion or i think you get what i mean in that seam nothing is going to stick inside the seam where you really need it to stick unless it was cleaned and sanded before you but it together. CYA later Danny from fiberglass supply depot.