Bonding surfaces is one thing, but making sure they stay stuck is quite another. The strongest adhesive on the market is two-part epoxy adhesive. The reason it comes in two parts is that one is the adhesive itself, while the second is a hardener. The parts must be kept separate until they are used. They become extremely effective and very hard-wearing when mixed.
What materials are you bonding?
Metals need metal bonding adhesives, and the integrity of the bond depends entirely on you choosing the correct type for the job. The effectiveness of epoxy adhesive is specific to the materials they have been developed for, and there is no point in using one that is intended for wood if you’re bonding metal.
All metal bonding adhesives will have been tested to the point of destruction before they ever appear on the shelf. Read the manufacturer’s literature, as they will have spent as much time and effort on this as on the materials themselves. There are no cutting corners where this product is concerned.
Say you’ve researched metal bonding adhesives and you’re happy you’ve got the right one. Before applying, consider safety first, and always use rubber gloves and safety glasses. You will need a mixing tool (preferably metal) and may need a weighing scale, depending on the size of the job. For safety advice, see the HSE guide to working with solvents.
Most importantly, the surfaces must be completely clean (preferably abraded beforehand) and wiped free of residual marks. Even oily fingerprints can prevent the adhesive from bonding properly.
Mix by hand or tool, depending on the size of the job. If you have a cartridge (prepacked) application, this should be poured at the same time into a suitable receptor. Use a mixing tool for bigger jobs, but make sure the tool’s materials do not compromise the effectiveness of the adhesive. Again, read the literature.
Once it’s mixed, use the adhesive immediately. It will cure (dry) at room temperature. Roughly 100 grams will take around 25 minutes, but smaller amounts or thinner layers will take longer.
In your efforts to keep costs down, you would be ill-advised to try to do this by buying the wrong product and your savings will have been in vain. The correct purchase of a quality product will give great results.