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Video: Glue Aluminum
If you want to glue aluminum to aluminum, the special chemical properties of the light metal must be taken into account. Here you should use a special adhesive for metal if you want to glue aluminum.
Aluminum is comparatively soft and easy to work with, which makes the metal so attractive for DIY enthusiasts. A fine oxide layer also protects the precious metal from further corrosion. But it is precisely this "rust" that is the problem when you want to glue aluminum.
The problem with the oxide layer: The thin, invisible rust layer is brittle - the adhesive adheres to it, but it is so strong that the adhesive point breaks under load because the rust does not adhere to the aluminum just as firmly!
Connect aluminum: 3 types possible
If you want to connect aluminum components together, three types of joining are possible:
- Riveting aluminum: The technology is only used in the aircraft and shipping industry.
Welding aluminum: The precious metal can be welded using the IG / WIG / CMT process (metal inert gas welding / tungsten inert gas / cold metal transfer) or soldered. However, welding work is not very common for do-it-yourselfers for everyday repairs. Solder
A special solder wire makes connecting aluminum easier than ever
- Gluing aluminum: Today, good adhesives allow even firmer bonds than a conventional weld.
Why is the joint more durable when I glue aluminum? Since there is no heating, unlike welding, the precious metal retains its material properties (such as strength, internal tension, …).
However, this only applies if the aluminum has been correctly pretreated before gluing to remove the disruptive oxide layer on the metal. The preliminary work is …
… Degreasing: Remove dirt, oil, grease and other residues from the glue point (use fat-soluble cleaners, acetone, isopropanol) - then do not touch them with your fingers (attention: skin fat!).
… Roughen the glue point: Sand the area with sandpaper (grit P120 to P600), which removes the annoying oxide layer.
… Work quickly after sanding: The gluing should now take place within 10 minutes so that no new oxide layer can form.
… Important: degrease first, then roughen! Otherwise, just push the fat particles deep into the grinding grooves!
For the commercial sector, the bonding of aluminum is regulated in VDI guideline 2229. For example, adhesive joints on aluminum components should only be stressed on shear and parallel to the joint surface, but this may be neglected for DIY use.
If you want to glue aluminum, special two-component glue is the best choice. Aluminum is then bonded to aluminum using the contact adhesive method (wet both sides with adhesive, allow to dry, then join components together). Note the open processing time (pot life) specified by the manufacturer and do not load the adhesive connection earlier than the curing time has elapsed and the adhesive has reached its final strength.
Practical tip: If you want to glue aluminum to other building materials (wood, stone, concrete, …), pasty assembly or construction glue is also suitable. Applied in dense snakes, the power adhesive also fills uneven areas in the surface and holds aluminum (plates) firmly on the surface.
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Glue the right glue to the aluminum
Gluing aluminum is a specialty: In industry, so-called "construction adhesives" are used. The generally two-component adhesives then usually contain epoxy resins, acrylates or polyurethanes.
The following adhesives can also be used to glue aluminum:
- PUR adhesive with primer
- Epoxy resin adhesive
- Methacrylate adhesives
- MS polymers