Brass is an alloy comprising zinc and copper. It is non-magnetic, resists corrosion, and is malleable. Various industries have brass bonding needs. Applications include pipe joints, hydraulic fittings, heat exchangers, door locks and knobs, munitions, and musical instruments.
A variety of different types of adhesives readily bond brass. Having so many options can make it challenging to choose. Sometimes choosing the right adhesive for each application is done by selecting the best cure process. Let’s look at the options.
Anaerobic adhesives cure in the presence of metal and the absence of oxygen. Brass is one of the most reactive metals, so the anaerobic adhesive will set up and cure much faster than the time listed for fixture speed on steel.
Anaerobic applications include threadlocking, thread sealing, form-in-place gaskets, weld sealing, retaining, and munitions sealing.
For threadlocking, permanent and removable grades are available in various viscosities (from wicking grades to high viscosity grades. Specialty products for use with potable water are also available. Product selection is based on the strength and gap (or bolt size).
Thread sealants are also available for sealing threaded pipe connections. Specialty grades for hydraulics contain no fillers which could cause blockages. Other specialty grades for sealing brass pipe include grades for use with oxygen, potable water grades, and UL Classified grades.
For form-in-place gasketing, consider Permabond LH197 is flexible and easier to remove from soft metals.
Retaining compound product selection is heavily based on gap fill requirements. They bond brass co-axial non-threaded joints permanently.
UV / Anaerobic sealants seal munitions. The UV light cures the surface of the adhesive, and then, the anaerobic mechanism cures the area hidden from the light by the brass.
Cyanoacrylate adhesives or instant adhesives are ideal for bonding brass. A common application is to bond pads to musical instruments. Methyl cyanoacrylates such as the original Permabond 910 form the highest strength bonds. Although cyanoacrylate adhesives form very high strength bonds, use structural adhesive if the bond requires resistance to polar solvents or impact.
Structural adhesives are adhesives that form bonds that bear a structural load. Examples include structural acrylic adhesive and epoxies. All grades bond well so you can choose based on the type of cure method that is preferable to your application. Single component epoxies cure with heat. Two component epoxies cure when mixed. There are several types of structural acrylics. First, there are two component acrylics that cure when mixed. Next are surface activated acrylics that cure by applying a water thin initiator to one surface and the resin to the other. Cure begins after joining the two components. Lastly there are Bead on Bead acrylics. A bead of one part is dispensed onto a bead of the other. Sufficient mixing of the two components occurs when the components are joined, and the adhesive is squeezed into a thin bond line.
