Bonding Acetal with Adhesive
Bonding Acetal for Maximum Strength
Acetal is a popular thermoplastic, its use spans a number of industries. This plastic is fairly low cost and has good structural properties – it is often used instead of metal. It is very high strength, with good impact resistance, low rate of water-absorption, good chemical resistance (even against solvents), high dielectric strength and good flame resistance. Acetal is available in a number of different blends e.g.
- Glass filled
- PTFE filled for improved slip properties (low friction)
- Toughened, abrasion resistant
- UV stabilised, pigmented
A common trade name for acetal is Delrin (DuPont). Acetal material is often used for cogs, gears, plastic bearings, conveyor rollers, impellers etc. where the low friction surface is particularly important. Pump housings, motor housings and some pipe fittings may also incorporate acetal parts.
Joining Techniques and Surface Preparation for Bonding Acetal
Normally for joining acetal to acetal a welding technique would be used (e.g. heated tool, hot gas, spin or ultrasonic welding). However, if you are bonding acetal to other materials such as metal then an industrial adhesive is a good option. As the material seems to have quite a lubricated surface then roughening it up will help improve adhesive keying and bond strength. Grit blast, wire wool, red ScotchBrite or gritpaper or emery cloth can be used.
Selecting an Adhesive
Cyanoacrylate adhesives when used in conjunction with Permabond POP Primer achieve the highest bond strength – for extra toughness, impact resistance and temperature resistance, Permabond 731 is a good choice. Heat cure epoxies (such as Permabond ES5741 for difficult plastics) also perform well. Threaded parts can be bonded with anaerobic threadlocker (providing an activator is used).
For more information on bonding acetal using industrial adhesives, please contact the Permabond technical team here.