Question: We are having trouble getting our Treadmaster deck covering to stay stuck to our bare aluminum deck. What can you tell me about getting epoxy to stick to aluminum reliably?
Answer: We did not have to stick our Treadmaster to bare aluminum, but rather to the filler that covers the entire boat. However, we do have some experience with getting WEST SYSTEM epoxy to stick to aluminum since that is what we use, thickened with microlight powder, to repair any dings or corrosion problems on the hull fairing.
Here is what I know:
- You only have about an hour after grinding aluminum to get the epoxy on it before the aluminum oxide re-forms. Once this happens you will not get a good bond.
- For the very best adhesion, we use the WEST SYSTEM two part acid wash treatment first and then make sure we get the resin on within one hour. This is about the only way we have found to make absolutely sure that the resin stays bonded to the aluminum. The down side is that the chemicals involved are really nasty.
- If you don’t wish to use the nasty chemicals in the above, a useful trick is to “wet sand” the aluminum using 80 grit wet or dry paper and the un-thickened WEST SYSTEM resin. This keys the resin right into the aluminum and does not allow any oxide to form because the wet resin keeps the air off.
- When bonding, WEST SYSTEM resin works a lot better if thickened with the appropriate powder. We used colloidal silicate on the Treadmaster job, available from WEST. You get much better void filling this way.