Any suggestions on how to paint a previously painted spar on an Irwin 30? I have no idea about who manufactured it or what they originally used to paint it.
Thanks for the question. Aluminum is a difficult surface to get paint to bond to, so you'll have to approach this project carefully. Our rigging experts at SailNet's Custom Spar and Rigging Shop in St. Petersburg, FL recommend that you start by cleaning the spar, sanding down any rough spots, and then etching it with an application of phosphoric acid. After you wash the acid off, immediately treat the surface with a zinc-chromate primer. Then you can add your top coats. We usually recommend a linear polyurethane paint. If you've gone through the preparation as I oultined it above, you shouldn't have to worry too much about the adhesion between the old paint and the new; the acid wash will allow the primer to coat the old paint, and the top coats will bond with the primer.
For additional information on this topic, you might want to contact Jack Corey in the SailNet Custom Spar and Rigging Shop (800-234-3220, ext. 1298).