I have been in the marine industry in salt...oops..South Florida for quite a while. Most keels on sailboats are iron and I had one customer that absolutely had to have his boat's keel stripped every year (of nasty bottom paint - it is heavy believe it or not, and he wanted to avoid the inevitable rust when he ran aground and the barrier coat of bottom paint was worn off exposing the keel. Iron and salt water are NOT a compatible combo.) He found a product at a local boat show called POR 15. I was skeptical of course. It is a bit pricey but is absolutely, without a doubt, the best stuff I have ever used. I used it on his keel with great success, and even took the leftovers (relatively short shelf life once opened) home and painted the rusted areas on my boat trailer and my 1980 Mazda. That was 12 years ago. The trailer is long gone, bearings/axle went..no rust! Still have the Mazda and there is NO rust where I painted with the POR! I have never had great success with Rustoleum. Last I checked, POR came in silver and black. If you don't want to spring for the POR, you may want to use a product called "Ospho" after wire-brushing the loose rust off that arbor and then applying an appropriate paint - oil based, brush on, read the instructions. I happen to like the natural, weathered, rusted look of iron. You could just leave it and enjoy its natural patina and save yourself a lot of money and work, but I see you are in So. Cal. where the salt will take its toll after awhile.

I just checked the POR website (I DO NOT work for them, I am just an impressed customer!) and it appears that they now have clear coats for metals. You can use it on your arbor and have it maintain its inherent iron beauty without having to paint it black or silver, and you will truly seal out the rust! Cool. Check it out!

http://www.por15.com/

If you compare their prices to the prices of other Home Depot paints that claim to seal out rust and figure out how much Brand "R" you will need to complete your project, I think that POR is, in the end, competitively priced...plus, I guarantee that you will be happy! Have I ever lied to you before??

Amanda

Thanks Amanda. And no, you have never lied to me before...

Amanda, you have answered a question that I have been trying to get answered at the "big box stores" for years.

I KNEW there were products that marine businesses had to be using to prevent rust and corrosion-- both on wood and metal. I KNEW it had to be possible to buy these for my outdoor furniture. But I could never find a salesman that had any clue if those things existed, if the stores carried them, and where I might find them if they didn't.

Kudos. I'm in your debt-- and will be buying some of this stuff soon!

Thank you so much Amanda,I will try this,as I'm sure this will last much longer than clear gesso!!