Clear coat sealer for cast iron

A. According to a metal sculpture workshop I took in preservation of metal/bronze items, the best coating is marine varnish with a UV additive. Even with that, the maintenance on the item should be every 6 months for upkeep. There is a book by Ron Young "Contemporary Patinization" that explains the care of outdoor fountains from rust and bird poop =>

"You must put a stop to rust..."

A. I was looking for an answer to this and have found on other sites a reference to a product called POR-15 [affiliate link to product info on Amazon]; I have not tried it yet, but will give it a shot. I just thought I'd share.

It is ridiculously expensive though :-(

A. The full process details would have been more helpful, but try heating the cast iron bathtub at 120 degrees C for about 30 minutes Effective Metal Temperature. That will drive the moisture out from the porosity inherent in the casting. All to cool before you carry out the next step but do no leave it long without the protective coating. All the best.

Gurvin Singh
Coatec India

Mohali, Punjab, India

A. Gurvin has a great idea. Another way is to use multiple steps, similar to the steps you are using now but to add a few additional steps. For example, you may need to use more than one coat and not just go straight to the lacquer, instead use a primer prior to final top coat. You may find it's best to use a color that mimics the original coloring or go with something more common like black.

Hi and many thanks for the responses, much appreciated. I will update once we have come to a resolved state of play.
Regards
Steve

I am also looking for a finish to stand the elements. This company claims to have a product specifically for fountains called Permalac 2k

A. Hi Barbara. I'm surprised that it's made out of cast iron rather than brass or bronze. But I think the thinner single-component coatings like Everbrite [a finishing.com supporting advertiser] are best towards not distorting the peal of a bell than heavier two-component coatings. If it actually is brass or bronze you might consider brass lacquer [affiliate link to product info on Amazon] because they are periodically redone fairly easily.

Regards,

A. Hi Bjean. Unfortunately I think your plan to maintain that lovely statue is unlikely to work. Clearcoats are not shrink wrap and will not stop the paint from flaking. Applying them on top of flaking paint and loose rust will likely only result in the clearcoat and paint coming off together.

But try a thin penetrating clearcoat like Everbrite [a finishing.com supporting advertiser] and hope for the best. Eventually you may want to have it abrasive blasted and phosphated before painting.

Regards,

A. Hi Harry. That's as much a question of taste as performance. Easiest and most durable would be black stove paint; it's made for the job. But covering up your polishing work with black paint may not satisfy you. You can also just do a clearcoat, assuming the atmosphere is not excessively corrosive. A middle of the road solution, and the one I'd prefer is stove polish; it is gray and matte, but does let some of the character show through.

You mentioned the weight of this fireback, which may limit how you can handle it, but ideally it should be spaced out a bit from the wall rather than being bolted tight to it because the way such a device helps provide fireproofing is by being cooled by the air, and it's able to do a better job with air flowing on both sides of it, and not conducting heat directly to the wall.

Regards,

Thank you, Ted. I used the stove polish you show in your answer to buff it up after I got all the rust off with a wire brush. It looks great, and I think I'm taking it as the middle road you suggest. I especially appreciate your suggestion about the space between it and the wall. It may have the be a small space, because the gap between it and the wall will be small, since the bottom will fit snugly between the burners and the wall. I'm thinking this will help keep it in place. But I have space above the burners and may lift it to accommodate the a gap.

Thanks again. I'll let you know how it turns out.