I used a gallon of por15 today

[JayDarden]

I painted the steel base of a very rusty communications tower with por15 today. First I scraped the loose rust then I sprayed with Marine Clean and rinsed. After letting it dry overnight, it still was a little wet. I used a propane torch to dry the rest off. I then painted the metal with gray por 15. It had a lot of small "holes" where bubbles popped and left a small void. I put a second coat on with the same results and found that if you wait until the paint is half dry, then brush back and forth over it, the paint covers some of the holes. I tried putting it on thin and thick, and the holes reappeared. I don't know if the small holes are just cosmetic, or if water will be able to reach the metal below, time will tell.

When I remove my engine this summer and paint everything, I will scrape and grind the metal much smoother. The sections that were smooth came out great. Also heed the warning about wearing gloves as this stuff will tattoo you.

Has anyone had the same experience with bubbles?

Should I topcoat it as is? Or is there something I can do?

[Zeke]

You must have had some contamination. The least amount of oil spread around during cleaning will "fish eye." Or was it in the direct sunlight? I think oil or something with silicone in it like WD 40. Lots of stuff has silicone in it. Probably even your shaving cream. Hard to get rid of, especially on porous surfaces.

[John2kx]

Jay,

I'm no expert on Por 15 but have used it to coat the inside of my doors and am in the process (today) of installing the truck restoration kit on my '73. This kit consists of about the same things you used except uses "chassis black" as the final coat.

The bubbles you describe sound just like what I see on the Por 15 website when they show the product being applied to a rusty battery tray. The finish on this piece seemed to have a less than desirable finish as compared to a freshly painted fender using normal car paint.

I think the bubbles are formed when the product enters the pits in metal.......maybe some chemical reaction occurs during the drying process that forms a bubble in the pit???? My trunk has pits in the metal even after I grinded most of the rust out. I believe the cure for this is using the epoxy filler that is applied between the first and second coat. This two part filler is applied and then sanded to a smooth finish.

I should know within the next 24 hours......as soon as the sun rises, I'll start the process........chemically treated the trunk last night and allowed it to dry overnight.

My engine is out and the next area to attack will be the engine bay. I'm hoping for a nice finish on both the trunk and engine bay prior to stuffing in the V8. Wild Bill shipped engine yesterday and this has sure got the ball rolling.

[Germain]

I've used Por-15 alot. Normally all I do brush the surface to remove the loose rust, and then clean the surface with a power washer. I then paint, not marine clean, no other cleaner. Never had any bubbles that caused holes on the Por-15 paint. The surface isn't perfectly smooth, and there are color changes in the paint. When I have used Por-15 on an area I wanted to look real nice (not a frame) I always apply 3 coats, sand between then with 150 grit paper, and on the last one wet sand using 1200-1500 grit. Then paint with a nice black or gray or what ever color you want.

HTH

[John2kx]

Jay,

Applied the silver followed by putty to fill voids and cover the glass cloth supplied with the trunk restoration kit. No bubbles what so ever in the entire trunk. Nothing special .......just followed the instructions as provided.

Any instruction that stated to "ensure completely dry before applying the product" was allowed to sit overnight to ensure complete dryness. This was also done indoors. Maybe the torch did not get your surface completely dry??????

The black chassis coat goes on tomorrow evening.


Interesting point with respect to sanding between coats for a nicer finish. Come to think of it, I should have used a tack cloth prior to applying my first coat of silver. I did see small particals of metal/dirt/etc. during the application but it was too late to stop at this point. I did blast the surface with my air tool but assume the trunk was too large an area for this to be effective and the fact that the trunk walls prevented all particals a path in which to escape.

The silver did flow nicely with a brush. Several of my buds could not believe a gun was not used (myself included).

This job has taken longer than I thought and mostly due to my experience with the product. The putty available from Por 15 reminded me of my first sheetrock job. .............only put on what is needed. This stuff is as hard as supermans kneecaps and takes alot of sanding to remove.......especially in tight spots where you can't get in big johnson sander. After more hand sanding that I could stand, I purchased one of the small dremel sanders (triangular shaped head). This was slow going. I guess I learned from this job and should be able to reduce my labor by 30-50% on future jobs.