Rust Prevention Side-by-Side Comparison

POR-15 Rust Preventive Paint, Rust Bullet, and Eastwood's Rust Encapsulator were chosen for this as they are the three generally most common rust encapsulating products on the market.  The carrier in this experiment is a rusty piece of flat stock.  It was wire brushed to remove loose scale (as all three products recommend), then POR's Marine Clean was used to remove any oils and residues from the metal.  One end was treated with POR's Metal Ready in preparation of POR's Rust Preventive Paint (as per instructions).  The Metal Ready went a bit further than 1/3 up the stock, so the middle sample (Rust Bullet) has the advantage, or disadvantage, of Metal Ready for about a third of the sample.  It's a new wrinkle, and not part of the requirement for Rust Bullet.  We'll see how that works, as Rust Bullet only requires a wire brushing and use of a degreaser.  Ditto for Eastwood's Rust Encapsulator. 

POR Application:  The POR product was painted one layer, and then another applied about an hour and a half later, when it was finger-drag dry. 
Rust Bullet Application:  As required, two coats were used, with four hours between coats.
Rust Encapsulator Application:  Per instructions, two coats were applied, with one hour between coatings.

Paint Prep:  Por-15 was lightly scuffed with 220 grit sand paper, and then sprayed with POR's new Self Etching Primer.  Rust Bullet requires no prep to topcoat, as long as the coat is within 72 hours.  Eastwood's Rust Encapsulator requires a scuff coat using 320 to 400 grit sandpaper prior to coating.

Paint:  Though my original plan was to use white paint, I ended up not having white on my shelf.  As my color choices were limited to black (rust would be difficult to see), red (nigh impossible to see rust!), and silver, I chose silver as my topcoat.

Method:  Once the paint has had at least 48 hours to cure, a scratch will be made on one side, along the length of the sample, penetrating to the underlying metal.  The other side will remain un-penetrated.  The sample will then be placed into a plastic container, with enough water to cover the sample.  The sample will then be placed into a freezer nightly, being removed in the morning to thaw in the hot Houston summer climate.  These extreme conditions will promote maximum rust growth, and should show which of the three products, based in part on their application instructions, will ensure the longest, rust-free metal life. 

7/24/05

First coat: Rust Bullet (in silver), and POR-15.

7/24/05

Addition of one coat of Rust Encapsulator, and second coat of POR-15 when it was dry enough to be slightly tacky, passing the finger-drag test.

7/24/05

Two coats on everything (after one hour for the Rust Encapsulator, and four for Rust Bullet), and we are almost ready for top-coating. I'll have to use POR Primer for the POR-15, but the other two don't require an interface for paint.

7/26/05

POR Self-Etching Primer has been applied to the POR end of the sample. This will allow good adhesion between the POR-15 paint and the topcoat.

7/26/05

Ready for topcoat.

7/26/05

Coated in silver. Too bad I didn't have white, but this should serve almost as well.

7/31/05

I couldn't get the whole bar into the plastic container, so I chopped the bar between the samples. I also scratched a line down the length and etched identifying marks on each sample.

7/31/05

All of the bits are under water, sunny-side up. Sadly, the POR sample didn't fare too well with the hack saw. Luckily, the sample only took a cut for a small portion, and should not affect results.

8/3/05

It seems that freezing the samples, and then thawing them daily, is already paying dividends! The steel is rapidly rusting. However, no samples have breached the protective coatings, yet.

8/31/05

Each sample has been exhibiting tiny bubbles. But they are growing! Which one will burst first?

8/31/05

Here are the samples, names scratched into them, revealing which is which. The Eastwood looks worse than it really is. It just happened to be sitting on a pile of dissolved rust, hence the discoloration.

9/14/05

We have a breach! It seems that the POR-15 sample pinholed two days ago, and that pinhole now is a rust hole.

9/14/05

The interesting thing is that, overall, the bottom side, which has the scratch samples, is probably in the best shape. Odd. We'll continue this until we have another breach...

10/3/05

Final photos: Here are the tops. The samples have had loads of time in the torture chamber. From the top side, RustBullet looks to be the most cosmetically appealing.

10/3/05

The interesting thing is that, from the bottom, POR is the clear winner. Though there are small breaches in the POR, there is not the substantial rust creep where the scribe line has been placed. All samples have been scraped with a finger nail, and here you see the results. This experiment, for me, is done.