blog.bharper: the blog of brandon harper

Just a couple of car related posts today.. the first being this message from someone named “Mike” on the RMSolo e-mail list on his personal experience with rust problems and products to use when trying to get rid of rust:

I’m currently doing a frame off on my Datsun Roadster and can answer quite a few questions about rust removal and prevention and preventing what you just cleaned off from turning into a much more even coat of rust. My “garage” is made out of HF tarps and duct tape attached to one of those car canopy things so I’ve tried a few anti-rust methods. For rust removal Home Depot sells Krud Kutter brand Must for Rust, (quarts only at $6.97) spray or brush on let it dry and it forms a powdery white / bumpy black coating that will prevent rust if not washed off by excessive moisture. Must for Rust must be cleaned off (more M for R and water rinse) before painting. Diesel fuel, sprayed or brushed on will prevent rust and attract dust and kill insects, cheap but you can’t paint over it. Sherwin Williams “W4K288 MET-L-ETCH” steel cleaner, available at most auto paint suppliers will prevent rust (2 months in the duct-tape garage so far), spray or brush, let dry and remove surface scale that forms with steel wool, the surface is then ready for primer. POR-15’s Metal Ready product is another one that works like the other two and you can paint directly over it with POR-15’s paints after dusting off the excess powder that forms. Metal Ready kept rust from forming for the month before I was able to paint and seemed to resist moisture pretty well. Phosphoric acid is the main ingredient in these products (except the diesel) and they form a phosphate coating of some type that prevents the rust, M for R and Metal Ready have zinc and Met-L-Etch has 2-Butoxyethanol, I’ll leave it up to the chemists out there explain further.

For paints POR-15 is what I’ve used so far but I’m considering Rust Bullet for my next round of rust prevention. POR-15 is available from Dale’s Paint in the Springs and from Auto Body Supply who have stores in Denver and CS. I’ve also ordered direct from POR-15 at www.por15.com with good results, everything in stock and quick to ship so far. Rust Bullet is available from www.rustbullet.com and probably local dealers. POR-15 and Rust Bullet are similar in price and each have their advantages. Rust Bullet claims best rust prevention and less surface preparation and can be top-coated without special primers or preparation. POR-15 requires it’s Tie Coat primer or sanding before top coating. POR-15 is a system that can also be used with fiberglass for patching, they have body fillers, industrial and marine topcoats, and other items. Rust Bullet make the paint only. Between the two the Rust Bullet is less labor intensive in some situations, small area of rust, no special prep for top coating. POR-15 forms a very hard and slick surface that requires either POR-15 Tie Coat Primer or sanding before top coating. In hard to get to areas I think the Rust Bullet paint would be easier to use and prime over. POR-15’s patch system definitely works better on holes and reinforcement of rusty areas. Reading the application notes I think both products are very similar, my suspicion is that POR-15 leans to more solids and Rust Bullet goes for the adhesion side, cost is about the same either way.