Engine bay painting & rust restoration questions

[Pete_89T2]

I removed my engine on my '89T2 to do a turbo rebuild & upgrade, and while I'm waiting for the turbo to get shipped back, I got into trying to detail the engine bay. Ran into two annoying problems, see pictures...

1. Some rust under the area where the ABS pump used to be, at the point between where the crossmember & frame rail meets and on spots on the inner fender down there. Years ago, the ABS pump leaked, and I had the bypass job done. At the time, the brake fluid stripped the paint there down to bare shiny metal, so I cleaned, prepped, primed & painted it as best I could with rattle can automotive paints. Apparently I didn't do as good a job as I thought.

2. I also noticed that in the past 2 weeks that my car was sitting in the garage with its engine out, the brake MC sprung a nasty leak! Fluid level in the MC dropped by at least 3/4", and it really stripped the paint well as can be seen in the photo. I'm just glad this didn't happen while the car was being driven. Makes me wonder if I banged into the MC or leaned on it too hard while working in there? Oh well, Mazda gets more of my $ again!

I'm looking at trying those POR-15 rust prep & paint coating products to deal with these two problem areas permanently. Since my T2 is black, color match won't be a problem. Have any of you used this stuff for similar restoration work? I found an online retailer that sells a POR 15 "starter set" that is good for cleaning, prepping & coating/painting up to 6 square feet for about $30. The paint/coating part is applied by brush, which should be OK since I have access to everything. The 6 sq. ft. amount is just enough to cover what I need, so I ordered it to try it out. My only concern is if it can stand the heat being a few inches away from the turbo & DP on the right side. Anyone know if that would be a problem? They claim this stuff it's suitable for painting engines, so I would guess it can handle a painted surface temp of at least 200*F.

[speedjunkie]

Let us know how that POR-15 holds up. I've been looking at some of that stuff myself. I also found Eastwood paints when I was looking for something for the engine itself, and I thought about using it for the engine bay as well since it has a good heat rating.

http://www.eastwood.com/ceramic_engine_paints?srccode=ga130050&gclid=COOxr4rnz6YCFQYLbAodiR35IQ

Also, I've been looking at this hand held media blaster for the prep work so I don't have to sand everything by hand...

http://www.amazon.com/UNITEC-Gravity-Speed-Blaster-Sandblaster/dp/B002C8E4YG

Someone suggested it and to use baking soda since it's water soluble, so you can wash it away when you're finished. Have you ever looked into anything like that?

[Pete_89T2]

I'll let you all know how it turns out. My starter set just arrived yesterday via UPS, so I'm getting myself familiar with the directions first. With the cold weather here, looks like I'll need to get a small space heater to keep my garage work area temperature over 50*F. Directions say to apply in temps between 50-90F, humidity under 80%.

[FD3sAutobot]

I'm liking the baking soda idea. After looking up more info on it, soda blasting is pretty cool. The baking soda is perfect for stripping paint. When I get back home I want to strip my engine bay down and repaint also. Looks like I might need a bigger compressor though.

[project86]

If i recall correctly POR-15 is a rust conversion fluid yes? I dont know if ive used that exact one but i have at least used a similar rust conversion fluid.. applied with a brush and all. it works great. The area does still need to be prepped though.

[firzen]

This may be helpful:

http://forum.eastwood.com/showthread.php?1431-Proper-Usage-of-Eastwood-Rust-Products?SRCCODE=1EM0534&utm_source=bm23&utm_medium=email&utm_term=Map&utm_content=Nick%27s+Picks%3A+What%27s+the+key+to+ beating+rust%3F&utm_campaign=1EM0534+2-7-2011+Nick%27s+Picks+-+Rust+Solutions

[Pete_89T2]

Well I finished using the POR-15 starter set to deal with the rust & stripped paint problem discussed in post #1 of this thread. So here is my POR 15 review & update. BLUF is POR-15 and the associated prep products that came with the starter set are great products, and not all that difficult to use if you can follow some simple directions.

The starter kit can cover an area of up to 6 square feet, which was more than enough for my little job. It came with a 4 ounce can of POR-15 rust preventive coating, an 8 oz. bottle of "Marine Clean" cleaner/degreaser, an 8 oz bottle of "Metal Ready" metal prep solution, a pair of heavy duty latex gloves, 2 paint brushes (1 foam, 1 bristle, about 1 inch wide each), and an instruction sheet plus a magazine-style catalog that describes the rest of the POR-15 product line up and provides some handy how-to info. I picked the semi-gloss black POR-15, the other choices are gloss black, silver & gray, IIRC.

In my case I was dealing with both bare shiny metal (stripped by brake fluid) and some surface rust spots. Reader's digest of the process is:

(1) Wire brush/sand off any loose paint scale & flaky rust if applicable -- just the loose stuff - you don't need to bring it down to bare metal
(2) Clean & degrease thoroughly with the Marine Clean solution, rinse with water & let dry.
(3) Prep the cleaned bare or rusty metal surfaces with "Metal Ready"
(4) Paint cleaned & prepped surfaces with POR-15 rust preventive coating (2 thin coats recommended)
(5) Optional but recommended - topcoat with paint of your choice. The one weakness of POR-15 rust preventive coating is that the pigments will eventually discolor if regularly exposed to UV light, hence the need for a topcoat.

For the cleaning phase, you dilute the Marine Clean with water. They recommend using no more than a 1/1 ratio (Marine Clean/water) but less concentrated solutions up to 1/10 will work on lighter filth. Hot water improves the effectiveness, so it's best to only mix what you need when you need it. Or if you choose to mix a batch in bulk, store it in a container that can be immersed in hot water to heat it up just before use. I was very impressed with this stuff, it worked better than any cleaner/degreaser I've used in the past to clean parts (i.e., brake cleaner, Castrol Super Clean, kerosene, etc), and I had plenty left over to clean other things. I used it to clean the carbon crud off the insides of my UIM & LIM and it literally dissolved that stuff in no time.

Once the cleaning is done and surfaces are dry, you apply the Metal Prep solution full strength with a bristle brush. You keep the surfaces wet with Metal Ready for 20~30 minutes, then thoroughly rinse off with water. Metal Ready is acidic, so it etchs the bare metal & painted surfaces just enough to give them a bit of "tooth" for the POR-15 to adhere to, and it leaves behind a zinc phosphate coating.

When the surface is bone-dry, you can start applying the POR-15. I used the foam brush for that, and did the 2 thin coats as recommended. POR-15 needs to be applied in temps between 50~80, and it actually cures faster in high humidity - opposite of most paints. Anyway, you can apply the 2nd coat after the first coat is a bit tacky but firm (i.e., you won't leave fingerprints on it, but you can feel the drag if you run a finger across the surface). It took about 4 hours between coats, but my garage was probably below the recommended temp when I applied it, around 40~45*F. When the 2nd coat of POR-15 was fully cured (I gave it an overnight), I used some black engine enamal to topcoat it. The pictures are the "after" result, see post #1 to this thread for the "before" shots.

Regarding durability, I decided to test POR-15's hardness claims. I painted a small piece of 1/8 thick scrap AL stock with the 2 thin coats. After it fully cured, I put the AL strip on a small anvil and started whacking it with a ballpein hammer -- I could not get that stuff to crack, chip or flake off; even after mashing the AL thinner than it's original 1/8" thickness, the POR-15 stuck to the AL substrate without compromise.