[kpbrown31]

I plan to put my car up on my lift and try to blast some of the surface rust off the frame, rear axle and other various parts on the car. It seems people on here report pealing with POR-15 on bare metal.

My question is what you all are using as a good coating for bare metal. I've seen DP90 epoxy primer mentioned on here a couple times and considered that, but wanted to see if anyone else had opinions.

[GTOLiam]

I'm interested in other opinions on this as well.

Here's a video comparing some coatings including POR-15 that might be of interest to you https://www.youtube.com/watch?v=oBOAkpujGBM

I think I'm just going to stick with SPI epoxy on properly prepared surfaces unless I'm convinced otherwise https://www.southernpolyurethanes.com/epoxy-primer

[Flynbye]

Epoxy is your friend here. Go with it.

[carcrazy]

DP-90 works well (but not cheap).

[roger1]

X3 for epoxy and nothing else except undercoating in the wheel wells. I used SPI black epoxy primer after blasting.

[kpbrown31]

Originally Posted by roger1

X3 for epoxy and nothing else except undercoating in the wheel wells. I used SPI black epoxy primer after blasting.

Very nice. This is along the lines of what I'm looking for as I'd like to do the engine bay area as well. You use a standard rubberized undercoating in the wheel wells you say? For added durability I assume...

[roger1]

Yes, I used the rubberized spray can undercoating in the wheel wells. For durability and for less noise if a tire throws a small stone.
One thing I did that I didn't mention is I spray the first coat of SPI epoxy using gray. This helps me get a more even second coat using the black. I do the same thing when painting frames.
Do check out the epoxy primer from Southern Polyurethanes Inc. There is none better and it's reasonably priced. Customer service is second to none as well and shipping is free. They have their own forum too and members are mostly professionals.

[HoovDaddy]

There are many ways to do things. I have always used an acid cleaner on bare metal prior to priming, it really improves adhesion and corrosion resistance. PPG SX579 super cleans and preps the metal, followed with SX520 which conditions the metal and leaves behind a layer of zinc phosphate for further corrosion resistance and improved adhesion. PPG DP Epoxy allows you the acid prep advantage. Whereas SPI is strictly a direct-to-metal primer, and they only recommend their Waterborne Wax and Grease Remover as a cleaner. The acid treatment gets into areas you can't get into with wax and grease remover and a rag, and wax and the grease remover remover needs to be wiped dry afterwards. The acid is rinsed with water and blown dry, less contamination. SPI is a great product and it's my go to after applying DP for all of my prep and block sanding, I just don't use it directly over bare metal.

[GTOLiam]

Originally Posted by HoovDaddy

There are many ways to do things. I have always used an acid cleaner on bare metal prior to priming, it really improves adhesion and corrosion resistance. PPG SX579 super cleans and preps the metal, followed with SX520 which conditions the metal and leaves behind a layer of zinc phosphate for further corrosion resistance and improved adhesion. PPG DP Epoxy allows you the acid prep advantage. Whereas SPI is strictly a direct-to-metal primer, and they only recommend their Waterborne Wax and Grease Remover as a cleaner. The acid treatment gets into areas you can't get into with wax and grease remover and a rag, and wax and the grease remover remover needs to be wiped dry afterwards. The acid is rinsed with water and blown dry, less contamination. SPI is a great product and it's my go to after applying DP for all of my prep and block sanding, I just don't use it directly over bare metal.

This is worth a watch and shows varies tests with SPI including an initial failure after using acid and then success .....check out 12:45 for the correct combo
https://www.youtube.com/watch?v=-yA8q4K-_Bo