undercarriage rust

[mastershake]

so the underside of my car is rusted pretty bad... parts of the rear axle are coming off in THICK chunks.

what i'm wondering is if it's safe to flush the underside every time i wash the car (every 2 weeks) or if it will accelerate the rust even more...

[[ion] C2]

water speeds up the oxidation process. rust is a natural thing to happen between air and steel.

coat it with something.

[mastershake]

can you recommend any spray products? i was looking at por-15 but you have to paint it on... which would be a bitch with just floor jacks lol

[xXManwhoreXx]

mine is the same... I won't worry about it until my car folds in half...

[mastershake]

yeah im trying to estimate how long it will hold up. how long does it usually take rust to eat the underside of a car in the rust belt?

[xXManwhoreXx]

depends.. if you dont wash the underside during the winter and let the salt eat it.. 10 years... even rusted, its thick solid metal and should still take 20 or so years to be ruined

[billytheman1188]

DO NOT pressure was the underside....use some low pressure. When you pressure wash it takes off more material.You should only really wash under there in the winter....summer doesn't matter....when you get rain and drive in it it will wash it for ya ;)

[zman246]

From what I've seen, POR 15 isn't all its cracked up to be but I'm no expert on that. Those kind of rust freezing products might help but definitely do not put on any kind of undercoating on it at this point. Trapping it the rust behind a wall of undercoating will just accelerate it now that its started.

[zman246]

Oh and you can spary POR 15 if I remember correctly. You'll need a spray gun though, it doesn't come in an aerosol can.

[[ion] C2]

From what I've seen, POR 15 isn't all its cracked up to be but I'm no expert on that.
Yeah, it is. I plan on having the entire body and underside coated in it before paint.

[zman246]

Have you ever personally worked with the stuff? It dries rock hard and would be a serious pain in the ass to sand for paint. Just sayin..

[[ion] C2]

Yes, I have. It's not that hard to sand. :huh:

[zman246]

But it would all have to be done by hand if you wanted it to look decent and that would take forever. Sand it down with a pneumatic/electric sander and you risk getting funky wavy spots like what can happen when you sand down bondo with a sander. If spending all that time hand sanding doesn't bother you then more power to ya :)

[Mike The Canadian]

Lol I plan to hit all of my rust spots on the body with por 15 this year.
I'm sick of it coming back every year...

Screwed on the underbody as I've got no lift..