Help My Undercoating Situation

[ns87]

Not looking to buy POR15, just want this to last through the winter. Bought the car two years ago rust free and used Kmart Undercoat in a can under the rocker panels. Undecoat chipped away (expected), but it took the paint with it in some spots! I now have a lot of bare metal under my panels and some of it is getting surface rust. Ignoring the surface rust (I'll sand that down), is it safe just to spray undercoat over it again? I don't want to come back from up north with a rusty car next spring. Thank You!

 

Before

After (Gotta wash ma car!)

 

Upclose of the surface rust starting

 

[CSI_MuNkY]

My suggestion would be to clean it up and apply a roll on truck bedliner. I've seen that stuff take a beating and fully intend to have the entire underside of my car done with it. You should be able to apply it right over the old stuff providing you knock off eveything thats loose because it is designed to go over the factory paint in a trucks box.

 

Jamie

[slick]

My suggestion would be to clean it up and apply a roll on truck bedliner. I've seen that stuff take a beating and fully intend to have the entire underside of my car done with it. You should be able to apply it right over the old stuff providing you knock off eveything thats loose because it is designed to go over the factory paint in a trucks box.

 

Jamie

 

That roll on truck liner traps in water and grease. Same with the spray on stuff you bought. The only good rust preventative is POR-15.

[19Cutlass94]

I gotta do mine over. I plan on getting that 3step thing from POR-15. but really thats not bad. Thats probably better than mine looks there.

[THe_DeTAiL3R]

YOu can also do an oil/waxed based undercoating, which runs about $100 and you gotta do it every year. They shoot it up in behind the panels (they drill holes if they need to) to protect the fenders etc. from behind.

 

check out http://krown.com that's the place I'm going to before the winter (It's a Canadian company but you get the idea...).

 

Yes, it's expensive, and messy... but IMO the best solution for a daily driver in salty Ontario winter roads....

[slick]

YOu can also do an oil/waxed based undercoating, which runs about $100 and you gotta do it every year. They shoot it up in behind the panels (they drill holes if they need to) to protect the fenders etc. from behind.

 

check out http://krown.com that's the place I'm going to before the winter (It's a Canadian company but you get the idea...).

 

Yes, it's expensive, and messy... but IMO the best solution for a daily driver in salty Ontario winter roads....

 

I've been wondering about this. Is it just and underbody undercoating, or do they spray it behind your bumpers, fender flares, side skirts, body cladding, etc....? If so, does it come out onto the outside sometimes?

[97loudcut]

My underbody is rally rusted but I think it may be to the point where you cannot do anything about it. O well Michigan sucks

[SigEpCutlass]

My suggestion would be to clean it up and apply a roll on truck bedliner. I've seen that stuff take a beating and fully intend to have the entire underside of my car done with it. You should be able to apply it right over the old stuff providing you knock off eveything thats loose because it is designed to go over the factory paint in a trucks box.

 

Jamie

 

That roll on truck liner traps in water and grease. Same with the spray on stuff you bought. The only good rust preventative is POR-15.

 

I don't seem to feel the same way Chris. My cutlass has been through 4 winters with just regular rubberized tar based undercoating since I've owned her. I sanded off any surface rust that I could before undercoating for the first time from all the previous winters that it had been through. The first two years I used just regular el cheapo stuff from Walmart. The past two years, I've been using the same can of Blue Magic Rubberized Undercoating. Last time I checked, I don't have any new rust really to speak of. I've never seen or had the same experience you did with the undercoating falling off. The only thing else I do is get a really good wax on for the winter and I wash my car regularly during the winter (including the undercarriage) to prevent rust.

[slick]

My suggestion would be to clean it up and apply a roll on truck bedliner. I've seen that stuff take a beating and fully intend to have the entire underside of my car done with it. You should be able to apply it right over the old stuff providing you knock off eveything thats loose because it is designed to go over the factory paint in a trucks box.

 

Jamie

 

That roll on truck liner traps in water and grease. Same with the spray on stuff you bought. The only good rust preventative is POR-15.

 

I don't seem to feel the same way Chris. My cutlass has been through 4 winters with just regular rubberized tar based undercoating since I've owned her. I sanded off any surface rust that I could before undercoating for the first time from all the previous winters that it had been through. The first two years I used just regular el cheapo stuff from Walmart. The past two years, I've been using the same can of Blue Magic Rubberized Undercoating. Last time I checked, I don't have any new rust really to speak of. I've never seen or had the same experience you did with the undercoating falling off. The only thing else I do is get a really good wax on for the winter and I wash my car regularly during the winter (including the undercarriage) to prevent rust.

 

I have just always read that the rubberized stuff holds in moisture.

 

But, I think we all can agree, the can stuff is not permanent. For how much you have spent on the can stuff the past 4 years, you could have POR-15'd your underbody once and never had to worry about it again.

 

For $35 of POR-15, you can undercoat 2 whole cars. Or, you could have 2 heavy ass coats of it on one car. It's worth the time and effort.

[SigEpCutlass]

My suggestion would be to clean it up and apply a roll on truck bedliner. I've seen that stuff take a beating and fully intend to have the entire underside of my car done with it. You should be able to apply it right over the old stuff providing you knock off eveything thats loose because it is designed to go over the factory paint in a trucks box.

 

Jamie

 

That roll on truck liner traps in water and grease. Same with the spray on stuff you bought. The only good rust preventative is POR-15.

 

I don't seem to feel the same way Chris. My cutlass has been through 4 winters with just regular rubberized tar based undercoating since I've owned her. I sanded off any surface rust that I could before undercoating for the first time from all the previous winters that it had been through. The first two years I used just regular el cheapo stuff from Walmart. The past two years, I've been using the same can of Blue Magic Rubberized Undercoating. Last time I checked, I don't have any new rust really to speak of. I've never seen or had the same experience you did with the undercoating falling off. The only thing else I do is get a really good wax on for the winter and I wash my car regularly during the winter (including the undercarriage) to prevent rust.

 

I have just always read that the rubberized stuff holds in moisture.

 

But, I think we all can agree, the can stuff is not permanent. For how much you have spent on the can stuff the past 4 years, you could have POR-15'd your underbody once and never had to worry about it again.

 

For $35 of POR-15, you can undercoat 2 whole cars. Or, you could have 2 heavy ass coats of it on one car. It's worth the time and effort.

 

I don't think I've even spent half of that yet. I've maybe spent $15 at the most total. I've never paid more than $4 for a can of undercoating.

[slick]

 

 

I don't seem to feel the same way Chris. My cutlass has been through 4 winters with just regular rubberized tar based undercoating since I've owned her. I sanded off any surface rust that I could before undercoating for the first time from all the previous winters that it had been through. The first two years I used just regular el cheapo stuff from Walmart. The past two years, I've been using the same can of Blue Magic Rubberized Undercoating. Last time I checked, I don't have any new rust really to speak of. I've never seen or had the same experience you did with the undercoating falling off. The only thing else I do is get a really good wax on for the winter and I wash my car regularly during the winter (including the undercarriage) to prevent rust.

 

I have just always read that the rubberized stuff holds in moisture.

 

But, I think we all can agree, the can stuff is not permanent. For how much you have spent on the can stuff the past 4 years, you could have POR-15'd your underbody once and never had to worry about it again.

 

For $35 of POR-15, you can undercoat 2 whole cars. Or, you could have 2 heavy ass coats of it on one car. It's worth the time and effort.

 

I don't think I've even spent half of that yet. I've maybe spent $15 at the most total. I've never paid more than $4 for a can of undercoating.

 

You are able to just use 1 can at a time? Thats not to bad then.

 

I just thing POR-15 is the smart way to go though. You only have to apply once, it will last longer than the person that applied it, and the next person that owns the vehicle after you croak, it will give whatever finish you want(silver, gloss black, flat black, clear if desired). Yeah, it may cost more initially, but after going under the car every year and having to reapply it, I just wouldn't want to crawl under there unless I have to.

 

Well, assuming you do it on the ground. Now, if you have a lift, thats a different story.

[SigEpCutlass]

 

 

I don't seem to feel the same way Chris. My cutlass has been through 4 winters with just regular rubberized tar based undercoating since I've owned her. I sanded off any surface rust that I could before undercoating for the first time from all the previous winters that it had been through. The first two years I used just regular el cheapo stuff from Walmart. The past two years, I've been using the same can of Blue Magic Rubberized Undercoating. Last time I checked, I don't have any new rust really to speak of. I've never seen or had the same experience you did with the undercoating falling off. The only thing else I do is get a really good wax on for the winter and I wash my car regularly during the winter (including the undercarriage) to prevent rust.

 

I have just always read that the rubberized stuff holds in moisture.

 

But, I think we all can agree, the can stuff is not permanent. For how much you have spent on the can stuff the past 4 years, you could have POR-15'd your underbody once and never had to worry about it again.

 

For $35 of POR-15, you can undercoat 2 whole cars. Or, you could have 2 heavy ass coats of it on one car. It's worth the time and effort.

 

I don't think I've even spent half of that yet. I've maybe spent $15 at the most total. I've never paid more than $4 for a can of undercoating.

 

You are able to just use 1 can at a time? Thats not to bad then.

 

I just thing POR-15 is the smart way to go though. You only have to apply once, it will last longer than the person that applied it, and the next person that owns the vehicle after you croak, it will give whatever finish you want(silver, gloss black, flat black, clear if desired). Yeah, it may cost more initially, but after going under the car every year and having to reapply it, I just wouldn't want to crawl under there unless I have to.

 

Well, assuming you do it on the ground. Now, if you have a lift, thats a different story.

I really don't mind having to do it. Generally, I do it while I'm under the car waiting for the oil to drain, or something else where I'm already under the car. It's not a big deal to me. After the initial coating, it's been more of a yearly touch up job really. However, had I known about POR-15 4 years ago when I started undercoating the cutty, I probably would have chosen to do that because it's a one time deal.

[per0781]

yeah get it done to prevent this:

 

 

yeah its completely rusted through

[digitaloutsider]

You think that's bad? You should see my Cutlass under the body cladding..

[SigEpCutlass]

yeah get it done to prevent this:

 

 

yeah its completely rusted through

 

Ouch Paul that sucks. I know what most people have done is just redo their rockers with fiberglass.

[per0781]

hey it still passes inspections and it gets me to where i have to go. thats all i care about.

[SigEpCutlass]

hey it still passes inspections and it gets me to where i have to go. thats all i care about.

 

...and it keeps the SS out of the shitty weather.

[ns87]

I wanted to update:

 

It came out really good. Unfortunately, most of my pictures were taken while it was still wet, so the camera picked up on that. Heres some good ones of my nice Black inside wheel wells. The last is how my driveway ate some of the jackstand

 

 

Some how for a while, the back passenger side just floated and wasn't on the jackstand. That scared me, so I put it under the trailing arm and after an hour or two my car sank down.

[SigEpCutlass]

Can't really tell from the pics, but it looks like it probably improved.

[ns87]

Yea good point. These pictures are kinda worthless. It is improved though!

[5speedz34]

You think that's bad? You should see my Cutlass under the body cladding..

 

Yeah, alot of the 88-91 rockers like to rust on the Cutlass'.

 

My suggestion would be to clean it up and apply a roll on truck bedliner. I've seen that stuff take a beating and fully intend to have the entire underside of my car done with it. You should be able to apply it right over the old stuff providing you knock off eveything thats loose because it is designed to go over the factory paint in a trucks box.

 

Jamie

 

That roll on truck liner traps in water and grease. Same with the spray on stuff you bought. The only good rust preventative is POR-15.

 

I don't seem to feel the same way Chris. My cutlass has been through 4 winters with just regular rubberized tar based undercoating since I've owned her. I sanded off any surface rust that I could before undercoating for the first time from all the previous winters that it had been through. The first two years I used just regular el cheapo stuff from Walmart. The past two years, I've been using the same can of Blue Magic Rubberized Undercoating. Last time I checked, I don't have any new rust really to speak of. I've never seen or had the same experience you did with the undercoating falling off. The only thing else I do is get a really good wax on for the winter and I wash my car regularly during the winter (including the undercarriage) to prevent rust.

 

This is what I've heard. I was listening to Car Talk on NPR, and what I've heard is that the truck type stuff cracks because the car flex's and those cracks allow moisture in. You're not going to see it because it is under the undercoating!

 

I've seen this first hand with alot of the cars that come into Wal-Mart.

 

My underbody is rally rusted but I think it may be to the point where you cannot do anything about it. O well Michigan sucks

 

One of the biggest reasons I've moving out of Michigan when I'm done with college.

 

 

[1990lumina]

since my car doesn't have any cladding there isn't much body rust at all (none)....underneath it's all galvanized so why would it rust?? I'm a fan of just doing the occassional under body wash and be done with it

[19Cutlass94]

Correct me if Im wrong, but dont the wheel wells already have a coating on them?

[THe_DeTAiL3R]

Correct me if Im wrong, but dont the wheel wells already have a coating on them?

 

 

I think inside the rear fenders and the struts are what really matter in that area.