ok guys I just found out unfortunately my camaro will have to be driven all winter long and not put into storage (garage) like I planned...so I need to know which is better to use...I do have some rust under the car in two spots so Im not sure what to do with it, can you please help my third gen survive the winter ><

ps what is the difference between the two?

 

go with the herculiner its cheaper and will hold up better.. u can get it at any pepboys/ autozone in complete kits.. just get ur car up on jack stands and clean the underbody. im currently doing the same.. its not easy but well worth it.. im using acetone to clean mine.. get some good shop rags and wipe it down get as much rust off as u can and scuff the surface ruff then apply the liner as directed on the kit

 

are you just scraping it off? there has to be an easier way...

 

POR15 is a rust inhibiting paint (it stops the rust)
herculiner is kinda like an armor coating

The best thing to do is sand off as much rust as you can, put on a coat or 2 of POR15 and then seal it with the herculiner.
If you just use the herculiner the rust will still spred and you wont be able to see it under the coating.

btw duplicolors version of herculiner is probably easier to find

 

The only thing I've found herculiner good for is truck beds. I have used Por15 on numerous utility trailer re-builds and when it comes to the underside of my T/A I will always use Por15. More expensive, yes, but well worth it in the end.

 

POR15 all the way. You can also sand and paint over POR15 if you need to.

 

No way POR15, it does NOT stop rust, it also does not adhere well to smooth metal.
The only reason it "stops" rust is that it seals it off from air and moisture. There's no rust conversion going on w/ POR

 

I beg to differ as I used POR 15 extensively (inner fenders, rad cradle, battery tray) when I painted my engine bay.

Before



After

 

Por is an isocyanide based paint, it dries from exposure to moisture and forms a hard layer, much like superglue (that's also the reason it becomes milky/chalky from UV exposure). It honestly does not inhibit rust, it simply encloses it, without exposure to air an water there simply is no rust forming but it does not stop rust as in forming a conversion layer.

Read the instructions about prep, needs a rusty, blasted or etched surface to stick.

Try it on some non rusted smooth metal. Let it dry end then peel it off, it comes off in large flakes.

I don't see what your pictures prove???

Here's that POR w/ a top coat, didn't blast that frame for nothing:





He wants to winter prep the underside of his car, he's better off with petroleum based stuff over por. For por he has to clean the whole underside, blast or etch it and then paint with POR. Simply dousing the underside in sticky undercoating will give the same amount of protection.

 

I'm well aware of the instructions and disclaimer.

I used POR on rusty, clean, smooth and rough surfaces with no issues.....brush it on, let it dry, sand and paint....simple.

Just sayin.

 

Have you checked if it's still on there? Did you log many miles since?

 

Still going strong.....no issues

 

try one-step it converts rust into black primer

 

What's best to use on floor pans to prevent rust?