body and interior Undercoating - Anyone Applied?

[FrictionTape]

This is great, thanks!

[Buckeye]

I'm the 4th owner. After some research I know car was delivered to delear in NJ. 1st. Owner must had it zibarted right out of dealer lot. I say that because is 99% rust free. There is zibart sticker on driver sdie door. I can't say if zibart has saved the car or if 1st owner driver didn't drive it during winter for sure, but I can say that buying decision of the car was much easier for me when I saw that sticker and all those black plugs.

[cwlo]

Pressure wash to get everything good and clean.  

 

Address the areas with surface rust with mechanical removal, or a conversion type coating.

 

Then use a quality undercoat 3m or similar.

 

 

 

Chris

 

[schoir]

Great!   Not sure if that gives me energy or kills my DIY inner child, but great knowledge none the less.  I'm more inclined to use the POR-15 brush on stuff rather than Eastwood spray.  Your thoughts?

Applying POR-15 after using their cleaner and their Metal Prep, following that with seam sealer, then 3M water-based "rubberized undercoating, then base coat, clear coat(s) will give you good-looking, long lasting results.

 

The most difficult part is removing all of the old paint, at least where there is any hint of rust (surface or otherwise) and then using the two prep products.  After that it's "fun".

 

I used that process in my current restoration effort in the front wheel wells, rear wheel wells, and parts of the inside of the trunk, 

 

Regards, Maurice.

Edited September 19, 2015 by schoir

[PaulTWinterton]

Thanks Maurice, I've done the POR-15 process before, but not followed by 3M undercoating. Please confirm that it's also a primer that paint can adhere to without any further prep. Also, is the 3M product brush-on?

[schoir]

Thanks Maurice, I've done the POR-15 process before, but not followed by 3M undercoating. Please confirm that it's also a primer that paint can adhere to without any further prep. Also, is the 3M slightlyproduct brush-on?

It's 3M 08804 and one of its best qualities is that there are no solvent issues typically associated with other undercoating products, most of which are solvent based.

Color (base) coat can be applied directly over it, but if you wait more than 24 hours after application of the 3M stuff, it's recommended that you first scuff slightly to improve adhesion. 

 

It's not brush on and has to be applied using their "No Cleanup Applicator Gun, 3M Part No. 08801).  Another really good quality is that it offers corrosion protection if it ends up being applied directly over bare metal spots (such as you get with cut-through when sanding for prep).  The sound deadening is an added benefit.

 

It's very easy to control and direct the spray to obtain the desired thickness and easy to clean up and you only have to wait for it to apply it in relatively light coats to allow the water to evaporate somewhat in between coats, until you get the desired thickness.

 

  They have about 6 different undercoating products at the body shop and this one is by far the favorite.

 

If you're planning on doing it soon, I'll post the process in my restoration thread as I have just completed inside the trunk area so that you can get an idea of what's involved.

 

Regards, Maurice.

Edited September 19, 2015 by schoir

[fjord-tii]

The unercoat on my car scraped off with no effort. I used a urethane-based truck bed liner followed by 3M underbody coat and then a single stage acrylic urethane color coat. Probably over kill, for sure. Truck bed liner is really tough and goes on easily with a roller brush, and some of them can be tinted. Requires far less prep than POR15, which if great but a lot of effort under the car. During this whole process, I fantasized about having a rotisserie.

[FrictionTape]

So I am going to rent a sand/medium blaster to strip down the front and rear sub-frame as we'll as the differential. While I have it, do I blast the underside of the car or just the few surface rust spots. The current undercoating is pretty solid. I'm curious to know what's there, but also hesitant to remove something that might not need it.

Thoughts?

[fastfredi]

we built a scaffold under the car as you can see in the pictures then pressure washed it out side.  it was squeaky clean afterwards. onto por 15 after patching paneling the rusted spots

[Simeon]

So I am going to rent a sand/medium blaster to strip down the front and rear sub-frame as we'll as the differential. While I have it, do I blast the underside of the car or just the few surface rust spots. The current undercoating is pretty solid. I'm curious to know what's there, but also hesitant to remove something that might not need it.

Thoughts?

The factory undercoat is pretty good, I would not remove it unless I suspected that it was loose or if you genuinely want to start from bare metal. Just make sure that you have gone all over and strip for several inches around any loose spots to expose any rust that may have crept underneath. If you at least scuff it all over with scotchbrite (which is useful as part of checking the condition) you can then spray it over with a light coat of the 3M product mentioned previously applying it thicker over the bare steel direct to metal. This can then be primed and painted with body coloured paint (I would probably just use a single stage acrylic unless I was spraying elsewhere on the car and had the paint on hand.

[FrictionTape]

Sort of inline with undercoating, I found what appears to be a thick tar like substance with a felt like layer overtop under the carpets in the front and rear footwell. Pretty nasty stuff and have to use the heat gun to loosen it enough to scrap off. It seems really solid and am contemplating leaving it as the underside is pretty solid.

[willys]

I was lucky - I cleaned the underside with some type of caustic chemical that took off everything but the paint.  I wire brushed the few small surface rust areas and treated them with POR 15 then top-coated with body color.  6 months later and every year since, i spray the bottom with waxoyl - so far so good

[Hans]

Hats off to those who scrape off all the old crud.

I would also be using some seam sealer to fill in potential water ingress spots.

['76mintgrün'02]

Just make sure that you have gone all over and strip for several inches around any loose spots to expose any rust that may have crept underneath.

 

 

This is one spot to take a look at.  Mine has rust at this seam (on both sides of the car).

 

 

Edited November 6, 2015 by '76Mintgrun'02

[Ian]

The factory undercoating does a remarkably good job, as long as there was no break in the underlying paint which would allow rust to start.  My strategy has been to leave the undercoating where no obvious rust, cut out rusted areas and weld in new metal, and then coat with POR15 and then rubber undercoating, to protect the POR15/paint from stone chips, which could put a new break in the protective layer.  I have been using POR15 for many years, and it is fantastic, but you must apply it to bare metal.  It will peel off of any underlying paint layer.  Also, a great tool for removing the factory undercoating is an oscillating tool.  I picked one up from HR for $30, and it works great.