Options for coating the underside? [Archive] - Classic Cougar Forums

: Options for coating the underside?

July 10th, 2009, 12:57 PM
I'd like to coat the underside of my 69 for looks as well as prohibiting further corrosion.
There are enormous swings in the price of rust inhibitors. Some are thick rubber coatings (3M) others are what appear to be rust inhibiting paint of multiple layers. Some seem little more that a rattle can of Krylon.

What have some of the board members used for this purpose?
I'm doing this myself in my garage and I'd appreciate any feedback and maybe any pitfalls to avoid.

July 10th, 2009, 01:06 PM
If you do a search, you'll find a lot of recent posts regarding various undercoatings/finishes.

Personally I like, and am currently using, SEM undercoating for both the inside and underside of our Cougar. It goes on smoothly and leaves a nice even textured surface that sort of looks like crinkle finish. It costs a little more than some of the PEP Boys/Kragen stuff, but I'm counting on the usual SEM quality.


July 10th, 2009, 01:55 PM
anything by SEM is usually a good product. i use just a rubberized undercoating, that sprays from a rattle can. looks like a mild "spay in bedliner" in a way.. kinda the "crinkle" finish as mentioned above. i usually always put some zinc chromate under any undercoating to prevent rust on fresh welds or bare metal.

July 10th, 2009, 06:34 PM
Check out Al's Liner. It is a professional grade spray on polyurathane truck bed liner but it has so many uses. I used it on my floor and trunk as well as resurfacing my old fiberglass patio deck and my truck box! It is tintable in any color just by adding a standard automotive paint pigment in what ever paint code you like and you can now add rubber granules to add to the sound deadening properties or media for better grip.

I have used allot of different liners in the past and now swear by this one! Check it out at http://www.alsliner.com and check out the pictures of other cars that have the underside done.

It's real easy to spray too as you can get their gun and it only needs a small compressor with about 25 psi to spray it.

July 10th, 2009, 07:05 PM
i sprayed mine with epoxy primer and shot it with silver urethane enamel.

July 10th, 2009, 09:23 PM
I use rubberized rocker-guard. Thick, black, nice texture, hides lots, and sprays on real easy.

July 12th, 2009, 04:23 PM
Great suggestions, thanks! I like the look of the rubberized coatings. That will sure improve over the current "patina" finish I have.
Of those of you who have used the rattle cans of rubberized SEM, how many cans did you need for the entire underside counting the wheel wells?

July 13th, 2009, 08:28 PM
usually 1-2 cans do all four wheel wells. not shure about under a car. might be best just to buy about 8 cans.

July 14th, 2009, 11:28 AM
duplicolor bedliner. perfect.

July 14th, 2009, 12:59 PM
duplicolor bedliner. perfect.

Funny as we were talking about the Duplicolor on another posting on here as well so I spoke to a couple of coating reps that I deal with as I sell Al's Liner and specialize in specialty coatings in my business and there has been alot of issues with bonding as per my conversations with them as well as the poster on the forum here.

July 17th, 2009, 11:16 PM
I used Duplicolor first and did not like it at all. Then I used Al's Liners and it was great. I will use it again. Unlike the Duplicolor it is a four part system. The price is right and it gose on easy.

July 18th, 2009, 06:03 AM
On the restorations we have done in our shop, an Epoxy primer followed by a coat of truck bedliner has almost become the norm. It is extremely durable, aids in sound deadening, and has a nice look to it if you keep it relatively thin.
It is also used alot in rear wheelhouses.

July 18th, 2009, 09:36 AM
Thanks for the feedback.
Now, is an epoxy primer something that comes in a rattle can or do I have to have a sprayer?

July 18th, 2009, 10:14 AM
Thanks for the feedback.
Now, is an epoxy primer something that comes in a rattle can or do I have to have a sprayer?

they make it in rattle cans , but its unproductive, easier to get a compressor and gun and spray the right way