Opinions of Undercoating

As some of you may recall, I also have a 1969 (former H-Code {351 2V}) Mach 1 that I am restomodding with a 428CJ and cast iron tailshaft C6. I have already added staggered shocks and a 31 spline rear with 3.91 traction lok.

Today, we installed the Global West Sub-frame Connectors and the question came up as to whether or not we should use undercoating. The car is EXTREMELY clean underneath with ABSOLUTELY no rust issues. I will also be using the ACC MASS carpets which we believe will do a lot to address the outside noise issue.

I have posted a thread up on the '69 Mustang forum soliciting opinions as to thoughts on undercoating and would also like to get y'all's take.

So, what are the opinions?

Thanks!

BT

If you plan on driving the car in all weather conditions, or you live in a humid or salt air environment, I'd undercoat it. If you're only going to drive it in nice weather and live in a dry area, I'd paint with an epoxy sealer. If you do undercoat, use the rubberized 3M stuff, not the cheaper asphalt based undercoating. JMPO.

Steve

Undercoating can actually enhance rust if water/moisture gets between the undercoating and the body. If you live in snow country and would be driving on salted roads, then the UC would be recommended. It's a tough choice.

What is on it now, paint or undercoating? If it is partially undercoated now getting it off is a bit of a PITA. If it is just painted, I'd clean it up and repaint using epoxy paint(s). Just an idea. Chuck

What is on it now, paint or undercoating? If it is partially undercoated now getting it off is a bit of a PITA. If it is just painted, I'd clean it up and repaint using epoxy paint(s). Just an idea. Chuck

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Yes, it currently has "just" paint.

One recommendation on the '69 Forum was to utilize a 3k clear.

BT

In Memphis? Nah, no undercoat.

On the underbelly, I'd do as mentioned with good primer/paint. At most, I'd use some "cavity wax" on any overlapping or spot welded seams after all of the painting is done.

In the interior, I like the idea of the good primer and some kind of sound deadener.

On my car, I plan on using good 2K spray on bedliner (since I already have a kit) over epoxy primer on the interior tin only. The underbelly will be epoxy primed with hotrod black 2K urethane paint.

I feel it will certainly outlive me. That's even considering living in the rustbelt.

Personally, I think heavy undercoating is poo.

Lord knows I've scraped enough of it off of these crusty PA cars. Doesn't work here worth a darn on a daily driver. Even our rain is more caustic than average.

Rust 'round these PA parts RARELY starts on flat or exposed surfaces. It starts in the aforementioned overlaps and spot welded areas and spreads like cancer from there.

I live in AZ and my car is from here. I have found that a constant addition of various fluid including oil, ATF and PS seems to protect very well.

Mine is just a mess. I hope one day to be able to both close the leaks and then do an awesome cleanup of the underside. Since I live in AZ and only drive when there is no rain I don't have to worry about rust.

My car was Zebart sprayed when it was brand new by the dealer at the request of the new owner. I never had a choice in the matter but if I did I would prefer it painted. I credit the Zebart for the condition of my car today. New England winters took it's toll on so many cars from the 70s and 80s that you rarely see them on the road.

Well I'll throw in my 2 cents.

I would not undercoat it. You will care for your car so rust should not be a problem.

If you sell the car, undercoating is often seen as a way to hide problems.

You may never sell the car, but someday it will be passed on in some manner.

Well I'll throw in my 2 cents.

I would not undercoat it. You will care for your car so rust should not be a problem.

If you sell the car, undercoating is often seen as a way to hide problems.

You may never sell the car, but someday it will be passed on in some manner.

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I couldn't agree more.

I wouldn't undercoat either, unless your going to be driving in the snow & salt. Just keep it clean & touch up w/a good quality paint.

GREAT responses, Folks!

I received essentially the same inputs on the '69 Mustang forum.

Since the undercarriage is EXCEPTIONALLY clean and already painted, I have decided to just hit it with a coat of clear and press on with the project. Good point about my living in Memphis "Midlife" as we do not usually receive snow here and I will only be driving the car about 2000 miles a year (I have three other Mustang "Toys"). Plus, the car will ALWAYS be garaged when not in use.

THANKS again for the inputs!

BT