I stripped off the dirt/undercoating from my Mach early on the project. I used a rotisserie to flip the car upside down (this was the thing that made the process possible) then lightly soaked old towels in kerosene, layed them over sections of the chassis then covered the towel with a plastic sheet. I'd come back a couple hours later and the goo would come off cleanly just using a plastic scraper (to heck with that wire wheeling).
Dave

 

I don't know what is FACT. I wasn't a coating engineer for Ford in the 60's. I just read on concoursmustangforum, that EPOXY was used. (see #6)

Here's what I DO know as FACT.
* Whatever is on there is HARD and Lacquer Thinner doesn't phase it.
* It sometimes had discarded exterior color mixed with it as a cost saving measure, often called "slop gray." This means it was chemically compatible with exterior paint, which in my understanding, was straight enamel in the early days, and replaced with Acrylic Enamel at some point.

Pertaining how the paint was deposited on the underneath, there is a lot of discussion in concours circles about the drips on factory coatings underneath. The way drips were numerous and usually had an air bubble in the tip of the drip that popped when the accelerated drying process heat was applied. When I think of EDP, I don't think of non-uniform wet film thickness with numerous drips. This looks to me like the paint was deliberately "loaded" up in some areas. Also where the dolly risers contacted the frame rails, there is NO PAINT on the downwind side of the round risers. I think EDP would have avoided that.

 

Don't know what Ford used as primer in the 60s. Just commenting on epoxy paint/primer.
In 1966 I was working in product development at Allis Chalmers. We were spraying sheet metal cabinet parts for a product to be used in a corrosive environment. We used a 2 part epoxy primer and paint. Most of Allis is now defunct.

Also I'm curious why a 11,000 mile car would be fully restored and then coated on the underside with undercoat goo. If it had the goo before resto one would think the goo would have been removed before resto.

Slim

 

I don't know of any kind of coating, that will take that without softening, except a 2-part catalyzed epoxy.

I'm not sure if water based primers were used during the 60's, but on they were used during the 70's. I remember trying to strip lacquer with aircraft stripper, the stripper lifted the topcoat quite easily but that under coat was tough. May have been just a GM thing, not sure. A Dupont paint rep told me it was water base primer. Come to think of it, one shop I worked at used a lot of water based sealers back in the early 80's. It was tough stuff and was often used over the top of lacquer finishes to fill crows feet if a customer didn't want the extra cost of stripping the roof, deck lid or hood.

 

Here is a link to my photobucket,it has a bunch of pics. Everything is SPI epoxy. The chassis is red oxide spi, the rear end and springs are the black SPI and the underhood is also SPI black.

http://s26.photobucket.com/albums/vtwindepot/Project pictures

 

Car looks great man. I'm going to pick up some stuff from SPI, thanks!

 

I have heard that por is designed to adhere to rusty surfaces, if you have clean metal I would apply epoxy primer with either a sprayer or a brush etc..

 

I think in remember you posting pics of your cars undercarriage a while back and it looked pretty amazing. I tried to dig up the post, but I couldn't find it. Could you point me to the products you used?

 

This is my next project while I have the drive train and exhaust out of the car. Really not looking forward to it. Have any of you used POR on your undercarriage?

 

Floor adhesive remover from Home depot. Messy but quick. Do a some searched I think you will find one of the best choces for removing undercoating

 

Aircraft stripper and a scraper. Just don't get any on ya.

 

The car has no miles on it and I know the history. Has not likely ever seen rain. must be dealer undercoat. nothing is being hidden.

I'm hearing to remove with a heat gun? I have all winter and it is cold here.

It will be spotless and rust free. Then what? Rattle cans of body color, red oxide or white?

 

Once you get all the undercoat off then you want to remove/repair any rust, especially the stuff that dwells in panel seams and joints. I'd be apt to remove all the old paint and seam sealer, treat with a product like Picklex20 and epoxy prime in red oxide, seam seal, 2nd coat of EP, then apply your sound deadener.

 

The primer wasn't epoxy and the "undercoat" is really sound deadener. You can soften up existing undercoating with a heat gun or propane torch (don't catch it on fire) to the point where it will scrape easily, and clean up any residue with mineral spirits. There are also some purpose-made undercoat removal sprays.

 

R U Sure?

...The primer wasn't epoxy....

Bartl,

I don't know your background but the gurus on concoursmustangforum have done exhaustive investigation on this topic.

They (Mainly Jeff Speagle, I think) have interviewed key players about products and procedures in all the plants. I think the product has pretty much been nailed down. Do a little searching on that forum. Unless you have more accurate information than they have. You may be surprised at how precise their knowledge is.

I have first hand experience that tells me it is a 2-part epoxy. On my car's belly, the original red oxide primer is present. I cleaned it with pure lacquer thinner, a scrub brush and rags. I don't know of any kind of coating, that will take that without softening, except a 2-part catalyzed epoxy.

Lots of folks say an epoxy wasn't available in the mid 60's but everything I have learned during this restoration tells me it was.

 

Scraped the whole bottom of my car, about 3/16 thick "goo". Steel was mostly good as well so the undercoating did it's job. It was old though and coming off in places- looks great now all painted satin black. Replaced all brake and fuel lines in the process (all ss now). Gonna replace the exhaust soon with 304 ss ($$). John

 

I'm just finishing this up on mine. What a messy job! Heat gun with a scraper and then I follow it up with my sandblaster. For the most part underneath my undercoat was pretty good steel although my sandblaster discovered some thin steel on the passenger side floor pan which it promptly put holes in. Also discovered that the drivers side floor pan had been previously replaced...with overlap welds...obviously a previous owner was using the undercoat to hide and/or protect this.

 

I hate the Goo! I hate it more when goo is used on a "Restored" car.

 

Dealers could install curb-feelers and fender flares and stripes.

That's not "original factory undercoat."

Few cars got dealer undercoat. If I were looking at a Mustang to buy, if it has an undercoated bottom, I say "I'm sorry. This is not what I am looking for." It can conceal too much.

 

here is what I did... it is a job if your exterior paint is not somthing you are planning on redoing... (should have done the bottom first)...

http://myrestomodmustang.com/articles/underneath/undercar.html

 

dealers offered it on new vehicles at time of sale!

 

My 65Gt has full documentation from when it was ordered to today and it has dealer installed undercoating over the red oxide.

 

The Concours guys have proven that our cars came with only epoxy primer underneath, in various colors, but most common, red oxide. It is fairly slick and shiny for primer. It was baked as proven by popped air bubbles in the dripped drops.

Some areas had overspray of sound deadener. Not very many areas got it. It was never undercoating.

If you ask the question on concoursmustangforum SPECIFICALLY about YOUR car, using your scheduled build date and assembly plant. They will probably be able to come up with a few pictures of an unrestored car built in that same plant and near your car's date, showing what's accurate for your car.

In my experience, a completely undercoated underneath is only done for 1 reason, to cover up or conceal rust, repairs, or something else the seller doesn't want you to see.

 

Scrape it all off. Thats what I did.

 

On the portal page only "Thoughts on stripping..." is displayed. Haha

 

Unfortunately, undercoating can have minute cracks as it dries and gets older. I don't think that the factory ever undercoated cars. In any case, the cracks admitted winter road salt water to get to the underlying sheet metal. I would strip every bit of it to see what is underneath.