I'm wanting to do the same thing and found my 77 to have been undercoated as well. So I am anxious to listen in and learn as well.
Help with Degreasing/Undercoating
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 1,155
Likes: 20
From: New Jersey
Help with Degreasing/Undercoating
I just picked up a 75 that is in great shape, but needs some major clean up underneath. To degrease I have always used the basic spray on, foaming stuff. Does anyone have any other suggestions or recommendations of something that will work better and faster? Also, the car seems to have been undercoated at some point. not sure if this was a factory thing or not, though I tend to think it was now. They even did the oil pan, so I need to get that off.
Any suggestions would be appreciated!
Any suggestions would be appreciated!
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
I use the purple stuff from Advance Auto or the 88 degreaser from Homey Depot both full strength and multiple times with a 3500 psi pressure washer on a 2 post lift.
It's a messy job so do the best you can to make a one time deal out of it and make rainsuits out of big garbage bags.
Years ago, had a steam jenny, and that worked much better than anything.
It's a messy job so do the best you can to make a one time deal out of it and make rainsuits out of big garbage bags.
Years ago, had a steam jenny, and that worked much better than anything.
Melting Slicks
Joined: May 2009
Posts: 3,079
Likes: 315
2024 C3 of the Year Finalist - Unmodified
Seeing as how you probably don't have a lift or a steam cleaner, then you will probably have to do it the hard way.
Use a heat gun and scrapers on the undercoating. The purple and 88 degreasers are quite harsh and tend to blister your skin, so make sure to wear a rain suit and long-sleeved rubber gloves as well as good eye protection. I switched to Spray 9 cleaner...just as effective, less toxic to you and your cars paint. Use parts cleaning brushes and Scotch Brite pads cut into small squares to scrub the surfaces before rinsing.
This is a dirty, nasty, tiring job laying on your back with the car on jack stands. It took many attempts for me to call it "good enough."
Use a heat gun and scrapers on the undercoating. The purple and 88 degreasers are quite harsh and tend to blister your skin, so make sure to wear a rain suit and long-sleeved rubber gloves as well as good eye protection. I switched to Spray 9 cleaner...just as effective, less toxic to you and your cars paint. Use parts cleaning brushes and Scotch Brite pads cut into small squares to scrub the surfaces before rinsing.
This is a dirty, nasty, tiring job laying on your back with the car on jack stands. It took many attempts for me to call it "good enough."
Senior Member
Joined: Jan 2008
Posts: 12,146
Likes: 2,038
From: Easton, PA
St. Jude Donor '10
Well fortunately I do have a lift in the garage, so that helps. What I don't have is a steam cleaner, but I can rent one. What I will need to do is build a "tent" around the lift to keep dirt from going everywhere else in the garage. Good idea though, thanks for the tip. 
David
David
Senior Member
Joined: Jan 2008
Posts: 12,146
Likes: 2,038
From: Easton, PA
St. Jude Donor '10
Thanks for your help.
David
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
It's well worth spending a full day at cleaning and degreasing as best you can so you don't have to deal with the grime at a later date. It is usually the first thing I do.
Here is a pic of a dirty grimey car. Pretty well the whole underneath was covered like this.
Here is after the degreasing/pressure cleaning.
After the car is mostly dry, I take a weed sprayer and spray the underneath with phosphoric acid (rust converter), and let it dry overnite. It will keep any surface rust from forming for up to a year and you can wire brush, sand or whatever easily to paint when ready. It won't hurt anything.
After painting with Rustoleum
A strong pressure cleaner will remove the undercoat from the frame but will also cut into the fiberglass, so a heat gun, scraper and eventually some solvent can remove that.
Here is a pic of a dirty grimey car. Pretty well the whole underneath was covered like this.
Here is after the degreasing/pressure cleaning.
After the car is mostly dry, I take a weed sprayer and spray the underneath with phosphoric acid (rust converter), and let it dry overnite. It will keep any surface rust from forming for up to a year and you can wire brush, sand or whatever easily to paint when ready. It won't hurt anything.
After painting with Rustoleum
A strong pressure cleaner will remove the undercoat from the frame but will also cut into the fiberglass, so a heat gun, scraper and eventually some solvent can remove that.
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Melting Slicks
Joined: May 2009
Posts: 3,079
Likes: 315
2024 C3 of the Year Finalist - Unmodified
I would not recommend a pressure washer either. A steam cleaner also sounds way too aggressive. I remember hearing once that we should drive these cars like we are making love to an old lady. Perhaps the same advice applies to cleaning them.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Team Owner
Joined: Jun 2000
Posts: 38,923
Likes: 1,482
From: Southbound
Cruise-In II Veteran
Easy Mike, my car has no coating on the oil pan or on the tranny cover, those are clean and look pretty good. My coating appears to be in the wheel wells and under the seats. There is some on the rocker panels as well. The frame itself looks to be bare metal, painted I think, but bare otherwise. Is that what you are describing as factory undercoating?
Thanks for your help.
David
Thanks for your help.
David
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 1,155
Likes: 20
From: New Jersey
Degreasing
It's well worth spending a full day at cleaning and degreasing as best you can so you don't have to deal with the grime at a later date. It is usually the first thing I do.
Here is a pic of a dirty grimey car. Pretty well the whole underneath was covered like this.
Here is after the degreasing/pressure cleaning.
After the car is mostly dry, I take a weed sprayer and spray the underneath with phosphoric acid (rust converter), and let it dry overnite. It will keep any surface rust from forming for up to a year and you can wire brush, sand or whatever easily to paint when ready. It won't hurt anything.
After painting with Rustoleum
A strong pressure cleaner will remove the undercoat from the frame but will also cut into the fiberglass, so a heat gun, scraper and eventually some solvent can remove that.
Here is a pic of a dirty grimey car. Pretty well the whole underneath was covered like this.
Here is after the degreasing/pressure cleaning.
After the car is mostly dry, I take a weed sprayer and spray the underneath with phosphoric acid (rust converter), and let it dry overnite. It will keep any surface rust from forming for up to a year and you can wire brush, sand or whatever easily to paint when ready. It won't hurt anything.
After painting with Rustoleum
A strong pressure cleaner will remove the undercoat from the frame but will also cut into the fiberglass, so a heat gun, scraper and eventually some solvent can remove that.
