Factory undercoating removal-78 280Z resurrection project

[One Way]

Slow progress continues on the resurrection Z.  I have the LF fender removed, ready to install lower patch panel for the rusted out section.  A few small pinholes on the top near the headlight bucket will also be handled with a home made patch.  The assumed factory undercoat is in great shape on about 70-80% of the fender.  The other 20-30% either had no undercoating or what was there has been scaling off the fender surface.  Heat gun and scraper is doing a slow but decent job.  Under the good undercoat is near perfect factory tannish color primer.  I will be coating the fender with some good rust converter and follow up with a rust cover satin black after the converter cures 48 hours.  Any better tips for removing the undercoating or should I just leave the good stuff intact on the other sections of the car as I proceed along? Whatever they installed on these fenders was some pretty good stuff.  The textured stuff comes off with some heat and scraping but some of the gray colored adhesive seems to remain in some spots over the tannish primer base.  Thanks for any advice, John-Lugoff, SC.

[bluez]

I’ve been working on removing 51 year old undercoating from my 240z for the last week. Some areas come it comes off easily other areas not at all. Have found using some heat that the paint comes off, or scratches.  Have been using Goof Off and a nylon brush with some success. A slow process..

[One Way]

Thanks for the response.  I think we can put SLOW in capital letters.  I am interested in what they originally used to do such a good job protecting some areas of the car.  It is kind of mysterious to me to have portions of this fender rusted away and much larger portions revealing the original tannish primer coat with absolutely zero corrosion underneath the removed undercoat.  Thanks again, John-Lugoff, SC.

[One Way]

Slow progress continues, emphasis on SLOW, with this resurrection project.  The small propane torch works much better than the heat gun for removing the undercoating from the frame rails and the large portions of solid original floor.  Still working on best solution to remove that final residue of the coating as I am covering all the portions with rust converter and then top coating with a rust cover paint.  Some portions under the removed undercoating look like new with that tannish primer and other areas have surface rust.  Just looking to get to the bare metal so the rust converter and rust cover can do their job.  Thanks for any input, John-Lugoff, SC.

[Mark Maras]

I used lacquer thinner on the residual undercoating. Mineral spirits took too much time and effort.

[One Way]

Thanks for the tip.  I do use acetone for some cleaning before painting the parts.  Not sure if that would work well on the undercoat residue. Scuff pads, wire wheels, etc are really tough to use on this type of removal.  I have been transferred to another store location and the new hours are not allowing me as much time as before to give to the project.  I will not have a good opportunity to try the acetone or lacquer thinner until next week some time.  Thanks again, John-Lugoff, SC

[One Way]

A little GOOGLE search tells me lacquer thinner is much better for removing hardened paint than acetone.  Acetone has more practical uses and is better for removing grease and wax and evaporates much faster.  I will pick up some lacquer thinner today at work and do a comparison test if I get some time next week on the project.  Thanks, John-Lugoff,SC.

[zKars]

I have resorted to the use of lacquer thinner for the final wash after mechanical removal of undercoating, and it works very very well.

However, it’s as dangerous as gasoline in-terms of the its flammability. I ONLY use it with the doors wide open and a breeze blowing through. AND with full face organic rated breathing protection. Bit chilly around here in January……

Diesel fuel is cheaper and safer and just as effective, though messier and involves disposal of rags that don’t dry out through evaporation. 

Let’s be careful out there and do our best to ensure we can continue to do this hobby for as long as possible with the least side affects. 

/end fatherly rant…..

[Patcon]

I agree with zKars

[One Way]

Working safely seems to increase along with our age.  Looking back over more years than seem possible, I thank the LORD for my continued health and safety.  I will be giving the lacquer thinner a try next week.  The project is in an open sided car port so that is always helpful with the resulting fumes, dust, debris, etc in this type of project.  Good safety reminder.  Thanks, John-Lugoff, SC.