Hi again,


the undercoating on my 65 Daimler is contaminated on the undercarriage with oil and trans fluid. In other places like wheel wells it is in good shape. I would like to strip it all and am having a hell of a time getting it out of the wheel wells. I searched the forum for methods of removal but only found discussions explaining how they applied it at the factory.... I have stripped a lot of chassis over the years but have to admit i have never seen stuff like this. I tried my favorite undercoat stripper, easy off oven cleaner with no luck. I tried "aircraft" stripper and that softened it a little but did not release it from the painted surface. tried a heavy wire brush on an angle grinder and that smears it and the wire wheel loads up pretty quickly. Tried heating with a heat gun and then scraping.... that works pretty good except that it warped the sheet metal in a small spot. I dont have a portable blaster, but will get one if anyone can tell me that it will work....

Thanks,

Steve

 

I'm assuming that it's the black underseal that you want to remove. If it's solidly attached to the steel below, I don't try to remove it. Where I do remove it, because it's flaking or, more likely, because I want weld in that area, I use hot air gun and a scraper. What that leaves behind can be cleaned off with a rag and white spirit (mineral spirit in the US?). Trying to remove all the underseal sounds like a horrendous task.

With the hot air gun, the setting shouldn't be too high, only sufficient to soften the underseal. Some professional grade guns are way too hot at their maximum.

 

Have you tried a needle scaler? I haven't used one myself, but I have heard they work well. Something like this: https://www.princessauto.com/en/air-...t/PA0008843617

 

I have seen the needle scaler on a u tube post.. it looks pretty good in the video and harbor freight has one for around $30... but the video says to use it in tight spots... not really a tool for the entire car.... i'll give it a try... i also saw a video for silicon carbide discs.. they look like the right tool for the job but might be too aggressive?

Thanks,

Steve

 

I've not tried them for this, but most types of disc tend to get clogged up when used on soft/sticky stuff. Flap discs and the poly type strip discs work reasonably on paint (apart from all the dust), but I'd expect they would become clogged and ineffective on underseal. Like I said, if it's well attached and there's no need to cut out rust and weld in new steel, why not leave it alone?

 

don't remove it. Oils in the engine compartment are a normal nuissance, but they protect the body.
There is a saying...
"Leave dirty dirty enough".

 

I have used needle scalers on rusted steel boats.
The concept is dozens of tiny chisel/hammers
There is no way I would use one on a car body.
It would stretch the lightweight body metal.
I agree with Jose and Peter re leave it alone.

 

Let me add a third "just leave it alone". I had places under my car where the factory undercoating had become soft from years of oil contamination. Those area scraped off easily with a putty knife. However, where is was stuck, it was really stuck and I just left it alone. The body man found a material (spray on truck bed liner) that matched the factory undercoating finish exactly. I now cannot tell where it is original and where it is new.

 

I have used a Harbor Freight scaler on several cars. It can work reasonably well, but its is very noisy, dirty, and uses a whole lot of air. So a decent compressor is needed.

It was used on frame rails, underside of the body, but I never used it on the inside of a fender or the inside of any external body panel.

https://www.harborfreight.com/profes...ler-57171.html

If one is going to use it, suggest also purchase an extra set of needles. I also fount that occasionally sharpening the tips of the needles can make it work a bit better on heavy undercoat and thicker scaled rust.

jjsandsms

 

Thanks for the feedback,,,, to those suggesting to just leave it alone.. All the cars i have restored, I stripped completely.. On an XJ6 coupe i restored, a previous owner brushed what appeared to be fiberglass resin over crumbling rust under the rear floor,,,, painted the top side and undercoated the bottom side... I did not discover it until i stripped the bottom undercoat.... Now, anytime i see undercoat, i look at it suspiciously ,,,,

Thanks,

Steve

 

I can't blame you, but it is a messy job and by the comments I read, easy to do damage.
However it sounds like you are experienced at undercoating removal and I wish you success.