Best way to remove undercoating

[plumcrazy021]

What is the best way to get this undercoating off the inside of my quarters as im changing colors and highly dought i can paint over it?

[green69rt]

What is the best way to get this undercoating off the inside of my quarters as im changing colors and highly dought i can paint over it?

I don't think there is a "best way".    If this is going to be a DIY job then it's going to take some elbow grease and time.  One way is to get a heat gun and heat the coating up then scrape off with a putty knife.  Clean up with solvent and sandpaper.  Others have used pressure washer, but I haven't heard if that worked out    .   I used a stripping wheel on a angle grinder, then solvent and sandpaper.   Good luck

[Charger-Bodie]

If it's still adhering you can paint over it.

[Ryan.C]

I used a propane torch and put a little heat on the undercoat and a putty knife to scrape it off. It works surprisingly well. I cleaned the residual with a kerosene soaked rag and lots of elbow grease. 

[Troy]

My new favorite toy is a needle scaler:
https://www.harborfreight.com/air-needle-scaler-61447.html

I have a video of undercoating removal in a wheel well on my Challenger with it that I should put online somewhere.

I also have one of these multi tool doohickeys with a scraper blade:
https://www.harborfreight.com/variable-speed-oscillating-multi-tool-63113.html

You can use heat to make it softer and a hand scraper but that's a lot of work. Kerosene will also soften it. Any method that softens it makes a gooey mess. Scraping it while it's hard makes a dusty mess (possibly airborne). Pick your poison. I've heard of people using dry ice to freeze it then bang on the panels and it falls off. This works better with non-rigid panels so not sure how well it will work in a wheel well.

Honestly, if it's very hard to remove, leave it there. Places where metal has rusted behind it will literally fall off so test lots of spots.

Troy

[E5 Charger]

I used a heat gun and putty knife. It doesn't take a lot of heat and scraped off in strips. Worked very well!

[1970Moparmann]

My new favorite toy is a needle scaler:
https://www.harborfreight.com/air-needle-scaler-61447.html

Never saw that tool before.   Found a few videos on it.  Have to get that!

https://www.youtube.com/watch?v=91wdTASf8iU

[Fitz73Chrgr]

Torch and a putty knife and many hours of work.

[Troy]

Videos...

This "action" video is only about 3 minutes. All the brown/gray stuff is dirty original undercoating. The black areas in the middle of the wheel well and along any edges are primer to cover bare metal from welded panel replacement. You can see how any undercoating near these areas is weak.
https://youtu.be/diOEKs84_1M

This is a look at the same wheel well 24 minutes later.
https://youtu.be/Ygs6KZ-o2kQ

Troy

[plumcrazy021]

Videos...

This "action" video is only about 3 minutes. All the brown/gray stuff is dirty original undercoating. The black areas in the middle of the wheel well and along any edges are primer to cover bare metal from welded panel replacement. You can see how any undercoating near these areas is weak.
https://youtu.be/diOEKs84_1M

This is a look at the same wheel well 24 minutes later.
https://youtu.be/Ygs6KZ-o2kQ

Troy

So this tool Doesn't dent the metal at all? It looks to good to be true ?

[green69rt]

Videos...

This "action" video is only about 3 minutes. All the brown/gray stuff is dirty original undercoating. The black areas in the middle of the wheel well and along any edges are primer to cover bare metal from welded panel replacement. You can see how any undercoating near these areas is weak.
https://youtu.be/diOEKs84_1M

This is a look at the same wheel well 24 minutes later.
https://youtu.be/Ygs6KZ-o2kQ

Troy

So this tool Doesn't dent the metal at all? It looks to good to be true ?

I have one and as long as you use it in places that won't show then fine.  If you are going to do a wheel well and re-undercoat it, there will be no problem.  I wouldn't use it on the painted surfaces on a car.   Also, the scaler is somewhat adjustable.

Also, if the stuff you're trying to remove is soft or oily then this won't work, the material will just move around and, maybe, gum up the scaler.

[plumcrazy021]

The coating is pretty solid and it's on the inside of the quarter panels i tried to put a pic up but wont fit it's to big. The stuff pretty much covers the whole quarter.

[Troy]

Videos...

This "action" video is only about 3 minutes. All the brown/gray stuff is dirty original undercoating. The black areas in the middle of the wheel well and along any edges are primer to cover bare metal from welded panel replacement. You can see how any undercoating near these areas is weak.
https://youtu.be/diOEKs84_1M

This is a look at the same wheel well 24 minutes later.
https://youtu.be/Ygs6KZ-o2kQ

Troy

So this tool Doesn't dent the metal at all? It looks to good to be true ?

Not really? That was my first ever attempt. You can see (and hear!) at the beginning that I has holding it perpendicular to the surface and it basically acts like a bunch of tiny hammers and does nothing to the undercoating (unless it's already loose) but will leave a whole bunch of tiny dimples in bare metal. After a few seconds of that I was playing with different angles. Once you have it at a fairly sharp angle it's more like a scraper and really doesn't seem to harm anything. All that green you see is the factory paint so it's literally removing undercoating without taking off the paint or primer. There's a mess of undercoating left (very small strips and specs) but they come off easily using "normal" means. The needles are basically steel rods cut at 90 degrees on the end so that have an edge. Obviously the greater the angle the more bite they have but too great and they'll just ride up the surface. Once they wear down they become rounded and don't work as well for this purpose (but still remove rust from my truck frames).

And again, these are wheel wells which are rather thick and solid so you can be a bit more aggressive. But most places that have undercoating are the same. Exceptions may be the underside of the top of the front fenders. Be careful there!

Troy

[green69rt]

The coating is pretty solid and it's on the inside of the quarter panels i tried to put a pic up but wont fit it's to big. The stuff pretty much covers the whole quarter.

If the undercoating is really tightly bonded and is not chipping off, you might consider leaving it alone.  Especially if you're going to put new undercoat on.  You can just pressure wash it and spray a light coat of new undercoat on to dress it up.  This stuff was sprayed on the inside of trunk on the quarters to protect the metal from things bouncing around in the trunk and denting the quarters from the inside.

[kent]

Torch and a putty knife and many hours of work.

That's what I did. Many many hours. Ok about 14 or 16 with breaks of course and could not do it steady.It took about 4 sessions in all. I also used a hand held wire brush, a bunch of different sized scrapers and believe it or not a table spoon just for those pesky rear wheel wells. It really worked well. What can I say it had a good contour. I did my whole car in one week or so and I saved all the undercoating and it filled a 5 gallon bucket. I'll try and post some pictures.

[Troy]

The coating is pretty solid and it's on the inside of the quarter panels i tried to put a pic up but wont fit it's to big. The stuff pretty much covers the whole quarter.

If the undercoating is really tightly bonded and is not chipping off, you might consider leaving it alone.  Especially if you're going to put new undercoat on.  You can just pressure wash it and spray a light coat of new undercoat on to dress it up.  This stuff was sprayed on the inside of trunk on the quarters to protect the metal from things bouncing around in the trunk and denting the quarters from the inside.

I'd tend to agree here and earlier posts. Even if you get all the undercoating off this area, most of it is really hard to reach and even harder to reapply. If it's very stubborn there's no reason to think it won't last. The exception being if you have to repair lower sections of the quarters or wheel wells as the heat will weaken the surrounding undercoating and it will eventually come off or rust underneath.

Troy

[plumcrazy021]

my pics are 418 and says has to be 400 how do i get it smaller to fit in my posts ? 

[kent]

I just really kind of figured it out this afternoon again. I you don't use that skill often and I tend to forget. Must be getting old.

One of the other guys might be able to help better then me. I down sized mine on my own "file explorer" sorry.

[Troy]

my pics are 418 and says has to be 400 how do i get it smaller to fit in my posts ? 

What do you take the picture with, what were the settings, and what are you using to resize them? The easiest way to do it is to save as jpg or jpeg with "quality" to 80% and resize (not crop!) to 1024x768 pixels (approximate resolution of a 17" monitor). This will almost always be around 200 KB and look good on most devices. There's not a lot of reason to go bigger on the dimensions (HD video is 1280x720 or 1920x1080) especially now that people are often staring at these things on 4" or smaller cell phone screens. Unless you're a professional photographer with great lighting, the difference in the highest quality and 80% is negligible but the file size takes a pretty good hit. Not all editors let you change the quality! In those cases you have to just play with the total pixel size. There are several threads on this topic in the help desk section.

Troy

[birdsandbees]

I use Paint.NET and resize my 4.0/5.0 meg pics at 850 x ~638, then "save as" and at about 94% is ~ 190KB. Takes me a few minutes to do a couple dozen pictures.

[plumcrazy021]

my pics are 418 and says has to be 400 how do i get it smaller to fit in my posts ? 

What do you take the picture with, what were the settings, and what are you using to resize them? The easiest way to do it is to save as jpg or jpeg with "quality" to 80% and resize (not crop!) to 1024x768 pixels (approximate resolution of a 17" monitor). This will almost always be around 200 KB and look good on most devices. There's not a lot of reason to go bigger on the dimensions (HD video is 1280x720 or 1920x1080) especially now that people are often staring at these things on 4" or smaller cell phone screens. Unless you're a professional photographer with great lighting, the difference in the highest quality and 80% is negligible but the file size takes a pretty good hit. Not all editors let you change the quality! In those cases you have to just play with the total pixel size. There are several threads on this topic in the help desk section.

Troy

My I phone Troy then mail them to my pc

[Troy]

my pics are 418 and says has to be 400 how do i get it smaller to fit in my posts ? 

What do you take the picture with, what were the settings, and what are you using to resize them? The easiest way to do it is to save as jpg or jpeg with "quality" to 80% and resize (not crop!) to 1024x768 pixels (approximate resolution of a 17" monitor). This will almost always be around 200 KB and look good on most devices. There's not a lot of reason to go bigger on the dimensions (HD video is 1280x720 or 1920x1080) especially now that people are often staring at these things on 4" or smaller cell phone screens. Unless you're a professional photographer with great lighting, the difference in the highest quality and 80% is negligible but the file size takes a pretty good hit. Not all editors let you change the quality! In those cases you have to just play with the total pixel size. There are several threads on this topic in the help desk section.

Troy

My I phone Troy then mail them to my pc

If you're following these instructions:
http://osxdaily.com/2014/04/21/resize-photos-from-iphone-mail/

There's a giant gap from "Medium" (640×480) to "Large" (1632×1224). Lame. If you're using large and getting something close to 400KB I can tweak the settings here (again) just to make it easy. Of course, the next guy's phone will require 500 sooooo...

It's definitely something I'm working on but I'm a bit hamstrung at the moment. I have to make lots of changes to implement the right solution.

Troy

[Alaskan_TA]

Be aware that some undercoating / sound deadners may contain asbestos.

So have a sample tested before attempting any dry method that can cause dust to be inhaled or taken home on your clothing.

One wet method that works great is a steam power washer.

For safeties sake, do some research for sure.

[Troy]

Be aware that some undercoating / sound deadners may contain asbestos.

So have a sample tested before attempting any dry method that can cause dust to be inhaled or taken home on your clothing.

One wet method that works great is a steam power washer.

For safeties sake, do some research for sure.

Oh great! Wouldn't there be similar issues with a wet method? Minus the airborne part. (I'll have to review some DIY house fixing videos.)

Troy

[68 RT]

Some undercoating too can contain PCB's. Would defiantly were a respirator when doing this.

[1970Moparmann]

In regards to picture, use windows "Snipping Tool".  It's like a screen shot of a picture.   The smaller the picture on your screen, the lower the resolution.   Works great!