Undercoating: Remove it all?

[YellowBee69]

Hello all,

I recently removed all the suspension from my 68, planning to upgrade all the suspension bushings and components...

While I'm here I would like to either re-do or make the underneath look a little better. If I had the money I would just have it all blasted and re-paint the underneath. However, I plan to drive this car A LOT so the thought of a hard undercoating would be nice I feel.

I've started to try to clean up the driver's side inner fender and there seem to be at least 3 coats of something on there. A white coating, a layer of undercoating, and then either another thin layer of undercoating, or paint. I hate whenever people undercoat and just coat everything, bolts and all. And that's what's been done on this car. So I for sure plan to at least clean all the parts up so they're not covered in coating.

My question is, would you all remove most of the undercoating that's on it now before applying a new one, or would you just clean what is on it the best you could now and maybe apply a coat of thin black undercoating or paint to it? Is the white coating needed? I can't help but imagine how much weight this is, and on top of that, I'd like to know what it looks like underneath. Everything I've done so far there aren't any real rust issues.

Yes, this car is a Swap project, don't hold it against me. I'm trying to get this car back on the road and enjoy it! She's come a long way! Just looking for advice on the undercoating. Thank you!

[GH85Carrera]

My opinion, if you plan to have a show car that is rarely driven, remove it all, and wax a and polish the area. For my car, I drive it and it has 193,000 miles. The factory put the undercoating on there to protect the metal of the fender from rock and road debris impacts that can and will cause dents, and impact bumps on the top of the fender. If you ever drive though gravel you will hear a lot of ting ting ting of gravel hitting the underside of the fender.

[Dpmulvan]

The white coating you’re referring to is the original, looks like someone sprayed black over it at some point. You’re already past the point of no return at least in that wheel well. Strip it to bare metal then use a good epoxy primer let it flash and then put a coat or two of chip guard over the top. It helps to use a pneumatic chisel and a heat gun to soften or a knotted wire wheel on an angle grinder just watch your eyes to remove undercoating. Being a 68 chances are you might find a few unpleasant surprises (rust) but maybe not. Also a rotisserie makes the job 100 times easier. I just did this last summer and it took a couple of days to strip.

[PeteKz]

Since you plan to "drive this car A LOT" you should put back the undercoating wherever you remove it. It not only provides rock chip protection but also sound deadening. If you really only intend to drive it short distances, to cars'n'coffee events on Saturdays, and such, then removing all the undercoating will save you maybe 20 lbs on the whole car. I don't think it's worth the time and trouble to strip the undercoating off the whole car, and repaint the whole underside to save that small amount of weight. Tradeoffs...

But, it's your car, so do whatever pleases you.

[tdw28210]

Probably would now that you've gone this far. get ready to get dirty. I did this and found the twisted metal brush disc on an angle grinder worked fairly well.

[YellowBee69]

I completely agree with keeping the undercoating, my think was should I take this off before I put more on, or just add to it and throw a 4th layer on LOL

[tdw28210]

Originally Posted by YellowBee69

I completely agree with keeping the undercoating, my think was should I take this off before I put more on, or just add to it and throw a 4th layer on LOL

I'd remove what's there and re-apply.

[PeteKz]

Originally Posted by YellowBee69

I completely agree with keeping the undercoating, my think was should I take this off before I put more on, or just add to it and throw a 4th layer on LOL

The original coating is still well-adhered on my 1973 car. I want to spend more time driving my car and less time working on it, so if it were my car, I would only re-coat the areas from which you already removed it, or where it came loose.

[YellowBee69]

Originally Posted by PeteKz

The original coating is still well-adhered on my 1973 car. I want to spend more time driving my car and less time working on it, so if it were my car, I would only re-coat the areas from which you already removed it, or where it came loose.

Makes sense! The inner fender areas are in fairly good shape, the rear is in better than the front, it should require just a clean-up and a coat of paint. The front is thin in areas that have been patched over the years and is starting to crack and chip off. Ill just focus on all those areas, Thank you!

[GH85Carrera]

Just pressure wash the inside of the fender, and spray on new undercoating. You fenders will appreciate it.

[YellowBee69]

Originally Posted by GH85Carrera

Just pressure wash the inside of the fender, and spray on new undercoating. You fenders will appreciate it.

I think that is my best bet! Thank you.