The Stovebolt Site Forums The Shop Area General Truck Talk Undercoating?

I recently got a ‘53 3800 back on the road. I had the body off and painted it piece by piece. Originally there was undercoating under fenders and cab, but I haven't undercoated mine yet. I like the clean look underneath with fresh paint and no undercoating but am worried about stone chips and stars in the fenders. I plan on driving it a good bit. Are you guys undercoating like original after a restoration or leaving them painted? I have only driven it a little bit because of concern of starring the paint on the fenders.

Your undercoating was likely dealer added or applied by some third party like Ziebart.

They were just painted with a flat/satin black from the factory.

Are you talking about chips in the paint inside the wheel well?

I doubt you're driving on salty roads or even in the rain so why bother with undercoating? The truck is going to be living the life of Riley from now on.

Pa, there were no inner fenders whatsoever in these trucks so if you use yours as a truck and drive it quite a bit (as you say), gravel and small rocks will indeed fly up and strike the inside of the fenders. Whether they leave dents, stars, etc is hard to say but for that reason and also for the quietness and the prevention against wetness, mud, salt, etc I go with undercoating every time. It isn't easy to get it done like it once was done but I have learned you can use a paint brush and fibered asphalt roof repair compound. After it dries, you can add more layers for thickness if you wish. It never seems to dry completely, you know. A five gallon bucket at a place like Lowes is around $50 and you can undercoat up a storm with that much. Last I looked a gallon was around $35, so there was a benefit to getting more. Good luck!

Pa Farmer - Just something I read somewhere, but I think some folks have used spray on bed liner as an under coating. Probably more expensive than Jon G's brush applied solution, but maybe an alternate option.

Others will chime in to offer more thoughts.

PS - Leaving this thread where it is for now, but it may get moved to the Paint and Body Shop in the future depending on if this is just going to be used for fenders, cab and other related sheet metal or the whole truck underside.

My '51 actually had remnants of undercoating under the cab floor. If there was any on the fenders, that was long gone.

I used spray-on undercoating. A couple of rattle cans (I believe it was UPOL brand) took care of the bottom of the cab, and a couple more cans for the fenders. My rear fenders were lumpy from driving around with loose snow chains (it was a fleet truck, so the driver didn't care about that.)

If you have the Factory Assembly Manual take a look at Sect. 14, Sheet 12.00 .

Excellent point Ron! Thanks for the reminder that is there. For those that don't have a 1947-54 Chevy Truck FAM, below is a pic of the page Ron referes to.

I've always thought undercoating protects the steel while rusting. We never did it back in the early 1960s.

Wally

If you decide to undercoat an assembled vehicle, do a thorough steam cleaning or pressure wash first. Otherwise, the salt, road grime and other corrosive stuff gets trapped under a protective layer of tar so it can really do its job of eating the vehicle.
Jerry

Would a product like rust reformer from rust oleum or something similar be beneficial prior to the undercoating, in case you missed some areas. Or doesn’t it work as well. I have used on some pieces like the mirror arm. Although it is on 3 months so I can’t testify that it works.

Glen

I think you're over-thinking this. How much driving on snow-covered, salted roads are you going to do? Your truck lives in a garage and is well taken care of.

Ol' Roy had no undercoating since new and was used as a regular truck into the 1990s. It has virtually no rust on it.

In my area the paint on rust proofing does not work as it gets under it .most rust proofing is a non drying oil .I use fluid film on my vehicles but the older trucks don’t have inner fenders protecting the fenders from rocks and most people don’t drive in the winter with the older trucks.i still use fluid film in areas like the floor support and rear frame by the emergency brake pivot but a rock guard or bed liner would be better for were the rocks get thrown up as you can easily wash out that area if you get some salt sprayed up from the road.

I used bed liner on my fenders and running boards and regular undercoating on the cab. I mixed paint in with the bedliner so it is somewhat the same color as the outside of the fenders and running boards.