The Stovebolt Site Forums The Shop Area Paint and Body Shop Undercoating

As I'm scraping off the old undercoating from my '59 front fenders to do metal work, I began thinking of how well this preserved the metal.
If the original owner paid extra for this, I think I'm the benefactor.
I want to apply something when I'm ready for the finishing part of this project.
One thing that came to mind is truck liner... else I was thinking primer.
I decided to pop in here to see what you guys thought. What did you use?
Jerry

My personal experience with undercoating is that it usually causes more problems than it fixes. Nearly every installer blocked drain holes with the undercoat, causing water retention and more rust than there would have been had it all been left alone. A far better solution IMHO is to regularly wash the under side of the body during salt season and to make sure the drain holes are open.

Nothing is better than a good epoxy primer on clean metal.

Thanks for the tip, Tiny.
I'm disassembling everything on the truck to rework/restore. I just finished the doors and they have drain provisions.
When I get down to the frame, I'll do POR15... maybe I should get the POR15 earlier and use IT on the underside of my fenders.
CASO how does that sound? Or is Epoxy Primer less expense for the same result?

I used bed liner for under cab and fenders.

I have no issues with rust or salt where I live, but wanted some protection from heat and noise.

very happy with the results
...pic 1...
...pic2...
...pic3...

good luck

Thanks!

Jerry

Upol Raptor is what I used. You can purchase a kit off Ebay.

Jerry,i'm an advocate of POR-15,i've never been a fan of textured underseal,I imagine the rough surface would be more likely to give dirt and crud a key to stick.
I used POR extensively,here's a picture of the underside of my rear fenders.
I double coated them so I hope they'll be good for another 60+ years!

I used Herculiner on the floor and bed of my Jeep CJ5 so I have some of that left over and available to use.
Though I agree is has texture and could allow dirt to stick, I don't think the dirt (or gravel) could ever penetrate to damage the metal... It's texture would deflect gravel. Removal of the bedliner stuff might be a bear though I doubt that would ever be anytime soon... or in my lifetime anyway.
The stuff originally used on the truck fenders was like tar, or WAS tar, I'm not sure. I'm using a scraper to remove it and it's a difficult job, but I can see it was very effective in it's purpose. It was obviously applied after the truck was assembled, as it was glopped on thick in some areas and thin in others. At least with the fenders off, I would be able to put a nice even coating of whatever I use.
I'm leaving that open, because I plan on buying some POR15 for the frame when I get the cab and bed off... so really I guess I could go either way. I'm assuming a gallon of POR15 will do the frame and enough left over for all the fender undersides?
I appreciate all the comments. It's always interesting to see what fellow bolters are doing and how well it worked... and I didn't find any posts on this topic.
Jerry

Por 15 @ Eastwood 1gal is 150 bucks

SPI epoxy primer. 2 gals for 180 bucks
Every bit as good as PPG's and better than Por imo.

Took a year of research before I came to that opinion but for the ease of use and simplicity of only buying one product to use for primer, build coats, and sealer (water proof all th way) I found it hard to beat.

CASO, is a hardener required for the primer?

The primer comes in 2- 1 gal cans... Part A and Part B mix 1:1 or reduce to use as sealer. Comes in qt's as well but for a full project 2 gals works pretty good. I
I'd say I used two gals up on the cab (inside and out) by the time I was done blocking. I'm just now ordering another 2 gal kit to finish up the bed but plan on using the left overs to reseal the metal garage doors that have started to rust m(once I get the blasted) one thing I really like about the EP is I can get things stripped and in EP then let it sit till I'm ready for it...

Jerry for what it's worth a quart of POR-15 did virtually my whole chassis.
It covers particularly well even when brushed,due in part to the 80% solids.

My main concern about buying a gallon of the stuff would be the use and storage of it.
Once opened you really have to make sure you don't let the lid get too gunked up with paint as it's darn near impossible to get the lid back off!
Some folks puncture the lid,decant what they need to use and then seal it with duct tape.
Others use a sheet of polythene or similar between the lid and tin.

I opted to buy smaller tins,which was a slightly more expensive way to do it,but it suited my time frame and wallet!

Finally....If do do decide to go the POR route most importantly,don't forget to wear a mask,long sleeves and rubber gloves.
Oh and I did say wear a mask!!!
(Been there, done that and suffered the effects etc...)

A quart... I never would've imagined that. Leaf springs, axle, front suspension and all?
I appreciate the tip on dispensing and sealing too, as well as the caution for saftey... well noted, my friend.
I will definitely be using the POR15 on my frame and applying it with a brush.
I'm leaning toward my herculiner for the fender undersides, only because I have it on hand and it should work well.
I also planned on using the herculiner on my inside step and floor of the truck, the raised ribs of my steps on the fenders and on the flat step-up areas of my fabricated rear bumper.
Jerry

There's nothing wrong with undercoating, provided everything underneath it is prepped and it's not trapping any moisture or rust. This is where the issues come in. As well, you need to make sure any drains are clear as was already mentioned.

Sorry I may not have mentioned, this is for my '59 truck and the fenders are on a bench.
I'm just looking at coating the inside areas of the fenders surrounding the wheels and I'll be using a brush so the application will be even and should turn out pretty nice when assembled.
I'll be sure everything is dry.
Thanks!
Jerry

Jerry,
By 'the chassis' I meant just the totally bare frame,sorry if I mislead you but even so a quart did go a long way!

Would applying POR 15 to the frame, driveshaft, and axle housings be a comparable substitute for a powder coating?


Mike

Mike, I believe a lot of folks on here would say 'yes' to that.
I plan on using POR15 on the frame and anything else I want to protect.
I'm going to get a gallon so I can cover all my bases while I have the truck disassembled.
Since I'm taking my time with the fenders, I could use it on the inside of them as well... still thinking...
Jerry

Mike,i'm no expert but assuming you follow the prep and application properly i've found the POR paint is really tough,I spilt a small amount on my work bench and 40 grit sandpaper would hardly even mark it!