Suggestions For Undercoating?

[Terrorist 5.0]

Hi everyone. After going through the next wave of repairs on my car (solved overcharging issue, clutch cable, rebuilt distributor, etc) I am pretty happy with it. I do however have some surface rust on the bottom. The car in general is in great shape rust wise except for the common front frame rail spot (which isn’t too bad at all yet, I’ve posted about it here a couple times), and some surface rust mostly in the rear. The black boxes behind the rear wheels have rusted through to the trunk but I have an easy fix for that I think.

I plan on using a paint stripper wheel to get the undercarriage down to bare metal and paint it with some sort of NON RUBBERIZED undercoating, and apply fluid film on top of that once it dries, just for peace of mind. My main question is, what does everyone recommend for said paint? I know rubberized is not good, as it traps moisture. Also, removing the undercoating in the rear wheel wells is gonna be a pain. Suggestions?

As for the rot in the trunk, it is a pretty small hole, about fist sized if even, and since it is in an area that is not visible (hidden behind rear bumper cover, I just plan on cutting it out and sealing it with paint. Yes, I am ok with a small hole in the wheel wells. I can block it off with something, but to do it properly is not exactly in the budget right now.

Thanks everyone!

 

[ttocs]

I had mine done 10+ yrs ago with lizard skin. It is nice because it also helps with heat if your headers are heating up the console like mine were.

 

[Wmac]

If you strip the underside panels, could use etch or epoxy primer to seal the bare metal. Both of these are available in spray cans. (Power wash first)

Let paint cure for about a week, then fluid film or rust check as required.

 

[ttocs]

I would suggest that if you ever planned on doing sub-frame connectors to do them first or you will just have to grind it away to weld them in later.

 

[Terrorist 5.0]

Don’t plan on those, I don’t think I will ever be making that kind of power and I won’t be taking it to the strip. Not really my thing. Good thinking though.

 

[Alexi]

For the undercarriage, skip rubberized coating go with POR-15 or Rust-Oleum Professional Rust Reformer after stripping to bare metal. Both are tough, moisture-resistant, and work great under Fluid Film. For the wheel wells, a wire wheel or flap disc on an angle grinder will make stripping easier.

For the trunk hole, cut out the rust, hit it with rust converter, then seal with fiberglass patch or sheet metal + paint. Not perfect, but it’ll buy time. Fluid Film over everything afterward will slow future rust. Solid plan overall just stay on top of reapplying Fluid Film yearly.

 

[Terrorist 5.0]

I am planning on taking it to a shop for this repair now. The area is pretty tight to work in.

 

[MyLittlePony]

For the undercarriage, skip rubberized coating go with POR-15 or Rust-Oleum Professional Rust Reformer after stripping to bare metal. Both are tough, moisture-resistant, and work great under Fluid Film. For the wheel wells, a wire wheel or flap disc on an angle grinder will make stripping easier.

For the trunk hole, cut out the rust, hit it with rust converter, then seal with fiberglass patch or sheet metal + paint. Not perfect, but it’ll buy time. Fluid Film over everything afterward will slow future rust. Solid plan overall just stay on top of reapplying Fluid Film yearly.

I hate it when people use fiberglass instead of correctly welding replacement panels/pieces. HOWEVER, done correctly (in regards to fiberglass anyway) it does preserve the metal from further corrosion, so when the next owner comes along, intending to do the repairs the right way, other than the obnoxiousness of removal, there’s the benefit of having a car that’s not as bad of a shape had the repairs not been done at all.

 

[white95]

+1 for POR15

 

[Terrorist 5.0]

+1 for POR15

Doesn’t POR15 have a very picky application? I have heard it not working for many people due to it.

 

[RAU03MACH]

my father used

Cooler Coating, Asphaltic-Coated, For: Evaporative Cooler Purge Systems​

• Fast drying
• Protects against rust & corrosion all season
• Replacement sku Ace No.49615- aerosol 13 oz
• Resistant to moisture
• Sound deadening qualities
• Spray, aerosol coating
• Designed to coat & seal evaporative cooler bottom pans
• Long-lasting and saves maintenance
• Protects against rust and corrosion.

 

[RAU03MACH]

i have tryed it on my 92 ford pick up 4x4 its still there 15 years ago
as long as everything is clean no dirt moisture it will bond good on frames and wheel wells
dont put it on thick

 

[ttocs]

por15 can be sprayed or I though even brushed/rolled on. I used it in my wheel wells (sprayed) and it held up nicely.

 

[Daryl]

POR-15. Did the entire underside of a ‘59 F-100 (my first resto mod). Rolled and brushed it on. Really lasts well. WARNING: WEAR GLOVES! Preferably long dishwashing gloves or a long-sleeved T-shirt that you don’t mind tossing out after done. Stuff is sticky, messy and difficult to remove from anything you didn’t intend for it to go on! But that’s a good thing because that’s what it’s supposed to do!

Good luck and please keep us updated on the progress and results. Cheers!

 

[Terrorist 5.0]

Alright, these are all very good suggestions and insight. I will let the body guy know, I really like the POR-15 idea, always peaked my curiosity. Thanks everyone!

 

[Terrorist 5.0]

POR-15. Did the entire underside of a ‘59 F-100 (my first resto mod). Rolled and brushed it on. Really lasts well. WARNING: WEAR GLOVES! Preferably long dishwashing gloves or a long-sleeved T-shirt that you don’t mind tossing out after done. Stuff is sticky, messy and difficult to remove from anything you didn’t intend for it to go on! But that’s a good thing because that’s what it’s supposed to do!

Good luck and please keep us updated on the progress and results. Cheers!

I sure will! I will include before and after pictures.

 

[Alexi]

I hate it when people use fiberglass instead of correctly welding replacement panels/pieces. HOWEVER, done correctly (in regards to fiberglass anyway) it does preserve the metal from further corrosion, so when the next owner comes along, intending to do the repairs the right way, other than the obnoxiousness of removal, there’s the benefit of having a car that’s not as bad of a shape had the repairs not been done at all.

Totally agree fiberglass is a band-aid, but at least it slows the rot. Still annoying to deal with later, though.

 

[MyLittlePony]

por15 can be sprayed or I though even brushed/rolled on. I used it in my wheel wells (sprayed) and it held up nicely.

Sprayed the undercarriage of my 1967 Triumph GT6 with it. That was glossy AF! Since it was done outside, and tilted, it reflected the sky. Can’t post a pic right now but it looked like I airbrushed the sky (clouds and all) on it.

Also brushed the frame as well as the frame of a 1957 Chevy. Both are holding up real well. The Triumph has actually been parked outside a lengthy amount of time. Complete frame off restoration, but because it’s British, if you even mention the word “rain” anywhere it can hear, it will rust right up! Even the brand new bumper overriders I got it rusted up! Anything that had POR15 on it is all fine though. No issues.

WARNING: WEAR GLOVES! Preferably long dishwashing gloves or a long-sleeved T-shirt that you don’t mind tossing out after done. Stuff is sticky, messy and difficult to remove from anything you didn’t intend for it to go on!

Always keep this in mind! That means that if it gets on your driveway or nice professionally epoxied floor, it will NOT come out! You do have to be careful about what kind you use because it may not be UV protected, so black will turn brown, and some things may even become brittle and flake off, especially if it’s a smooth surface. But concrete isn’t a smooth surface. Every couple of years, I will try to pressure wash it off, but no luck. It’s been almost a decade and most of it is still there. I always use cardboard and other masking attempts. This was just my husband being careless.

But it IS very sticky, and I never wear gloves. I found that the orange Gojo or equivalent is good at getting it off your skin.