Fender undercoat? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

MiraclePieCo · 07-01-2018, 02:11 AM

Question 1) Do ADs need fender undercoating?

Question 2) Which works better as a fender liner: rubberized undercoat or spray-on bedliner?

Question 3) What if I need to work on the fender later - will all the lining be impossible to remove?

.

Matt_50 · 07-01-2018, 02:46 AM

Rubber stuff can be a pain to get off later if you had too. Gums up on blades or wire wheels. Will this be off road, in snowy weather...? A PO did the undercoating on a bed I traded for. Looked great under fenders, but I think it really depends on how clean you'll keep the truck. A good sealed coat of paint is fine as long as you don't let mud sit.

MiraclePieCo · 07-01-2018, 03:11 AM

Thanks Matt. I was hoping to prevent rock dings and maybe get some sound deadening on those big "kettle drum" fenders too. Model A's are notorious for star dings in the fenders, but I don't really see those on ADs. I think I'm inclined to go with the bed liner - strictly DIY, probably a roll-on.

Or nothing at all.

**mongocanfly** · 07-01-2018, 09:41 AM

I'm sure this'll start some disagreements...but I'm using lizardskin on my fender undersides....I know others have done the same....flying rocks is my biggest concern...

Speedbumpauto · 07-01-2018, 11:44 AM

I used bed liner and bought the gun and sprayed in on, two coats. The hanging from the rafters and masking was a pain but the stuff went on easily after that. Did it for rock"stars" and I don't have any but who knows?

DransportGarage · 07-01-2018, 02:33 PM

Quote:

Originally Posted by Speedbumpauto

I used bed liner and bought the gun and sprayed in on, two coats. The hanging from the rafters and masking was a pain but the stuff went on easily after that. Did it for rock"stars" and I don't have any but who knows?

Hanging from the rafters isn't too bad, unless there's no one around to get you down.

_Ogre · 07-01-2018, 11:50 AM

commercial rhino liner bed liner under fenders, inner fenders and bottom of cab for 9 years and 35,000 miles not an issue
it would probably be a pia to get off
i've seen the home spray and roll on kits used with success too

my56chevytruck · 07-02-2018, 09:06 AM

Quote:

Originally Posted by _Ogre

commercial rhino liner bed liner under fenders, inner fenders and bottom of cab for 9 years and 35,000 miles not an issue
it would probably be a pia to get off
i've seen the home spray and roll on kits used with success too

I'm with Ogre, I used a commercial rhino liner I bought from a local auto parts store and have YET to see any fender stars. Good stuff for sure

DransportGarage · 07-02-2018, 09:17 AM

Has anyone actually seen stars on these TF factory fenders? They weigh a ton, and probably are 18 gauge.

1project2many · 07-02-2018, 09:13 PM

Quote:

Originally Posted by DransportGarage

Has anyone actually seen stars on these TF factory fenders? They weigh a ton, and probably are 18 gauge.

I tried taking pictures of the star chips in the lower rear of my RH fender. They're between 1/4" and 1/2" diameter. But in the low light in the barn they don't show up on a camera.

DransportGarage · 07-02-2018, 10:15 PM

Quote:

Originally Posted by 1project2many

I tried taking pictures of the star chips in the lower rear of my RH fender. They're between 1/4" and 1/2" diameter. But in the low light in the barn they don't show up on a camera.

Thanks 1project2many. That answers my question, but that's a weird place for them. I expected they would only be a problem on the top of the fender. Are you talking about a rear fender? That would explain it.

Black_Sheep · 10-14-2018, 02:11 PM

Quote:

Originally Posted by _Ogre

commercial rhino liner bed liner under fenders, inner fenders and bottom of cab for 9 years and 35,000 miles not an issue
it would probably be a pia to get off
i've seen the home spray and roll on kits used with success too

I used SEM bed liner and rolled it on heavy. It should offer some protection from minor stone bruises and sand. It should clean up easy too...

MiraclePieCo · 10-14-2018, 05:09 PM

Quote:

Originally Posted by Black_Sheep

I used SEM bed liner and rolled it on heavy. It should offer some protection from minor stone bruises and sand. It should clean up easy too...

Looks great - you've convinced me!

**mr48chev** · 07-01-2018, 01:30 PM

Anything you coat the underside of the fenders with is going to be a royal pain to get cleaned off if you have to do body work on the fender at a later date.

That said, if you are going to have really nice paint and intend to drive it a lot of miles I'd do it. No matter what you put on it you need the metal on the inside to be fully sealed with proper paint that won't absorb moisture before you put the coating on though. I've worked on too many cars that were undercoated when they were new at the dealer that a few years later rusted out .

OrrieG · 07-01-2018, 03:13 PM

Rattlecan rubberized from paint store, easy to control where it goes. Also used on cab bottom and angled part of firewall, I will drive mine all four seasons.

GreasyLikeaBurger · 07-01-2018, 05:37 PM

Quote:

Originally Posted by OrrieG

Rattlecan rubberized from paint store, easy to control where it goes. Also used on cab bottom and angled part of firewall, I will drive mine all four seasons.

Wait, there's 4 seasons? Please explain, I live in Socal. Haha

lv2tri2 · 07-01-2018, 09:24 PM

Quote:

Originally Posted by GreasyLikeaBurger

Wait, there's 4 seasons? Please explain, I live in Socal. Haha

We have 4 now with the Fire Session

MARTINSR · 07-02-2018, 01:26 PM

Quote:

Originally Posted by GreasyLikeaBurger

Wait, there's 4 seasons? Please explain, I live in Socal. Haha

I was wondering what these "season" things are, and four different ones? Hmmmm Hope they have them where my retirement home is in Idaho.

Brian

my56chevytruck · 07-02-2018, 02:26 PM

Quote:

Originally Posted by MARTINSR

I was wondering what these "season" things are, and four different ones? Hmmmm Hope they have them where my retirement home is in Idaho.

Brian

Don't know about IDAHO, but i can assure you, here in the midwest, we get sometimes all 4 seasons, in just a few weeks time.

OrrieG · 07-02-2018, 08:08 PM

Quote:

Originally Posted by GreasyLikeaBurger

Wait, there's 4 seasons? Please explain, I live in Socal. Haha

Summer, early winter, winter, late winter with two weeks of fall and spring before and after summer.

lv2tri2 · 10-12-2018, 08:51 PM

Quote:

Originally Posted by GreasyLikeaBurger

Wait, there's 4 seasons? Please explain, I live in Socal. Haha

We have four seasons if you include drought and fire.

1project2many · 07-01-2018, 08:20 PM

Quote:

Wait, there's 4 seasons? Please explain, I live in Socal.

From the northeast:
Almost snow, snow, melting snow, and road construction.

I did not undercoat. The tires I was using were agressive enough to catch and throw gravel. There are a few dents in the rear fenders...

vintovka · 07-01-2018, 10:41 PM

Locals use rustoleum

markedgar5 · 07-02-2018, 09:19 AM

Is there any problem with just using rustoleum? I've seen people put fenders on and never even coat the back side. It makes me cringe. When I redid a newer truck I painted the backside with primer and about four coats (all rattle can). Then installed the fenders and took to a paint shop. The old fenders didn't have much on the backs.

Quote:

Originally Posted by vintovka

Locals use rustoleum

**jweb** · 07-02-2018, 11:20 AM

The inside of my fenders, inner fenders and bottom of cab are sprayed with Raptor bedliner. You can get the kits on Amazon. I also used Rustoleum Bedliner from Walmart for the bottom of my bed wood. Both products worked well but the Raptor is nicer.

My truck seems quieter and I don’t hear the rocks hitting like I used to. I would only do this after the bodywork is finished, it would be a pain to get off.

07-01-2018, 02:11 AM	#1
MiraclePieCo Registered User Join Date: Sep 2014 Location: USA Posts: 2,249	Fender undercoat? Question 1) Do ADs need fender undercoating? Question 2) Which works better as a fender liner: rubberized undercoat or spray-on bedliner? Question 3) What if I need to work on the fender later - will all the lining be impossible to remove? . __________________ 1951 Chevy Panel Truck Last edited by MiraclePieCo; 07-01-2018 at 03:05 AM.

07-01-2018, 02:46 AM	#2
Matt_50 Registered User Join Date: Jul 2017 Location: Joshua, Texas. Posts: 1,303	Re: Fender undercoat? Rubber stuff can be a pain to get off later if you had too. Gums up on blades or wire wheels. Will this be off road, in snowy weather...? A PO did the undercoating on a bed I traded for. Looked great under fenders, but I think it really depends on how clean you'll keep the truck. A good sealed coat of paint is fine as long as you don't let mud sit. __________________ 1950 Build

07-01-2018, 03:11 AM	#3
MiraclePieCo Registered User Join Date: Sep 2014 Location: USA Posts: 2,249	Re: Fender undercoat? Thanks Matt. I was hoping to prevent rock dings and maybe get some sound deadening on those big "kettle drum" fenders too. Model A's are notorious for star dings in the fenders, but I don't really see those on ADs. I think I'm inclined to go with the bed liner - strictly DIY, probably a roll-on. Or nothing at all. __________________ 1951 Chevy Panel Truck Last edited by MiraclePieCo; 07-01-2018 at 04:20 AM.

07-01-2018, 09:41 AM	#4
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,670	Re: Fender undercoat? I'm sure this'll start some disagreements...but I'm using lizardskin on my fender undersides....I know others have done the same....flying rocks is my biggest concern... __________________ Mongo...aka Greg RIP Dad RIP Jesse 1981 C30 LQ9 NV4500..http://67-72chevytrucks.com/vboard/s...d.php?t=753598 Mongos AD- LS3 TR6060...http://67-72chevytrucks.com/vboard/s...34#post8522334 Columbus..the 1957 IH 4x4...http://67-72chevytrucks.com/vboard/s...63#post8082563 2023 Chevy Z71..daily driver

07-01-2018, 11:44 AM	#5
Speedbumpauto Registered User Join Date: Aug 2011 Location: Tucson, AZ Posts: 917	Re: Fender undercoat? I used bed liner and bought the gun and sprayed in on, two coats. The hanging from the rafters and masking was a pain but the stuff went on easily after that. Did it for rock"stars" and I don't have any but who knows?

07-01-2018, 11:50 AM	#7
_Ogre Registered User Join Date: Jan 2012 Location: Motown Posts: 7,680	Re: Fender undercoat? commercial rhino liner bed liner under fenders, inner fenders and bottom of cab for 9 years and 35,000 miles not an issue it would probably be a pia to get off i've seen the home spray and roll on kits used with success too __________________ cool, an ogre smiley Ogre's 58 Truk build how to put your truck year and build thread into your signature shop air compressor timer

07-02-2018, 09:17 AM	#9
DransportGarage Registered User Join Date: Feb 2010 Location: Lebanon, Ohio Posts: 1,359	Re: Fender undercoat? Has anyone actually seen stars on these TF factory fenders? They weigh a ton, and probably are 18 gauge. __________________ Bob "It won't take long and it won't cost much." '55 3100 (383/700R4)--'55 Belair Sedan (350/4-speed)--'64 'Vette Conv. (327/4-speed)--'68 GTO Conv. (462/4-speed)--'69 Cutlass Conv. (350/TH350)--'06 'Vette Conv. (LS2/6-speed) Bob's Retirement Build - My 55 TF Bob's 700R4 Build (how-to)

07-01-2018, 01:30 PM	#14
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,711	Re: Fender undercoat? Anything you coat the underside of the fenders with is going to be a royal pain to get cleaned off if you have to do body work on the fender at a later date. That said, if you are going to have really nice paint and intend to drive it a lot of miles I'd do it. No matter what you put on it you need the metal on the inside to be fully sealed with proper paint that won't absorb moisture before you put the coating on though. I've worked on too many cars that were undercoated when they were new at the dealer that a few years later rusted out . __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

07-01-2018, 03:13 PM	#15
OrrieG Registered User Join Date: Jun 2006 Location: Idaho Posts: 8,800	Re: Fender undercoat? Rattlecan rubberized from paint store, easy to control where it goes. Also used on cab bottom and angled part of firewall, I will drive mine all four seasons. __________________ 1959 Chevy Short Fleetside w/ 74 4WD drive train (current project) OrrieG Build Thread 1964 Chevelle Malibu w/ 355-350TH (daily driver) Helpful AD and TF Manual Site Old Car Manual Project

07-01-2018, 10:41 PM	#23
vintovka Registered User Join Date: Aug 2016 Location: Hunkered Down Posts: 1,895	Re: Fender undercoat? Locals use rustoleum __________________ 1954 USAF 3100 http://67-72chevytrucks.com/vboard/s...d.php?t=714917

07-02-2018, 11:20 AM	#25
jweb Senior Member Join Date: Apr 2010 Location: Oregon Posts: 1,208	Re: Fender undercoat? The inside of my fenders, inner fenders and bottom of cab are sprayed with Raptor bedliner. You can get the kits on Amazon. I also used Rustoleum Bedliner from Walmart for the bottom of my bed wood. Both products worked well but the Raptor is nicer. My truck seems quieter and I don’t hear the rocks hitting like I used to. I would only do this after the bodywork is finished, it would be a pain to get off. __________________ 1951 Truck, LS1/4L60 1964 Suburban, current project 2014 Silverado daily driver 1953 Westerner "canned ham" trailer, rebuilt 1974 Prowler trailer, rebuilt

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