Best under coating?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Scott>72-GMC · 01-31-2013, 01:14 PM

I think I'm going with POR 15 with the frame but what have u guys used on the underside of the bed and cab itself ??
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~Whitey~ · 01-31-2013, 02:26 PM

Spray/roll on bed liners (Raptor, Herculiner, Rhino, Monstaliner) would be great IMO and are what I plan on using on mine with as soon as I get done with my metal work. I haven't heard of any downfalls or problems to using bed liner as an undercoat. I've used 3M professional undercoating before but it was very ugly after spraying and always rubbed off on my hand if I touched it well after the cure period... And the dirt stuck to it like a magnet. Might just be the 3M stuff. :-/ I'm interested to see what others have to say.. I'm not 100% set on using the bed liner, but don't see any problem with it.

68gmsee · 01-31-2013, 02:45 PM

This will probably turn into another pro and con thread...

My vote goes with POR or even Rustoleum or similar unless you intend to do a lot of gravel roads driving. My truck had sprayed undercoating under the wheel wells when I bought from the p.o. since he was a rancher and drove a lot of gravel roads. He had the dealer spray it on when he bought new in 68. When I got it about 20 years ago, some of the coating was cracked and moisture got under it creating rusted areas.

1972SUPERSB · 01-31-2013, 02:51 PM

I use the 3M undercoating. I like it a lot. Finish comes out like a rough sandpaper finish. I can take some pics tonight if you want.
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Scott>72-GMC · 01-31-2013, 02:52 PM

I love pics gives me a good idea where to go
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1972SUPERSB · 01-31-2013, 02:54 PM

Quote:

Originally Posted by Scott>72-GMC

I love pics gives me a good idea where to go
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Will do, be later tonight after work
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sprint_9 · 01-31-2013, 03:06 PM

Quote:

Originally Posted by 68gmsee

This will probably turn into another pro and con thread...

My vote goes with POR or even Rustoleum or similar unless you intend to do a lot of gravel roads driving. My truck had sprayed undercoating under the wheel wells when I bought from the p.o. since he was a rancher and drove a lot of gravel roads. He had the dealer spray it on when he bought new in 68. When I got it about 20 years ago, some of the coating was cracked and moisture got under it creating rusted areas.

Could you do POR 15 for rust protection under the undercoat if it were to crack like highlighted above.

Then add a coat of either undercoating or bedliner over the POR for added protection against rocks? Might be alot of work but it should last I would think.

Not sure if that would work or not, just throwing out ideas as I will be in the same situation in a few months.

teeitup · 01-31-2013, 04:41 PM

subscribed, very curious about this

Scott>72-GMC · 01-31-2013, 05:53 PM

My under and frame have held up well being from the desert but I don't want it bare here in iowa
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Madtat · 01-31-2013, 05:57 PM

subscribed

aventur1 · 01-31-2013, 07:59 PM

Myself ..I would like a smooth appearance protective spray on coating...easy to spray wash down when needed, yet heavy duty to protect.

rkintn_68 · 01-31-2013, 08:05 PM

subscribed

midniteblues · 01-31-2013, 08:13 PM

I had bought a camaro one time that was completely covered underneth in roofing tar granted it wasnt pretty but definitly effective as that was one of the only ones i parted out that the rear subframe and trunk drop offs were not rusted out it added some weight to the rear also there would be no way in h*ll i would've tryed too scrape that stuff off

68_-c\10 · 01-31-2013, 08:21 PM

I used Rustoleum professional undercoating. Its really durable and has a good hard textured finish

68gmsee · 01-31-2013, 08:30 PM

I guess any protection in an environment where there are rocks and gravel or salt on the road would help short term. Reason I'm not sold on undercoating is the long term effects. Even the best undercoating will eventually dry and develop hairline cracks then moisture, salt and road grime will eventually take it's toll. Unseen, it can cause long term problems.

I have seen what cracked drip rail sealant has done to a lot of cab tops as well as bed coating.

Again, this is my own personal preference to use a good paint and be able to see if there's any damage that I can see.

ffk · 01-31-2013, 09:14 PM

3m makes good stuff..no problems..going to use on my 68

ecgate · 01-31-2013, 09:25 PM

I have a friend that used 3m on his truck and the finish looks great. If it were to ever crack you can easily touch it up and it blends in well without any or little prep work.

gotchamel · 01-31-2013, 09:42 PM

I used POR15 then used their chassis paint to avoid discoloration after time.POR15 has no uv protectant.

trevrolet65 · 01-31-2013, 11:06 PM

Good epoxy primer and then bedliner works well.

1972SUPERSB · 02-01-2013, 01:20 AM

Here are some pics of my truck with the 3M undercoating. You can see the texture in the pics may be hard to see. But I like the way it comes out.
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1972SUPERSB · 02-01-2013, 01:21 AM

Here is another
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Scott>72-GMC · 02-01-2013, 01:42 AM

I like that color different from typical black
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1972SUPERSB · 02-01-2013, 01:46 AM

Quote:

Originally Posted by Scott>72-GMC

I like that color different from typical black
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Yeah me too. You could just buy a can and try it out to see if you like it. They have 2 different 3M undercoatings. One is rubberized and one isn't. I use the one that isn't. The number on the can is 8881
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1972SUPERSB · 02-01-2013, 01:49 AM

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Scott>72-GMC · 02-01-2013, 01:50 AM

My truck won't be a day to day driver either so this might work great for me. Looks like u did the frame as well?
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01-31-2013, 01:14 PM	#1
Scott>72-GMC Registered User Join Date: Jan 2013 Location: New providence ia Posts: 1,018	Best under coating?? I think I'm going with POR 15 with the frame but what have u guys used on the underside of the bed and cab itself ?? Posted via Mobile Device Attached Images

01-31-2013, 02:26 PM	#2
~Whitey~ Registered User Join Date: Jun 2011 Location: Springfield, MO Posts: 677	Re: Best under coating?? Spray/roll on bed liners (Raptor, Herculiner, Rhino, Monstaliner) would be great IMO and are what I plan on using on mine with as soon as I get done with my metal work. I haven't heard of any downfalls or problems to using bed liner as an undercoat. I've used 3M professional undercoating before but it was very ugly after spraying and always rubbed off on my hand if I touched it well after the cure period... And the dirt stuck to it like a magnet. Might just be the 3M stuff. :-/ I'm interested to see what others have to say.. I'm not 100% set on using the bed liner, but don't see any problem with it. __________________ Jimmy .69SWB Build.

01-31-2013, 02:45 PM	#3
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: Best under coating?? This will probably turn into another pro and con thread... My vote goes with POR or even Rustoleum or similar unless you intend to do a lot of gravel roads driving. My truck had sprayed undercoating under the wheel wells when I bought from the p.o. since he was a rancher and drove a lot of gravel roads. He had the dealer spray it on when he bought new in 68. When I got it about 20 years ago, some of the coating was cracked and moisture got under it creating rusted areas. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...

01-31-2013, 02:51 PM	#4
1972SUPERSB Registered User Join Date: Sep 2012 Location: San Antonio, TX Posts: 1,026	Re: Best under coating?? I use the 3M undercoating. I like it a lot. Finish comes out like a rough sandpaper finish. I can take some pics tonight if you want. Posted via Mobile Device __________________ Jeff 1972 Cheyenne Super SWB 350, Auto, Bucket Seats w/Console, Tach, Factory A/C, P/S ,P/B, Tilt 1998 Chevy 1500 Ext Cab 5.7, Pewter w/blue interior

01-31-2013, 02:52 PM	#5
Scott>72-GMC Registered User Join Date: Jan 2013 Location: New providence ia Posts: 1,018	Re: Best under coating?? I love pics gives me a good idea where to go Posted via Mobile Device __________________ 72 GMC super custom.

01-31-2013, 04:41 PM	#8
teeitup Just like to part out trucks!! Join Date: Nov 2001 Location: Meriden, Ks-North of Topeka 10 miles Posts: 27,395	Re: Best under coating?? subscribed, very curious about this __________________ 67 Chev swb stepside 4x4 283 4 speed SOLD 72 blazer 4x4 4 speed Cheyenne 72 GMC swb 4x4 fleet 4 speed, original paint 1958 Cameo (one of 1405 built, it was my dads) 2020 chevy Apex 4x4 crew cab 1969 Z28 with the 302 1980 chevy swb 4x4 1964 chevell Malibu SS 1976 K20, sold new originally out of my dads chevy dealership Members that I've met, over 200 probably closer to 300 in the 12 years I've been on this site, everyone I met "It was a pleasure"

01-31-2013, 05:53 PM	#9
Scott>72-GMC Registered User Join Date: Jan 2013 Location: New providence ia Posts: 1,018	Re: Best under coating?? My under and frame have held up well being from the desert but I don't want it bare here in iowa Posted via Mobile Device __________________ 72 GMC super custom.

01-31-2013, 05:57 PM	#10
Madtat Registered User Join Date: Jan 2013 Location: Hell Paso TX Posts: 804	Re: Best under coating?? subscribed

01-31-2013, 07:59 PM	#11
aventur1 Registered User Join Date: Aug 2007 Location: Boise, Idaho Posts: 676	Re: Best under coating?? Myself ..I would like a smooth appearance protective spray on coating...easy to spray wash down when needed, yet heavy duty to protect. __________________ 1968 4x4 Frame, with a 67 Cab and Bed A Shorter Step 1999 Dodge 2500 Cummins Diesel

01-31-2013, 08:05 PM	#12
rkintn_68 Registered User Join Date: Sep 2012 Location: clarksville tn Posts: 806	Re: Best under coating?? subscribed __________________ 72 GMC K 1500 SWB W/ 68 CHEVY FR/CLIP -- SOLD 70 CHEVY C/10 LWB x 2 ----- SOLD 67 CHEVY SWB IN PROGRESS " ALMOST HEAVEN " Build thread : http://67-72chevytrucks.com/vboard/s...15#post6826315

01-31-2013, 08:13 PM	#13
midniteblues Registered User Join Date: Jul 2011 Location: strausstown pa Posts: 3,394	Re: Best under coating?? I had bought a camaro one time that was completely covered underneth in roofing tar granted it wasnt pretty but definitly effective as that was one of the only ones i parted out that the rear subframe and trunk drop offs were not rusted out it added some weight to the rear also there would be no way in h*ll i would've tryed too scrape that stuff off __________________ 81 camaro 355 4/spd 342 posi my first love. 67 swb step 454/4spd ott 373 posi 4/7 drop. 2000 s10 zr2 little blue truck that never gets stuck. '74 heald super bronc vt8. tecumseh powered moon rover.

01-31-2013, 08:21 PM	#14
68_-c\10 Registered User $68_-c\10's Avatar$ Join Date: Aug 2012 Location: Scottsburg,IN Posts: 85	Re: Best under coating?? I used Rustoleum professional undercoating. Its really durable and has a good hard textured finish
$68_-c\10 is offline$

01-31-2013, 08:30 PM	#15
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: Best under coating?? I guess any protection in an environment where there are rocks and gravel or salt on the road would help short term. Reason I'm not sold on undercoating is the long term effects. Even the best undercoating will eventually dry and develop hairline cracks then moisture, salt and road grime will eventually take it's toll. Unseen, it can cause long term problems. I have seen what cracked drip rail sealant has done to a lot of cab tops as well as bed coating. Again, this is my own personal preference to use a good paint and be able to see if there's any damage that I can see. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...

01-31-2013, 09:14 PM	#16
ffk Registered User Join Date: Oct 2010 Location: lowell, in Posts: 271	Re: Best under coating?? 3m makes good stuff..no problems..going to use on my 68 __________________ my build thread -- (http://67-72chevytrucks.com/vboard/s...d.php?t=438604)

01-31-2013, 09:25 PM	#17
ecgate Registered User Join Date: Aug 2012 Location: Council Bluffs, Iowa Posts: 280	Re: Best under coating?? I have a friend that used 3m on his truck and the finish looks great. If it were to ever crack you can easily touch it up and it blends in well without any or little prep work.



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01-31-2013, 09:42 PM	#18
gotchamel Registered User Join Date: Feb 2011 Location: islamorada fl. Posts: 466	Re: Best under coating?? I used POR15 then used their chassis paint to avoid discoloration after time.POR15 has no uv protectant.

01-31-2013, 11:06 PM	#19
trevrolet65 Registered User Join Date: Nov 2010 Location: Venus Texas Posts: 217	Re: Best under coating?? Good epoxy primer and then bedliner works well.

02-01-2013, 01:20 AM	#20
1972SUPERSB Registered User Join Date: Sep 2012 Location: San Antonio, TX Posts: 1,026	Re: Best under coating?? Here are some pics of my truck with the 3M undercoating. You can see the texture in the pics may be hard to see. But I like the way it comes out. Posted via Mobile Device Posted via Mobile Device Posted via Mobile Device Posted via Mobile Device Posted via Mobile Device Posted via Mobile Device Attached Images __________________ Jeff 1972 Cheyenne Super SWB 350, Auto, Bucket Seats w/Console, Tach, Factory A/C, P/S ,P/B, Tilt 1998 Chevy 1500 Ext Cab 5.7, Pewter w/blue interior

02-01-2013, 01:21 AM	#21
1972SUPERSB Registered User Join Date: Sep 2012 Location: San Antonio, TX Posts: 1,026	Re: Best under coating?? Here is another Posted via Mobile Device Posted via Mobile Device Posted via Mobile Device Attached Images __________________ Jeff 1972 Cheyenne Super SWB 350, Auto, Bucket Seats w/Console, Tach, Factory A/C, P/S ,P/B, Tilt 1998 Chevy 1500 Ext Cab 5.7, Pewter w/blue interior

02-01-2013, 01:42 AM	#22
Scott>72-GMC Registered User Join Date: Jan 2013 Location: New providence ia Posts: 1,018	Re: Best under coating?? I like that color different from typical black Posted via Mobile Device __________________ 72 GMC super custom.

02-01-2013, 01:49 AM	#24
1972SUPERSB Registered User Join Date: Sep 2012 Location: San Antonio, TX Posts: 1,026	Re: Best under coating?? Posted via Mobile Device Posted via Mobile Device Attached Images __________________ Jeff 1972 Cheyenne Super SWB 350, Auto, Bucket Seats w/Console, Tach, Factory A/C, P/S ,P/B, Tilt 1998 Chevy 1500 Ext Cab 5.7, Pewter w/blue interior

02-01-2013, 01:50 AM	#25
Scott>72-GMC Registered User Join Date: Jan 2013 Location: New providence ia Posts: 1,018	Re: Best under coating?? My truck won't be a day to day driver either so this might work great for me. Looks like u did the frame as well? Posted via Mobile Device __________________ 72 GMC super custom.

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