Booger Posted February 16 Report Share Posted February 16 Does an undercoating make sense? Protect the raw steel floor pan? DIY Flex seal? Professionally done?Its gotta quiet road noise. Of course no drive shaft.....or tranny stuff. Quote Link to comment Share on other sites More sharing options...
Eneto-55 Posted February 16 Report Share Posted February 16 I would probably use something different if I was doing it now, but undercoating was pretty much all that was available back in 80-81, when I was at that point. (Maybe rock-guard was already being used, but would have been really expensive compared to the stuff I used, and at that time I was just looking at rebuilding it as a daily driver. Also, seems I heard some negative things about that early rock-guard stuff.) Anyway, I did mine both inside and underneath. Did it with the body off of the frame, so it's completely coated. Afterwards I wished I hadn't done it inside because of the smell, but it cured over time, and then I painted it with enamel. Quote Link to comment Share on other sites More sharing options...
Los_Control Posted February 16 Report Share Posted February 16 I think I walk a lonely path .... it is every day accepted practice to use under coating. I guess if I lived in a snow belt area where road salt was a common practice I would think of undercoating as a lesser of two evils. I also will not use the dynamat floor insulation and sound deadener ... I'm concerned about trapped air, condensation and creating the perfect habitat to create rust. I suppose if there was 100% contact and no chance of trapped air ... it would be safe and not cause perfect conditions for rust. .... there is no guarantee though. Same with undercoating ..... A possibility to create trapped air. Then there is future considerations of having to remove it for some sort of future maintenance. ..... Paint did a fine job for 75 years and will continue to use it. While I really would like to do the cab of my truck, ceiling and floor for insulation against heat and sound ..... imho, it is not in the best interest of my truck and will not apply undercoating or stick on insulation. Just my personal opinion and shared by nobody I know of. ...... You asked Quote Link to comment Share on other sites More sharing options...
Booger Posted February 16 Author Report Share Posted February 16 Both good points and well taken. It's why were here Quote Link to comment Share on other sites More sharing options...
desoto1939 Posted February 16 Report Share Posted February 16 They found out that undercoating was not a good practice. At first the product was ok when it was first applied and sealed the undercarriage. But as time went on and driving on the roads and also on tar an chipped roads in the country they found that the undercoating was getting worn away from the road salt and rocks flying up chipping the undercoating. Then the rain water and salt water would get inot the crack and start to rust the underside of the metal. Might use PORS 15 to seal the underside of the body. Rich Hartung 1 Quote Link to comment Share on other sites More sharing options...
Bob Ritter Posted February 16 Report Share Posted February 16 I'm not a fan of undercoat because it is a oil base material. I like to use bed liner spray material it comes in aerosol cans and can be used on bear metal and dries quickly to a hard finish... Quote Link to comment Share on other sites More sharing options...
plymouthcranbrook Posted February 16 Report Share Posted February 16 I coated my car with POR 15 both under the body and frame and also the floor of the interior. I have seen no rust at all and at this point in my life any rust that does show up will be the problem of the next owner. Quote Link to comment Share on other sites More sharing options...
Adam H P15 D30 Posted February 16 Report Share Posted February 16 I use undercoating inside the fenders only to prevent rock damage visible on the shiny side, applied over paint. Floor pans get painted with enamel with no undercoating. Sound deadener gets installed inside only after painting the metal. 1 Quote Link to comment Share on other sites More sharing options...
Young Ed Posted February 16 Report Share Posted February 16 I know it gets a bad rap but I feel it does help. Our 66 fury wagon has 252k miles on it and was sold new in Sioux falls SD. Now I don't know the driving habits of all those miles but it's still a solid car at this point. Quote Link to comment Share on other sites More sharing options...
FarmerJon Posted February 16 Report Share Posted February 16 16 hours ago, Los_Control said: I think I walk a lonely path .... it is every day accepted practice to use under coating. I guess if I lived in a snow belt area where road salt was a common practice I would think of undercoating as a lesser of two evils. I also will not use the dynamat floor insulation and sound deadener ... I'm concerned about trapped air, condensation and creating the perfect habitat to create rust. I suppose if there was 100% contact and no chance of trapped air ... it would be safe and not cause perfect conditions for rust. .... there is no guarantee though. Same with undercoating ..... A possibility to create trapped air. Then there is future considerations of having to remove it for some sort of future maintenance. ..... Paint did a fine job for 75 years and will continue to use it. While I really would like to do the cab of my truck, ceiling and floor for insulation against heat and sound ..... imho, it is not in the best interest of my truck and will not apply undercoating or stick on insulation. Just my personal opinion and shared by nobody I know of. ...... You asked I am a big fan of using actual sound deadening products. I would NOT lay them on a raw steel floor pan though. Clean, paint, clean, heat, apply deadener. If done correctly there should be no air bubbles. POR 15 is a great product. There are also phosphoric acid based wash primers that can be used to make bare, clean steel more corrosion resistant AND help paint stick better. If you look at floor pans that have rusted out, you will find that most are from moisture being trapped in the carpet/padding, usually from a leaking windshield, not from moisture trapped under the actual sound deadening (jap cars will usually rust out around the bonded ruber deadening, but not under it, since the metal is protected there) So if you are going to be paranoid about stuff causing rust, avoid carpet! Quote Link to comment Share on other sites More sharing options...
Solution Dan Hiebert Posted February 17 Solution Report Share Posted February 17 Our Terraplane was undercoated when it was "restored" the first time, long before we got it. It did not adversely affect anything preservation wise...but...it covered some repairs that were not well done. I've had to add significant time to any work under the car to remove that undercoat. It's actually made me defer some repairs because I usually don't feel like dealing with it. So, I wouldn't recommend undercoating. You can achieve sound deadening and insulation with interior applications. A good clean, prep, and paint job on the underside will serve well to preserve that. In these parts, folks lean towards epoxy paints for any parts of the vehicle with weathering concerns. Quote Link to comment Share on other sites More sharing options...
Booger Posted February 17 Author Report Share Posted February 17 There you have it kids and thanks to all our contestants. Booger sez steer away from all that goopy stuff Quote Link to comment Share on other sites More sharing options...
Eneto-55 Posted February 17 Report Share Posted February 17 47 minutes ago, Booger said: There you have it kids and thanks to all our contestants. Booger sez steer away from all that goopy stuff Sorry - You're around 43 years late for me. Quote Link to comment Share on other sites More sharing options...
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