If you're doing a frame off on a car, and this is a car you plan on really putting some miles on would you paint the underside of the body or undercoat everything? Will trips to Bonneville clean up better if the underside is nice and clean and smooth to start off with? Or maybe just undercoat every nook and crannie as you are building the car so you don't have to overly worry about salt, mud and road grime from road trips? Curious what people have done...thanks.
Living in the desert I always say PAINT and/or TINTED BED LINER because I HATE undercoat. My experience with this stuff is that it's tacky nature never really dries and this crap gets all over you whenever you work on the car. My way of thinking is that I have suffered through getting nasty dirty the whole time I have taken the car apart and then cleaned up to go back together. One of the positives about doing all of this work is to be able to work on the car and stay a little cleaner. I would think that a 2 part bed liner would provide as much or more protection against rust as undercoating.
paint, if you ever have to take undercoating off you will know why, a nice paint job that you look after and dont let it rust then you wont ever need undercoating.
I wouldnt under coat any thing.. It traps moisture , any open spots where water can absorb into will cause you grief..
I say Seal it up in some epoxy primer then use a product called Lizard skin to use as an undercoat. Its a ceramic coating that deadens sound or helps to keep the inside of the car much cooler keeps engine heat out and it isnt as heavy as bedliner, and undercoating is hard to clean and looks dirty and chips off easily. There are two different kinds. Check it out at Lizardskin.com.
this stuff works nice....... http://www.autobodytoolmart.com/pc-...x|3857288015&gclid=COnShJy1kZkCFQFvGgodp2j1aw and the applicator gun....... http://www.autobodytoolmart.com/p-15981-upol-applicator-gun-for-gravitex-0726.aspx it does need to be top coated, though.
If you are doing a frame off build, I'd use POR-15. It's not the cheapest way but it wears like iron and you'll never have to coat the frame again. You'll have to brush it on, and wear gloves, sleeves, etc., because it's not coming off your skin either..
undercoating is the tool of the devil. it is evil and it will make your car rust through prematurely. it lifts and holds moisture to rot out your car. -90% Jimmy
The problem with a painted under body is that rocks and road grit will cause chips which will lead to rust. Typical, cheap "rubberized undercoating" can trap moisture which will obviously lead to rust. If it were me and I was looking for the ultimate underbody protection, I would prep the underbody just like you would prep the top surfaces all up to and including the epoxy primer stage. Then I would coat every surface, that will exposed when assembled, with Wurth Products SKS Stone Guard, painting over the SKS Stone Guard, when dry, to finish it off. SKS Stone Guard is the same product that you will find on the underside of Mercedes, BMW, etc. It is water based and can be shot out of a regular Body Shutz gun. When dry, it remains very flexible and resistant to damage. The only downside to this product is that if you ever have to repair one of the panels it has been applied to, it can be a real pain to get back off, but it offers a level of protection that is second to none in my experiences with it.
Thanks for the input fellas. Never heard of the SKS Stone Guard, sounds like this is a good way to go. Hope all is going good for you Chris, I always appreciate your input.
I 2x what Loogy said we used sks stone guard when i worked a the chevy dealership body shop. its good stuff.
Por 15 is great, any one think of 3m body shultz? Its tintable and hardens. By the way, Por 15 is sprayable if it is thinned with Naptha. Just allow three to five days dry time. jon
I used the 'do it yerself' spray on bedliner stuff on my 'daily driver '40 Ford pickup. You can buy it in quarts and gallons, and in spray cans too.
I was told by several guys that driveway asphault sealer works great? I've never used it, but several people I know coat the underside of their commercial truks with it. The winters here are a killer. Obviously not for a show car, but might work good for a driver. Interested if anyone has done it? I have seen it painted down on the deck of a car/equipment trailer and seems to hold up great. Drys good dosen't stay tacky.
A++++ This stuff is awesome. I use it on every car we do at work. Topside and underside of floor pans. It's not super thick and gummy, but is nice and flexible. You can leave it black or paint it and b/c it's water based it's resistant to just about every chemical once it's dry.
If you have a high end body shop or restoration/custom shop in your area they should be able to get it. If nobody around uses wurth products, I can get their phone number you.
Hey Gator, how long has your 40 been a daily driver, and how well has the DIY bedliner held up. I sure have heard some bad reports on that stuff. What brand did you use? Joe
I would think the spray bed liner too. I was thinking of using it on my truck. would like to hear though people opinions.
just be sure you don't breath in while painting. the por15 guy at the swap meet who sells it recommends not spraying it.
I used roofing asphalt for some sections of a nova about 6 years ago. It's held up really well and has never fully dried out it's got a lot of oil in it. So when you put your fingers between the tire and the rear wheel well to see if their rubbing you get nice and dirty. I would never do it again it's way too messy. Whatever you use your still going to have spray down your underside after an eastcoast winter.
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