To undercoat or not to undercoat?

[carcrazyguy]

With the Barracuda at the body shop I had said that I would like to "over do" the car and paint the bottom of the car body color.  Now I am having second thoughts on just going back with undercoat like it was from the factory.     I see undercoat on a fresh car and think, what is hiding in there?  But on the other hand.  Driving around with a full painted under carriage... rock chips, water and just the hassle of keeping it clean?     So 

[OUTLAW]

I'd undercoat it, look how well it held up with the crappy factory undercoating .Just think how well it would  last with good undercoating put on really well

[carcrazyguy]

My plan was using something like "rock guard" in body color.  So it would be protected but it will have a texture. Just not sure if that texture would also look out of place enough that undercoating would just look better.     Plus trying to keep yellow clean on the underside....

[CudamanTom]

For my two cents, I would use regular undercoat. But that's just me. I've seen painted or colored undercoating and they've looked good.
To each their own. 

[twalker]

Body colour, no undercoat...ok, I'm biased... :-)

[67vertman]

What are your plans for the car?

Daily driver = undercoating, either black or tinted body color

OEM restoration = Factory undercoat treatment, grey primer with rust proofing

Show car = Body color

[carcrazyguy]

This car will probably never be at anything other than local car cruises. I do plan to show once at the local Make A Wish indoor car show before I drive it.  Other than that it will get probably 1000 miles a year.

Just seems strange to clean up the bottom then spray it with undercoating.    Probably should have just painted the car and put a motor in instead of putting it on the rotisserie and going all the way.

[67vertman]

"Probably should have just painted the car and put a motor in instead of putting it on the rotisserie and going all the way."

Yeah, you are a lot like most of us, once you start you can't stop until its right. If all I was going to do was put a few thousand miles on it and take it to local show, and going to paint it while it on the rotisserie, I would paint it. 

[V8Cowboy]

Hi,

As it is already cleaned I would probably paint it body color (with all the rust primer etc...) and then use a transparent undercoat on a wax basis, like "UBS 220" - guess it's german, but there will surely be something similar in the USA.
Ofc. it's not totally transparent but a bit brownish, but it's easy to identify any possible rust much easier and earlier as you could with standard black bitumen undercoating. Often it's too late then and bigger repair is needed as probably one or two years earlier, before the rust breaks through the black, dried bitumen.
The wax also can be applied in rather thick layers and hardens enough to keep off stone chips, at the same time stays smooth enough to "fill" holes especially when warm outside.

[burdar]

Here's my take on it.  I had my Challenger painted body color on the underside and it's one of two BIG mistakes I made on the car.  The other mistake was adding dual exhaust to a 318 car.  I tried to get the rest of the car back to factory as much as possible.  I really wish I would have stayed with primer on the bottom and single exhaust.

These cars were never painted body color on the bottom from the factory.  They were dipped in primer.  After the body was painted, there would have been "some" body color overspray on parts of the underside.  That is the look I should have gone with.   If I were you, I would have the bottom painted with a single stage "paint" that is the same color as the factory primer.  Then have the body painted.  Let the overspray go where it goes.  This looks much nicer then a completely painted underside IMO.

ALL cars(built at Hamtramck)had the wheelwells undercoated.  It was for impact protection.(rocks)  If this were my car, it would have the underside painted a primer color with body color overspray and undercoating ONLY in the wheel wells.

[JoeGrapes]

I painted my car back in '97 and at the time I thought the factory painted the bottom body color and the under coating was put on at the dealer. I guess that wasn't the case. I put undercoating only in the wheel wells. It looks so much better in body color than with undercoating or with just primer. I've been driving the car all these years and while there might be some chips in the paint it still looks great. Unless you are going for factory correct go ahead and paint it. When you are lying on your back under the car doing some work the scenery is much more enjoyable!

[jimynick]

Were you figuring on putting that 1000 miles a year on the car, on salty, dirty and rocky roads or just out for a nice putt on a nice Saturday? Are you a purist, who must have the car exactly as made or are you a guy who'll build the car the way he likes best? Do you like the look of primer and undercoat partially applied all over a la factory or do you prefer a homogenous colour underneath? Ask yourself these questions and try to answer yourself honestly and then.... do what the hell you want to. Just my 

[Topcat]

This might help prevent chips on your painted underside in likely prone areas

http://www.amazon.com/gp/product/B000LNN11G/ref=pe_254750_133357030_em_1p_0_ti

[Denison636]

I am one the few members on here that will say this. Ask your self what you like to look at when you go to a car show. Or even when you work on it. I say make it your own and heck with what other people think. If they want to do something they can do it to there's.