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Discussion Starter #1
I heard that back in the good old days they used asphalt as either an undercoating or sound deadener coating. Is this true? And if it is could I use roofing asphalt or something like it to replace it?
 

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On my 1935 Buick 4door there was a wad of black snot inside each door skin.
I would assume that it was there for sound and vibration. I did remove the hard caca and I will replace with hard foam.
Hope the info helps.
 

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Of course you can use it - but I wouldn't!! It will probably never more then surface harden, it will soften and drool. If this is a restoration car, clean, derust then paint/seal with epoxy primer and then paint with a chassis black or something better like John Deere Blitz black. If you feel that you need something for sound deadening, pickup truck bed liner is a lot better then undercoat. It doesn't come off at the first rock strike.
 

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The "good old days" is relative here. Maybe they did use asphalt back then but, if it's all you have, that's what you use.... Today there is a much better selection of coatings to use that are purposed to rust proofing or sound deadening.
Another issue is "roofing tar" is NOT asphalt. If you did this it would be requisite that you post up photos after the first real warm day sitting out in the sun. :)
May I also state that this stuff burns very well once it gets ignited.... Don't add fuel to the fire, so to speak.
Mark
 

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I recall my car didn't have tar or asphault, but had something that resembled tar paper with plastic on it. It was real sticky and difficult to remove. If you use asphault or tar, I'm sure your car will stink when the temps go up in the summer. Undercoating doesn't cost that much these days. I definitely wouldn't use asphault unless your going for the concourse/ original look.
 

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You know it runs out the seams on hot days and stinks like, well, stink!

Some joker was trying to push me into using roofing tar. I have seen and smelled his mess he calls a car too. Not for me. Heck I get mad when I have an oil drip let alone tar!
 

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Discussion Starter #7
Thanks for the advice I didn't think something like that would be a good idea. I figured it would grow to be a runny stinky mistake. I am restoring a 51 Desoto and something that resembled tar and was just curious of an equivalent. I have just heard mixed reviews on undercoating. Some people put it on everything and others would sooner be shot than use it.
 

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The thing is, we thought covering it up with thick crap kept it from rusting when actually made it rust! The thick crap kept it protected alright, except for some tiny spot where the water did get in, and then couldn't get out! How many of us have broke off a big chunk of underseal to have it pull off a piece of rusted metal and expose a big hole!

Todays cars have zero underseal because every bit of metal on todays cars are galvanized (zinc) coated. But water control is much more important than covering up everything. Making sure that water doesn't get trapped anywhere is WAY more important than what you put on it. Think about it, if you were to make a bowl out of bare metal. Then make another one coated with underseal with a crack right down in the middle and put that bowl outside in the rain with the other one but put the bare metal one upside down the undercoated one right side up to fill with water, which one would last the longest before rusting out?

Making sure water doesn't get into pinch welds, into anywhere that it can't get out, THAT is way more important than anything else.

Brian
 

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Discussion Starter #9
The thing is, we thought covering it up with thick crap kept it from rusting when actually made it rust! The thick crap kept it protected alright, except for some tiny spot where the water did get in, and then couldn't get out! How many of us have broke off a big chunk of underseal to have it pull off a piece of rusted metal and expose a big hole!

Todays cars have zero underseal because every bit of metal on todays cars are galvanized (zinc) coated. But water control is much more important than covering up everything. Making sure that water doesn't get trapped anywhere is WAY more important than what you put on it. Think about it, if you were to make a bowl out of bare metal. Then make another one coated with underseal with a crack right down in the middle and put that bowl outside in the rain with the other one but put the bare metal one upside down the undercoated one right side up to fill with water, which one would last the longest before rusting out?

Making sure water doesn't get into pinch welds, into anywhere that it can't get out, THAT is way more important than anything else.

Brian
Thank you for that advice. I actually have been peeling back all the undercoating like material back to bare metal and am going to paint it. Therefore I will know that the rust is fixed and that the metal is covered well with no gaps for water to creep in and cause trouble.
 

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My uncle used some of that tar like stuff on the back of the cab down low on the Ranchero.
Looked pretty much rust free until that stuff came off.----Replace lower cab and the floor under the bed cover/access panel.

Pain in the butt to replace that back floor in a Ranchero----good thing I had to replace part of the lower cab as well-----had to cut about 8" out of the bottom of the cab to get the new (Donor car) floor in.
 

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The thing is, we thought covering it up with thick crap kept it from rusting when actually made it rust! The thick crap kept it protected alright, except for some tiny spot where the water did get in, and then couldn't get out! How many of us have broke off a big chunk of underseal to have it pull off a piece of rusted metal and expose a big hole!

Todays cars have zero underseal because every bit of metal on todays cars are galvanized (zinc) coated. But water control is much more important than covering up everything. Making sure that water doesn't get trapped anywhere is WAY more important than what you put on it. Think about it, if you were to make a bowl out of bare metal. Then make another one coated with underseal with a crack right down in the middle and put that bowl outside in the rain with the other one but put the bare metal one upside down the undercoated one right side up to fill with water, which one would last the longest before rusting out?

Making sure water doesn't get into pinch welds, into anywhere that it can't get out, THAT is way more important than anything else.

Brian
every inch is galv?? having a hard time with this.. as everyone in the body end of the line would be deathly sick every day from the robot welding the panels.. never mind the amount of rust through still happening.. at points that don't get blasted with road crap and salt/etc.. I have I piece of sheet galv that's been stored outside for 20+ years and still isn't having the rust issues cars still have.. you got any real proof of that "every inch" cause if it is. the people coating the sheets, really need to be fired.
 

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Brian Martin,Freelance adviser
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every inch is galv?? having a hard time with this.. as everyone in the body end of the line would be deathly sick every day from the robot welding the panels.. never mind the amount of rust through still happening.. at points that don't get blasted with road crap and salt/etc.. I have I piece of sheet galv that's been stored outside for 20+ years and still isn't having the rust issues cars still have.. you got any real proof of that "every inch" cause if it is. the people coating the sheets, really need to be fired.
Yes, every single panel is zinc coated. Which is why I preach so much about safety, we just don't know. Hell, "weld thru primer" is 95% zinc! The cars are being welded together by robots so there are no people to speak of, and they are behind plexiglass walls that I assume have a vacuum system to pull the fumes out.

There is a guy who visits the forums who a number of years ago was welding a rad support onto a Honda over in the corner of the shop and was found unconscious on the floor! He spent a while in the ICU and his lungs are permanetly damaged.

Yes it's a REAL danger.

These cars have gotten so complex it would blow your mind. They are made up of many different hardnesses of metal, some LAUGH at a spot weld drill bit like Boron that many cars are using now in the rockers and rear body panels for instance. The drill bit needed costs about $65.

Brian
 

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Brian Martin,Freelance adviser
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And by the way this is the reason for the fillers being changed over the past few years so they can be applied over zinc.

http://www.evercoat.com/productDetail.aspx?pID=11

Z-Grip®
An advanced, clog-free, lightweight body filler for today’s high tech metals. Formulated with ZNX-7® for superior adhesion to galvanized steel, bare steel and aluminum. Part of the MetalWorks® System that honors the OEM corrosion warranty. Contains Hattonite™ for effortless sanding. Blue cream hardener included.


You are instructed by auto manufacturers to NOT use any kind of grinding disc to remove paint because it will remove the zinc coating. A Roloc disc is now common so that the paint gets removed but the zinc remains.

Brian
 

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Yes, every single panel is zinc coated. Which is why I preach so much about safety, we just don't know. Hell, "weld thru primer" is 95% zinc! The cars are being welded together by robots so there are no people to speak of, and they are behind plexiglass walls that I assume have a vacuum system to pull the fumes out.

There is a guy who visits the forums who a number of years ago was welding a rad support onto a Honda over in the corner of the shop and was found unconscious on the floor! He spent a while in the ICU and his lungs are permanetly damaged.

Yes it's a REAL danger.

These cars have gotten so complex it would blow your mind. They are made up of many different hardnesses of metal, some LAUGH at a spot weld drill bit like Boron that many cars are using now in the rockers and rear body panels for instance. The drill bit needed costs about $65.

Brian
then why the rot through.. there are dodge and ford trucks a couple years old with tail gate and 1/4's so bad you'd think it was in the boston harbor for months never mind you'd not be allowed near a welder without a fresh air hood on..
 

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I'm going to add something to this discussion. I have read that the "asphalt-like stuff" used as undercoating years ago contained asbestos! I cannot confirm that, but when I was working on my 1948 Plymouth, some of that stuff I encountered was difficult to remove, even when heated with a propane torch. I'm just suggesting that you realize it might have asbestos in it, and take some precautions when removing it.:pain:
 

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Brian Martin,Freelance adviser
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This is why we have welding respirators, it doesn't have to be a fresh air, though that would be much better. I have been protecting myself welding for years and I can smell it RIGHT NOW when I walk into the shop. It kills me when I see some of the guys not wearing protection, I can only suggest it so many times.

On the rot, the Zinc is a "sacrificial" metal. That is all zinc is, it doesn't so much "block out" moisture from getting to the metal. It sacrifices it's self instead of the metal under it, well that can only happen so long before the zinc is gone and the metal rusts.

If you will notice rust on cars is very localized now, right next to the rusted hole the metal is solid, where in the old days the whole area would be rusting.

Brian
 

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Thanks for the advice I didn't think something like that would be a good idea. I figured it would grow to be a runny stinky mistake. I am restoring a 51 Desoto and something that resembled tar and was just curious of an equivalent. I have just heard mixed reviews on undercoating. Some people put it on everything and others would sooner be shot than use it.
I coated the inside of the cowl on my 68 Fairlane with truck bed coating. This was after I repaired the rusted sections with fiberglass and Eastwood's rust encapsulator.

I'm thinking of applying this to the wheel wells and other areas on my Trabant instead of using asphalt under coating where water can sit when I start working on the body.

All my collector cars I keep in the garage so it's probably not a big deal anyway.
 

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Discussion Starter #18
Thanks for the Asbestos heads up. While working on my car the thought usually doesn't even enter my mind. I bet it does have Asbestos, I will be wearing a respirator from now on when I am scrapping up the stuff. Thanks
 
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