I was watching them do the junkyard dog 56 chevy. It looked like they did a skim coat on the entire body in what looked like yellow filler (bondo). is this normal practice for a job of this nature. I'm fair at bodywork, did it for a few years in college, but I though high end work like this,the idea was to use little to no filler if possible. I realize using filler is not a problem as long as its done sparingly but I just didnt expect to see this. I would think filler primer would have been better to smooth the panels. If it was filler, what kind was it?

Most of the high end show cars are done this way. The metal work is done including panel alignment, then the entire car is skimmed and cut with a long board. This way the panels appear to fit perfectly flush with each other. I'm not talking about filling 1/4 inch voids here just leveling minor waves etc. Polyester doesn't shrink so in order for this work to be done in say a urethane primer multiple applications would be required. The polyester saves work and doesn't show up down the road. Polyester primers are also used a lot on these custom vehicles where heavy blocking is required. I didn't see the particular show you were referring to but I smile.gif hope I explained the skim proceedure.

It may have been a polyester primer?

Listen, there are many different levels of "High end" sort of work. MOST custom and rod work is going to have a skim coat AT LEAST of filler over 100% of the car. I have seen MANY top cars, we are talking six figure cars prior to paint and this is common.

Then there are another "high end" cars (both equal competitors) that are truly metal finished works of art, without any filler what so ever. I have to say, these are big time rare. They also may be called "metal finished" and "filler free" cars, but have a TON of primer on it to make them perfect for paint.

So what is better, a super close metal with a skim coat of filler, we are talking less than a 1/16" or less on 90% or so. Or piling on a urethane primer or a couple coats of polyester primer (basically sprayable bondo) JUST to toot a horn saying it has no "Bondo" on it?

Most high end cars have filler all over it, that is why you hear few of these guys make a big deal about filler use. There are plenty of true craftsmen who are making panels from scratch even, but I tell you, most will then apply a bunch of primer to finish it off to perfection prior to paint.

Yes, there are some who wouldn't need the primer, they are that good. But I am talking about the average, the average super high end car on the cover of your favorite mag or winning the big awards.

thanks guys, I dont have a problem with bondo like a few do, I know its a good thing when done properly, I just never thought about doing entire panels like that. I know when I painted my recently sold 69 bu I went through about 3 gallons of filler primer to get the panels smooth. probably 85% ended up on the ground, but when finished the panels were nice.

If you watch any of the 'motorcycle' TV builds, you will notice that EVERYTHING is covered with the Green/Yellow stuff prior to paint. I thought it was just a 'show car' thing. Never thought it would hold up in the sun and on the road. Guess products have evolved to where the "old school" tales aren't valid anymore. Where's that plastic speader...... :D

Using a quality filler or polyester putty to finish off the panel is MUCH better than a over use of primer, any primer.
However, the other day when I was watching one of those motorcycle build shows on Discovery, when I saw them spread that filler over the fenders, I couldn't believe it.

First off, the guy really isn't that good of a metal man to begin with. I am no master at metal fab but I sure know who is, and that guy wasn't. To need that much filler over a freshly fabbed part is nuts. I know, because some of my parts have looked the same. No, there are plenty of Motorcycle guys out there who would make those tanks and fenders without any filler.

And the guy who was spreading all that filler on, man, he needs to listen to the salesman who offers the polyester primer. Polyester primer would make that job SOOOO much easier. I don't think it was "that" far off, I know I couldn't feel it. But these parts looked pretty good. Maybe a spot or two over a weld could have been polyester puttied and then polyester prime the whole thing. It could be done MUCH faster than they did with that skim coat of filler, that is for sure.

ok Brian, not trying to beat a dead horse here :D but I know I havnt painted my last car,and anything that gives better results I want to do, so what you are saying is, its a good idea,after taking panels to bare metal, is to use a skim coat of polyester filler on each panel, block then use a polyester primer over that? does the polyester primer etch the metal? would you be able to paint over the polyester primer or would you need a coat of sealer between primer and paint. thanks.

Epoxy primer works great below and above the polyester fillers. I like to do all the bump work and corrosion cleanup then epoxy the entire panel followed by filler work and another application of epoxy then urethane primer or polyester depending on how much straightening is left to do. Some prefer the metal etch primers or use it in conjunction with epoxy but I use epoxy alone without any problems. Not every job requires the complete panel skim, it depends on the amount of correction needed. The human eye can pick up on imperfections as slight as .010 of an inch so a perectly straight car requires a lot of concentration as a whole not obtainable by working each area seperately, The entire side of the car needs to be blocked assembled as one, for the body lines and panel surfaces to flow perfectly from one end of the car to the other.

I use a poly primer that has an etch in it and it can be applied over bare metal,cant be sparayed over any other ethch prime or acid wash though. Having a brain freeze and cant think of the name right now. :confused: But three coats will fill 36 scratches,not that i recommend doing that but it gives you an idea of the fill it has.Like an old timer told me, you can lose your watch in it if your not careful. ;)

There are no polyester primers with an "etch" in them. There are polyester primers who specifically say DO NOT apply over an etch primer. Evercoats for instance. When I started repping a relabeled Evercoat Polyester primer with M-S (part number 5190) I was told that the polyester resin "didn't like" the acid in the etch. However, in a year or so after that we got a PCL polyester primer relabeled with the "Econobody" label for NAPA Martin-Senour and it had a recommendation for etch primer! I have used it and like it alot. It doesn't have quite the solids of the Evercoats, so it won't fill quite the same as Evercoats. I do like it more, SPECIFICALLY because of the etch primer recommendation.

Depending on the primer, some polyesters say that no sealer is needed. I honestly don't know why one would and one wouldn't. Evercoat has a couple that do, and a couple that don't. PCL says no sealer needed. I have to tell you, I like to ABUSE products when they are used on my person projects or tests to see how much they can take.

I have done a number of projects where I blocked the plastic filler with NEW, sharp 36 grit paper on a block. I wanted the deepest most "vicious" scratches to fill so see what the stuff could do.

I applied the Evercoat polyester primer over these 36 grit scratches. Two or three coats one after the other, one "application" if you will. Blocked it with 180 on the block and long board, then guide coated and sanded with 400 (I told you I abused it) then painted right over that. I did this on a black (your going to kill me for this) 1970 SS Elcamino. A super nice black bc/cc car that was being sold. I repaired a few dents and did the repair. Ok, so I sprayed the paint, clear and cut and buffed the next day. I saw this car about six months later and there was ZERO shrinkage, ZERO anything. Now, there were some 400 DA scratches but that was paint that had shrank, NOT the primer. I am telling you, this stuff is wild. I did the same thing on a display that I used at Dealer and trade shows when I was a rep. I had an old banged up Harley gas tank that I made a stand for and did the exact same thing with the filler sanded with 36 (the ENTIRE thing was covered with filler). I sanded the poly primer with 400 after blocking with 180 and did a three stage pearl job with a stripe under the clear. Again, I used this as a display to show off the product I was selling, so you know it had to look GOOD. I would throw a quick coat of wax on it and be sure it was perfectly smudge free before any display. After about five years, it still looked as perfect as the day I finished it.

The product does work. It has it place remember, it isn't the "best" primer or anything like that, but it has it's place.

Good info here from MartinSR, private product testing is cool! I just picked up a quart of Sikkens polyester primer to try, kinda expensive at $65 per quart my cost, we'll see how it performs :D

Boy, that is REAL expensive. A gallon of Evercoat or PCL is about $55.00.

Martin you willing to stand behind your claim that there are NO poly primers with etch in them? Its called Z-Chrome Rust Defender Polyester Prime. Its says on the label that it contains an etching agent.

70isfine, who makes this stuff? My nephew is buildin one of those bondo bikes and he was interested in a good sprayable polyester.Can ya wetsand this stuff? Thanks, Mike

Can't answer for Martin but I am using Evercoats Featherfill G2 on my 67 Chevy shortbed 1/2 ton project and it fills awesome :cool:

Sands easy too, I did a final 600 sand prep on the hood last night, filled 180 sand marks without a sweat and cut real nice. I recommend it, I hope this is the product Martin was referring to.

Originally posted by 70isfine:
Martin you willing to stand behind your claim that there are NO poly primers with etch in them? Its called Z-Chrome Rust Defender Polyester Prime. Its says on the label that it contains an etching agent. No, I am not. In fact, I would love to be proven wrong. Sounds like a super product it if does what they say. The thing is, the marketing dept. came up with the "Etching agent" smile.gif What exactly IS this? The name "Z-Chrome" implys a "zinc" and/or Chromate. Both of these are corrosion fighters, neither are adhesion promotors. Any primer I have ever seen with the name "etch" had acid. If it doesn't contain acid, than it isn't an etch. What other componant could actually produce and "etch"? I don't know of any. So I imagine it is a polyester with a small amount of zinc and/or chromate.

I am playing a Clinton game "That all depends what the definition of is, is" smile.gif If it doesn't need etch because it provides a good protection with the zinc and/or chromate, that may very well be good enough. Do you have a company name so we can get an MSDS?

I dont have a can now so i can't get the name of the company that makes it. I tried an internet search but only came up with some people talking about it,no manufacturer name.Eastwood used to sell it. I can call my old supplier in NJ and get the company name. It probably contains zinc and chromate for corriosion protection,not sure if it actually has acid in it. I started using it at a resto/rod shop i worked at.We would get the parts/car media blasted,3 coats of Z chrome,Apply filler where needed after sanding,then after bodywork,apply three more coats and wetblock with 220.Seal,sand sealer with 600 and paint. We had two cars on the Dupont Top Gun calendar(of course it said the car had Dupont Uro-prime on it when it was actually Z-chrome from metal to sealer. Another shop from the same area took home first place at Pebble Beach last year and they use Z-Chrome also.

I have a can of the Zchrome in the garage, it is made by the Clauson(sp?) paint company. Says nothing about acid etch, or shows any ingrediant related to acid. My HOK/Valspar distributor talked me into trying it out but the can hasn't been opened yet. $70 for a sprayable gallon. It does say it meets oem warranty specs for what that claim is worth.

I was curious how the Z-Chrome works so I popped the can open tonight and applied three coats to a snowmobile cowl I'm restoring for a friend, we'll see how it sands this weekend. Like most polyesters it is very thick. The manufacturer is Clausen which I misspelled in the previous post.

Hey Bob, could you check something out for me? You would have to sand to metal to do it, but it is a decent test.

Sand it down with something course like 80 or 120 at the finest. As it feathers off onto the metal, look at the scratchs the paper creates and see how "sharpe" the edge of the scratch is. Some urethane and polyesters will leave a sharpe scratch which shows poor adhesion. If it feathers off nice and the primer actually turns transparent as it feathers off, it shows more adhesion.

You can do this test, then guide coat it and sand with something finer to bring it back up to finer scratches for reprimeing or even painting.

MartinSR, I'll do a direct to metal test with the stuff this weekend. I know exactly what you are describing.