Any scratches or chips thru the paint to metal need to be feathered out. Use 180 grit open coat paper (a light grey color with a wood grain like look) on a DA or rubber sanding block and sand until you have ~ 1" of bare metal around the chip or scratch and the feathering extends ~ 6" out from that in all directions. i.e. if there is a 1/4" chip down to metal the feathering would be down to a bare metal bullseye about an 1" in diameter in the center of a 12" diameter feathered area. If that doesn't get the metal completely rust free at the chip, I would spot sandblast, wire brush with a stainless steel wire brush or use a course 3M surface prep disk to remove the last traces of rust or dark corrosion. If the spot is dark, I would also poke and scratch at it with a sharp pick to see if it does indeed poke thru, I'd rather know now and fix it rather than it pop up a bubble in the finished paint later. If the spot has any size to it and/or you want to do a first class job, I'd dab it with some rust converter as well.any scratches or chips that aren't feathered enough will telegraph thru the final paint, especially if you use a single part paint.
I prefer to use Dupont or Sherwin Williams products because I've had good luck with them, but I'm probably going to use Alsa on Gracie because I like the colors in their line.

 

Some paint manufacturers are getting away from that now. SPI recommends sanding with 80 grit. Then spraying with epoxy primer. Then filler (sanded of course). Then seal it with a reduced epoxy primer. The filler is sealed and can't get moisture that way.

I know Barry Kives the owner of Southern Polyurethanes Incorporated.

 

Not disparaging Barry, but does SPI make body fillers? I tend to follow the instructions of the product I'm using.
Here's another expert from the filler side:

Using body filler, by Reed Overson Last updated on January 1, 2007

Reed Overson lives in Bismarck, North Dakota, and has been a bodyman, painter, sales rep, and technical rep for thirty years.

Reed used to work as a technical sales rep for the company that makes Rage filler, and knows the chemists that developed the resin for it.

The following article contains some of Reed's thoughts on using body filler.

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The resin used in Rage and other body fillers is fiberglass (polyester) resin. Today's resin technology makes the adhesion of these new resins as good as or better than most epoxy adhesives. They are designed to really stick. Also, they are somewhat flexible when used properly.

Most, or probably all, filler manufacturers design and recommend them to be used over clean and prepped (sanded with coarse 36-grit), rust-free (sandblasted), dry (free from moisture), bare metal. They will stick to epoxy primers with mechanical adhesion. Body fillers do not chemically bond with epoxies. If you put filler over epoxy primer, it has to be fully cured, with no solvents such as thinner or reducer left in the primer, and still should be sanded with a coarse grit and cleaned. In other words, using epoxy primer under filler is a wasted step that may or may not cause adhesion problems later on.
The full article is here: http://www.roadsters.com/filler/

I've done enough work with polyester and epoxy resin to verify that poyester will not chemically bond to cured epoxy. However epoxy will bond to cured polyester. Epoxy resins are anaerobic, they will not cure hard unless sealed from air. the method most widely used to accomplish this is to add a small amount of wax to the mix. In the heat generated by the chemical reaction the wax migrates to the surface and forms an airtight seal. If this wax coating is not removed by mechanical means even epoxy will not bond to cured epoxy. Epoxy used in fiberglass laminating comes in two formulations, with and without wax. The wax free formula is used for all layers that will have additional coats applied and has a sticky surface when cured so that additional layers will bond. The final coat of glass is impregnated with the wax containing formula so it will cure with a hard surface.

 

I am not arguing. Just saying what a lot of people are doing now. It is recommended by SPI and their epoxy.

Check this link under the question :


http://www.evercoat.com/faq.aspx

<TABLE id=37_Table1 style="BORDER-TOP-STYLE: none; BORDER-RIGHT-STYLE: none; BORDER-LEFT-STYLE: none; BORDER-COLLAPSE: collapse; BORDER-BOTTOM-STYLE: none" cellSpacing=0 cellPadding=0 border=0><TBODY><TR><TD>Q. Can Evercoat fillers be applied over bare metal? Can they be applied over paint? </TD></TR><TR id=37_answerRow><TD>A. Our fillers are designed to work over bare, properly prepared substrates such as: steel, aluminum, galvanized, stainless steel, fiberglass, and SMC. Some people prefer applying an epoxy primer over bare substrates to enhance corrosion protection. Our products don’t need to be applied over an epoxy for corrosion protection as long as the bare surface area is clean and no surface rust or contamination is present. However, some auto manufacturers do require body technicians to coat the bare metal surface with an epoxy before applying fillers. If you are performing warranty work, you should consult the manufacturer of the automobile for the recommended procedure. Fillers and putties will normally work OK over properly sanded (80-180 grit) cured OEM paint. However, with so many different types of aftermarket paint available (lacquer, enamel, urethane, water-based). We recommend that all paint be removed where filler is to be applied.









It is not necessary, but won't hurt anything and is required by some manufacturers. Read the directions and recomendations for the product you are using (epoxy or whatever).

As long as the metal is clean and rust free it is fine with most epoxys. Or am I missing something?

Mine will get stripped, epoxied, filled, primed, based, and clear coated...one of these milleniums.







</TD></TR></TBODY></TABLE>

 

If I sold paint I'd recommend putting it on everything, I sell jewelry, I recommend people put jewelry on their pets and hang it on their walls. but why do something that is unnecessary and could cause problems per the filler manufacturer, and epoxy primer isn't cheap. I have had excellent results using filler on bare metal so I will continue doing so. If your method works for you I say go for it.

 

Read what they say on the evercoat site. Some manufacturers require it. How can it cause problems? Evercoat says that right on their site.

Where does it say on the evercoat site that it could cause problems using it over cured epoxy? That gentleman is an expert I am sure, but evercoat (the manufacturer) does not say there is a problem.

There is no problem with using fillers on bare metal. It has been done that way for who knows how many years....unless moisture gets to the filler somehow. I have seen that happen over the years. Then you have a sponge soaking up water and rust behind your paint.

There is no problem with using it on top of epoxy either. For us non-professionals it is an extra safety measure. Epoxy primer is not that expesive.

I cannot speak for other brands like PPG, but 1 gallon epoxy primer is $64.62 and one gallon of epoxy activaor is $64.62 from Baker PBE wareouse. That is two gallons sprayable. Way more than anyone should need (I think).

I am just saying that some paint manufacturers recommend it as well as some vehicle manufacturers require it.

Yes...I will do it the way it is recomended with the products I will be using. Again...everyone needs to read the labels, instruuction sheets, and MSDS of what they are using.

It was the "bare metal only" statement that I was offering a different opinion on. That is all.

 

John,
I have used the "All Metal" product you are about to use and have found it to be alot tougher to sand than more conventional fillers, I think it's because of the aluminum filler material in it??? 80 grit is typically recommended surafce prep for fillers.

Filler over bare metal or over epoxy primer??
To each his own, but, I vote for over the epoxy. I like the aspect of getting down to bare metal, doing the metal work, sanding entire surface with 80 grit and then protecting them from corrosion with the epoxy primer on a panel by panel basis. Then I come back and do the filler work over the epoxy. I will scuff the epoxy with a red scotch-brite pad, if the epoxy has set for more than 7 days and then apply the filler. As stated in Axe's post the fillers have excellant bonding capacity and should not have any problem mechanically bonding to the epoxy primed 80 grit surface. prep.

 

Thanks for all the discussion on this subject, I just find it a bit nerve racking to start the finishing touches,not ever doing it before. I know that it's not going to be a prize winner when it ever gets done but I do strive to make it the best I can, I just have a tendency of backing my way into a corner and saying to myself why the heck didn't I do it this or that way or something like that. Any way I did start and filled and sanded one seam along the top passenger side, the All metal I found wasn't to bad at sanding out and feathered quite well and I'm pleased with the results, although I have to apply another thin coat on a few spots.

Another question though while we are on the subject, the epoxy primer I have I discovered is not a high build primer, should I see if I can exchange it for high build or use what I have and apply a non epoxy primer after that as a high build or will I be doing unnecessary work. The guy that sold me the primer said to do it that way but maybe he's just selling me paint

 

The epoxy primer you have is an excellent seal for the metal and provides a good foundation for the next step (high-build primer). The paint guy told you right.

BTW, I hope you are at least tack welding those seams before you fill them. They can crack out later if you don't.

 

Epoxy, filler, high build, base, clear. I think those are the typical steps.

I will do it slightly different. Epoxy, filler, reduced epoxy (as a sealer), high build, base, clear. Then again...I might never get to all that.

 

sealer base clear. Atleast w/ppg, The sealer is a nuetral Grey to prevent the primer from "bleeding" through the base coat. Of course, there's always more than one way to skin a cat.

 

Ahh...another one of those check the labels things.

 

The best results I have had is by using a small air grinder with an 80 grit disc to clean the paint and rust off of the area, it will scratch up the metal just enough for your body filler. Apply the body filler directly to the metal and let cure. Stay on this as to there is usually a working window in which the filler is a lot easier to sand, if you wait until the next day it will wear you out. after it has been smoother and ready to go, I always seal it with epoxy primer. After that has dried usually 24 hours I then scuff it lightly with a scotch pad. Then I prime and paint. This method is pretty basic and standard but it has worked for a long time. but usually you can check web sites or call product manufactures and they will help you out.

Kyle

 

Thanks for the conformation on the epoxy that I have and to Randy yes I did weld up the seems before I starting to fill. I think it was your recomendation on a previous post I had. Thanks for keeping me in line and as my luck has been, the weather is getting better now that I'm back to work, I just hope it holds out until next weekend, as if.

John