The last 16 yrs. of my bump and grind career was at a major fire truck builder. We had more than one company try to get the business. We were using an Evercoat product, Rage Gold Ultimate or Ultra. This stuff spread easily, great sanding properties, and if you did not ABUSE it very little or zero pinholes. It is expensive, I think in the range of 50$ or more per gallon.
Great info in this thread, thanks! I can't add anything, aside from I always mix on a sheet of old laminate glass. I've had the same side window from my Diamond T pickup that I've been using for over a decade. Before that, a cracked w/s glass from my Chris Craft! Gotta have quality tools...
As I mentioned I am not going to get into specific products as that was not my intent with this thread others are certainly welcome to add their experiences. I will say in general you get what you pay for with fillers and putties from all companies. Heat, especially cyclical heat like an oil pan is tough and I wouldn't recommend using any polyester based products for that type of application. You would need to look into fillers used in powder coating like LabMetal's high temp filler or Tiger Drylac's epo strong or something along those lines.
Yep. LabMetal and other powder-coat fillers are exactly what I had been considering. Thanks much. - EM
I have no direct experience with these products so I would suggest contacting them to confirm. The cycling of the heat is my biggest concern as it can work things loose over time.
I worked with and for companies that used Labmetal filler as a means to salvage die-cast parts when working with the powder coating industry. The only experience I don't have with it is in applying it and working it to shape. But, I know it's quite a bit harder than regular body filler. The temperature capability however is over 2X what the oil pan will see. - EM
Unless there is more then one choice of Bondo on the shelf, in my opinion, leave it there. There is a higher quality of Bondo available then the cheap stuff on most store shelves, but my experience with the cheap stuff makes me unwilling to try even the better stuff. Sanding the cheap stuff seems to be a lot like sanding on concrete, not much seems to happen very fast. You will eat up more the difference in price between the cheap filler and the best filler in sandpaper costs. Now, how about that sanding tech? Gene
Bump & grind, must add to cave & pave and scuff & puff repetoire. Used Rage on my heap at my auto body class (free) but had to buy a pint of Bondo at Oreillys for some minor work at home. No comparison.
Best info would come from an automotive paint store/supplier. Both of the big ones here will talk at what ever level you want, from beginner to expert. Mostly they make there money off the pro collision shops, but it has been my experience that they enjoy sharing knowledge and helping the novice. Stay away from the "drug store" filler, it is junk at best and only God knows how long it has been sitting on the shelf!
Very interesting thread. My question if for the grit of the sandpaper. I only do metal work. I only do drywall work on my own stuff, not on anyone else's. I grind the welds down with 3M green corps 01991 wheels on a die grinder. I have been using 36 grit 3 inch roloc discs for the final finish on bare metal, once all the weld bead is gone. The only negative feedback I have ever gotten was by one painter who bitched that the 36 grit marks were hard to cover up. My response was that he obviously didn't need any filler in those areas, BUT, perhaps I should be going to a finer grit to make everyone's life easier. I always figured the coarse grit scratches were a good thing, to enhance the surface grip. I do pretty much zero bondo work, but everyone knows you are still going to need a little filler. I use 24 inch stainless steel ruler, laid flat on the panel surface. If I can see light under the ruler I bump up the lows, and/or take down the highs with shrinking disc. (I find it much more satisfying to do metal work than to sand the filler) I don't promise anyone that they won't need a little filler, but it will be damn little, so that is why I ask about the coarse grit sanding paper on bare metal before filler application. Your comment on body shops wanting to use 80 grit made me think about that. Thanks. Great thread.
I can't think of a primer that is designed to go over 36 grit. The minimum is usually 80 and more often than not 180. Rolocs put in the worst kind of scrartch to try and cover because they are straight line scratches that require a lot of primer to bury and can often lead to problems like sand sctrach swelling or die back. Now having said that the standard procedure should be to sand the bare metal before applying anything anyways so a shop should be doing at least one step of sanding prior to any product being applied. Probably best to ask whoever you are doing the work for what they prefer. Lots of old school guys down in the Lethbridge area that are hard to convert to new ways. Believe me I have tried.
Thanks. Biggest reason I use 36 grit is that after about 2 minutes they are 60 grit, and another 2 minutes they are 80 grit it seems. I am a cheap sob, I guess. I think I'll try some 80 grit next time I buy a box. Appreciate the info.
When I managed a body shop I wouldn't let my guys use anything coarser than 80 grit. It may take longer but I didn't want issues later with primer/paint shrinkage and sanding marks showing back up later. If im shaping I'll use 36 grit but I come back with a body file and then finish of with 80. I actually enjoy using the metal body file.
Filler use after a fresh bead blasted body? I should'nt prime first? or 2part primer and then filler ? I'm just getting my blasted body back and begging for the correct procedure ?? I have to stop surface rust and do body filler at same time ! thanks for advice ron
You’ve got to get it clean and get a decent coat of epoxy primer on it. Then you have some breathing room.
I like to lay it on thick to cut down on the remixing and re applying. I recently switch from icing to dolphin glaze, it seams to dry faster and sand easy. In general with all fillers: I don't know how they make them so good and sell so cheap.
try the dolphin glaze, its inexpensive and user friendly. after you apply primer, let it sit for 2 weeks before you sand.
Paint Guru, good to see your still around!!...one of these days I'm going to get around to painting a project and want to deal wit you...could you publish an email address or " conversation " / private message me an address??... or is there another way to contact you??....and K13, thanks for the tutorial....very useful, even for a hobbyist that started slinging mud 44 years ago!!... that old DC3 that NAPA sold sure was hard shit to sand!!
Maybe I missed a post that answers this, but is it best to put filler over bare metal that has been sanded with 80 grit, or to put it over epoxy primer that has been scuffed? A friend and I have been working on some fenders and we both researched for the "right" answer but there didn't seem to be one "correct" answer to the best approach. It seemed opinions varied like those on a topic like what is the "best oil", or "is red better than blue"! I did see one response that you discouraged filler over self-etch primer because of reactions with the acid in the primer, so at least I gleaned that and much more out of this helpful thread. So, what is best......A) filler (like Rage) over bare 80 grit scuffed bare metal, or B) filler over cured and scuffed epoxy primer? FWIW, I'm not going to go back to start over on the current two fenders since so much work has already gone into them, but I would want to proceed on future work using the best method! Thanks. Lynn
I may have answered it before but it doesn't hurt to have it on here again if I didn't. It is fine to put filler over epoxy if the epoxy is compatible with polyesters and if it is has fully cured. This is again where reading the TDS of products is so important. It usually won't say if the products are compatible but will indicate if they are not and full cure times should be indicated on all TDS sheets. If they are not you should wait a minimum of 24 hours before applying any polyester based product over an epoxy. As Lloyd said it will be fine if properly sanded. They are both polyesters.
^^^^ Thanks! After our reading on the topic of primer and filler application, we finally decided to go with filler over the 24 Hr. cured epoxy primer, so with any luck at all it shouldn't all slide off onto the floor right away. Lynn
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