wildjyoung

iTrader: (6)

Okay, I was watching Muscle Car a few weeks ago and they were prepping a car for paint. To make everything smooth they spread a thin layer of premium body filler (not Bondo) over the body panels and sanded it smooth. I realize doing this would make produce a great paint job but would it last? I would just think that the body filler would break apart over time due to the expansion and contraction of the metal. Would using body filler to even out body panels last?

Thanks,
Josh

CYARS92

It must, cause some of the nicest street rods in the country have filler on em. Then again, they're not exposed to the elements like most cars also.

Sickness91Z28

iTrader: (1)

Body filler now days acutally expands with the metal. Unlike the old type fillers, with the new fillers, you don't even have to grind down what your going to fill. You can sand the area with 80....then apply the filler right over the finish. It doesn't even compare with the old body fillers. So, will it crack and fall off......no.

Jim85IROC

iTrader: (2)

Body filler is a necessary step in the process of restoration if you want anything that resembles straight panels. Very few have the talent to work the metal that smooth, and even less can do it in a reasonable amount of time. Lead is expensive and heavy, and really isn't as good when your goal is to block a large panel.

when done properly, body filler will last as long as the rest of the paint and body work. It's only when it's on too thick, or not used properly that it causes the sort of problems that it's famous for. Proper body work means that you're using bondo as that last element to ensure that the panels are perfectly smooth, and not to fill craters, dents or rust.

KEVIN G.

Jim is one hundred percent correct. I couldn't have put it any better.

wildjyoung

iTrader: (6)

Thank you for the help guys! You gave me the exact information I needed and now I am off to buy some professional grade body filler. I know I should run away from Bondo but is any brand preferable?

Zed'er

Evercoat's Rage Gold is the best filler I have ever used. Sands very easily, and fills nicely.

crazycrocket

Bondo is like everything else their cheapest product is going to suck. The idea is to use the body filler properly and get the best of whatever brand you choose for the best results.

Im curious about them bondoing the whole car.. was it in rough shape? The reason I ask is because generally a good high build primer will take the small waves out of any paint job when it is block sanded correctly.

wildjyoung

iTrader: (6)

No, the car was in very good shape. They used the body filler to make the hood, fenders, and front end the exact same level. They spread body filler over the whole front clip and sanded flat. The most significant use of body filler was the height difference between the top of the fenders and the hood. If I had to guess, they put about 5/16 inch of body filler over the sides of the hood and fenders. The finished product was great because the light flowed flawlessly over the entire front end.

I hope I am making sense........

crazycrocket

Yeah I understand that. Personally that would scare me because at the joints of panels is where body filler is the most likely to chip off. Then again I guess the shop would know what they are doing.

Generally things can be adjusted so they match or come really close.

Jim85IROC

iTrader: (2)

5/16" is way too thick for bondo, even though it'll probably hold up just fine. If you need bondo more than 1/8" anywhere, you should have done better body work.

I'm also not a fan of bondo on hoods if it can be avoided. A hood goes through far more drastic temperature swings than any other panel, and also has a lot of vibration to deal with. Plus, opening and closing the hood puts a lot of stress on it. You need to be careful with too much bondo on a hood.

wildjyoung

iTrader: (6)

Should you use bondo on the hood at all? It would make sense that it would be very hard for any type of body filler to withstand conditions of the hood.

GodSpeedGTA

iTrader: (1)

they always coat the cars in those shows with body filler bc they are trying to do it fast! Ask any true body professional...you dont coat the entire car or huge sections of a car in body filler...if you are taking your time and doing a truely professional job then you will fill where necessary and check all panels by hand to test for imperfections...

i worked on the body work of my car with a 67 year old mechanic/automotive everything who has been doing this stuff since before there was even bondo of any kind and they used lead...i asked him the exact same q...why do they always coat almost entire body panels in bondo on overhaulin...etc. He said its just a quick fix and it might not be a totally wrong way of doing things but its not the best/right way to do it

wildjyoung

iTrader: (6)

I went to the local paint shop today and purchased a gallon of their premium body filler. The guy at the shop told me I also need to get sealer and glazing putty. Is this true or are they trying to get more money out of me? He said that you have to seal the body filler, than go over it with glazing putty, primer, and then paint the surface. I have never heard of sealer for body filler......

white91formula

iTrader: (4)

the primer/paint should seal it... but you do need to seal filler beacuse it will soak up water if its left on the car unsealed... thats why all the honda's that have backyard body work done and then dont paint over it, its always cracking and falling off

Sonix

iTrader: (1)

you have different types of primer

primer surfacer - usually thicker, acts like thin bondo. you can sand this. It's NOT waterproof.

primer sealer - you can't sand this. It's waterproof.

there's a few others too, like self etching primer (bare metal only usually, very thin coats, most $$), epoxy primer (I think this is a type of primer sealer)... etc

After filler, and after primer (any kind), if you notice any more imperfections, you can use glazing putty. Glazing DOES shrink and contract (last I checked, that true guys?), so use it very very sparingly. I wouldn't even use it at all, just use your primer surfacer. Or if it's a BIG error, just sand, and re-fill, then reprimer. These last two steps I mentioned should be repeated as many times as you can stand, for a good paint job.

Your base coat will seal it (urethane base), but some people like to use primer sealer as well. So once your filler is perfect, and you've used primer surfacer if needed, and it's bang on perfectly straight, then primer sealer, then base then clear. The sealer also keeps your old finish from reacting with the new one, if they're not perfectly compatible. (at least in theory, it can help that way).

So you can do:
bare metal / scuffed old finish - filler - primer sealer - base - clear
or
bare metal / scuffed old finish - filler - primer surfacer - base -clear
or a base/clear... or.... Lots of permutations and combinations that'll work with varying degrees of success depending on the brand. Sticking with one brand is a good idea too. If you mix and match brands, every brand will point the finger at the other one as the source of failure (this is common). So stick with one.

There's some debate on "filler on bare metal"... it kinda makes me uneasy, but according to Len at Welcome to Autobodystore.com, it's the best way. (he did a trial of it).

Hope that helps.

wildjyoung

iTrader: (6)

Thanks Sonix, you're post helps a lot! I never realized I would learn so much while trying to restore this GTA. In your expierience is primer sealer a necessary step? I do not want to do another paint job in a year or two.

Sonix

iTrader: (1)

I've never painted a car before

I don't think it's necessary, but i'd trust one of the experts here before my opinion.