In autobody, there are many different types of fillers or Bondo.
The most commonly used ones are body filler, metal filler, fiberglass, and glaze/Bondo.
Every type of filler has different benefits and uses. Metal filler is no different.
In this article, I will explain everything you need to know about all metal body fillers.
I’ll also compare all metal body filler vs Bondo.
The short answer is that they’re completely different products.
Keep reading to find out why they’re so different and when to use each one.
If you already know the difference and are looking for the best metal body filler; My recommendation is Evercoat metal 2 metal.
What Is Bondo?
I’ve covered the different types of body fillers before.
They tend to vary based on the fill depth, material types, and stage of repair.
To accurately describe the differences, I need to explain what Bondo is.
Bondo is a 3M brand that has many different types of auto body filling products.
Yet, when most people say Bondo, they’re actually referring to a glaze or glazing putty.
On occasion, it will also mean a deeper fill body filler, but most people today mean a glaze-type product.
For the sake of this article, I’m saying it’s a glaze.
Glazing putty is a much thinner product and is rubbed with 120-320 grit paper.
It’s designed to fill in scratches, pinholes, and other imperfections.
Most of the time it’s going to be the product you use for final skims.
It can also be mixed with other fillers to thin them out.
What Is All Metal Body Filler?
All Metal Body Filler is a very different product.
Metal body fillers are often aluminum reinforced. This means it has real aluminum flakes in the filler.
All the leading brands within the auto body industry have their own all-metal body filler.
It’s typically a “deep fill” product that’s used on bigger repairs that need more build.
Depending on the brand, it can fill up to 6mm in depth.
Metal body filler is very dense, has excellent filling properties, and is much thicker upon application.
I also find it much harder to rub.
The initial sanding is very hard, and if you overfill it, you could be sanding forever.
P80-120 is the grit you want to use when rubbing all metal body fillers.
Sometimes you may even want to take your DA sander to it, to bring the edges down.
Metal filler is more of a specialty product that’s used on occasion.
In my shop, I see it used on big repairs where the metal cant be reshaped. I also tend to use it as my first skim on panel joins in hope that it provides some corrosion resistance.
Metal Body Filler Vs Bondo
These products couldn’t be any more different if you tried.
First of all, you have the stage of repair that they’re used.
Metal Body fillers are a deep filling product that fills major dents and helps to shape a panel.
Bondo is a thinner product that’s designed to fill imperfections and minor dents in a panel.
Secondly, you have the materials that they’re made up of.
Metal filler has real aluminum flakes in it and is much tougher and harder to rub.
Bondo is a polyester putty and is designed to be easy to rub.
Finally, the metal filler is considered to be less porous than Bondo.
This means it’s less likely to hold water and cause rust to the panel you’re repairing.
I tend to use metal body filler on my joins when doing panel replacement jobs.
I’ve seen other people fill minor holes with it, but I’m not confident recommending that as a repair method.
Traditional Body Filler Vs All Metal Body Filler
More traditional body fillers such as rage ultra are a lot more similar to an all-metal body filler.
They can fill similar depths to each other and are used to fill dents and shape a repair.
The main difference between a traditional filler and a metal filler is the hardness.
Traditional body fillers are much softer and easier to rub.
You’ll still be blocking them down with 80 grit, but the process will be much faster.
With Metal filler, the aluminum flakes make it much harder than a normal filler.
This is probably a good thing, but when it comes to rubbing the filler it’s very annoying.
Fibreglass and all metal body filler are the most similar. They’re both harder to rub and are arguably more resistant to corrosion.
The Best All Metal Body Filler
There’s no doubt that metal body filler has its use.
I normally use it on the joins of my panel replacements and on smaller aluminum dents I cannot get out.
Buying a metal filler from one of the leading brands is the best way to go. Either Evercoat, U-Pol, Eastwood, or USC will do.
Evercoat Metal 2 Metal
If you’ve read any of my other content, you’ll know I’m a big fan of Evercoat.
Evercoat metal 2 metal filler offers maximum adhesion, corrosion resistance, and strength.
They claim that using this filler will result in a water-proof and impact-resistant repair
Using Metal 2 metal filler in high-stress areas will provide extra strength and be less likely to crack.
It’s also a good choice for areas where you may be mounting things. Its compression resistance means it won’t crack when drilled.
As I’ve already mentioned, it’s a great specialty filler.
The main downside of this product has to be the price.
There’s a good chance you buy it, use it for one job and then don’t use it for another 3 months.
Depending on the line of work that you’re in, a 1.1kg tub will sit around for a long time.
Secondly, I’m not a fan of how much effort it is to rub.
Granted it’s a result of its properties. But its hardness is annoying, especially when it’s in an area that needs to be rubbed by hand.
I recommend only applying metal filler to areas that are easily sanded with a da sander.
Finally, even with metal filler, you’re probably going to use normal filler and glaze.
Depending on the repair, metal filler will only really be necessary for the first fill.
This is a good thing if you can find a smaller tub, but buying 1.1kg for occasional use is a bit wasteful.