Hey Shawn here from 3M. I really appreciate you joining me today for this video.
The topic we're going to discuss today is body filler and hardener, what is the proper ratio.
And the reason we're going to talk about this is we get a lot of questions all the time especially
when there's temperature changes during the summer or winter when it gets hotter or colder,
humidity, all those things are a factor in how much hardener we
need to use, so let's talk about the proper way to do that.
Okay so a couple things we need to cover here first is, first of all let's wear the proper
protective equipment. Make sure that we're wearing what we need to what's appropriate
for the job we're doing. For this video I'm going to wear a respirator when I need to,
safety glasses, and some gloves. The second thing, is keep in mind these videos were created for
a professional setting such as a body shop. If you have any questions about the personal
protective equipment or our warranties there is a link in the description below.
Okay so a while back I was mixing up some body filler and I kind of thought about is my mixing
ratio in the right range? Okay the proper mixing ratio is two percent hardener for the body filler,
the weight of the body filler. So I was thinking about that and you know sometimes you mix body
filler over and over and you get a little carried away with the hardener. And again it's going to
depend on the temperature in the shop how much hardener we need to use. Now like I,
said two percent is the proper ratio but we can vary that slightly. Maybe down to one and a half
and maybe under just three. Now I don't expect you to know what those what those amounts look like,
right? That's hard to tell, so I thought about it and thought you know why don't I
just go over the paint scale and throw some filler on there and the hardener
and see what it looks like, right? Now I'm not talking about doing this every time we mix up body
filler. That would that would be ridiculous right? So I'm just saying maybe every once in a while,
maybe even just at the change of the season when it goes from hot to cold or vice versa,
just go over put it out on a scale and see what that two percent looks like. Okay?
So I mixed up some previous amounts here and as you can see here for this amount of body
filler when I put it on the scale I have about a three and a half inch puddle here
and that ends up two percent is about a 7/8 inch bead of hardener. Now,
keep in mind this is going to vary by the product you're using right? Some fillers will make a
larger puddle or or smaller puddle depending on their thickness, so this is all relative to the
products you use and the way you mix your body filler or even the way you dispense the hardener.
For example you might squeeze out a fatter bead or a skinnier bead, so it all depends on your
personal habits. Ok? But what I did and the way I mixed it up I ended up with about a 7/8" bead and
this is I just looked at it, measured it, it's about 5/16", right? So it wouldn't go very far
across that puddle. Now if I made a much skinnier bead and went across the puddle it would probably
be much farther right? So again it's going to depend on your personal habits and how you squeeze
it out of the tube. So this one over here I did with about a little over a five inch puddle and I
ended up with 1 and 3/4" for the hardener length, but again depends on your your thickness or the
width of your bead. So you can see these are both two percent with the amounts that were mixed,
okay? So I'm going to do that right here set this out on a scale and again, guys we're not expecting
to do this every time, just maybe kind of spot check every once in a while. The other thing I
did, by the way, after I finished these puddles is I measured them and then I just drew this out here
where you can see, I'll show it for the overhead camera here, so you can see what that a puddle
size looks like and then how much hardener goes across, okay?So again depends on how you mix your
filler and dispense that that hardener. But let me go ahead and mix some of this up. I'm
going to put my respirator on. Before I do that though let me talk about hardener a little bit.
Hardener is critical to body filler, okay? So a lot of guys are worried
about the type of filler and they don't pay attention to the hardener. Number one,
make sure you knead this really well. I'm sure you've all had it where you dispense little out
comes out like water. We don't want that to happen so make sure you knead it very very well. Also
use fresh hardener and sometimes, um, you know they may just throw it in a box where there's
all these different hardeners in there. Try to keep the hardener that you got with your can
and keep it with that can. Then you know it's the same freshness as your body filler.
So knead that really good, make sure it's fresh. I always also like to dispense a little bit onto
a paper towel just so you don't get any of that watery stuff first, all right? Because it still
happens once a while even if you knead that. So the last thing with hardener, make sure you're
using the same brand. So use a 3M hardener with a 3M body filler. There is a difference,
all right? So I'm going to gear up here and then I'll mix that and we'll discuss it when I'm done.
I'm going to zero out the scale.
So okay one thing to mention, too, is to always close the lid on your body filler.
Sometimes you'll see guys with the stick sticking then sticking out of the lid the lids open,
air gets in there, those solvents evaporate. It'll change the viscosity of your filler so
make sure you close that lid. You also won't get any little dried out chunks or anything as well
or dirt in there, so close that lid. The other thing I like to do and especially in the summer
is I don't put my hardener right on my puddle. A lot of people do, but remember especially
when it's hot those chemicals start to kick right away and right under where there's direct contact
between the two it's hardening up you might get some little chunks in there. So I like to mix mine
or spread mine out here off to the side and then mix it together because you may not even use that
immediately, right? You might have to walk over the vehicle or whatever you're doing. It's just
easier to do that way. So you can see what I did here is I put out 50 grams of filler
and then I put out one gram of the hardener so as close as I could possibly get you can see let's
see the scale moves just from the air, but that's as close as I can possibly get. Now you see I did
a little thinner bead on this one than I did on this one here, thus it's a little bit longer.
So you can see there's a little bit of difference. So again, you're just getting that range so you're
not wildly off of the the mix ratio so that's your two percent. So some guys might mix up a lot of
body filler like i've seen in bus or truck places where they mix up a quart at time. How how do you
know what two percent of that is, right? Very difficult to do, so if you mix a lot of filler
that would really be important to check that mix ratio make sure it's okay. So again you can
always after you're done draw this out see what it looks like, hang this up you know by your toolbox,
whatever, use it for a reference but that is going to help you identify again whether you're
way off or if you're in that ballpark and again especially when you get that temperature change.
Okay now we see what our mix ratio looks like here and again keep in mind
you could adjust that slightly, use a little bit less in the summer,
a little bit more in the winter, but stay between at one and a half percent to under
three percent range. There's some bad things that can happen with too little. Obviously
it will never fully cure and harden the way you need it to and then with too much you can get
air pockets, you can get staining and all kinds of things, even bubbles behind it from the heat
if it's way over catalyzed so that's why it's important to really understand that catalyzing
and have that ratio fairly close. I'm going to mix this up and I'm going to show you a couple things.
Notice that I'm going to mix and not stir and I'm going to keep flattening, and as i'm flattening
I'm pushing all the air out at the very end I'm going to spread it all over my board very thin
so that I get more work time. The thinner it is, the less heat buildup you get. If this is in a
massive glob it's going to heat really quick and kick fast but if you spread it out all over your
board you'll have much more working time with it, so let me show you what that looks like.
So as you can see I've got it all flattened out and you can see that you could see pulling and air
pockets until I flatten it out. Now all the air is out of there and it's spread out thin where it's
going to take much longer for those chemicals to kick and start curing. That'll give you more
time to get to the vehicle spread, it on the car, and not have it harden up while you're working.
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Thanks for joining me again. We'll see you next time.
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