Tech Tips: The Do’s and Don’ts of Body Filler
Tom Cornelius, 3M application engineer, shares best practices, tips and tricks for mixing and spreading body filler.
Important notes (00:24)
Wear proper PPE: safety glasses, protective gloves, respirator. This video is intended for a professional setting such as a body shop or paint shop.
Step 1: Clean thoroughly (00:40)
Use soap and water as well as a solvent-based wax and grease remover.
Step 2: Sand with 80 grit on a DA (01:14)
Sand 2 to 4 inches beyond the damaged area down to bare metal.
Step 3: Remove pitted paint at center of dent (02:08)
There are a few options for this, but a handy tip is to use the 3M™ File Belt Sander.
Step 4: Reclean the area (02:42)
Again, use a folded paper towel and a solvent-based wax and grease remover.
Best practice: Apply body filler quickly after cleaning (03:27)
Apply within 30 minutes for steel and within an hour for aluminum.
Step 5: Mix filler (03:41)
Only use 3M™ hardener with 3M™ filler. Make sure to knead the hardener and use the correct amounts and proportions to get a 50 to 1 ratio. Fold and flatten instead of stirring, which can introduce air.
Step 6: Flatten body filler across mixing board (05:42)
This will force out any air and extend work time of filler.
Step 7: Apply filler (06:08)
Start with a tight coat and follow with thin build coats. Let cure, then sand.
Best practice: Do not exceed a quarter-inch in any single application of body filler (07:08)
This is to avoid air entrapment and other issues. Refer to your OEM recommendations for more information.
Best practice: Use a mixing board (07:28)
Cardboard and other substrates often have contaminants like wax, fibers and inks, as well as grooves that can cause air entrapment.
Important note:
There are of course many factors and variables that can affect an individual repair, so the technician and repair facility need to evaluate each specific application and repair process, including relevant vehicle, part and OEM guidelines, and determine what is appropriate for that repair.
Products used in this video:
3M™ File Belt Sanders for Body Repair
www.3m.com/3M/en_US/company-u...
3M™ Cubitron™ II Hookit™ Clean Sanding Abrasive Discs 737U
www.3m.com/3M/en_US/company-u...
3M™ Platinum™ Plus Filler
www.3m.com/3M/en_US/company-u...
3M™ Cream Hardener
www.3m.com/3M/en_US/company-u...
3M™ Disposable Paper Mixing Board
www.3m.com/3M/en_US/company-u...
For more advanced tutorials, check out 3M Collision Repair Academy
www.3m.com/3M/en_US/collision...
You’ll find courses that will expand your knowledge, deliver practical procedures that you can use right away, and, in many cases, earn you I-CAR credits.
Safety and warranty information
www.3m.com/3M/en_US/collision...
Website: www.3MCollision.com/
Instagram: / 3mcollision
Facebook: / 3mcollision
I learned a lot from this, thanks guys.
Thanks for posting, using this info soon to help out some family.
Amazing techniques
As a subscriber, I would wish the video could extend passed the 8 minutes, even with some of the younger generation has the attention span of a “Moth on a hot Light Bulb. The reason is, sanding and the squeeze bottle of product sitting right there. Show what grit you start with, it can be sped up and played fast, but go to the next grit. Stop, get good light and a tight shot on the repair. Let’s say, no air bubbles or defects, perfect. Introduce the next product as if we where moving along, trying to get the repair cured as a tech goes to lunch. Use the squeeze bottle that I guess is a polyester fill to cover finer sand scratches, needed or not. Lightly scratch the repair as if there was a defect in the patch, mix the other product, clean with air and tack rag to remove dust, apply it. Kill the camera and finish with a short-stroke palm sander DA 3/16” orbital action and some 320. Gee, you missed an opportunity to get a repair from fill, build, get close and perhaps reach a point to open the door for a high build, straight primer or epoxy for corrosion protection. Then mention the different path a tech cabin go if the job calls for it. There, you go, 11 minutes. Was that so bad? Even for video on filler. As Joe Biden said “Come On Man!” ASE Master Tech 1978 + L1 and paint & body DIY.
Came here to learn something. I did. D G is perfect and doesnt have to watch these videos, but he does.
As one who worked at a German car specialist body shop I can tell you once knocking down the 1st coat of bondo you need to come back with ever coat putty and overlap the paint by a 1/4 inch the Preppers will never feather the paint out properly
Why is it necessary to have that irritating background music? Informative video, thanks.
Makes the bondo stick better
What I wanna know is why all these bondo instruction video people use SO MUCH bondo for such small demonstrations
@@johnboysautobody4214 to make you buy more bondo
Its cool
To get comments. Rank higher in the algorithm when people comment. Whether it's a complaint of a compliment
Wasn't expecting to learn anything new here... But some good tips!
I love that yellow filler. I sand it just before it's completely hard so as not to dig into the surrounding primer after the first coat. When it's hard though it's tough. It doesn't clump up on the sand paper like the pink stuff does.
3m platinum Select ! My favorite filler of all time !!
10-4
me too!
Z-Grip
You did spread the filler even across the board, you even mentioned there was two reasons for this but…. Never spoke! #1 An even spread allows for even spreader pickup amount, making application more controllable! #2 Catilysed filler produces heat, an exothermic reaction. Spreading it out helps keep this reaction slow down allowing for more time to apply without getting chunks, dragging harder material into a smooth fill and waisting product! (How Did I Do?) I am a retired auto repair tech, but learning never stops and products change along with best practices. There is no law on KZhead keeping videos to 3-4 minutes. An explanation is great but pictures (Video) is worth a thousand words. I am subscribed but can’t afford everything 3M offers to do my old pickup! But knowing what’s out there allows me knowledge to spend good hard earn money where I need it. Not so much on other things like spreaders. The putty boards are nice but I use a glazed floor tile I epoxied onto a cut plywood with hand-holes 1/2” larger than the tile. Bright white and super flat, work great but it has some weight to it but I have portable SnapOn roll carts and seat foam to adjust my position to a comfortable height as I am 6’ 3”. If you are comfortable, spreading filler or sanding allows you to focus on the task and not a sore back. Please send an email when 3M Elbow Grease becomes available! No charge on the tips 3M. Send my $100 credit voucher to DK, Omaha, NE. Thanks
He did mention the two reasons lol
@@jonathanyates5198 Yes, but what? Help remove air bubbles and extend the working time of the filler. No mention of why, air bubbles obvious, but no explanation of the chemical reaction called exothermic reaction, reducing the heat build up as a thicker pile on the board would create. Don’t say it, don’t spray it, explain it. Tight coat? Tight like torque, pushing down tightly? Don’t say it, don’t spray it, explain the introduction of the plastic talc-filled resin catalyzed with methyl ethyl ketone peroxide, perhaps at slight different ratios within 2-4%. The lack of explanation is fine with those that already know, don’t know yet want to learn and don’t care! It adds up! Explain “Tight Coat”! Explain introducing the chemicals into the pores and sand scratches left by the 80 grit. Let see you stand for 3:40 minutes in a room with over 100 service tech with a lame book & Power Point presentation and explain “Advanced Charging Systems” with up-integrated control software and why. How about 7 types of GM serial data systems, how it works, what is looks like on a DMM or O-Scope and diagnostics. How about 4 hours of liquid / gaseous hydrogen fuel cell vehicles with De-Ionized water used to cook electronics, voltage produced and the four other proven types, that happen to be stationary not mobile! How about 3 strategies to detect ethanol in the fuel from 0 - 85% and how to detect it with special tools or not! Let’s see, oh 26 others! Which ones have you done? And no, he did not speak…as to the reason why! Do it right or leave it out because some actually like to learn. Teach voltage drop? What is a sensor’s reference low mean and the industry standard “Max” for voltage drop on this circuit and under what conditions. What does a PCM do, during the first 4 minutes after starting? What type of test is it called when air temp & coolant temp are within 10 degrees F upon start? How does the PCM check a “EVAP” system purge solenoid with out turning it on at idle? Did you pass the 100 questions given on the “L1” test to achieve emissions certification? Or “P2”? No. I didn’t think so. Sorry, but study and learn, someday you too will get there! I did.
Even he mixed more than he needed! So it's not just me then.
Yes, WAY more than he needed. I was thinking that exact issue myself.
He reminds me of "Hi I'm from head office and here to help you"! Surprised 3M would use such a novice.
Looks like my man knows what he's doing to me.
Well, if I was a company selling body filler, I guess I might show a lot of waste too. It's like the toothpaste commercials that show probably 10x as much toothpaste as is actually recommended.
hes a engineer thats why
very informational
Thanks very informative 🤙🏾
Great video nice and perfect 👍 10/10
I've never done it. But I know it when the reasoning takes me there before I screw it. I did the global journey on this subject on KZhead . This is the first video to mention where serious attention to technique has an important role. 4:50 shows the techniques of mixing: "fold and flatten" the body filler-hardener mix - NOT stir it in order to avoid-air pockets in the mix. 7:39 Raises the essential point of using a 3M mixing board not cardboard for mixing. Because of cardboard's surface contaminants. As a rule, the “people” that make the “stuff” know what it can do and how best to use it. Many thanks.
Ive had a bondoboard made out of card board for about 3 months now, the thing weighs about 4-5 lbs
@@andrewjefferys443 Great! In a year and a quarter it won't weigh more than 20 lbs. With continued use and this "linear" accumulation of hardening Bondo residue, however, at some point the cardboard will stiffen and possibly crack under its own weight. Not knowing exactly how much the Bondo-cardboard will weigh by then, might just save your life.
The music is like on mad max. It sets the anticipation level.
Easy and excellent demonstration, thanks.
excellent demonstration with the best materials in the automotive market
thanks ranga
Good video, clear explanation of what to do and why not to do. Only minor negative is the excessive amount of product recommended for such a small application resulting in more product wasted than actually used. Most people should figure out quickly how to estimate the amount required.
💥 183 Bondo videos and I STILL haven’t heard anyone mention how long to wait until you sand…!! The search continues for complete step by step usage.
That depends on how much hardner you put on! Usually I wait around 10 minutes because if you wait too long it kinda gets way too hard and also you have to let it dry enough so its sandable, with a little bit of practice you will find the perfect point to sand it. I like to start with 80 grit sand paper, when the panel is completely flat i block it with 180 and i finish with 240 before primer, 3 coats of primer and i block it with 320 and finish with 600 grit. I dont recommend lacker primer it wont fill good.
@@jvanpr3563 Thank you for this and also mentioning to not wait too long to sand it. I did not know that was an issue.
Application engineer. thats hilarous
Yeah lol such a technical position title for someone who...What, engineers mixing plastic/hardener n also how to spread it over the dented area?? DEF need a scientist or an engineer for that one, Bro..yeah Lol or at least for sure 4 years of college n a degree to prove you're capable of such an advanced topic! Lol yeah man, I ageee - it is hilarious. xD I work with this every day n have never been schooled on it, nor do I carry a title for it. I just work at my Dad's body shop.
thanks
Is tight coat just applying more pressure?
Quick tip but when mixing up filler, always mix up less than what you think you need, if you need more that’s ok it’s better to have less than to have a good 1 or 2 wipes being wasted.
So wich is better? 3m or bondo?.i know both have been around for a long time. I'm about to do allot of body work on my truck to get ready to paint. Just curious if anybody knows if ones better than the other?
Please can you list the tools used in this video.
To clarify do you let the tight coat set up prior to adding the filler coat? Or is the tight coat done with more pressure to ensure a tight bond and then immediately followed up by the fill coat before letting them both harden?
Definitely let first coat fully harden,and cheesegrate it AND sand it before applying further coats ,super important when using a fiberglass basecoat of filler,I just recently saw a PrOfeSsInAL guy put filler over a Duraglass base without sanding it at all on a major restoration if that guy did that crap in my shop ,his tools would be on his truck before lunchtime
@@jeffrogosz9995 if you cheese grated at my shop you'd be out the door by lunch. Cheese grating means you applied wayyyyy to much filler
Shit I've been stirring thank you great tips
Which type of respirator do I need? Would N95 or P95 be ok? Thanks.
The respirator is only really there for dust so an N95 or equivalent disposable would be suitable but a replaceable filter mask is better for long term use
I got a question I sanded down my fender and applied bondo to fill in some spots. After sanding down the bondo. I applied 2 coats of sanding primer and now I have what looks like little bubbles but they feel smooth. Question will It show in the paint job?
Hell yeah. You need to sand it smooth and prime again. Make sure your surface is clean to help prevent that. Rubbing alcohol is handy to use and cheap
Its satisfying watching people mix Bondo body filler . I can careless what his advice it's prolly really really strict about this stuff nothing personal I know this is all your job bro. Gr8 vid
Absolutely horrible grammar
I can’t believe how long he stirred that filler and it wasn’t locked up after he messed with it and talked about it. Then again, my shop is 90F or higher right now lol
So many debates over this. Just got off the phone with Tamco they said no filler on bare metal creates heat then condensation on metal and to put over there DTM high build 5310. I do not need epoxy if car is inside all the time it will save you a lot of money just block and top coat your done and still have epoxy properties in the DTM. #3mcolisionrepair
I love the concise presentation.I often see people roughing down filler with a cheese grater type file before the filler is fully cured.Isnt there then a risk of pulling the filler away from the base metal? I suppose with experience you would be able to gage the sweet spot in cure hardness.
I just use a 40 grit on my da for the big damage jobs, it takes the first layer off like nothing. Just avoid the sheet metal as much as you can to minimize deep scratches.
What about rust? Real world applications like pinch weld in a windshield it’s impossible to remove all traces of rust without demolishing the whole window. Can we treat the rust with a rust converter phosphoric acid or treat with POR 15 encapsulator before Bondo?
Por15 is hard to sand. Best way is to grid blast the rust and then 2k epoxy primer
Use a fresh clean spreader to apply filler, the spreader you mix with can have un-mixed product up high near where you hold it, an gets on your repair at the top of the layer as you get to the end of the wipe.
Oh please
"and" not an!
I like to use a 3 inch putty knife for the mixing and a clean spreader for applying...
I like to use a dirty speeder and a bowl.
Someone needs to teach 3m on how to use their products
6:44 whats the build coat?
So you mix up 3 times more filler than you need then?
How many of you are like me and do a half ass'ed job on everything you do. Realizing it after watching a video on how it should be done. I leaned about deburring copper pipes before soldering the other day. After time the water travelling over the burr will create a pin hole a cm or two past the burr.
i just did a shit job on bondoing my truck and as i sit down waiting for it to dry i think to myself "hey why not watch a video on it?" now i learnmed about 50% of what i did was wrong...but hey at least its only the farm truck right?
@@sockpuppets7256 how's it holding up?
I would like to know who is working that way...
Filler on OEM finish?
That was a LOT of body filler for that tiny dent!
What is the point of cleaning it really well when you're just going to make more dust isn't that kind of like wiping before you poop
Worth time, Solid methods, Well done. Time well spent listening and visualizing work while instructor Tom added key details like a) clean grease and dust b) sand on and outside repair area; don't apply to body paint c) clean again / wipe off dust => ratio = 3-inch product to "1" hardener bead line --> 50:1 d) use a quality mixing surface to avoid cross-contamination like cardboard particles, ink, other dirty surfaces contaminants vs use of a quality mixing surface =>fold+ flatten, not mix and stir, ~1 to 1.5 minute => mix & stir = air bubbles = issues => flatten thin on mixing surface = increased application time > 1st pass: thin product and press hard to get into defective area >> 2nd pass: add more to complete necessary fill >>> final pass: steady stroke to help leave smooth thanks! ~isntructor.brian
For the wax and grease remover, I just use isopropyl (91%) and it works great
9% water
@@hotrodray6802 Good thing. Can bind proteins and aid removal, with an adequate cloth. Reduces volatility.. Edit: Plus alcohol evaporates the water, pretty sure..
I use acetone myself... Never ever had any issues. Probably acetone in the spray can. IDK
Panel wipe
I use spray way glass cleaner and microfiber rags only no wax and grease remover
What temp are you mixing and applying in
In this video the temperature in the shop was approximately 70 degrees Fahrenheit.
Will brake cleaner work for cleaning?
Just by a decent quality degreaser they sell it at Walmart for a couple of bucks, bake clean can cause weird break down of the body filler and paint in the future if you don’t get rid of all of it.
Of course he's going to use the file belt that most of us don't have. Nice video though
They're not expensive. If you can buy these 3m products you can buy a file belt.
I'm just a simple do-it-yourselfer work on my own stuff.. I have taken three cars down to bare metal 74 CJ5.. 67 and 70 Volkswagen. All three cars had Bondo on them. The Bondo was applied to bare metal. Every Bondo patch that I removed had rust underneath. Everyone!... So I looked into this because it got my curiosity... And I found that when you apply Bondo directly to metal the Bondo heats up in the curing process.. this causes condensation or sweat in between the Bondo and the metal. So before you even start to apply paint or primer... It's already starting to rust. What say you?
I've never had such a problem
Most likely who ever fixed the cars waited or drove around with just the Bondo and even primer is not water prof, you have to paint it and not have any water over the Bondo or primer or they wet sanded the Bondo or primer, when primer is applied it is some what water resistant BUT as soon as you sand it it will absorb water like a sponge, how ever you can wet sand primer if it is applied over paint, you just have to let it dry completely...
didnt learn a thing , big reason we dont use cardboard is the resin soaks into the cardboard ruining the mix ratio
Why did you wash the panel BEFORE sanding it?
So you don't take the dirt and grime and wax and tire dressing and silicone and smear it into the panel you're about to sand and put body filler on.
to remove wax and grease
use glass pieces to mix body filler
are you the same guy trying to mix filler in the DMS video lol
I think he really works for Charmin
why sometime body filler can crack after several years
What is the product no. Of the yellow body filler
Hi, the product number of Platinum Plus filler (Gold) is 01131. Please check the video description to access the product page.
Wasting sandpaper and ruining e-coat. I guess you missed the memo from I-car in the nineties that polyester body filler was reclassified as a paint product able to to be applied over other properly abraded paint products.
I was wondering why pin holes develop, ,now I know not to stir it .
Would have watched it why why the rock music ??
What's the maximum thickness for applying body filler?
He says at the end that they don't recommend over 1/4" of body filler in a single application.
do light coats always, more coats the better
After watching this I can consider myself a noob
a simple plain piece og plexi glass or car door glass
An onion board makes cleanup easier though, just take the top sheet off and boom clean surface.
Why clean it before you sand?
Because that way , you have to clean it again. 🙃 😒
You mean you don't wipe before you dump?
So you're not moving wax from the painted surface onto the metal you will be applying filler to.
To not contaminate the work surface
Epoxy? Not Epoxy? Body Filler goes on bare metal?? What about corrosion protection?
Essentially all body fillers are polyester. Epoxy is too hard and does not sand well, plus triple the price. Some people prime first with epoxy and put filler over that, but the advantage of putting filler on fresh sanded metal is the tooth in the metal gives much better adhesion for the filler. The layers of primer and paint over that will keep corrosion out, and one of those layers might be an epoxy primer.
@@DNomer not sure what epoxy you've been using . epoxy sands very easy
Everybody puts epoxy on first today. You still sand it. Most quality fillers will adhere to it just fine.
Well i figured out what ive been doing wrong. Couldnt for the life of me figure out why their was pin holes
Why in the world would you degrease the panel before even sanding?
Because grease or oils can get in your sandpaper and the sand dust and get spread around and ground into the metal. The one that has less relevance is the degrease AFTER sanding. You need to clean it, though, and it might as well have degrease capability while you wipe it off.
Also why in the world whould you wash your hands after eating hhat greasy pizza after lunch?
@@DNomer also the abrasives last longer when you have a clean surface
I enjoy learning the repair steps but why the crazy music?
The Bondo God says directly over steel!
This guy would get sacked putting filler in like that 😂
YOU remind me of every bad teacher, I have suffered under. Indeed as most of the comments suggest, Mr Arrogant.
umm... sand first, then clean and apply, no ?
I wonder it video is for the benefit and education of the viewers or is it to garner more sales. I’m really particular on my bodywork .I even cringe at touching the panel with the same glove that handled the (oil contaminated) d/a (compressor and tool lube oil) I’ll stick to using a free piece of sheet metal and putting filler over epoxy primer (even though I know it’s compromised and lacks critical ingredients that now makes it’s use a gamble)
please sir toking typing transparent
My boss would cut out my paycheck if i use that much filler for a lil dent hole :))
1/4 inch thick ..... 😱😱😱😱
Pretty big window before the bondo dries. Just saying
mask ✔ safety glasses check ✔ gloves check wet suit check ✔
whats up with that filler at the end... it was turning black 8:19
Dry guide coat
@@skippy075 i was thinking that... maybe .. but we never saw him apply that.
Dry coat applicator is on the bench next to him... They just didn't show it...
The music doesn't fit with the video.
Drop the music.
By the book for sure, but we know that If we sit and do this, paper towels and all we will make no money ;)
Body filler on bare metal is a big NO.. etching primer or anti corrosion primer first before body filler
that's 75% more hardener I've been using. very interesting...
You've not been using enough
really dont need to be serenaded with music when learning........
paint stick in the bondo can is an amature move
hmmm no epoxy primer down first to help with rust and corrosion? Body filler cataylist contains bonzol peroxide that can cause a rust problem on bare steel. Epoxy primer provides that moisture barrier and body fillers adhere extremely well to epoxy primerr. Epoxy primers do not lend them selves well for production shops and a drying time is needed....just my thoughts on the subject.
Is ok to use zinc primer first then body filler. I'm covering treated rust.
So to do this work I need $765 worth of 3m products and tools lol
👍 🏎
Think you got enough filler there buddy?🤪
This guy sounds like jason sudeikis lol
I dont need a shop to do this I'm 18 at my house working on my 32 year old car lol
Jeez how much filler for a pin dent!!!
crazy hey! what a waste
Good video but why the stupidly loud music?
Why does everything have to have a soundtrack? It feels manipulative. I just want info, not infotainment. Good info, BTW.
Dumb background "music" Maybe some repair shops play this kind of sound.
Thought filler wouldn’t stick well to shiney metal?
it was sanded with 80 , not really shiney
So much filler for so tiny dent .
Can you pass a fit test with that fuzz on your face. I had to shave to pass, and the mask so tight that my eyes bugged out. Good information, but when you are the experts, you need to dot all the “I”s and cross all the “t”s.
Oh please