Mark Simpson

Filling a Dent

Mark Simpson
Duration:   12  mins

Description

Cars get dented, even classic cars. We’ll go step-by-step through the process of filling a dent, from proper surface preparation to filler application to final sanding. When done right, no one will ever know you made the repair.

Share tips, start a discussion or ask other students a question. If you have a question for the instructor, please click here.

Make a comment:
characters remaining

2 Responses to “Filling a Dent”

  1. Robert

    How do you know how much hardener to use? It seems like a lot of "by guess and by golly" To much and you are not able to spread it correctly. And I've always wondered if it cures correctly with to little. I see you use Sharkbite, most places sell Bondo. Is one better than the other?

  2. walter

    enjoyed the video - what brand is the sanding block you used - have been trying to find where it can be purchased buzzybtag@aol.com

A very Common process, you know, any guy who's going to restore a car, you know you're gonna to have to fill a dent at some point. And the process, whether you're doing a big dent or a small dent is all about the same, because you, you want to make sure that your body fillers are no thicker than a 1/4 inch tops. And I really recommend about an 1/8 inch. You don't want to go thicker than an 1/8 inch, because then you know, the thicker the body filler gets the more prone it is to actually fail. And the process to actually fill a dent is you know, pretty much universal regardless of you know, how big or the size of the dent. So let's, we've got one of our little donor hoods here. We'll, we've got a couple of dents up in the front here that we're going to, you know fill in real quick and show you the process of actually prepping the surface and filling the dentS and sanding them out. To begin we're going to get this area down to bare metal. One of you know, could use paint stripper. We've used some paint strippers and some abrasive fillers on this hood before. This is a paint and rust removal disc or prep disc and its made by 3M. This one in particular fits on my, my polisher and does a good job of getting the paint and the surface ready, getting the paint off and the surface ready to accept body filler. Before I get too far I should probably put my safety glasses on, always a good idea when you're, working with flying material. As you can see, the abrasive disc has done a good job of actually getting in and getting, you know, not only the the paint and the primers off, but also prepping the surface. You can say, you see the surface has a little bit of tooth to it. And what that does is it creates a good place a good surface for body fillers to actually attach. It's important to recognize that body fillers, and primers, and paint, not only adhere with a chemical process but also a mechanical process. So you want a little bit of tooth to that surface so it's got something to stick to. We're gonna kind of work this little spot here and see if we can get some more of that paint out of this dent. On this particular hood or on this panel we really can't get to the backside, so if we wanted you know, take these dents out there's it's a solid double panel here. So, you know, we're in a case where we could, you know you could, if you had a stud welder, you can, you know weld studs under these and pull them out. But really they're not that deep. So we're going to just go ahead and fill them. With the surface prepped, we'll just get the body filler mixed up, and we'll get that filled. Once we have the filler mixed up. And much like mixing it, you want to kind of pull the body filler in one direction. It's when you start like going back one way and then the other that you start trapping air into to the body filler. And I never assumed that, like, I'm going to get all of the body filler I need in the first batch. Most cases you'll find that, you know, it'll take you a couple of rounds before you have enough filler in there to complete the job. With that we'll wait, and then soon as that hardens up, we'll be ready to sand. Okay, we've waited about 15 minutes and now the body filler has gotten hard enough where we can actually sand it. To sand it will be starting because it's just a small area. We'll be starting with an 80 grit paper. I prefer to use a hand sander. They do have, you know, in line pneumatic Sanders I find you get in a lot of trouble real quick with those. And also a DA is not a, you know, while it does a good job at removing a lot of filler in a hurry it's not a good tool to actually block out and get this surface smooth and flat. So I really encourage you to get a good hand sander. I prefer a stick it or hook at ones where you can like you know, use the paper over and over again. Or if you want to switch to a lighter one you can do that pretty easily. Again, it's you want to get, you know it's a staple of doing any body work. I do probably 90% of my body filler leveling with just this sander. And to start out, we'll go at like about a 30 or 45 degree angle and then we'll come back and we'll also come across in just the opposite way in a cross hatch. Okay, you can see that we've made some good progress on getting these dents filled. There's another dent up here that apparently we're starting to fill too, this hole. This old demonstrator hood here has got a few dents all over the place. But, like I say we've made good progress, but you can see even though we've like filled it and sand it we still have a few spots that are actually lower than the the areas we've sanded. So we need to apply another coat of body filler bring these areas up, and we should be able to get it on the next time round. And that should get us close to being done there. We'll let that Bondo sit and sand it off, once that harden. Okay. We've now waited at least another 15, 20 minutes and our body filler is hard again. We're ready to sand off the second coat. Again We'll go in a cross hatch motion and keeping the trying to keep the, your body, body sander as flat on the surface as possible. You know, the hood itself has a little bit of a crown so you want to work it back and forth. You want to try to bring down the whole circle. Okay, if you look the we've got these, the dents we were working on are filled really nicely at this point. We're gonna next follow up with some light grade paper. There is still a dent here, but this isn't one that we picked out that we were working on. Like I said, this, this whole hood got more than a chair of dents, been in a few hail storms. So we're going to follow this up now with follow the 80 grit up with someone 180 grit, and bring this down a little bit closer. Again, we're using sticky type sand paper. We can get it on a roll. The well there's the 18 inch sander. You can get Sanders, you know, much longer. I know the guys that like sand on boats and stuff like that. They'll even custom make their own and have like a four or six foot long sander. And then you can just use the roll sandpaper to the, cut that to the Length you need. Now that we're happy, we got that with the 180, We'll finish up, With some 400 and we'll be ready for, take this to primer Again continuing to work in a cross half pattern. That is real good right now. Okay, We've got this all prepped and ready. We've taken the dent, then we've prepped the metal beneath it, filled the dent. and then block sanded it out. If we're gonna say that, we're gonna complete this hood. We'd next take it to a primer surfacer which is a heavy primer. And then after it was sprayed with the heavy primer surfacer, again we would block it out. And we may apply two or three coats of primer surfacers, until we got, we are sure that we got every last defect out of it, but from here, she's ready to go.
Get exclusive premium content! Sign up for a membership now!