The Stovebolt Site Forums The Shop Area Paint and Body Shop Removing filler?

When working on a fender or other such body part, that has been previously repaired inadequetely with filler, how do you remove the filler to repair it properly?

Is there some fancy product you can use to get it out of the places where some dork filled in deep cracks and crevices that should have been straightened out better before finishing with a filler?

Just one of my wandering thoughts.

Thanks, Jeff

Not an expert here, but I have done my share of bondo removal and pounding metal. Most of the time if you have access to the back side of the dent you can tap it first. This will release some of the bondo making it easier to remove.

After the initial pounding, I use strip-it type disks for removal of everything including bondo. This allows you to go directly to the metal without destroying it. They are available on-line and swap meets too.

I am with you though, I don't understand why someone goes through all of the trouble to fix the dent with bondo, when with just a few minutes of hammer and dolly work you can have a near perfect surface and with experience you can have a perfect surface without bondo.

A stiff wire brush on a dotco (right angle die grinder) would probably do the trick. For that fact a regular die grinder would probably work OK. After using a dotco for 30 years I'm kinda partial to them.

I have been using a heavy duty knotted wire brush about 5" in diameter mounted on my 7" Craftsman sander/polisher. It works great, but dust is EVERYWHERE. My shop is a one car garage in the basement, which is where my indoor fan unit for the heat pump is. I have been having to change filters more often than usual. Wish I could take it outside.

I have been using a heat gun and mini pry-bar, (screw driver) for years. The heat gun softens the bondo making it easy to remove. Then I use a wire brush by hand to get the remainder out of welds and crevices. Makes less of a mess than grinding it out with a wire brush or paint stripping wheel.

Interesting...

My concerns werent for the skim coated areas, but those 2" deep or more hidey holes where some [censored] used the whole can.

Thanks!

I won't tell you about some of the "repairs" I saw back in the day when I spent some time working in a used car body shop.

C'mon Tiny, try me!

Ive hardly dealt with body work, but I remeber looking at my first truck to buy at about 16-17. My dad came out and picked up the hose and sprayed her down. He showed me how much bondo was all over that truck and we walked away very quickly!

I bought a set of SCRAPERS from HF and chip the stuff out with them and a hammer... and trust me, I've got bondo.

Woody, believe me, all the bondo is here, or at least several gallons of it I'm sure

places it's quite thick chiseling works OK [I use an old wood chisel], but when it's spread thinner over a wide area, turning it onto dust with a knoted wire cup on an angle grinder is really the only way makes ya glad ya don't do it for a livin

Bill

For the thin stuff and paint I use one of THESE but the ones with an arbor that you can use in a drill motor. I also have one of THESE which I highly recommend. I've used mine to strip my hood and front fenders down to the bare metal... on one disk.

Its been my experience that someone who would gob on a load of filler without first at least trying to hammer and dolly the surface close to original probably didn't spend a lot of time on surface prep before applying filler.
If you can remove the panel and work on a bench, or have access to the back side, a rap with a hammer from behind will usually pop the filler, or at least send the sheet metal back toward original, leaving broken edges of filler you can get a good thick scraper under.
While it amazes me how much backyard band-aid bodywork goes on, the great part is.. its usually easy to remove.
As a last resort I have used an oxy-acetylene torch to heat and soften filler making it easy to scrape. Standard open flame precautions should be followed.

not always the case Edge - lots of situations when it's not possible or cost effective to get at the back of a wrinkled panel, especially on a commercial vehicle like these trucks or my bus, but it hasta be made presentable to continue in commercial use ... the thickest areas of filler on the back of the bus were very well prepped to clean metal, and the filler is tight enough after years to hang on in spite of hammering .... also using heat is a very slow process ... unless ya wanna set all the paint on fire to heat it all at once

Woody - paint stripper takes care of everything down to the skim coats, even softens that in some areas and no dust ... THE tool for cleaning everything off down to shiney metal is a mop disc - available [here anyway] in depressed center discs for angle grinders and Rolocs for die grinders - works wonders


Bill

OK, one of the more minor examples: A '64 Impala with the RF fender caved in behind the wheel. The bottom of the fender was shoved in about 6". No damage to the rocker panel. My boss did the "repair". No jack or hammer work at all, three gallons of plastic later & a good 5" to 6" depth of putty and the fender is ready for paint. Real quality work there.

Bill,

I agree, throwing down a coat of Aircraft Stripper will get you a good head start. That's what I did with my hood but still finished up with my Wagner.

You aren't the first person to snicker at that little tool but I like it. It's light, you can hold it a couple different ways and it gnaws through paint and bondo like a termite through balsa wood. It uses the same 3M disk you can buy for use in a drill motor... and those work good too until you get into real tight spots.

I have been tempted to try one of THESE. Have you ever tried those?

yes, see your other thread - I've tried everything available for the Roloc pad I have for the die grinder, including those bristles - what works best [aside from the mop] is the burnishing discs similar to the 'clean & strip' or your 'paint eater' but finer. and I've been using the medium and fine ones after the 120 mop - ready for first finish

I'm hoping to strip the elephants butt tomorrow, maybe Ill be able to get some sequential pics - I'll do something with the bristle pad I have too

Bill

Thanks Bill that's good to know. I used to use the Rolocs back in the day... I'll have to look into getting set up again.

BTW, da bus is amazing... I couldn't imagine having to face that much work. It's looking great!

Hey there Woody, you say you did buy one of those Wagner thinies? It looks kind of awkward, no? I've always been kind of prejudiced toward Wagner ever since they started peddling that Power Painter. I know they’ve sold a billion of them but everyone I know that bought one has had nothing but bad to say about them.
Before I sink a hundred bucks into a Wagner gimmick seems like it might be a better investment to put it toward a good 7” polisher.
Those knotted black 3m striping discs do work great. I usually do the same, i.e., chemical strip the panel before with Marhyde Aircraft Stripper then its just a matter of minutes to clean up a panel with the 3m stripper disc or Scotch Brite disc on a grinder or polisher. Still would like to know the process Curt used on his cab, that turned out slicker than snot. I can't see any paint or filler left any where on it.
Denny Graham
Sandwich, IL

Yes, I did buy one and no, it's not awkward in the least. Being able to hold it a couple different ways reduces fatigue and it's light weight and it didn't cost $100. I bought it with the intention of returning it if I didn't like it and it's turned out to be my weapon of choice for stripping paint. A couple people have PM'd me saying they bought one and share my opinion.

You should know by now that you and I have something in common... we think for ourselves. I use what I use because it works for me regardless of what other people think. But if someone offers good advice on something I know little or nothing about I usually take it. Everything that was done to my engine was done because someone with experience recommended it.

BTW, I wouldn't own a Power Painter if someone gave it to me... so we have something else in common.

OK, I did it! started on the engine door so I could use a range of things in a short period and take pics - there's a sequential album here - can view as a slideshow, or see individual pics in the album, which have notes added ... I found filler over paint can be removed with the stripper, but tedious and slow - I use PolyStrippa, cuz I have it - might be cheaper than stuff designed for aluminum, although I believe the chems are the same ... waste of time to try removing well applied filler from bare steel w/ stripper

Woody - spent as long with the bristle disc as the mop disc and hardly got past getting paint off ... it did cut the filler, but slow ... I haven't found anything it does well

spent about 2 hours on the hatch [including taking pics] and then about 4 hours to use the stripper on the whole tail [pics at end of album] - would have worked better except the constant breeze dried it too fast .... ready for the wire wheel and big mop disc tommorow [prolly], which I expect to take another 4-5 hours. and after patching the hemorrhoids, it's on to paint prep

Bill

I got the hundred bucks from the link to Northern Tool, it was priced at $89 plus S&H.
Now don't cha go takin me wrong here Woody, remember I got me one of those TSuppy gravity feeders out in the barn I've yet to try. I might just go look at one of those Vagner's next time I go into town.
Denny Graham
Sandwich, IL

Bill, Very informative series of photos with explanations. The bristle disk looks like it's off my list. I think that I'll take some time to strip a portion of my cab with the Wagner just so you can see how it works and how fast it works. But instead of big chunks I'm going to wind up with dust and I don't have anywhere near the amount of surface to strip that you do.

Denny, I got mine at Home Depot and it was $79.95 plus 7.5% tax... and that price includes a $15 disk... which lasted through a hood, two front fenders and most of a gas tank, which I forgot to mention earlier. It would have laster longer if I hadn't loaded it up with the gooey paint on the gas tank.

I found that being able to hold it with one hand came in handy on several occasions when I had to use my other hand to hold a part, like when I just laid my fender on some saw horses.

Here you go... Four minutes with a Wagner Paint Eater. PICTURES

I didn't rush to get a false result. I did this at about the same pace as I would any time, and I even did a little touch up to make it look pretty... and I did it using one hand to hold the part and the other to run the tool.

I also included pictures of the disk I ruined by stripping some kind of gooey paint off THIS TANK. If I hadn't messed up the disk I know I could at least get one more fender out of it.

That's at least three fenders, a hood and a gas tank for a total of $15 in consumables. DISK

Oh and BTW, if you order on line they are on special until 8/31 for $64.99. HERE

yeah, but where's the rivets? ya ripped the heads right off!

it does look to do a good job, although the one-hand part isn't unique, I regularly clean small parts with the die grinder while holding them, right down to bolt heads

the Roloc discs don't maintain their aggressiveness that long, but contrary to Brads[?] suggestion in the other thread, I've gotten hours out of'em, and coarser last longer ... but sometimes there's too aggressive, I had to be careful with the big mop discs on the aluminum roof, although at the same time the die grinder mop worked a treat to do the smoothing on new aluminum welds, almost to a polish

I've got the die grinder, and it does lots of jobs well, so I use that and spend on the consumeables rather than more special purpose tools, too many already!

on another note, I put some more pics in that album [including one of the dust ] ... and interestingly, webshots sent the weekly hype this morning, in the first day for that album there was 125 hits! must be lots of bolters watchin this shop

Bill

Heat gun or torch, prybar and putty knife.

So what is wrong with a DA and 36 or 40 grit, aside from dust everywhere?

Bill, why are they called "mop" disks? I think I have some, but have never tried them.

I think I like the bristle disks for cleaning rust out of pits. They come in 3 "grits", but seem sort of spendy. A wire brush will do the same thing, but I hate pulling the wires from my feet just cause I walked in the garage in socks or barefoot 2 weeks after using one despite cleaning up really well. I've had them imbeded in my shoulder too after laying on the garage floor.

Finally, I'd guess if you can load up the same disk from Woody's Wagner, into an angle grinder it would work as well, just probably heavier.

It's usally not the outside surface that's hard to strip. The inside or underside of my rear fenders was a pain because of the shape.

nothing wrong with the DA and coarse paper, but I think the mop and wire brushes [especially] are faster and last longer ... called a mop disc cuz that's what it sez on the label some call them flap discs, but I think 'flap' really applies to the wheel type

speakin of spendy, and Woody's Wagner, I noticed at the tool place this morning that they had a 7" depressed center wheel that had the same coarse 3M kinda stuff as that Wagner disc - thought about trying it until I realized why I never had - the mop disc was $15, the 'stripper' disc was $25

and Builder - heat and a chisel is fine if you've only got a patch or 2 to remove, but pretty slow doing a lot, and like our Joker is fond of saying, time is money

Bill