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Using Acrylic Fingernail filler for bodywork


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OK, here's my first attempt at a tutorial here on MCM's forum, let's see what you guys think. This will be in three posts, due to picture uploading restrictions, here's the first post!

I use Acrylic fingernail filler almost exclusively for my custom work, for a multitude of reasons. It's incredibly strong, versatile, and impervious to stripping methods we use, unlike putties and Bondo. It strengthens the joints made when mating dissimilar parts together, can be used to create small parts, and after 5 years on my Concept Camaro (See my avatar), it shows no sign of shrinkage. The downsides are the smell, and it's very hard to sand compared to putties and Bondo. But with some practice on a scrap body, once you get used to it's application and sanding, you'll be hooked! This is a "beginner" tutorial on the use of Acrylic filler, hopefully I'll have an "advanced" tutorial someday!

1) Here's the basic supplies. You'll need Acrylic powder, Acrylic liquid, a real Camel hair brush, a bottle of Lacquer thinner (For cleaning the brush between applications), and some food coloring. Put a few drops of the food coloring into the Acrylic liquid to tint it, since this stuff is nearly transparent when it dries. The food coloring pictured works the best, but if you can't find this specific one, experiment for yourself. You'll also need some sanding sticks, 80 grit, 100/180 grit, and 240/400 grit work fine. All of these supplies are available at Sally Beauty supply (Or any other Beauty Supply store) with the exception of the food coloring.
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2) Here's an old body I couldn't get right using putties or Bondo, so let's apply some Acrylic filler to this troublesome old custom. That big gap and the seams will be taken care of with ease.....
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3) Apply some of the Acrylic liquid to the area you want the filler on to "prime" the area.....

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4) Dip the brush in the Acrylic liquid again, and then dip it lightly into the Acrylic powder. The size of the filler ball can be regulated by how long you leave it in the powder. The longer you leave it in the powder, the thicker (And larger) the ball of filler will be.....
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5) This is a medium sized ball of filler, ready to be applied to the body.....
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6) "Paint" the filler onto the area you want to fill in, getting it roughed in as best you can. You can always add more , but this stuff is a bear to sand, so you want as little excess as possible.
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7) Clean your brush immediately after applying the filler. Do this between every application, because if you put a brush with filler back in the bottle of Acrylic liquid, you'll end up with a bottle full of very thick, useless Acrylic liquid. This will also save you a lot of money when it comes to brushes, because if the filler hardens in the brush, you'll never get it out.
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8) Here's how the "tinted" filler looks after it dries. If you don't tint it, it's very hard to see, so unless you like eye-strain, tint this stuff!
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9) Our second application is done, now to do some filling of low spots....
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Edited by Custom Mike
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10) I'm going to apply a light "skim" coat over this low spot.....

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11) Once you've applied the filler, you can "thin" it out by applying more liquid before the filler hardens. Clean your brush, or have a second brush handy before doing this. Simply "paint" over the filler with more Acrylic liquid to get it smoothed out.....

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12) This part is now finished, and ready for sanding.....

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13) Here I'm filling in a seam in the license plate area....

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14) And the finished results....

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15) Now we're ready for some sanding, starting with the 80 grit sanding stick. This is one of the big advantages of Acrylic filler, it can be sanded in 15 - 30 minutes, depending of the thickness of the filled areas.....

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Edited by Custom Mike
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16) Here's the finished results prior to primer. Once you've roughed it in with the 80 grit, move up to the 100/180, and then the 240/400. You can use 600 grit sandpaper to get it really smooth at this point if you'd like.....
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17) And the completed area after the first coat of primer/sealer. Notice the "ghost" area where the filler is. This can usually be taken care of with a second coat of primer. Once the second coat cures, if the "ghost" is still visible, get some 600 grit sandpaper, sand the area, then re-prime. This should eliminate any signs of your work. After years of trying to do this one with various putties, Bondo, and just about everything else I could find, this one may actually get completed someday.....
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Edited by Custom Mike
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Both are about $7 each in the sizes pictured, and the powder will last for quite a while. It took me almost 3 years to use up the powder, but the liquid goes much quicker, about a bottle a year depending on usage. Don't leave it uncapped for long, it's just like Ambroid Pro-Weld or Tenax 7R, it'll evaporate really quick.

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Great job on the tutorial. Would have never thought about tryin that, might give it a whirl. We are in Sally Beauty supply from time to time stocking up on sanding boards, they work great on the resin and are about a third of the price there vs the hobby shop.

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Great tutorial!

It seems there's nothing that will dissolve the filler once it's dry. Have you tried acetone? I've never used acetone for anything, and I have no idea what it does to styrene. And I hate the smell of my wife's nail polish remover. So that's a big question mark. But it would be nice if there were something that would completely remove the filler, short of sanding it off.

It looks like it would hold edges - like panel gaps - very well. True? Have you tried to re-cut repaired panel gaps with a gap cutting tool?

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Great tutorial!

It seems there's nothing that will dissolve the filler once it's dry. Have you tried acetone? I've never used acetone for anything, and I have no idea what it does to styrene. And I hate the smell of my wife's nail polish remover. So that's a big question mark. But it would be nice if there were something that would completely remove the filler, short of sanding it off.

It looks like it would hold edges - like panel gaps - very well. True? Have you tried to re-cut repaired panel gaps with a gap cutting tool?


First, repeated trips into a brake fluid bath will cause pinholes, but will not remove it. I found this out after stripping my Concept Charger 7 times, the first 5 trips just removed the paint, trips 6 & 7 caused pinholes. I haven't tried acetone yet myself, I'll have to give that a shot someday. Second, it holds edges incredibly well, you can make gentle curves, sharp curves, or near knife-edge panels with it. Here's a couple of pics to show how well it holds panel lines, the first shows the area prior to the lines being cut (With the filler appearing as the translucent area), and after the line has been cut, with primer applied. The third is a shot of the panel I cut into the rear of my Concept Firebird, it's the lower line on the hatch.

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ConceptFirebird0014-vi.jpg Edited by Custom Mike
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...it holds edges incredibly well, you can make gentle curves, sharp curves, or near knife-edge panels with it. Here's a couple of pics to show how well it holds panel lines...

SamsDuster1007-vi.jpg

Wow, that is incredibly good. I am a total believer.

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Charlie, since this stuff is similar to a superglue, I'd imagine it could be used on resin, but I've never tried it myself.

Dan, I've made parts like the spoiler, and the entire panel between the fenders up front on my Concept Charger, but never tried casting parts with it, I've gotta give that a shot!

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Charlie, since this stuff is similar to a superglue, I'd imagine it could be used on resin, but I've never tried it myself.

Dan, I've made parts like the spoiler, and the entire panel between the fenders up front on my Concept Charger, but never tried casting parts with it, I've gotta give that a shot!

It works well for small parts with lots of undercuts (an Enderle barrel valve, for instance) because you can use a brush to get the liquid into the dead ends, then add more liquid, then the powder, more liquid, then powder, etc. to fill any voids as you go along. Give it a try, it works great!

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Great tutorial Mike, once again shows that if we limit ourselves to the hobby market we will end up missing great products.

I had thought about using this stuff a couple of years ago, went to Sally's Beauty Supply and bought the Contour sample/starter kit. It's been sitting on the shelf above the bench for at least 2 years, long enough for the super glue to now be a solid bottle.

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The kit is pretty complete with Primer, Sculpting Liquid, Sculpting Powder, Super Glue, Brush and a dozen fingernails or so. At $12.99 it's not a great investment in case it isn't what you hoped it would be.

IMG_3619-vi.jpgHosted on Fotki

Edited by Fletch
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Neat tutorial! :lol:

The only caveat I can see is that since it's so hard to sand, I'm not sure I'd want to put it on resin. Resin is "softer" thus will sand at a quicker rate than the filler. You'd end up sanding away more resin than the filler creating another problem.

Just an FYI! B)

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Bill, I've had very little experience with resin, so thanks for that little tidbit of information, you'd probably lose all the resin around the area you filled, so using it on resin would be a no-no! ;)

One question. You mentioned tinting it. Did you just add the food coloring to the liquid? Seems logical, but you never know.

Pete, I add about three drops to the liquid, shake it up, and it's good to go. I have tried another brand of food coloring, but it didn't seem to mix with the liquid as well, I had to shake it every time I used it. The McCormick "Neon" food coloring mixes perfectly, shake it one time and it stays mixed until the bottle is empty!

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Bill, I've had very little experience with resin, so thanks for that little tidbit of information, you'd probably lose all the resin around the area you filled, so using it on resin would be a no-no! :rolleyes:

Pete, I add about three drops to the liquid, shake it up, and it's good to go. I have tried another brand of food coloring, but it didn't seem to mix with the liquid as well, I had to shake it every time I used it. The McCormick "Neon" food coloring mixes perfectly, shake it one time and it stays mixed until the bottle is empty!

Thanks, for the tip. I think I will have to make a trip to the beauty supply house soon!

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  • 4 weeks later...

Great tutorial!

It seems there's nothing that will dissolve the filler once it's dry. Have you tried acetone? I've never used acetone for anything, and I have no idea what it does to styrene. And I hate the smell of my wife's nail polish remover. So that's a big question mark. But it would be nice if there were something that would completely remove the filler, short of sanding it off.

It looks like it would hold edges - like panel gaps - very well. True? Have you tried to re-cut repaired panel gaps with a gap cutting tool?

the acetone wont work out well it will eat the plastic i use alot of nail polish to airbrush my cars with custum colours and i use non acetone nail polish remover to thin it because of such thing and i loe the acrylic i have always wondered if it would work just never tried it but thanks and great tutorial

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