Body Filler

[patrol52]

Like I said, I don't know what is widely used for model car filler putty, but I use 3M "Piranah Putty" or some variation thereof. It's official name is flowable finishing putty.

I have used other brands, and all seem to work about the same (I use a version from a auto-body shop wholesale due to it being less expensive.)

The reason I use this is because it is a 2 part epoxy type, where it will get hard once mixed. I tried the Testors filler sold at walmart, and have never had good result from it. The piranah putty is ready to sand within an hour (depending on how hot you mix it, usually less.). It is real automotive filler, but unlike garden variety bondo or the heavier fillers, this is easy to work (application) and also easy to sand to the tune of 400 grit sand paper will knock it down easily. Unlike the walmert filler, the piranah putty does not have little bubbles in it and seems to weigh less. It can even be wet-sanded before primer to get an ultra-smooth base coat.

[RJWood]

Ok, sounds like its worth a try. is it comparable in price to most of the other brands ( squadron, tamiya ) and where can I find it. Thanks for the tip Wes.

Ron

[patrol52]

The bad news is that it's fairly expensive, but there is a lot of it as it's for full size cars, (24 oz. tube is about the size of a model car.) They use the stuff as a skim coat over any body-work and sometimes the whole car to get it straight. According to this, eBay the seller says the price per tube is about $30 online (I would guess this to be the approximate name brand price.) We have bought the off-brand on sale at like $10-$15 per tube.

I do not know if you can find it at stores like Autozone, but Napa stores that sell Valspar paint have a version of it. We have a local Carquest that sells Dupont paint, which has it. The main thing to look for is something like flowable finishing putty. I would guess if all else fails, stop by a body shop and see where they get theirs. A useful idea is to sign up for a "corporate account" with the supplier for local body shops, as they often have the sales of filler, paint, and sand paper. The other good thing is they might deliver every couple days to bring stuff to the body shops and could deliver your order while in town (not all do, but it might be worth looking in to if you do much painting.) My dad and I get our supplies from Keystone Automotive, which is one such body shop/crash parts supplier.

It uses a creme hardener component that should come with it, but can be found in most places that carry normal bondo (like walmart and autozone, or the paint supply stores) (usually mix mine hot, so I have extra hardener around.)

[Phil Patterson]

I use 3-M Acryl Blue or Green spot putty quite a bit, it drys quick and I'm used to using it on 1/1 scale cars. However, it is somewhat brittle and will crack if flexed, so you have to not put it on too thick. I've been using Tamiya 2-part putty for places that need extra strength, but it can be hard to get around here a times.

I didn't know that 3-M did a two part spot putty, so thanks for the info!

[RJWood]

For the amount you get, the price is not that bad. I'm gonna be on the look-out for the flowable finishing putty. Thanks Bro.

[patrol52]

My dad still has a tube or two of that green acrylic sitting around from the good old days. The biggest problem we had with it were 1) takes a while to dry 2) it will eventually shrink 3) it's pretty hard to spread, even when new.

We painted my dad's 66 Chevy II in red lacquer and had used old filler technology (acrylic spot putty, lead, bondo) in several places, which are now beginning to show up (not bad, since it was painted over 10 years ago, but it has been cracked for awhile.)

When we started building an Auburn replica, there were large amounts of fill work on top of the fenders, where ironically even though 1:1, it had mold lines. The fill had to be done in layers with heavy filler (Duraglass) and lightweight (featherlight), but both required sanding with 40-80 grit sandpaper. Obviously, there were very deep scratches that needed to be filled, and that's where the finishing putty became wonderful, because it dries fast and can be sanded with 400 grit sandpaper, which is a perfectly acceptable surface for a slight build primer. Because the filler is all reaction based, filler shrinkage is minimized, and dries usually within 30 minutes, which can really speed up your work.

On other thing I forgot to mention, is that you need to make sure you give it something to stick to, otherwise it will not feather out very well. I usually sand the area to be filled with 360 grit, just to be sure that the filler adheres. It will also work if you have a deep scratch and fill it in, then wet-sand it smooth.

I used it here, around the bottom of the trunk opening, to get the body to match the lid. I also used it to fill around the tail lights to get them level with the surface. Sorry about the bad photo, I still haven't got the hand of taking pictures of the models.

Here I just filled in the gap down the hood for the chrome strip and sanded it into the peak shape on the front. I also filled in the bumper notches, and just sanded smooth.

With the chrome strip, it would look like this.

[FloridaBoy]

I am a long time custom car builder and probably have gone through more tubes of different puttys than just about anyone out there. I started in '61 with Plastic Wood, which was horrible, until AMT Putty came out, then that was great. I found with a TLC that AMT putty will not shrink, craze, chip, disintegrate over time, and I still have 2 models which have AMT putty and they are holding up as if the day I painted them.

I used AMT putty until discontinued, then sort of drifted away from the hobby for awhile, but still did some body work on some old cars using old tubes. Then in the mid eighties, I tried Testors Putty (lousy), the Sherwin Williams Spot Glazing Putty, (Ok, but shrank and needed several thin coats), then Squadron Green (ok), then Squadron White.

I had a terrible experience with my favorite '40 Ford custom when re-doing it with Squadron White. I was rebuilding a quarter panel benind the door, and it caved the entire door in. What a mess, and I fixed it, in about 6 weeks, and now the car is ok, but I do not use Squadron White or Green now.

Then I went to an auto store and found that bar of expoxy like the old Milliput, all you ahve to do is to cut off a section, twist and mix it, then dabble it on. This worked, but in a few months it bled through my several coats of primer, underbase paint top coat and clear. Again, trial and error.

By now, I was really forming a demand and expectation as to what I wanted in a putty. Pliable like soft clay, dries quick and has some strength, bonds to plastic without killing it, doesn't craze, or cave in, or bleed through, and sands easily. Then by accident I found it at Discount Auto Parts store. Bondo in the tube!!!! Great stuff!!!!!

First, I use the one part mixture, but several guys in my club tell me the two part works well, too. It goes on easy, fills, sculpts, molds, sands and dries quickly, doesn't shrink, or fail in any way. I swear by that stuff. The only drawback is that it makes a real mess of the "sawdust" when you sand it. It wet sands perfectly and doiesn't wilt from the more rigid plastic. I always use a large fingernail file first, then go to fine sanding and at the most, use only one of two coats, and it is ready for primer. Nothing has bled through in a year, no shrinkage no nothing except like the old days of AMT putty!!!!!

So I keep a roll of paper towels on hand all of the time, for clean up and it dusts right off clothes. Because I use my hands to apply the putty, it washes off, or when dried, just sands right off my fingerprints.

All this for 4 bucks a large tube which should do about 20 cars.

Nothing better.

Ken "FloridaBoy" Willaman

[Steve H.]

FloridaBoy, I agree with the one part Bondo glazing putty. I've been using it for several years and have yet to see anything ghost back up. I only use it in thin skim coats though. I strive for a good plastic surface before I putty it up. Two part Bondo has given me problems adhering to the plastic.

Recently found Tamiya one part putty... Its a love/hate relationship. Applies nicely, dries quickly, sands/feathers great... but Duplicolor primer seems to attck it and make it shrink. Sometimes I'll do a bottom up Tamiya paint job, but usually I use duplicolor... I'll have to give up the tamiya putty before you can pry the Dup from my cold, paint spattered hands!

True Milliputt brand epoxy is great stuff. I've never seen it age poorly. I've used it several times to build sculptural detail.

My 2 cents... Do I get change back?

[LVZ2881]

I have been using Tamiya 2 part polyester putty for my last couple builds, and it seems to ghost real bad....

I just got a 3/4 full tube of the "Piranha Putty" today from a 3M rep for free, and cant wait to try it out..

he was using it in a demonstration for 1:1 plastic bumper repair for my job as an insurance adjuster, and it seems to sand real nice....