Technical Using acetone when using body filler ?

Read several articles about doing this .Would like your opinion.
After applying body filler shortly after it is no longer workable but still not hardened, with a clean rag with Acetone on it wipe it across the newly applied filler and it will smoothen it out,knocking down the rough edges and making it easier and faster to sand with no bad future affects. ? Gene

 

its a chemical, chemicals are bad one way or another , I wouldn't add a chemical for no gain. Filler usually has enough time before it goes off to get it where you want it unless you mix it hot. Just sand it down, the dust is bad enough without adding more stuff to the mix.

 

That's when you'd use a cheese grater! With todays products there is no reason it cannot be applied smoothly.

 

I used to smooth it just before it would go off using an old T-Shirt and water.

 

They used to do it that way if they laid it rough. It's too easy to sand it smooth when it's done properly. Sanding properly is not hard when a little elbow grease and proper technic is used.

 

Sometimes I will mix just a little fibergl*** resin with my bondo to make it spread more easy. Try it . It makes

 

Try the evercoat products, goes on smooth & clean, sands easily, seems to be holding up very well for me.

 

Back in the late '60s we thinned a 5 gallon bucket of White Tiger with enough acetone to apply it with a paint roller. Had it repainted at Earl Shive every six months or so for $20. I still believe there is a plastic '56 Ford body sitting around somewhere.

 

I use the acetone before the body filler, cleans the metal of oil etc. Gotta be quick.

 

My buddy show me a new way ,for me, to work bondo.......you guys probably already know this.....
mix it the usual way you normally do, apply it....
after about 1 min. sand with 60-80 grit, if it balls up wait another 30 sec. then board sand it and shape it . When the paper gets filled with material, and it will constantly, just blow it off with an air gun. So actually you're shaping wet bondo. It sands and shapes incredibly fast. It's so sweet.

 

No matter what you do you'll be sanding most of it off. You have to put on more than you need and the rest is necessary but dust.

If your having trouble getting it smooth just resolve yourself to the fact that you're going to get yourself a gallon to practice with. Try different techniques, different tools, different mixes and have fun learning.

What's important :::
It's mixed with enough hardner - too much is not better. It needs to kick over but give you enough time to work it.
-Mixed without air bubbles
-that it gets forced into the surface
-That is gets sanded.

Everything else doesn't matter.
I've seen guys work it like drywall mud, like paving, like Pic***o, like a baker, like a bricklayer, like plasterer, once in a while like a body man. plastic spreaders, flimsy plastic, plexigl***,stiff steel, 6" putty knife, credit card, custom cut profile, 18" angle for a screed.

 

I've done that but for another reason. To remove the sticky film that gums up the paper on initial sanding.

 

No harm done.

 

Maybe if you're filling in tiny spots right before paint and you don't want to break through the primer smoothing out the spot putty, I could see how this might be useful. I generally spread with a razor blade at that point, just for very small imperfections.

But anything bigger than maybe a pencil eraser, I can't see how that's more helpful than just block sanding. A spreader with a nice clean edge, a clean board, and getting it on the car before it starts to set, usually gives a nice smooth surface to start blocking from.

 

It sounds like you're using to much filler and putting it on to thick, Anything more than a skim coat of filler tells you that you need more time metalworking. Get the metal prep as good as possible and the filler work will be much easier. Watch the American Hot Rod episode on the 32 Roadster Anniversary car where Charlie Hutton is doing the filler work. As he says 90% of the filler ends up on the floor.

 

We used to do that when I worked in a kick n fill shop. Usually when hot patching over a rust hole when the customer was too cheap to pay for welding wire. Faster than shaping with the cheese file. That was sleazy used car salesman type work.

The most important part of using filler is getting the metal straight before even thinking about opening the can. If you have to use any "tricks" to work filler, your probably using too much.


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I myself like to use good business cards. Got to find the thicker ones so when you do ask for a few extra cards to give to your friends.
Even my paint jobber has great thick cards and they wonder why I rarely buy bondo spreaders. Also as soon as your done with your plastic bondo spreader clean it good with acetone and they will last longer.

 

Let me say that I know nothing about the correct answer your question but if it was me I would be afraid that something would come up in the future that would make you wish you didn't. Use the cheese grater file and forget the acetone.`

Charlie Stephens

 

regardless, acetone is relatively harmless. Women soak their hands in it to remove nail polish!

 

Now there's an acetone to keep away from your filler. If I have to explain why, one shouldn't be doing body work then.

 

If you have trouble getting your bondo down smooth try waxed paper. Put your bondo or fibergl*** down and take the waxed paper and smooth it with your hand or a spreader,then pull the waxed paper off. It leaves a very smooth surface. Trick I learned fixing rust belt cars that wouldn't p*** inspection.
Do your metal work and you only need a skim of filler. You can't fix a panel right with bondo and no metal work. It will come back and bite you in the *** eventually. I am fixing a Grand Torino right now that a guy paid $ 5k for a paint job and it rusted before it got on the road. Now he is paying double to have the rust cut out and metal welded in.

 

In the Car audio world, we refer to that as a "milk shake".
Sands harder, if you don't get your rough sanding/cheese grating done, before it fully cures.

 

YUP, Slopok, that's the way I do it.Bruce.

 

https://www.youtube.com/shared?ci=9sxMwpkGrOA

Use this. It will change the way you do filler work forever.

 

And they wonder why breast cancer is on the rise.

 

It would be best to keep wax away from the filler. Wax goes against the three rules of body work given to me. 1st keep the work clean, 2nd keep the work clean and 3rd keep the work clean.
If you like wax paper then try parchment paper as it is wax free and releases easy. I have done a couple large wood patches with PC7 restoration epoxy by trowelling on the epoxy, covering with parchment paper and then screwed plywood over to keep the patch flat and flush. Point is that the parchment paper easily comes off the epoxy. Parchment paper resists any sticking and does not leave anything behind. Parchment paper is used between an iron and aircraft fabric to set and smooth glued fabric seams for finishing. It should release easy from filler.

Agree with the general consensus. It is optimistic to chemically breakdown the filler to move and reshape it then expect that it to be long lived. Mechanical shaping of filler is fast, effective and maintains the integrity of the filler.

 

I can't imagine how that would have any kind of positive effect. at best you have just wasted some acetone, at worst it could effect your paint or the bondo itself. sounds like a waste of time to me.

 

Wax paper works well for a hot patch, lots of hardener so it actually gets hot and melts the wax and the paper peels off
People doing this type of work obviously are not concerned with longevity.


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Ok here's the deal with what you're talking about doing. In a production body shop time is money. Sometimes when body filler is drying it leaves a sticky sort of skin/ film on top. That will dry eventually if you give it time, but when you're in a hurry you can take a rag with solvent (acetone or lacquer thinner) and wipe the film off. You are not doing this to shape the filler in any way, it just to save time so you can start sanding faster. at the time its done the filler is too hard to cheese grate. Acetone can be used to the fibergl*** filler and resin, but I've never used it in regular filler. If you need a thinner body filler get a glazing putty.

 

The film on the filler is what makes it work. It sealed the air off the resin so it will get hard and not sticky. There is a special resin to thin bondo with it has no styrene wax in it. Fiber gl*** resin has styrene wax in it , when you thin bondo with it it gets real grease loads up paper faster. You can take a welding rod and make a loop out of it like a fly swatter and slap the paper with it and it will knock the dust off your paper. If you have ever used wax free resin in fibergl*** it will stay tackey and not completely dry. Years ago you had to mix the resin with styrene wax ,also had to add kobalt dryer to it before you added the activator
(MEK)
It's best to do your metal work and use the LEAST amount of filler, on large area use a larger squeegee, I have used a venitan blind slat to spread it out.
On wax free resin you can spray a coat of PVA over it to make it harden it seals the air off.
Always use quality filler, I know it is more expensive but it sure works better, this is over 60 years of experience. Frank