The Stovebolt Site Forums The Shop Area Paint and Body Shop body filler

This question certainly comes from a novice firstimer..

Today I asked a body man how does he spread body filler over a
large area without it hardening so fast...He said he adds a
agent that slows down the harding procedure...Does anyone
know what it is called?..I seen him put on a very light coat
almost over a complete fender...

I'm kinda cr@ppy at bodywork, but if I don't want the filler to harden real fast, I just use a litte less hardener. My son is way better at it than me, and he's the one who suggested it. Works pretty good.
Hope this helps.

yea, you can always tell when you add too much, too hard to work. wonder why he's putting it over the whole fender?

If hes doing the whole fender,he may be using a "glaze".
Probably about 95 percent of it will be sanded off. I went thru the same deal with my truck, they called it "frosting" and dam near all of it ends up on the floor. But......when they were done,those ol beat up fenders were really,really nice!
With Bondo,,using a little less hardener gives you more working time.

You have to be careful when using less hardener, because if you don't use enough you will end up with sticky goo. It is better to use a slower hardener. Most products have alternate hardeners available. Same with paint.

thin layers are better than a thick one. adding less hardener can create issues. heat or hotter days quicken the hardening process.

to answer your queerie
no i have not.

glazes: as marty mentioned...
http://www.evercoat.com/productCategory.aspx?cat=1
Spot putty is another version of filler, but much finer and easier to sand. It doesn't need to be mixed and can be applied directly from the tube to the repair. The spot putty fills in any tiny impressions in the filler. Smooth (or glaze) spot putty across the repair surface with a flexible plastic spreader. It dries faster than the body filler, but be sure you give it enough time before you begin to sand it. Using 400-grit sandpaper, lightly and evenly sand the spot putty away. Sand it all away flat, and you'll be left with only tiny amounts of putty remaining in small scratches and gaps. These may seem minute, but even the smallest flaw will show up in the paint. o further prepare and protect your repair, you'll spray the surface with a primer/sealer. Mask off an area around the repair to avoid getting paint on any trim or other non-painted areas (don't forget, you don't want paint on your tires, either). Apply the spray primer in light, even coats. Three light coats are better than one heavy coat.Allow the primer coat to dry, then remove your masking tape and paper. To smooth the repaired area for painting, you'll use your 400 grit wet/dry sandpaper, but this time you're going to wet sand the repair. Fill a spray bottle with clean water and spray the repair area and the sandpaper. If you don't have a spray bottle you can use whatever method you can to keep the paper and repair area wet. Smoothly sand the primer using a straight back and forth motion. When you begin to see the old paint show through the primer, you've gone far enough. If you sand away too much primer and you can see metal again, you'll have to re-prime and re-sand.
You've now successfully repaired your car's body! Well, almost. It still needs to be painted. While you can buy touch up paint in a spray can at automotive stores, they pretty much suck. I've never seen a repair that's been spray painted at home look good at all. Paint is best left to a professional. With all the money you saved doing the repair yourself, you can afford to have it properly painted.
http://autorepair.about.com/od/fixityourself/ss/bondo_6.htm

Exactly right. To add just a bit, body filler depends on a chemical reaction to harden correctly. If you use too much OR too little hardener (catalyst) you change the base chemical properties of the filler. I still remember the day I learned that lesson. I added a lot more hardener to speed up the cure time and it actually slowed it down because I added too much. When it finally did set, it pealed off the panel when I tried to sand it. It isn't so touchy that you need an exact measurement of the amount of hardener but adding substantially more or less can backfire.

The hardening process is affected by heat. It will go off faster on a hot day than on a cold day. Experience will tell you how much to mix at a time on any given day.

Another question from newbee..

Is there such a thing as using a old spray gun to apply thin
layers of bondo...Can bondo be thinned out and sprayed..

thanks in advance

I've never heard of anyone thinning bondo & spraying it but that isn't saying it can't be done although I think the thinner would mess with the chemical reaction. Last week I saw a product at the body shop doing the work on my 38 that is a sprayable body filler that swells as it sets. It won't fill large dents but they say it works well on minor imperfections. I don't have a name for it or where to buy it.

Hey Tiny, you're right about "too much or too little" hardener. (don't ask me how I know).
After I "fouled" things up a few times, I just got my son to teach me to use the exact amount. So far, so good.

He was probably using a 2part glaze, a thinner, finer version of body filler.
I taught vocational auto body for 13 years and the rule of thumb was 1 inch of hardener to a golf ball sized portion of filler.I've never heard of an agent to slow down the hardening process.
Also the spot putty you apply right from the tube is a lacquer based product and tends to shrink after it completely cures and you could end up with the scratches showing up in your final finish. I recomend the 2 part glaze,it's easy to apply and sand,even with a finer grit of sandpaper.
Always use a catalyzed primer-surfacer, it doesn't shrink.

Evercoat Spot Putty is my choice, and I use it daily as the filler for the majority of small dents/repairs, and as a glaze over large repairs based in regular bondo.

Remember that the less hardener you use {to slow it down} means the more you must mix to ensure the hardener is distributed.

Is there such a thing as using a old spray gun to apply thin
layers of bondo...Can bondo be thinned out and sprayed..


Sprayable fillers (i.e. bondo) are a different product. Their technical term is polyester primers. The brand names are Evercoat Featherfill and Marhyde Quicksand. Here is a link for the Marhyde:
http://www.smartshoppersinc.com/closeouts/MarHyde-Clearance.HTML

Regards,
Steve
New Orleans

A high build urethane primer can go on thick enough to eliminate glazing or spotting putty. Makes for less mixture of products on there too.