Sandpaper preference

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Kentf1003

Senior Member
While doing some body work on my old Ford I noticed that my coarse (3M 40 and 60) sandpapers are doing a slow job when making the first cut on body filler. I remember similar paper doing a much faster job of sanding in years past. Is the paper of lower quality now?

What kind of paper do you Barners prefer when making your first pass on body filler?

Thanks.
 
As it dries, the filler gets a sticky film on the outside...This is what plugs up the paper. Use a cheese grater file to remove the shiny film before it hardens, or you can wet a rag with lacquer thinner and wipe it off after it dries. The grater works best. What brand of filler are you using? Some are worse than others...

And yes, in my opinion, sandpaper quality has gone down hill...price keeps going up though.
 
In the past I used Allsteel, but this current project involves Bondo for finished work on mig welded repair panels.
 
Try rubbing an old tennis shoe sole on your sandpaper to remove buildup.

Works good
Lasts long time
 
I do my rough shaping with 80 grit on a DA on fully cured filler. I find using sand paper on filler before fully cured is a waste of sandpaper. If your metalwork is properly done, you shouldn't need much more than a skim coat that can be shaped close to final before it kicks.
 
I use the Norton 40 and 80 sheets for long boarding. They cut pretty well so you don't have to press down which would deform big panels like doors and hood. Then skim coat and 180 adhesive backed roll on my long board. Primer and guide coat with another 180 cut or two. Then prime and 400 dry to smooth 180 scratches. Depending on what topcoat I use I still get sand scratches visible with 400. So I do 500 or 600 wet sanding last if I have a rolling chassis that I can take outside.
 
I am a fan of Norton. I used their 80 grit self adhesive on my hand board and air powered board sander. I used some USC Clear Coat filler and found it to be very easy to work with and not alot of issues with build up on the sanding sheets.

The idea, as pointed out is to use as little as possible, but I have been there, where the only way you get the panel satisfactory is to coat the whole darn thing and keep at it.

The quarters on my ute could have used another 3 months in my mind.

I have rarely needed to use anything lower that 80, only because I didnt want to cause more problems with heavy scratches.

I even preferred using 80 on some of the panels on my 31 Chevy project after stripping off the years of gunk that was on them. The 80 really cleaned and effectivley prepared the surface for the next process without causing more headache.

The hard part about filler is knowing when enough is enough.
 

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buy a vexon file, the one used for lead work, it works xlnt for pre shaping bondo, and if it plugs you simply run a wire brush across it and its clean, you can use the file by itself or buy the holder that lets you adjust the curve in the file
 
I use 36 Grit for my first sanding with either an air powered straight line sander or a hand powered long board. After the first sanding I usually switch to 40 Grit and either hand long board or the straight line sander. It all depends on the size of the area to be worked. I finish off with 80 Grit by hand. Use 3 or 4 coats of 2K urethane primer on top of self etching primer on metaL. The secret to sanding plastic filler is to let it fully cure before trying to sand but I sometimes use an old piece of sand paper by hand to scuff the surface to remove the sometimes sticky layer before using powered sander or long board. I also use a DA sander with a 36 grit 6" disc on it to remove that first layer. It works for me. I wet sand it with a little soap in my water with a long block and let it dry over night before painting. I also use a cheap rattle can of black paint and mist it over the surface before block sanding. It will show all the pin hiles, sand scratches etc so they can be removed. When you hit metal stop sanding and reprime if necessary.
 
I've been painting cars for about 20 years now. Sandpaper used to last alot longer than it does now. Not sure if paper is of poorer quality or if the urethane primers and clears are just that much harder to sand. I think a little of both. I've always stuck with the 3M Gold.
 
I have been using 3M's Pro Grade 60 grit for sanding filler. It seems to last a long time. I got it from Home Depot I think. It's not too expensive if you buy it in the larger package.
 
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