Sandblasting and body filler?
 

I just got my 54 F100 back from the sandblaster... I had them blast the entire truck and epoxy prime it. However, when I got it back, the truck still had body filler all over it (which was now covered in primer). I was under the impression that blasting would remove the body filler? I asked the owner and he told me to remove the filler, it would have to be done by a grinder because the metal would get to hot. Wondering if this is correct or if he just doesn't want to go back and fix it? Also, will I need to remove all body filler before I paint it? Looking for some opinions from those who have more experience than I do!

Your blaster is correct and wise. He did you a favor by not blasting all the filler out and warping your panels. It comes off much easier and faster with a grinder, and without all the heat. If it was me and I spent all the money and time on sandblasting and taking everything to bare metal, I'd take out all the old filler so I know what's underneath it, then do whatever metal work is necessary to bring everything back to perfect. Good luck with your project. :-X22

Use a 3M clean and strip disk to remove filler without removing/thinning/overheating metal.
IMHO the blaster did not do you a favor, he should have shown you the filler and allowed you the opportunity to remove it before priming over it. It would have come off very easily with the C&S disk then, the epoxy primer will make it much more difficult to remove now. I would remove it tho, you don't know what is hiding underneath it, i.e. poorly done patching, bondoed over rust, etc. that will come back to bite you later.

I agree with the previous comments and would add...if there is enough filler on that body that the sandblasting did not remove, then there was TOO much filler on the body to begin with. I would bet that whoever did the bodywork was less than professional and more than likely had similar methods for handling the metal below the filler.
As for the primer...people think that if they don't primer sandblasted metal immediately that all kinds of bad things will happen. While it's true that bare metal will rust quickly, this action needs moisture (either from hands or air) to happen. If the metal is handled correctly it will stay clean for quite awhile after blasting. I make this point because I too have had a lot of "interesting" features in the metal hidden by primer from a sandblaster. Good luck with your project...

This post reminded me of something I read on the HAMB ? about Gibbs Brand Penetrating Oil.... | The H.A.M.B.


I used Gibbs years ago on some magnesium wheels, and as you know magnesium will corrode if you just look at it. I stripped the entire wheel and eventually ended up painting the back sides because they did require frequent re-coating which was easier to do if I didn't have to remove the wheels each time. They always looked like I had just polished them.


I also used it on some old school lockers that I sandblasted. They set in my shop for over a year before I got them painted and I just wiped them down with a tack rag and rattle-canned them. I am not that confident I'd do that with an automotive finish but according to these guys it does work. I still keep a couple of cans of it around as it is the best penetrating oil I have found.

Yes, just have the metal phosphate wash treated after blasting rather than primered, then take it home and put it inside immediately. Handle with clean work gloves or neoprene gloves. Wrap parts in heavy plastic until ready to work on them. Once you have the body work completed try applying the direct to metal primer with a foam roller/brushes (check that your primer solvent does not eat the foam) if you don't have spray equipment. That primer coat is going to get sanded again anyway, and the paint manufacturers are even recommending it for spot repairs.
Check out my F1 fender rust repair tutorial to see some of what was hiding under the primer the PO's sandblaster applied to Gary's truck.

Thanks for taking my words out of context, Chuck. It's always interesting to read your comments belittling others while making yourself into a big shot.

I thought that was just to be expected on this forum. I think its in the fine print when you register

The epoxy primer is not going to make it difficult to remove the filler. Once you strip it if you find rust just buy a cheap spot blaster or if you have a blast cabinet take the nozzle out of there and put the siphon in a bag of media and clean/blast the area and re-prime.

Sometime lessons are learned the hard way and that is not necessarily bad. If this situation was in my hands I would do just as you have done sought advice and than process into an appropriate response on my part.
If it was me not knowing where or the condition of the filler. I would find a different blaster who uses different media than sand (walnut shells, alum oxide etc) and blast again exposing the filler, than remove filler by hand and re-evaluate as what the next step is.
The blaster I use owns a powder coating business so he is real versed about the blasting process and the different medias for the many processes.

It sounds like the OP is describing skim coats of bondo, not blobs of bondo and chicken wire used as a rust repair?

Thank you ;-)

Bondo Removal
 

I had allot of bondo on my roadster body, up to 1/2" thick. I elected to use a Fortney course wire brush on a 4 1/2" grinder. It makes quick work of the job.
Don't forget good respiratory, ear, and eye protection.

Thanks for everyones response... I think what I'm going to do is grind down/scrap off the body filler and then have it re-primed... I'm hoping the blaster will work with me and blast some of it so I can find where exactly all the body filler is... Wish me luck!

Good luck :)
Sometimes you do get lucky, I have removed bondo that was used to fill repairable dents, little hammer work and almost no filler needed.
Dont forget the dust mask and goggles, grinding bondo makes one heck of a snow storm.