shaving anything question

so i shaved some things on my car...and painted it today at a friends shop..keep in mind it was a repaint on these panels..do to some imperfections..anyway the first time a painted it i let it air dry and it was fine..then this morning my friend baked it and now u can see all the places where i welded. he claims that baking it would not cause this...we argued over it and im the one stuck with fixing.so does baking cause material to shrink up on shavings?and would it be suffice if i just blocked it back down re primed and started from there?or do i have to take it all the way back down?thanks a lot.

depends on what body filler you used some chepo body fillers tend to shrink .u can block it down and re primer if u think the body filler is still good

Need to strip it back down weld it all solid (tacking here and there keeping cool) grind it smooth slowly so u dont warp then sandblast it. Run back over with 24-36 grit paint buster. Put a skim coat of fiberglass reinforced filler(kitty hair) on let dry knock down then coat it with filler of ur choice. Be sure to apply proper amount of hardner to each product and allow dry time. Also i like to let the filler once all the way finished out sit overnight before priming then let the primer sit at least a day before blocking.

so is that what happened the heat shrunk it?should i not bake these shaved panels? why do i keep hearing mixed opinions on welding solid versus just tacking?

Dont weld solid at once tack till its solid and the sandblastin g is to be sure all the black residue from gas is completely removed. The bodyfiller cant stick right to that residue and usually when it gets hot lifts up slightly is why u see ur tacks now that is baked.................

keefs right I would also recomend sealing the back side of it with a good seam sealer.... to stop moisture......

werd, it does not matter if you bake it or not, all baking does it speed up the cure time of the materials. If you did not fully weld the fillers in then there is a good possibilty that it will ghost line.

is the sandblasting part really necessary...i understand about the black residue from the gas...but thats gone after u grind the welds. what about when people weld all the way around by slowly tacking and it still ghost lines?ive seen that several times as well?

when you weld it completely around (one spot at a time, very slowly and let it cool) there will be no line to show. if you did the body work, then painted it right away, the body work/primer prolly did not have enough time to fully cure. so when you painted it, and "baked" or cured the paint, primer, bondo, it shrank, and thus now you have lines. depending on how back the lines are, you might get away with color sanding it and buffing.. but if your lines are bad, then no, you will have to start over. if it is not fully welded 100% then the sand blasting is your only bet to get all the bondo/primer out of the places that is not welded..
also you have to be very clean. if you did not wipe it down with wax/grease remover, that will also add to your problem

Originally posted by KEEF



Need to strip it back down weld it all solid (tacking here and there keeping cool) grind it smooth slowly so u dont warp then sandblast it. Run back over with 24-36 grit paint buster. Put a skim coat of fiberglass reinforced filler(kitty hair) on let dry knock down then coat it with filler of ur choice. Be sure to apply proper amount of hardner to each product and allow dry time. Also i like to let the filler once all the way finished out sit overnight before priming then let the primer sit at least a day before blocking.

Keef is right and baking it only sped up the cure time of the material you used. I am guessing you didnt give your filler enough time to cure before you primed and blocked it. So even if your buddy didin't bake your car, the body work would have shrunk up over time anyway.

Follow the same steps that Keef gives and you should have no problems. These are the same steps I took when I did my doors and haven't had any problems. Being clean and cure time are your best friends!