So I was watching hot rod tv the other day, and I think they were doing a 74ish charger for Kenny Wayne Shepard or something like that and the started stripping the paint on the fender, and it was super fast, looked like a DA sander but it looked like they would have the fender done in about 5 minutes, what were they using? Granted my DA sander is a budget IR one but no way it would knock the paint off that fast.
There's no trick to getting paint off fast, just doing it without damaging or warping the metal. Norton makes a red 7" disc that looks like it has gravel bonded on it, it is mostly for prepping steel shapes for painting. It'll strip epoxy like no tomorrow.
Yes that's true getting old paint off isn't a big problem. The challenge is getting it off without digging troughs in the layers of paint underneath. Remember that eventually you are going to have to hand sand that fender smooth and feather it out if you expect to have a decent paint job.
An electric orbital sander with 80 grip paper will take a fender down in 30 minutes. Or if you have a compressor with a 9cfm flow rate you can orbit sand it off.
One of the reasons you have to be careful is because you don't know what's under that paint and if there's some filler or bondo you don't want to gouge into it.
Mine has spray paint, rustoleum, and who knows what on top. It is really soft and clogs the sandpaper fast . I use a chemical stripper to get the junk off the top (scrapes right off with a putty knife). Then I switch to my electric rotary sander ($25 at HF on sale). I have an 8" ferro backing pad and 8" indasa 80 grit disks. You can strip most of a panel fairly quickly, but again..be careful.
I them switch to a little (air) angle die grinder. I use 2" roloc 50 grit disks on it. Again being careful.
There will always be spots that need to be hand sanded.
I am going to bare metal. I will not leave filler or anything on the surface. The particular epoxy primer I am using requires an 80 grit surface to stick. A couple of coats and it is pretty smooth.
If you go the route of sandpaper...do not...I repeat...do not buy the cheap stuff. It will work you to death with very little results. Believe me..I tried it at first.
Now..that works on a panel at at time. I intend to media blast the bigger stuff when I get to it.
Unfortunately (and very fortunately!!!) I received a kidney transplant last spring. I didn't much at all done on mine this past summer. I will continue when the weather warms up. I don't have a place to get it indoors to work on it.
I've used a product from 3M called a ROLOC BRISTLE DISC, fits on a 4 1/2 grinder, takes it to bare metal in seconds. But like any friction pad you have to keep it moving so you don't build up heat. I paid $32 for it and it does last for a fairly long time. I found out about them watching Trucks TV.
I usually try to distinquish which panel is original paint/painted multiple times or bondo and go from there.
If I think the panel is nice--I will strip it with a roloc--or a 24 grit disc.
If panel is 50 yrs of old body-work--you had better decide if you are going to dig out all the old stuff--or sand it and refinish it.
On a 53 that I have--it is at least 7 paint jobs old, and I sanded it with da and primed it.
In spring--I will decide to strip roof/hood/and MOST LIKELY just sand and refinish the rest. You do not have to make a show finish on every panel--if it is a driver--make it presentable and drive it.
Bondo and lead are in alot of old trucks and if you want ALOT of work--start digging it all out....haha
You may be buying a new panel when you see under all that paint and filler!!
When you grind a panel--try to machine it and make it look machined--instead of gouged up!! I have taught alot of laborers this technique--and when it is gouged up--you have alot more to do!! Bill