OK, I have all my trim holes welded, so there is a bead both inside and outside of the sheetmetal. Now, before I make a mess of this, what is the best way to grind these down flat without warping the metal? Rolandag2 suggested to use a Tiger wheel, fits on my 4" grinder but has overlapping sheets of flapper sandpaper. I have one in 80 grit and 60. I figured I would use this for the main bulk of the metal. But when I get close to level, what is the best tool to finish it off? Also, should I worry at all about the bead inside the fenders/doors, or just POR-15 over them? It seems that the more I grind on these, the better chance of warping... I am thinking of getting the fenders down to metal, then painting POR-15 top and bottom, and drive a couple years with glossy black. It should protect the metal, plus look cooler than multiple colors. I hear you can use POR-15 as a primer, so I will test it out here. (BTW, I understand the POR-15 fades in sunlight, but this is a garage-kept car with 3-6 hours driving per month. Also, I have a spot of POR-15 on my truck for a test, and 6 months later, it has faded just a few shades and is still a very dark grey-black.)
Just like welding, keep the flap disc moving. Do not let heat build up. The flap disc will give you a finished surface. Try to get a 40 if you can. The flap disc are not nearly as aggressive as straight sand paper of the same grit.
So keep moving, maybe tap at it and move from spot to spot? Do I grind down until it looks flush, or leave some material for sanding by hand? I mean, will it be paintable flat when ground down, or will I have to use a filler no matter what?
Grind flat with 40 grit flap wheel, then apply a skim coat of filler a little lager than the area, sand smooth first with 80/100 grit on a long board ( thick paint stir stick with the sand paper wrapped around it) check by feel if you need another application of filler. If not, apply 1 to 2 good coats of primer surfacer. ( if you use a laquer based product it will dry faster, 1/2 hour to an hr, than enamal, and you can paint enamel over laquer, but not the other way around). after primer has dried apply a guide coat of another color ( I usually use grey primer/black paint) ( guide coat means: hold the black spray can about 2 fett away and spray so that the gray is covered with dots), let that dry 3to5 min. Then you can sand with your paint stick again this time using 120 grit. sanding in a criss cross pattern holding the stick as flat as possible to the panel. If there are any low spots they will show up as black spotted primer. If there are any highs they might show up as bare metal, ( the highs may need to be hammered down w/ a pointed hammer( more filler/same process over again) ). If everything looks good then apply 1 more coat of primer. At this point you can leave it and go onto another area, or wet sand w/ 400 and your almost ready for paint. Now then, if you stand back and can see circles in the primer in the area that you worked then you better keep filling/priming/sanding etc. until you cant see them anymore. Because if you see them in prime, you'll see them 1000 times worse in paint. Also dont let your filler repair get wet. Whether its primed or not moisture WILL get through and start rusting (por-15 or not). If all else fails puton some spray can enamel overlapping onto exsisting paint and this will seal the repair better than just primer. Long story short, hope this helps, Rob
Rob, that is a really good post!!! We need more posts like that on this forum, where have you been all these years? my only question is when you say "sand with your paint stick" you lose me. What does that mean? Also, since you sound like a body man, have you seen POR-15 rust through?
Ok that was your long board ( paint stick rapped with sand paper( not to many raps because it will be uneven)) . No I havent seen por 15 rust through, I was just saying that if you dont seal out the moisture, the moisture will get through at least the filler and primer, hence causing corrosion to start. And yes , Ive been doing body work for 25 years. Most noteable for me was building my brother in laws 56 chevy pickup and him taking it to Hot August Nights and the officials putting him in one of the front rows for the show because they liked it so well( no trophies though). If you have any ??s just ask. Its like my dad always said when I was growing up " the only dumb questoin is the one you dont ask".
OK, gotta ask, since I don't speak "body shop" as Rick Book puts it... What is a paint stick...I am picturing those cheap thin mixing sticks you get from Wal-Mart, but can't believe those are good for anything, other than using as a tongue depressor
But, not all paint sticks are created equal. Try to find some that are good quality and straight. The real thin ones that are warped don't work very well for blocking.
Yep, nice straight and about 1/4" thick. found some good ones at Ace Hardware lately. And blocking is what you are doing when your sanding with the paint stick. just remember to criss cross /////////// \\\\\\\\\\\\ your work, not back and forth -----------.
Cool, I think I will start on this this weekend. I want my fenders and hood painted in POR-15 by the Texas Mini-Meet Sept. 23. Gotta get rid of some of the colors on my car.
