Taking it down to the metal?
Hey all what kind of grit would you suggest to take paint all the way down to the metal on a set of fenders and doors? D/A or ??? give me some input on this one!
Originally Posted by Brian Felts
The best method we've found is to use 80 grit disks on our Makita at slow speed. We can do an entire car in a day. Check out the page shown below.
The only problem (esp. for the uninitiated) with "grinding" it off is overheating the metal and gouging. As well, grinding creates a LOT of dust. In my shop, I also do a lot of mechanical work and like a clean workspace - so I try to minimize dust whenever possible (vacuum vs. airgun, etc.).
I use Aircraft Stripper whenever I want to remove everything on the panel. Slather it on (wear a good mask), scrape it off, pick it up. Then you just need to go over it with 120 on the DA to remove remnants and OEM primer prior to primering.
We find that there's not many jobs in the shop that don't generate dust so we learned how to clean it up. Sanding off the paint usually generates dust but we can either exhaust the floating dust or wait until we're finished then sweep and blow until it's gone. The best method we found for stripping is to take the vehicle to a "plastic media" blaster but the price is prohibitive and we can usually sand off the paint in about 8 to 10 hours. As far as heating the metal goes you should use a slowly rotating disk (around 1000 rpm) and you don't need to worry too much about heat. The biggest problem is when you come across a peak or edge and allow the disk to cut into the metal but the slow rotation will usually give you time to correct that problem. After you sand for an hour or two you learn to run the disk along the edge and not across it.
Originally Posted by e-tek
We use chemical stripping on paint with a soft substrate like fiberglass but it can cause too many variables with the residue and takes a lot longer than sanding. We usually use a little stripper or a small amount of blasting in areas where the sander can't reach but that's about it.
So..Im not the only one out there who vacums my panels instead of using an air gun?I use a high powered vac set up with a soft horsehair brush for a lot of my dust removal and it works well to clean and reduces the spread of dust.Mike
Originally Posted by e-tek
Len - as usual, great info. The thing is though, what works well in a production shop (I've worked in them), doesn't often translate to the DIY'r in a home shop. At work, I was all about speed and dust and blowing it around. At home, I'm all about taking my time and keeping the dust to a minimum.
Originally Posted by Len
As well, I think (I may be wrong??) the poster is a hobbyist, so probably hasn't had time to practice with the big wheel - heck, he may not even have one. Sounded like he has a DA though.
Brian - Am I right? And no, you're not the only perons to use a vacuum!! I find it keeps the dust to a minimum. The only time I BLOW the dust off in my home shop is just prior to Prime or Paint. Then you need the dust out of every nook and cranny - but I still use the vacuum first!
Well I'm a hobbiest and I much prefer lens method of stripping. I started off using aircraft stripper and the stuff was stinky, left a sticky mess on the floor when you scraped the paint off, and you have to worry about all the seams and unseen areas that the stripper can find its way into. I find its much easier to sweep and vacuum up a little dust than go through all that gooey mess.
Boy you're right about that. We've stripped a hundred cars and the rotary sander is A LOT easier than chemicals. The chemicals are fine for small hard to reach areas but the big panels are a lot faster, easier and cleaner when sanded clean. We are frequently reminded of this difference whenever we strip a fiberglass car because we can't use a sander on paint with a soft substrate.
Originally Posted by BradNes1
As another hobbiest, I'm with e-tek on this one. What could be easier than
applying a thick coat of remover, covering it with plastic then go inside and finish the paper and a second cup of coffee. Come back in an hour, scrape off the loosened paint, apply a second coat if needed and back to the paper.
I scrape off right into a plastic lined garbage can and put canvas drop clothes below everything to catch the excess. The glop will be dry next day and can be shaken off. As the shop owner, Len must have forgotten what it's like to spend 8 hours behind a 7" sander. My arms still vibrate just thinking about it (ex boatbuilder).
So it's up to me!
- Len's way (Sanding w/#80 grit)........2 votes
- Etek's way (Spreading on paint stripper)...2 votes
I'll have to break the tie and vote for...
Len's way of sanding with #80 grit.
There's no gooey or caustic mess of paint stripper plus you will still have to sand off the residue anyway. In addition if the paint stripper drips between panels, removing the paint, you'll have rust there when the bare metal gets wet.
I use the shop vac with soft brush for getting sanding dust off the car in the garage, too.
Originally Posted by All Dry
As for paint stripping, I've done it both ways, and like neither pretty much equally. Stripping paint is just no fun...
I just stripped 80% of the car chemically with Zip Strip and here is my opinion-
1. Chemical stripping material is expensive. I went through (3) $30 gallons and it's still not done.
2. It takes a long time. For me, I had 3 paint jobs on my car, so it takes a long time. Also, when I say long, I mean long. It would take me about 3 hours to do a fender. Again, I had multiple layers.
3. Use a very good respirator and have proper air movement-it stinks!
4. Make sure you get the residue out of the seams. You don't want chemicals sitting on metal. And you don't want to primer over this stuff.
Even with the above said, I'm still going over the car Len's way.
Next time use the 80 grit method and you'll appreciate the difference especially since you've had a taste of the chemical method.
Originally Posted by dundeedude
Oh you guys - afraid of a little goey mess....what would your girlfriends say?!?
Like anything, you just have to be a little careful & a little smart about it . As said already, throw down a little carboard or plastic, then just pick it up/roll it up and toss it - wa-la - no mess!! Also, don't slap it into the gaps! I just put it on close to, but not right to, the edge. I'm going to use the DA in the end anyways to get the last bits off and prep the metal for my primer/etch, so I can get the edges too.
Again, to each his own, but I just find that the less flying dust I make in my combination mechanical/body shop, the better. Most of us with home shops store stuff right beside the place we are working, have shelves and maybe photo's on the wall, a tool box nearby....again, for me, the less dust the better. BUT - in a production shop, where all you do is sand, I would definitley "Len" it off!!
As for speed, you can put on and do something else (more fun like mechanics, reading the paper/coffee as said!!). If you have multiple coats, I believe the stripper takes 1-2 coats off at a time, so it would take only 2 applications (see my pics). As for expense, I use 1 gal for above job, INCLUDING under trunk lid, and it was 30.00 total.
Last edited by e-tek; 08-10-2008 at 09:00 PM.
As far as protecting parts you don't want the stripper to get to, use the blue cellophane like tape that powder coaters use. That stuff is impervious to anything I have tried. Tape off where you want the stripping to stop, add paper to prevent any splashed drops, and your edge will be perfect. Another tip if your determined to use a grinder, attach a rope to the grinder, run the rope thru a pulley that you can connect above you (I used the boats guard rails) attach a counter weight just slightly less than the weight of the grinder
and go. The grinders weight will be counterbalanced and all you have to do is guide it. I'll still take stripper.