My car was a collection of primers, original green paint and rust, so it was decided that I would strip the
paint to bare metal. The goal is to quickly strip the old layers of paint and primer and end up with nice clean
bare metal. First off, as I've found out, there is no best way to strip the paint to the bare
metal. All have problems. Here's a few methods:
You can't use on sheet metal panels cause the heat
can supposedly warp the panels. Incredibly messy unless you can take your car to anyplace different from where your garage
is situated. The sand gets everywhere which means you have to clean every nook and cranny. You definitely don't
want to have any mechanical parts installed or anything that could become damaged from the sand or sand
blasting. Sand blasting is quite slow but does an excellent job. It allows you to get into any nook or cranny
that you can see. I find that sand blasting is great for small parts or the areas that a wire brush/grinder can't
access. It also cleans out rust spots quite well.
Hand held Siphon feed sand blaster
Pressure sand blaster
There are two types of sand blasters: siphon feed and pressure feed. Siphon feed sand blasters suck the sand
from a reservoir and require more air pressure to operate. Pressure feed sand blasters pressurize the sand
reservoir and need a smaller compressor to run. Another advantage of pressure feed sandblasters is that you can
get much finer gun tips than a siphon feed unit. The speed blaster shown above is a great quick sand blast tool.
It's very easy to set up and use. I use it about 99% of the time over the pressure blaster mainly because I'm
doing small items and areas. The sand is very inexpensive, $7 for a 50 lb bag.
- Media blasting
This is similar to sand blasting but you use some expensive media like crushed wallnut shells or plastic beads.
It can work but can cost more money than sand. Usually, you want to recover the media and reuse it to save costs.
Sand is so cheap that who cares if it's not used. Again any type of blasting is messy... You do get to wear a full body suit
- Acid dunking
Acid dunking is where you take the complete body and dunk it in a bath of acid. This means that the car has
to be completely stripped down. It's supposed to work very well, but I've heard of cars
that weren't cleaned properly after and the residual acid ate away the part from the inside after a few
years. This happened to my buddies' hood where they couldn't clean behind the hood braces properly.
- Wire Brushing
Twisted wire brush on 4 1/2" grinder
A wire brush on a 4 1/2" grinder works pretty fast but I've had problems
getting through some of the old primers. It worked very well on the firewall and front wheel wells where it
looked like there was no primer. It's very messy as the old paint is thrown everywhere as a fine dust.
I use it mainly on heavy parts like the frame or undercarriage, or for rough cleaning off surface rust, dirt
- 6" Dual Action (DA) sander
6" Dual Action (DA) Sander
This is about the best choice so far but you need lots of air pressure 9cfm and 90 psi which translates into
a 5 hp compressor and not one of those 120V oiless compressors that peak to 5 hp. The DA sander with 80 grit
paper works very well.
- Chemical removers
They are just plain messy and don't remove as well as
you would expect. I happened to have a can of Polystripper around and gave it a try. It works about as well
as any other stripper. Usually you have to do several coats to get everything off, rub/scrape the old paint
then wash the bare metal and dry before it starts to rust. The chemical drips everywhere and you need a
proper respirator. I understand that there are some aircraft quality chemical strippers that work very well
but I don't feel like dealing with gallons of chemicals in my air tight garage if you know what I mean.
I have read articles where a complete car was stripped in one day out in the driveway. Plastic was laid under the
car to catch the drips and several applications were required. I guess for all that mess to strip a car in one
day is worth it.
- Flap Disk
Flap disk for 4 1/2" grinder
A flap disk is a disk with overlapping layers of sandpaper on it. You use it on your 4 1/2" grinder. They
work quite well but can easily cut into the metal leaving gouges. I tried a 40 grit and its brutal, a 60 grit
works well if you use a very light touch. A worn 60 grit is ideal. I would really like to try an 80 or 100 grit
disk if I could find one.
- Drill based Paint strippers
Drill based paint stripper
I picked up one of those paint strippers that you attach to your drill at the local auto parts store.
It looked like a pretty good idea as they remind me of sponge toffee but
they are brutal. I thought that I would use it for those hard to get places but it really gouges the metal.
I found that my drill speed was too slow, heavy and awkward to hold. I experimented and used it with my die grinder (dangerous idea!) it cleaned
like a hot damn.
Drill press, extension and paint stripper
The stripper is only rated for 3500 rpm so using a 10,000 rpm die grinder is a bad idea as there is the
chance that the stripper may explode from the rpm (bad thing). Instead, I hooked it up to my drill press
using one of those flexible drill extensions and set the drill for 3100 rpm. It works wonderful, its
light weight, easy to hold and strips rust and paint cleanly.
I have a cheap $70 drill press with a 1/4 hp motor which is perfect for this application. There is one danger
in that the drill extension cable can twist itself up when the stripper is pressed to hard. You can easily
stall my drill press with your hand so there's no danger of the drill extension cable wrapping itself up
and damaging anything.
- Heat style paint stripper
I haven't tried one of those heat style paint strippers that you use on
your house, that could be interesting..
- Sandpaper on grinder on drill
Sandpaper attachment for drill
This is a bad combination. The edge of the sandpaper easily gouges the paint and you don't notice it until
its too late. The original owner of my car used coarse grit sandpaper to "quickly" sand off the paint in places
and I'm paying for it now. I will have to spend "a lot of time" on finishing those areas with
finishing putty to get the gouges and scratches out of the metal surface. Strips quickly and spend lots of time
on body prep - not worth it...
What worked for me
On my 54 Pontiac, I found that I have to use a combination of the above. Here's two methods that work for me:
- Flap disk and DA
- I used the 60 grit flap disk on a 4 1/2" electric grinder to remove the top paint layer. I use hardly any
pressure. The original primer is very tough and the flap disk doesn't remove it easily. There's also too much
risk of gouging the metal. The disk worked best when it was well worn - it was more forgiving. Ideally, I would
like an 80 or 100 grit disk to try.
- Next comes the 6" air DA sander with 80 grit paper to remove the old primer. It works great and leaves
an excellent surface for the new primer.
I only have a 2 hp compressor with about 100 gallons of reservoir so I run the sander at about 70 psi
which makes for slow stripping. I would love to have enough air to really use it to its potential. I alternate
between the flap disk and the DA as I run out of air. I use the flap disk until the air pressure comes up
and the compressor stops (125 psi reservoir). Then fip over to the DA until I run out of air (80 psi reservoir).
- After the metal is bare, I use a rust remover like Rustoleum or equivalent. NOTE: use gloves as the muratic
acid will turn your skin green or worse burn your skin. When it turns your skin green, you can't wash it off
(experience talking). You brush on the rust remover and let it dry.
- Next you clean off the rust remover residual with water and dry. You can use a towel or an air compressor.
- Finally, I clean the metal with a degreaser. I use acetone cause I happened to have a bottle of it lying around.
- Wirebrush grinder and drill based stripper
- I found that the wirebrush on a grinder sometimes works wonders on paint that has no rust. I've used
it to clean up the inner fenderwells and firewall quite successfully. If there is lots of tar and dirt, it
cleans it up for the next stage.
- For areas with surface rust and paint that the wirebrush doens't remove. I use the drill pressed
based stripper. It works very well.
- After the metal is stripped, I prepare the surface in the same manner as previously described.
Just remember to wear a respirator or good quality dust filter mask because lots of the old paints and
primers are lead based. I check to see if my dust filter mask is working by blowing my nose into a kleenex.
If the tissue is clean, than the mask is working. I've gone through about 6 throw away style dust masks in the
last 3 months. I prefer the dual elastic band style as they seal better around the mouth and the nose. They
cost about $3 each.
Impromptu stripping room
There is quite a lot of dust generated when stripping paint. I wish that I had put up sheets of plastic earlier
in my garage to control the dust. It is much worse than regular bodywork which tends to just drop to the floor. The
flap disk and DA sander throw the dust every where. I had to vacuum the walls and every inch of the garage. The
lead based paint sands to a fine powder that even the vacuum can't pick up.
I bought some medium gauge poli and used some C clamps to clamp it to the garage door rails. I have a nice size
room to strip the fenders in. Unfortunately, there is still some dust that gets over the top 4" of the plastic and
floats around the garage. I wear a dust mask, full face shield and ear protectors and have to take a shower immediately
after. It's a horrible job that I'm looking forward to finishing soon.