DIY: Wet Sand a Body Panel on your BMW 330 ZHP doityourself
My car never had any paint work when I bought it, but it did have a ding in the trunk. I had it painted by my local body shop about a week after I bought the car. Ever since, I had been just slightly irritated by the orange peel on the trunk. No one but me (including other car people) noticed it, but I wasn't having it. The paint itself is of good quality.
I figured some of you guys might appreciate this. While I doubt your cars have had any paint work, I know the level of OEM orange peel can by itself be annoying to some people.
So this morning I went for it, here's a quick DIY:
Disclaimer: I am not responsible for ANY paint or clear coat damage you do to your car.
Do this job at your own risk.
Read through all of the directions several times before starting. Do not skip steps, and be patient.
If you skip any steps, you may cause permanent paint damage.
Be prepared to accept the consequences of this type of project before beginning. If you have:
-Had a detailer or body shop guage paint thickness and deemed your panel safe to sand
-Do not skip any of my directions
-Be patient
-Don't use a rotary buffer
You will have a very small probability of damaging your paint.
* Before starting, I highly recommend you use a paint guage to see how thick your paint is. You may not have a safe margin (remaining clearcoat) to wet sand.
This is typically a job for professionals. You should have prior experience detailing if you are attempting this project.
Things you will need:
- 2500-3000 grit sandpaper (use rougher sandpaper at your own risk)
- Good working light
- Several clean microfibers
- A bucket with soapy water and an old but not contaminated wash mit.
- A bucket with warm water and a touch (only a few drops) of car wash solution for the sandpaper
- Clay bar
- I also recommend a spray bottle with warm water and car wash solution.
- DA buffer such as the Porter Cable 7424 (no orbitals unless you are trained with them)
- High quality polish such as Menzerna. (low quality polishes will not be able to remove the sanding tracers)
- A reasonably agressive cutting/polishing pad.
Process:
*Soak the sandpaper you are using prior to wetsanding. 24 hours is the safest bet; minimum of 30 minutes is recommended.
Before:
After:
1. Start by washing the whole car- you might as well.
In my case I removed the license plate and license plate holder prior to cleaning. Make sure you get ALL surface contamination off of the panel, otherwise you will just be grinding it in to your paint. I run my hand over the panel I am working with after washing it to feel for any ground in contaminants.
Some more befores:
2. To be safe, I recommend claying the area you are working on prior to sanding it. I did my whole car last week, so I skipped this step today.
3. Tape off all lights, rubber trim, and anything else you do not want to sand.
4. Wipe down the area you are working on with a clean microfiber to remove any surface dust.
Ready to sand:
5. Begin by spraying a small section of the body panel you are working with (preferably in an inconspicuous place as a test.) Remove your sandpaper from your solution, and begin sanding in one direction. Do not sand in a circular pattern. In my case, I sanded the trunk horizontally.
Frequently spray the area you are sanding with the bottle of solution while you're working.
*Remember to dunk you sandpaper in the bucket to remove any particulate from it every few passes.
6. After sanding to a point where you don't think will take care of all of the orange peel, stop sanding and wash the area with your wash mitt and dry it with a microfiber.
You will now be able to see what your car color would look like in matte form.:
Inspect the areas you sanded under direct light to see where you missed. Even under the matte paint, you should be able to see the state of the orange peel from the side. (The lighter the color the harder this is). Evaluate how much farther you want to go, and check for any problems you may have caused. Often the edges of panel will be ignored more than the middle sections subconsciously.
An intermediate step after my first round of sanding:
7. Repeat step 5 and 6 until you think you will be happy with the results.
Stop sanding and wash/dry the area you are sanding often- you should annoy yourself with the level of caution you use here. Sanding the clear coat is harsh, and burning through the clear coat can cost thousands of dollars.
8. Wash the area you sanded and wipe it down, making sure to remove all particulate.
9. Polish the area with your DA buffer. After 1-2 passes, you will see the gloss return to the body panel. It may take many more passes to remove all of the tracers. If you do not know how to polish, look on autopia or autogeek for a guide. I assume you have prior knowledge with a DA buffer if you have the balls to wet sand any panel on your car.
If you sanded with dirt on your sandpaper, didn't lubricate properly, or didn't soften your sandpaper, you may have deep tracers. In this case I wish you best of luck; follow directions!
I used Menzerna Intensive Polish with a Blue cutting pad on my Porter Cable DA. I buffed for about five minutes, surveyed what I had left (some small tracers) then polished for another 5 minutes or so and I was done.
Polish until you cannot see the tracers any more, but use common sense. Your really do not want to burn your paint.
First pass of polishing:
10. Take the tape off and wash the area you sanded to remove all grit, tape residue, and polishing compound.
11. Wax or seal the paint, stand back and admire!
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