can someone teach me to wet sand??
Im looking to paint some of my interior panels, and I know that I need to sand the hell out of them first with a very high grit, and I was told that it is much easier/better to wetsand when using a high grit. First off, is this true?

Second- then I would proceed to sand/wetsand the panels until what point? When would I know that I have sanded enough and they are ready for paint?

Any help from experienced sanders/painters would be most appreciated. Thanks.
If it helps you to know, the piece I was planning on first was the center console.

 

Well, the reason they prolly told you to wetsand is that it wears down the material faster and also increases the life of the paper, especially higher grits. If you were to try and trysand a piece of graded plastic like the center console with say 600 paper, it would take a reall long time and the paper would wear down very quickly.

All i would do is sand untill the surface is completely smooth. Im not sure who gave u instructions on how to do this. Im thinking it was either boogymike or gundam, but otherwise THESE are the steps I would follow, and the steps Im going to follow when i do mine.

- Clean the panels to remove grease and other heavy contaminants by using:
simple green/wax & grease remover/tsp (mild solution) - I prefer the following method:

- Obtain spray bottles of simple green or a gallon of simple green to mix your own batch of strong simple green solution and put in a spray bottle. This solution is used to remove the mold release agent that continuously bleeds from the plastic. When plastic panels are manufactured the mold release agent is readily absorbed into the plastic product and if it is not painted at the factory it will continue to bleed the mold release agent. You could also use one of the paint company's plastic prep solutions but I find that in bulk amounts simple green works great for the price but use what you feel will do the job for you. You must understand that it is imperative that you clean the panels well prior to sanding dry. I like to "clean and sand" at the same time.

- Spray the solution generously over the panels while sanding with #320 or #400 grit wet/dry sandpaper. Use a small rubber squeegee often to see how well the sandpaper is cutting out the texture. Note: if the #320/400 grit s-paper is not cutting out the texture fast enough for you then you will need to obtain #180 grit dry sandpaper and a foam sanding pad and cut the texture out with this grit. Then you will need to apply a couple of good wet coats of urethane primer surfacer - let dry a day or two - then come back and spray guide coat and block sand with #500/600 grit s-paper wet - dry off - allow an hour before sealing and spraying the basecoat/clear coat.

If the #320/400 grit s-paper is cutting the texture out fast enough for you then continue with the following steps.

- Sand the panel smooth to rid of the texture completely

- rinse the panel well with clean water

- respray the simple green/plastic prep cleaner over the panel and scrub it well with a sponge then rinse once again very well

- dry off (do not use any shop rags that have been used before to wipe off grease/oils etc., even if they are laundered - you'll be asking for trouble!!) My recommendation is Scott Blue disposable paper shop towels. (Note: if you use a compressor with a air blow gun to assist in the drying of the panel I highly recommend that you attach a moisture filter right at the air gun to prevent blowing oils/moisture onto the panel that will contaminate it. Ask your paint supplier about it. Do not use the round orange filter (I can't remember the brand of it) it will work but could break at the threads - which happened to me - obtain the black filter which I believe is made by either DiVillbiss or Motorguard.

- After drying off allow the panels to sit for about 30 minutes or so to allow any moisture that is remaining in the sand scratches to evaporate. If the ambient temp in the room you will be painting is less than 70 degrees you will need to allow for longer dry time.

- I use a product by PPG DX103 - which is a universal plastics cleaner. This a alcohol based cleaner used prior to painting. Spray the panel with the DX103 and wipe dry immediately being sure you flip your paper towel often.

- Then apply DPX801 which is a plastics primer/adhesion promoter/sealer. This product is RFU (ready for use) RTS (readly to spray). Shake the can well prior to spraying - no need to mix with anything else

- Allow the sprayed DPX801 plastics primer to sit one hour prior to topcoating

- Spray basecoat/clear coat - no flex agents required (note: when spraying the basecoat color you notice that there is "fuzz" or small little hairs standing up, this is what happens when you cut into plastics. If this should happen apply 4-6 passes of wet basecoat color. Allow to dry for 24 hours then come back and wetsand the panel with #600-800 grit s-paper just enough to remove all the fuzzies and hopefuly not cut thru to the plastic- wipe clean - let dry. Then respray a coat or two of basecoat color.

- Apply clear coat

- sand and polish if necessary to match the factory orange peel texture

- wax/seal panels

- reinstall panels

- admire your accomplishment!!!!


But to answer your original question, to wetsand, all you need to do is soak the paper in water and then sand, you can also rinse the surface as you go. Block sanding is very important cuz hands create grooves.

 

hey thanks for the detailed writeup bryan.
where do you think I can get my hands on the simple green, the PPG DX103, and the DPX801 that you referred to?

 

Bryan,

Sure can tell you've done this before
I was pretty much going to say something similar but looks like you explained enough already

 

simple green is available at most grocery stores; also almost all auto parts stores; and Im betting home depot and lowes would have it too. its great for almost everything. its like windex/fantastic on crack but not over done. you can use it straight or dilute it big time which is nice for value.

 

You can get the preping stuff here

http://www.autobodydepot.net/scripts...OVMTC=standard

id also call ur local auto body paint supplier, you could get it there as well it would be easier also because you could ask them in person and theyd make sure you got all the right stuff, just take a look in the yellow pages.

-B-

 

Hmm. My uncle has an autobody shop. Maybe I can get him to get some for me at his wholesale price. Im sure he has connections for painting supplies.

 

Hey I just sanded and painted all of the plastic in my car. I can't imagine how long it would take or y you would want to start with such a fine grit paper.

I started with 80 grit, moved to 120, then 220, and finished with 360. I tried starting with 120 but that would have taken for ever.

Now I wet sanded btwn each coat of paint but not from the start.

 

Im doing the same project lol,

Z/g day IS coming up Raceway park here we come.