PDA

View Full Version : Questions on Color Sanding


TheCoatingStore.com

psyclone07
04-05-2010, 10:51 PM
Hello everyone just want to say before hand that this site has been very helpful and I have learned some cool tricks going through the forums. I have some questions though.

In a few days (hopefully) i will be painting my car. It will be a bc/cc job and i do know i can lay paint pretty good but i need some help on getting that "final touch". Im sure dust will be in a few places on the car and I know i should buy some nib files and such. How long should i wait before i start to attack the dust (and possibly runs) with the nibs? The car will NOT be baked is why so im not too sure on how long I should wai before i touch anything? Also should i use the nib for soft paint or the more coarse one? Im trying to let the car dry for some time but I actually have to drive it an hour and a half or so away back home. So was just wondering how long should i wait before it is safe to do that. Dont want dust and stuff getting caught in clear on drive back because its too soft.

Also I've never wetsanded and buffed a car. I was thinking of wetsanding by hand to keep things simple since i fear i may mess up using a da. I actually have a palm sander around here that i think is similar to the airvantage. Not too sure on the throw though. What list of parts should i buy to ensure i can properly get the orange peel,runs and dirt specs out of the clear. Should i do all panels and bumpers when wetsanding? Also when using the nib do i need to apply pressure on it or just kind of glide it on top of the dust/runs.

I want the job to be drop dead gorgeous. I dont have a buffer but im thinking of investing in one. Do they rent these out lol? If someone could please help i would appreciate it. I was originally going to use a rubber block to wetsand but i think i read somewhere that i should just do it by hand , thought that would give me an uneven sand though.

Len
04-05-2010, 11:33 PM
The timing before nibbing and buffing will depend on several variables. The type of paint you use can get hard fast or take weeks to harden. The temperature of the vehicle after it is painted can make the paint cure quickly if it stays warm or take a long time if it's cool. The speed of the hardener can also effect the time it will take to correct mistakes then sand and polish the paint.

All of these variables can be judged by a simple test.... The day after you have sprayed your paint press your thumb on the surface for about 10 seconds then remove your thumb and rub the surface. If your thumb print goes away you can sand and polish but if the print remains in the surface the paint is still soft. You can still sand and polish soft paint but care needs to be take that you don't sand too deep or use paper that will scratch too deeply.

I use two nib files, a coarse one on soft paint and a fine one of hard paint. My method for using these files is explained HERE (http://autobodystore.com/run_repair.shtml). Remember that almost NO PRESSURE is applied when you first start to file out a defect and if you're repairing a run you want to run the file along the run and not across it.

If you want the car to come out well and hold up well then you will need to invest in good tools and materials. Using a cheap spray gun or cheap buffer or cheap paint will usually result in a sub-standard finish. However if your expectations aren't too big then low cost tools and materials may satisfy you.

Be sure to protect yourself when spraying hardened paint products they are VERY dangerous. Proper breath protection as well as coveralls and gloves will help you live long enough to enjoy your work. This is not a cheap hobby and if you skimp on your safety it may cost you a lot more than money. It may or may not kill you but it could sure make you sick for a long time.

On your first attempt at sanding and polishing new paint I'd say to start by wet sanding by hand so that you know the amount of effort it takes. If you sand a couple of panels you may decide to go with a DA because hand sanding is a lot of work. The grit sandpaper that you use will depend on the amount of peel but most folks use either 1500 or 2000.

psyclone07
04-06-2010, 07:58 AM
As far as materials this is what im using.

Im using Standox paint (Audi Phantom Black is the color)
Im using Nason 2k Select Clear 496-00 with medium reducer

Im spraying this with a Devilbiss Plus gun that i picked up after some searching in the forums. They said it would be a great buy and i have used it once with pretty good results. I got a paint job with some very little amounts of orange peel and a bit of dust and i just want to attack it when i need to. The other car i painted i said i would not wetsand or buff on an agreement and the guy said he would do it himself. I believe i have a charcoal filtered spray mask if im not mistaken as well. I forget what material it is made out of. Here are pics of my first job with the devilbiss and with no color sanding.

http://autobodystore.com/forum/showthread.php?17021-Pics-of-my-paint-job

and heres some pics of it assembled.
http://i362.photobucket.com/albums/oo62/fedeuruagu/DSC00063-1.jpg
http://i362.photobucket.com/albums/oo62/fedeuruagu/DSC00061.jpg
http://i362.photobucket.com/albums/oo62/fedeuruagu/DSC00055.jpg

Len
04-06-2010, 08:36 AM
Your first job looks good. Be sure to purchase a new mask or cartridges for the mask you have before you start spraying again. A charcoal mask is MINIMUM protection and the cartridges need to be changed regularly since they only last a day or two after opening. If you're going to continue to spray paint I'd recommend that you get a supplied air system like the one below. You can spend more on paint materials to paint one car than you will on a breathing system like this and it can save you a lot of health problems later.


http://autobodystore.net/Merchant2/graphics/00000001/hobbyair2.jpg
LINK (http://autobodystore.net/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=HP)