Thinking of trying wet sanding, few questions

[dash50]

Would like to try out some wet sanding, and have a car with i can practice on that has some pretty rough marks on the hood. I do not have a rotary so I was thinking of just trying 2500/3000 with a sanding block in hopes of being able to get the sanding marks back out with my PC.



Doing just 2500/3000 unigrit by hand do you think I could get away with the PC using a LC Foamed 4" wool pad or LC flat 4" yellow pad and 105/205?



Outside of just keeping the area wet when sanding then trying to remove the sanding marks is there anything else in the process I may not know or realize when attempting wet sanding?



Thanks

[wannafbody]

Don`t do it on a good car unless you`re willing to live with tracers that can`t be fully removed. Chances are you`ll end up with some.

[shaunls1]

i have wet sanded before and its not that hard and 2k paper traces are removeable with a pc.

i had some bad touch up spots the previous over did and i wet sanded them with 2k paper then with a yellow 4in pad and some megs ultimate compound took the traces out.

came out perfect.

i also spray tinted/clear coated an extra set of tail lights for my camaro then let them cure for a few days then gave them a wet sand with 1500 paper then 2000 paper and buffed then with the same pad and compound and with out a lot of work the clear looks like glass.



if you do a bigger area to use a rubber block.

[LICamaro85]

You wont get tracers if you do it right. I do not understand where you are coming from saying do not do it on a good car... Every good painter has their paint wetsanded to get rid of all the peel... does this mean they are ruining that car?



use 3000 keep it very wet use a spray bottle with a few drops of soap as a lube and do not press hard at all let the paper do the cutting and use a flat block not your hand.



- LI 85

[xbbsupra]

I have a black Toyota single stage car that was recently keyed. Damage wasn`t too deep. Should I wetsand with 3000 grit with the method in the last reply using a sanding block while adding no pressure whatsoever? When should I know when to stop wetsanding?



After sanding, my plan is to use Megs 105/205 with my FLEX XC 3401 + Meguiars Soft Buff 2.0 Yellow Polishing Pads. Does this seem correct to you guys? It`s my first time wetsanding as well.

[toby tyke]

None of you have mentioned using a paint depth gauge. You need to know how thick the paint is before you start wet sanding, it will tell huge amounts about your paints history, ie has it been sprayed or had some form of smart repair carried out.

You will probably know that total paint thickness is around 120 to 150 thou or approx 0.1mm to 0.15 mm, and thats on a decent car!! with the clear coat making up 0.05mm of this measurement.

Taking repeat measurments after wet sanding is essential, take it from me!, that feeling of polishing through the clear coat is one you dont want to have.

[David Fermani]

Would like to try out some wet sanding, and have a car with i can practice on that has some pretty rough marks on the hood. I do not have a rotary so I was thinking of just trying 2500/3000 with a sanding block in hopes of being able to get the sanding marks back out with my PC.



Doing just 2500/3000 unigrit by hand do you think I could get away with the PC using a LC Foamed 4" wool pad or LC flat 4" yellow pad and 105/205?



Outside of just keeping the area wet when sanding then trying to remove the sanding marks is there anything else in the process I may not know or realize when attempting wet sanding?



Thanks



You don`t need a rotary to remove wet sand marks if you have a PC. Here`s an example of what can be accomplished easily:



http://www.autopia.org/forum/machine-polishing/125074-porter-cable-xp-sanding-kevin-brown-method.html

[Accumulator]

Some random thoughts follow:



Use good paper, keep it clean and lubed, and you`ll be less likely to get tracers.



The PC can fix 2K sanding scratches with 3.5-4" pads.



I`d avoid both yellow LC cutting pads and (too gentle) yellow Meguiar`s polishing pads for this (but those might work on black single stage, which is usually soft). Generally, I`d use the PFW or orange light cut, or Cyan Hydrotech, or...don`t they make the Megiuar`s cutting pads in 4" now?



Paint readings are helpful, but I don`t consider them 100% mandatory. But don`t thin the clear too much; you can do serious damage to b/c paint without going through to the basecoat.



When to stop depends on what you`re gonna do afterwards. If you stop sanding with just a little bit of residual sanding scratches, perhaps the subsequent compounding will get rid of them. But I generally think you oughta go as far as you`re gonna with the sandpaper, finishing with the mildest you can (3-4K) and then only using the polisher to bring back the gloss (not do any more correction).



I also think that if you`re remotely concerned with whether you`ll damage the paint, you oughta think twice about sanding the vehicle in question.

[wannafbody]

If you decide to wetsand ONLY use unigrit paper. Stay away from 3m paper. And some GM clear is really hard and a rotary and wool pad may be needed.

[David Fermani]

What`s wrong with 3M paper and what makes Unigrit better?

[wannafbody]

What`s wrong with 3M paper and what makes Unigrit better?



I didn`t have good luck with 3m paper but it probably was poor technique as well. Unigrit seems more consistant.

[David Fermani]

Via DA or by hand?

[wannafbody]

Megs sanding block.

[David Fermani]

Makes sense. I prefer sanding with a DA with the new technology out there. The chance for error is close to zilch and it`s pretty easy for beginners like the OP. With a sheet of 3000 Trizact slapped on a PC at speed 3-4, nothing but smooth sanding w/o tracers.

[bwalker25]

not to hijack the thread but....when using a DA and Trizact papers do you just let the weight of the DA Polisher do the work for you?