PC speeds and wet sanding?

[oh3svt]

I have a few questions about speed using the 105-205 and also polishing. I use a PC 7424 with foam pads with the 105 I have been experimenting with spreading the product evenly on 4-5 then moving to 6 to work the product for 2 passes each direction with the red cutting pad. This has given me really good results rather quickly, then switching to the 205 on the polishing pad spreading on 4 and working on 5, usually 2-3 passes or until the product starts to dry out. I usually follow that with UP, I find it easier to work with than m7 glaze, with a finishing pad. As for pressure I usually use just enough to control the machine with one pass applying firm pressure. This process has worked very well for me thus far, but I have all day and a ****** car to play with today, so im open to suggestions.

I would also like to get a little advise on wet sanding. Starting grit, finishing grit, how many steps? Is there a particular soap I should use whe soaking the paper? How long should it soak?

I have a 90 LX 5.0 Mustang I bought a while back for DD purposes, it cost me $800 so you can imagine the condition LOL. Its a great test bed for different techniques and products though and its dark blue! If I screw it up, no one will notice.


As always, thanks for the tips!


Nate

[Michael Stoops]

Re: PC speeds and wet sanding?

You may be getting good results thus far with our W7xxx burgundy cutting pad, but there will come a time when it's overly aggressive and will noticeably haze the surface. Just know that going in so it doesn't surprise you down the road. We don't really recommend this pad with the DA due to how aggressive it is. That said, the hazing/marring it can create is generally quite easy to correct by following up with a polishing pad and a less aggressive liquid, but if you can avoid it by starting with a less aggressive approach in the first place, you should do so. Also, using that pad at speed 6 can create a ton of heat where the pad and backing plate come together and this can lead to premature pad failure.

As for sanding with the DA, you should really stick with our Unitgrit Sanding and Finishing Discs as they utilize a damp sanding rather than true wet sanding process. This means you do not need to soak the abrasive media in water overnight, you don't need any specialized sanding lube since plain water is all you need, and just a couple sprays of that plain water from a typical spray bottle is all that's needed. This is pretty important when using an electric power tool that is not rated for wet use as electricity and water don't mix well together!!

It is critically important that you use a foam interface pad between the backing plate and abrasive media - this gives a lot more control over the process and prevents you from cutting really deeply on high spots that might otherwise be susceptible to cut through while you're barely touching the surrounding areas. Unless you're cutting down extreme orange peel from an aftermarket or custom paint job, you should stick with 1500 grit finishing discs to start, and refine your sanding marks with 3000 grit finishing discs prior to buff out. You might want to check out The Power of 3000 Grit before doing any of this type of work.

[oh3svt]

Re: PC speeds and wet sanding?

Thanks for the info Mr. Stoops! Does the yellow polishing pad better suit the PC? I was refering to wet sanding by hand originally, but your info on the Unigrit discs is very helpful. Like I mentioned I have a DD car that I like to test things out with that will probably get some Unigrit experiments done on it.

[Michael Stoops]

Re: PC speeds and wet sanding?

The pad you select really depends on what you're trying to accomplish. And if you're thinking about removing your sanding marks with a DA buffer and a yellow pad, think again. You're going to need a rotary buffer with either a wool pad or foam cutting pad, some M105 Ultra Cut Compound, and about 1800 rpm. Or you can refine your sanding marks down to 3000 grit (DA applied, preferably, since it's actually less aggressive than hand sanding) and then use the DA Microfiber Correction System on the DA buffer.