New paint job - Buffing questions

[xanth]

I just tried to ask this question, but something froze up so if it's a duplicate, my appoligizes.

So i'm in the middle of painting my truck, and moving on to the cut and buff stage (I think that's what it's called). First time painting a vehicle so It's been an expirence, and as any first time painter, I have some items to fix.


I've painted the hood (and the rest of the truck) black. It has 4 coats of clear on it. I've taped all the edges and high points in an attempt not to burn through them with the buffer.


First time using a buffer and taking it pretty easy as I'm worried about burning through the paint.


Tools - Rotary buffer variable speed. Using M0116 on a white foam pad twice, followed by M0916 swirl remover on a white foam pad.

I've wetsanded the hood, one side with 3m 1500, the other side with 1500 then 2000 (just trying out different techniques to see what happens). As to shine, really didn't seem to make a difference.

I've heard good things about M105/M205, but they don't have it around here and I like to see what i'm buying sometimes. So I went with somethign they had aroun dhere.


Both sides seemed to come out nice. very reflective, but still have a very slight haze to it (though I haven't taken it outside yet).

Two part question. First, does the above sound like the right steps? Any suggestions?

Second, should they be followed by another polishing compound, or should the M0916 make it haze free, if I did everything right (which means there's a problem with my technique)?


Thanks!

[xanth]

Re: New paint job - Buffing questions

And, I put this in the wrong section... sorry.

[Michael Stoops]

Re: New paint job - Buffing questions

And, I put this in the wrong section... sorry.

No worries, we've moved it for you.

Welcome to MOL, by the way.



OK, now on to the good stuff!!



M01 Medium Cut Cleaner on a white foam pad (we assume either 3M or Lake Country) followed by M09 on a similar pad and you've still got some haziness to the finish after working against 1500 to 2000 grit sanding marks. We aren't at all surprised given that even your most aggressive combo here, M01/white foam, isn't hugely aggressive and 1500 grit marks can be a challenge to remove if the paint is pretty hard. You didn't mention what speed you were running the buffer at, and that's going to make a difference too. What you're most likely seeing is remnants of the sanding marks, regardless what area of the truck you're working on given that you've experimented a bit with final grit.

We would highly recommend going with something more aggressive, both in liquid and pad, for that initial cutting. Optimally for that initial cutting process we'd go with M105 and a wool pad spinning as high as 1800 rpm (try starting at 1500 rpm first though), although a foam cutting pad can work equally well. Wool is generally going to be more aggressive (and throw a fair bit of wool batting with a new pad) but it won't generate as much heat as a foam cutting pad can. And it's that heat that can be really dangerous - a foam cutting pad can heat up the paint very quickly and bite you before you know what's happened. Still, the choice between wool and foam for the initial cutting stage is a bit of a personal preference. With either pad just be sure not to use much pressure at all - this is especially true with a foam cutting pad. Even moderate pressure at 1500 rpm can heat things up in a hurry, so with this being your first time out get into the habit of stopping every so often and just put the palm of your hand down on the paint. If it's a little warm, you're good. If it's getting hot - stop. You need to either slow down the buffer speed or, more likely, ease up on the pressure.

Now, regardless of pad choice, odds are you're going to have some holograms after this step, and that's perfectly normal. But your sanding marks should be gone. Removal of the holograms (aka buffer swirls) should be taken care of by that M09 Swirl Remover 2.0, although for the highest level of finish we'd recommend M205 Ultra Finishing Polish. Either way, you really want to step down to a softer pad here. Our W9207 Soft Buff 2.0 black finishing pad or the equivalent from 3M or Lake Country would be a good choice here. As long as you weren't overly aggressive with your cutting process and the buffer swirls aren't all that deep, you should pull them out quickly with this process. Drop the tool speed to somewhere in the 900 to 1100 rpm range, keep the pad as flat against the paint as possible, and move the tool slowly but steadily over the paint with just light pressure - the weight of the tool or maybe just a tad more.

[xanth]

Re: New paint job - Buffing questions

Thanks for the advice. I guess I should of asked before I started buying stuff :-)

Just ordered some m105, wool pad and a black finishing pad.

Another question. I've been reading on here and, m105 van be used by hand. I'm guessing that that'll work for the edges and close body lines that are a little too close for comfort with a newbie and the buffer?

[xanth]

Re: New paint job - Buffing questions

And another one...

Will m105 get out 1500 scratches? Is there a need to go to the 2000?

[Michael Stoops]

Re: New paint job - Buffing questions

Thanks for the advice. I guess I should of asked before I started buying stuff :-)

Hey, it's better than burning the paint first and then asking for advice!!

Just ordered some m105, wool pad and a black finishing pad.

Another question. I've been reading on here and, m105 van be used by hand. I'm guessing that that'll work for the edges and close body lines that are a little too close for comfort with a newbie and the buffer?

Yes, that's not a bad idea at all.

And another one...

Will m105 get out 1500 scratches? Is there a need to go to the 2000?

M105 should be able to get the 1500 grit marks out, but there's a lot to be said for refining your sanding down to a finer level, like 2000 or even 3000 grit. It can actually be less aggressive overall than high speed, aggressive compounding.

Out of curiosity, what technique are you using for wet sanding? Pneumatic DA or by hand? If by hand, you are using a backing pad, right? And keeping the paper and work area very clean? Sloppiness here can lead to tracers, those random deeper scratches that happen when debris builds up and is trapped between the sanding media and the paint. Often times you don't even know they're there until you start compounding and all of a sudden you notice these random deeper marks. Working clean is important when detailing in general, but when sanding and rotary compounding there's no such thing as being too diligent about it.

[xanth]

Re: New paint job - Buffing questions

Wet sanding by hand with a block. A little too concerned to try to use a DA.

And just about continual water. Keeping it as clean as possible :-)

[xanth]

Re: New paint job - Buffing questions

Just trying to get a handle on where to stop.

But your sanding marks should be gone

If it's still a bit hazy after 105 on a wool pad, and I can see some sanding scratches (2000), keep buffing? When do you move to the 205?

[Michael Stoops]

Re: New paint job - Buffing questions

Just trying to get a handle on where to stop.



If it's still a bit hazy after 105 on a wool pad, and I can see some sanding scratches (2000), keep buffing? When do you move to the 205?

Yes, you need to remove all the sanding marks with M105 before stepping down to M205.

The crazy thing about wet sanding - doing it with a DA is actually less aggressive than doing it by hand, and more uniform as well. And it's as easy to mess this up by hand as it is with a DA - plenty of people use more pressure than they should by hand, or they sand in a circular pattern, etc.

[Wills.WindowsAndWheels]

Re: New paint job - Buffing questions

Reallly good read. Just curious...what type of sanding paper and what type of rotary are you using? Any chance you'll post some pics?

[xanth]

Re: New paint job - Buffing questions

I'm using 3m Paper, 1500 and 2000. A Harbor Freight buffer. It's worked OK so far.

I have a DA sander, but I've still been a bit concerned about using it on the new paint, though I still have some runs to fix so I might have to do it.

When using a DA, it's kinda hard to keep it flat on the paint, Is it ok to use the edges of the DA when sanding out runs?

[xanth]

Re: New paint job - Buffing questions

Oh, and after letting the truck sit for a few days, some haze starts to appear in spots again. Have more buffing to do!