perfect removal of sanding scratches
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I have a long standing issue with not knowing exactly when I’ve removed a certain grit of scratches in clear coat before I move on. I look over the panel and think I’ve got it covered well, but by the time I get up to polish I see some particular grit showing. This last job I start the rough polish thinking it will look great….. 400 grit showing….
is there something you pros do to check to see if you’re 100% before you move on?
thanks in advance.
ps – I’ll post up some pics of the blend job I started the other thread on.
i think starting with 400 grit is over kill if your planning on polishing. i usually go with 800 to spot nib and work my way up with 1500, and final sand with 3000. you can use water/alcohol mixed 50/50 in a spray bottle to clean between steps, blow with air to dry the panel and inspect with a sun gun if you have one. the 3000 grit on a soft interface pad and a d.a is the best way to finish up before compounding. if you have access to norton or carbo products, try 1500 dry ice paper and 3000 grit. much cheaper and better in my opinion compared to 3M
I only have up to 1500g available in town, so that’s what I’m stuck with on this job. I can sand up a little finer to perfect it later, if I feel like it, but this job isn’t a biggy.
Thanks for the info.
regarding the starting at 400, that’s where Jim C said he starts to flatten clear down. it was already quite flat over most of it, with a handful of runs…. I used the run poly trick starting at 220, then 400 over the whole panel and up.
I guess I should flatten with a finer grit to start, and just not shoot any runs! 4 or 5 coats of nice heavy orange peel would have been funner to me than sanding a few runs…
jim c is doing custom work. if you want it really smooth. your better off sanding and reclearing. then a light sand and buff
jims doing that if im not mistaken because his intention is to reclear the whole job
400 is overkill for anything but a reclear.
It’s going to take some serious film build to sand and then polish out 400 grit scratches on an entire car.I’ve tried starting with 600 and 800, and 1000, and 1500.
And to be honest the results between them are miniscule.To be honest, it’s easier to just buzz a surface with 600, and reclear it, then do the last coat with 1500, step up to 2000, 2500, then polish.
And the results look virtually identical.
In my personal opinion, anyone that is starting their color sanding (On an overall) with anything below 800 is nuts. Hell, I won’t go under 1000, because the difference in the end just isn’t there. And the additional time working out the 800 grit ain’t worth it.
Yes, nibbing a spot, and working out imperfections in specific area’s is an exception. in this case I’ve even gone down to 220 (But only to work out bulk)
It’s easy as shit to work out an area with such low grits. it’s HELL working out an entire car that way.
If you hit it with anything under 800, save yourself the headache, and finish it with 600 and re clear.
gotcha. well I just wasted some time sanding on this god forsaken honda. I’ll see if I can shine it up good without reclearing.
I knew Jim’s a custom guy, I just took his advice without fully understanding it. I read guys starting with 800 or thereabouts, and he said he uses 400 dry to flatten it down. Now I see he wasn’t taking it all the way up to a shine from that course of grit.
thanks fellas
be careful when your using your heavy cut or compound after you do your 1500, because you
are only going to get so much of your gloss back that you took out by sanding it.
Ive made the mistake before of taking too much clear off with the 1500 or 3000, then going into it
with the 3M #1 rubbing compound or trizact xtra cut (depending on the grit i finished) and torching
the clear trying to get my gloss or Distinction of image back to as it was before polishing. my 2 cents
😛I’m extremely leery of that happening. I take WAY too long polishing, but I have never had that problem yet….. there’s a first time for everything…
As above, I’d never go as high as 400, unless it was as a first stage in removing a run or similar large defect.
But a good way to ensure you remove all the sanding scratches from a previous grit is to finish each one in a slightly different direction. That way, when you’ve finished (for example) blocking with 2000 in a North – South direction, any marks from the previous grit (where you went East – West) will stand out like a sore thumb.
It doesn’t have to be such a dramatic change in direction, that was just for ease of example, as even a 10 degree change will do the trick.
[quote=”Andy T” post=18864]As above, I’d never go as high as 400, unless it was as a first stage in removing a run or similar large defect.
But a good way to ensure you remove all the sanding scratches from a previous grit is to finish each one in a slightly different direction. That way, when you’ve finished (for example) blocking with 2000 in a North – South direction, any marks from the previous grit (where you went East – West) will stand out like a sore thumb.
It doesn’t have to be such a dramatic change in direction, that was just for ease of example, as even a 10 degree change will do the trick.[/quote]
that makes sense. I suppose when you’re ramping up the grits the direction doesn’t have to be an X pattern, like I have been doing.
thanks
if u start ur sanding to buff with 400 ur going to take to much mill build off the clear unless u have 4 coats on and then its going to break down over time..
I put on 3 runny coats, and I didn’t go down to 400 everywhere. I’m pretty sure I have plenty of build on this job.
Now i know why my painter buddy in town here said he has spent as many as 10 days polishing clear! :blink:
[quote=”bobwires” post=18881]I put on 3 runny coats, and I didn’t go down to 400 everywhere. I’m pretty sure I have plenty of build on this job.
Now i know why my painter buddy in town here said he has spent as many as 10 days polishing clear! :blink:[/quote]
he must be on straight time 😆
evidently it was a chevelle that won best of show in a car show with 1000 cars in tacoma about 10 years ago.
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