# Mirka sanding discs



## wadoryu (Jan 28, 2010)

Hey people, doing some work on a lanica beta spyder, being fully repainted and it's my job to wetsanding and polish. Question is how far do the discs go? I mean polished bliss do them in singles of a box of. 20. Am I going to need 20 to do a whole car?


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## squiggs (Oct 19, 2009)

The answer is going to depend upon what grade(s) you'll be using (coarser grades last longer than finer grades) and what size discs you'll be using (although I'm presuming you're asking about 125 or 150 as opposed to 77mm). Obviously larger discs last longer.


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## Paintguy (Oct 31, 2005)

As above.

Plus it depends how bad the paint is to start with and whether you're sanding it with anything else before refining with the Abralon.

So there are loads of variables, but as a bit of a guide I expect a single 2000 disc to do an average sized front end on a job that's come out with a decent finish but needed the odd bit of dust and dirt sanding out with 1500. Going on that you'd be looking at around 4 for a full car of that size with no roof. I'd then go straight to polishing from there (3M Fast Cut Plus & green foam or wool pad) but some would refine further with a 4000 to use a finer polishing combo.

As squiggs and I have said though, there are lots of variable so it's hard to make anything more than an educated guess, but I'd be very upset if I had to use a full box (of regular sized discs) to do a full car!


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## wadoryu (Jan 28, 2010)

That's fantastic, cheers for the help 
Yeah I'll be using the 150mm pads going from 1000, 2000, 4000.
It's not the best paint in the world, but it's as good as we're gonna get with the price we've got. Luckily I have a lot to play with.


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## Paintguy (Oct 31, 2005)

I don't want to be rude but have you done much of this type of work before?

1000 is a very aggressive disc and you'll need to take extreme care when using one as you can cut through an edge in seconds. Even I would think long and hard about using one for this kind of job and I've been doing it every day for over 20 years. I generally use 1000 to prep the surface _before_ painting, not finish it afterwards. 1500 sure, 1200 maybe if it's really bad, but I can only think of a few occasions over the years where I've had to go as mad as 1000.

If you do decide to risk it, be aware that it's also a big jump to the 2000 afterwards and an intermediate stage with 1500 would be better. You'll need to spend quite a bit of time to remove the 1000 marks if you go straight to a 2000. Wipe the surface dry and inspect regularly to check if all of the deep sanding scratches have been removed.

I really would recommend you have a rethink, unless the paint is really bad and there's lots and lots of it. The (pretty much) standard bodyshop practice is to start with a 1500 grit film disc (like a Mirka Polarstar or 3M 260L) then refine with either 2000/3000 Abralon or a 3M 3000 grit Trizact disc. Very few places would start with a 1000, and I know of no manufacturer that suggests a grit that high for rectification.


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## wadoryu (Jan 28, 2010)

Oh yeah, fair comment. Ideally I knew I wanted 1500 just said 1000 because it's available on polished bliss. 
I have done a lot of sanding before just none with discs.


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## pcm1980 (May 4, 2009)

Also a smaller orbit size on the sander helps to minimise pigtail scratches, aim to have an orbital sander with a 2.5-3mm orbit pattern as apposed to a 5-7mm pattern, it does help make the polishing stage easier.


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## Paintguy (Oct 31, 2005)

I agree with you pcm, although I find a small orbit sander to be a little slow for large areas.

My ideal is to do most of the sanding with a 5mm orbit machine (Mirka ROS650), then a final run over with a 2.5mm orbit one (ROS625)


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