Wetsanding Questions

[RAG]

I'll admit - my wetsanding experience is limited to a handfull of times and usually just spot sanding with 2500. So I have a couple questions:

A lot of guys on this board recomend Mequiars Unigrit paper (so I just ordered 150 sheets of 3000). What makes this paper superior to other papers?


Second I have a question about grit choice. On the last car I buffed out for a near by body shop, they had repainted an entire car (another black one), sanded it with 1000, followed with 1500, and turned it over to me. These scratches were difficult to remove (especially on portions where I could tell they missed with the 1500). They told me they typically buff out with a twisted wool pad and Diamond Cut and then follow with a polish. Well, I ended up using another one of their wool pads, but there was NO WAY I was following with a final finish-type polish and done - I compounded with a medium cut pad and then final polished. Later the owner said he should have had his guys finish with 2000. No sh%#.

My question is this: What would be a good sequence of sand paper to buffing to get the job done properly in a reasonable amount of time? (from my perspective, it would be real nice to finish with 2500 or 3000) I would think going from 1200 to 2000 to 3000 or 1000 to 1500 to 3000 would save 2 or 3 hours of buffing would allow me to go to an honest two-step buffing sequence (compound to polish) while only taking an extra 20 minutes of sanding.

Thanks for the input - Ryan

[Accumulator]

I've never needed anything harsher than 2K (my Meg's sanding block) and I only use 3K when using paper. Anything that 2-3K won't handle I'll either live with or have redone. I'd much rather have OP than thin clear.

I can't help but wonder why the shop needed to wetsand their paintwork with 1K grit

The Unigrit seems more uniform than the 3M paper I used to use. Takes a lot less polishing to get the scratches out and there's basically no incidence of isolated deep scratches. Sometimes I'd get a nasty-deep scratch or two with the 3M paper.

[the other pc]

Originally Posted by RAG

...A lot of guys on this board recomend Mequiars Unigrit paper (so I just ordered 150 sheets of 3000). What makes this paper superior to other papers?...

As Accumulator points out uniformity is the key. A typical paper marked as #1500 will have an average grit size of #1500 but can have some percentage of the particulates that are larger or smaller.

Unfortunately, the amount of work it takes to buff out sanding scratch depends on the deepest scratches, not the average. Even if 99.999% of your particles are #1500 or smaller and only 0.001% are #1200 you'll still have to buff it as if they all were #1200.

The particulates on Meg's papers are practically all the same size so the scratch pattern is more consistent than with other papers and buffing is easier.

Originally Posted by RAG

... What would be a good sequence of sand paper to buffing to get the job done properly in a reasonable amount of time? ...

If you really want to cut your sanding time down switch to power sanding. With a power sander (an OEM will use air powered DA sanders) you can step through to finer papers and still do it much faster than you're hand sanding now.

With the finer scratch pattern compounding will go faster and you can you can get to final gloss with fewer steps.

Since Meg's doesn't make disks for DA sanders I'd recommend Mirka Royal papers and Abralon pads for power sanding, using the Meg's by hand where the DA won't fit.


PC.

[turbomangt]

Wet sanding is the most aggressive way to remove scratches in the finish and should NOT be attmepted unless you know what you are doing. Sometimes this is nessesary, procedure here was 3000 grit, then 2000 grit, high speed rotary with Meguiars Heavy duty cleaner, followed by fine cut cleaner, then dual action cleaner polish, switch to DeWalt 443 with SSR1 polish, then my sealant.

[turbomangt]

Corre3ction, 2000 comes first then 3000, just wanted to see if anyone was awake. gary

[rwh]

Originally Posted by turbomangt

Corre3ction, 2000 comes first then 3000, just wanted to see if anyone was awake. gary

Ah ha, we caught you Gary, the old switcharoo trick.

[Picus]

When I did my car I used 2000 first and learned quickly that with a PC it takes way too much time and effort to remove non-unigrit 2000 marring. I switched to unigrit 3k and the difference is probably 10-15 minutes per touchup.

[DanoWatt]

When I wetsanded my whole car, I started with 1500, then 2000, 2500, and 3000. Buffed it out with a rotary and it came out looking amazing. In some spots, I had to use 1000 because the orange peel was so deep.

Some pics:

Before:





After:

[Wanted]

Danowatt - on your wetsand project with the orangepeel, was that a repaint or OEM? Was it on your older benz?

[DanoWatt]

That was a repaint by the previous owner.

[LucentTeg]

wow, great job on getting rid of the OP. I need to do that on the hatch of my integra where it was redone, I am too scared to try though.