Wet or dry? Fresh paint...

[gtijon]

I've finally gotten around to spraying my Golf, in solid Spies Hecker two pack. Being me, I've sprayed it despite my total previous experience of spraying being painting a tractor bonnet

So, the finish varies from being very good where I was getting the hang of it, to having orange peel, to having runs, to having a print from the fabric of my trousers when I got a bit too close taking masking off it...

Anyway, I want to flat the paint back and polish it up again - I've done bits and bobs of this previously when I've done touch ups, but never a whole car. I blocked and DA'd the entire car and have the worn fingertips to prove it, so I know where the odd high spots and low spots are, and know that there are bits and bobs of filler and heavier areas of primer, so a paint thickness gauge isn't going to do me much good.

Now, I'm happy using a DA (air powered) and I'm happy to block it if needs be, and I want the best finish possible. Zero orange peel would be lovely. I've already spent 8 months working on this car so how much time I spent polishing the paintwork isn't really going to make me any more nervous about parking it up.

So, what's the best way? 1500 grit on a DA then polish or block it wet with 3000? My gut feeling is that a DA gives a hell of a lot better finish than I manage with a block, as long as it's working on what's already a surface that's basically the right shape. I'll be doing final polishing with a rotary polisher, not a dual action / random orbit one.

The paint's mostly shot already, and being finished this week - the book drying time for this paint is 16 hours at 20 degrees celcius (70ish in old money) which I can easily manage, but I know the paint under drips and sags doesn't really set up that fast from experience, so some sort of idea on a timeframe for flatting and polishing would be helpful - I see all sorts of answers from get it done within a few days of the datasheet drying time to make your job easier to leave it 3 months to make sure the paint's set (although that seems more common on the UK forums - I can easily keep the car at more than 20 degrees for a few days to make sure it's set).

And the paint's white - I'm not a complete lunatic.

[Mike Phillips]

Re: Wet or dry? Fresh paint...

Is this a single stage white paint or are you going to apply a clear coat finish over it?

Regardless, if you have a air DA then by all means machine sand it, if you can get it, go for the 3M Trizact papers, #1500 to remove the orange peel and flatten out the paint and if you don't mind doing the extra step get the #3000 Trizact and re-sand everthing... in most cases your sanding marks will buff out very fast.

You can use this paper wet or dry, using it wet will allow you to sand longer before the the paper loads up, if you sand dry you can keep a fluffy, clean terry cloth towel handy to hold against the paper and remove the built-up paint residue.

After sanding the finish flat you'll want to remove your sanding marks using a wool pad on a rotary buffer, at least that's the traditional way and the fastest way to do it effectively. You can also use a foam cutting pad but you have to be careful because foam cutting pads can generate more heat faster when compounding, just use the hand test to see how warm the paint is as long as you can place your hand on the paint and your instant reaction isn't to quickly remove your hand, (that is you can place your hand on the paint and easily keep it there), your in a window of temperatures that are okay.

There's always a lot of talk about using a DA polisher whether air powered or electric to remove sanding marks instead of a rotary buffer and this may be possible if the paint is very soft but if the paint is hard at all then using a dual action polisher is not going to be fast or effective at removing sanding marks.

As for chemicals for use with the rotary buffer we offer

• M85 with a wool cutting pad
• M84 with either a wool cutting pad or a foam cutting pad
• M86 with a wool cutting pad
• M01 with a wool or foam pad
• M04 with a wool or foam pad
• M02 with a wool or foam pad

With a dual action polisher... we don't have a recommendation for this, but if you were going to try this as some are doing then M83 is the most aggressive product we recommend for use with a dual action polisher.


Here are a couple of threads with more information... take pictures and post your results...


Switching from 3M to Meguiar's - Rotary Buffer Questions?

Can You Use the PC to Polish-out #2000 Grit Sanding Marks?

Hope this helps...

[gtijon]

Re: Wet or dry? Fresh paint...

Thanks for the advice. My local paint factors sells Mirka rather than 3M disks - are the Royal Micro sanding disks up to it?

The paint is single stage white - no clear coat.

I've got to be honest and say that I've already got a bottle of Farecla G3 in the shed from other work that I've done so that's what I'll be compounding with, purely because I've already got it and I'm used to using it . I do however need some sort of sealant to keep the paint happy - I buffed the very tired old paint (previous owner didn't wash the car for years at a time, I swear), and whilst it would shine well, stuff would just stick to it and stain it.

Just to clarify, I'll be using an electric rotary polisher, not a DA / random orbital one - the air sander runs more towards 10000RPM

[the other pc]

Re: Wet or dry? Fresh paint...

... My local paint factors sells Mirka rather than 3M disks - are the Royal Micro sanding disks up to it?...

The Mirka system works great with the DA!

Depending on the paint's hardness and level of orange peel you'd typically start by dry sanding with Royal #1500 or #1200 then pull out those scratches by wetsanding with Abralon #2000. To make the buff out really easy you can finish up by wetsanding with Abralon #4000.

Ask your supplier or check with Mirka directly to see if they have a factory representative in your area. They should be able to walk you through the process in detail.


PC.