Polishing questions

[little.dipper]

Hello. I just finished my final clearcoat on my first refinish job. I'm going to wait a few days, then do the finish sanding and polishing. I wasn't able to find the polish that was mentioned in ReRanch's article (Finesse It II, I believe it's called), so I got an auto polish called Meguiar's Deep Crystal System Polish. Does anyone have any idea if something like this will work? A few of the polishes available said not to use over laquer, so I stayed away from them, but this seems to be a pretty straight forward polish.

Also, this seems like a silly question, but when I'm doing my final block sanding, is it proper to sand in random circles as if I was buffing it, or should I sand in one direction?

And finally, in a somewhat unrelated topic - I recently bought a new pickguard that has alot of the routing scratches showing from where the pickup holes were cut out (a very sketchy job). Is there any way to kind of smooth those out, possibly by fine sanding? I know it's plastic, but I didn't know if maybe there was a secret to it.

Thanks for any help.

Dave

[Lex Luthier]

I've used the Meguiar's compounds, #2 - #9 - #7, in that order.

Always sand in one direction, even on a painted surface try to go with the grain of the wood. Do not sand in circles.

EDIT:Regarding Drak's post, wait at least one week. If you're using lacquer, waiting a month is best. I once refinished one of my Strat's neck's with Deft gloss from a rattle can, and waited over three months before I did the final sanding, and it was still soft.

[Drak]

Hello. I just finished my final clearcoat on my first refinish job. I'm going to wait a few days, then do the finish sanding and polishing

_____________

A few ----DAYS???----

[JTisMe]

Dave, you didn't mention what type of finish you used, but acrylic urethane clear systems from PPG and Dupont can be ready to sand overnight. The tech sheets provided with these products, or available on the web at the manufacturers site, will give more specific recomended times based upon the particular product selected.

-jeff

[little.dipper]

Well here's what ReRanch 101 says:

After allowing the instrument to dry at least three days (with nitrocellulose lacquer, the longer the better) final sanding and polishing can be done.

I used acrylic lacquers from an auto store. So how long should I wait before final sanding? This is my first refinish so I really don't know. Thanks.

Dave

[litchfield]

usually within a week.

[Gorecki]

Well here's what ReRanch 101 says:

After allowing the instrument to dry at least three days (with nitrocellulose lacquer, the longer the better) final sanding and polishing can be done.

I used acrylic lacquers from an auto store. So how long should I wait before final sanding? This is my first refinish so I really don't know. Thanks.

Dave

You'll probably want to wait about a month. I've heard Acrylics still being soft after a month.

The big clue, if it still smells, it's not ready yet.

Otherwise, use the search feature here. Questions like this are often asked.

[Lex Luthier]

I used acrylic lacquers from an auto store. So how long should I wait before final sanding?

You mean like car touch-up paint? I've used that two or three times, and got fed up with the fact that it seemed to stay kind of soft for, well, ever basically.

[Drak]

Plan on a MONTH, 2 is BETTER.

Do the SNIFF TEST. If you can smell any fumes, any -HINT- of fumes, keep it in the closet until you can smell NOTHING.

This will normally take about a MONTH.

usually within a week.

[westhemann]

drak is right...i have never been able to buff laquer that quickly...the longer you wait,the better it works

[Jivin]

I have some acrylic stuff ive just used to paint a design onto a body I have here and it says you can start buffing out the clear after a week, provided its stored in fairly neutral environmental conditions. I was going to leave it 2 or 3 to be safe... but 2 months seems a bit drastic? Im aware nitrocellulose lacquer -needs- to be left for quite some time before its good to go, but considering oodles of reading basically led me to beleive acrylic automotive paint sets quicker... and now its being said it never cures enough to be not considered soft? :S

Not that I mind waiting, so I think ill just use draks sniff test

Edited September 8, 2004 by Jivin

[Drak]

Reasons To Wait:

1) If it's still soft, it'll scratch easier.

Once you've buffed it out, you're going to assemble it and play it...while it's still soft and still curing...I don't spend the better part of a year building a guitar just to rush everything at the last minute and have a guitar that will scratch at the drop of a hat.

2) The longer you wait, the more the finish will have 'settled in', so when you do your levelling, the chance of any depressions or sink spots showing up later on is lessened.

If you level and buff too quick, you'll have a finish that will settle in later on and be very UNFLAT. It will be full of waves and depressions and pore sinks.

Again...I don't spend the better part of a year building a guitar to have a finish full of sinkholes and waves in the finish. If you're OK with that, hey, you go baby.

3) If it's not cured, when you start your levelling, going thru the grits, the finish will clog your sandpaper easily and make the finishing a real pain in the arss.

Then you will get frustrated.

Then you will start to compromise

Then you will start to rush it, or not be thorough enough

Then you will have ruined everything you worked for up to this point.

4) Also, the sandpaper will cut deeper into the finish, making it harder to get those same scratches back out as you move up in grits.

5) The longer you wait, the harder the finish becomes.

The harder the finish is when you buff it out, the glossier it will become when buffing.

The harder the finish is, the better it reacts to levelling and buffing.

Basically, you'll wind up with a suck, poor-grade, second string finish job.

So, if you want a guitar with lots of humps and bumps and depressions 6 months down the road, with a finish that probably wasn't buffed out 100% properly, that still has deep scratches in it from the levelling, then go right ahead an buff after a few days.

Or as one put it, 'within a week'.

This obviously does not pertain to those reactive finishes that DO cure 100% within a few days. But if you're using a finish like that, you already know what you're doing. Most amateurs don't use reactive finishes.

[Jivin]

Hmm

Food for thought

Cheers Drak

- Dan

[erikbojerik]

Yeah, I think most of the directions on acrylic rattle cans might have been written with the automotive user in mind. But take a close look at any automotive finish...definitely not guitar-worthy.

Listen to Drak, you can't argue with results.

Maybe that's why he's got like a dozen projects going at once...makes it easier to wait for the finish to cure.