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Polyurethane, wet sanded with 1000...what next??

fretman_2
December 2nd, 2011, 11:03 PM
I've sanded my polyurethane coat with successive grits to 1000 and went straight to turtle wax to no avail...still that dull sheen that was present after the 1000 grit. Do I need a polishing compound next.

I tried the turtle wax with a cloth...not a polishing pad on a drill.

Tnx,

Sleph
December 3rd, 2011, 12:10 AM
Polyurethane is not meant to be sanded and polished. Sprayed in the correct environment and with the right technique you get a gloss off the gun.

With a polishing pad you will probably achieve more of a gloss - albeit with swirly buff marks - I'd scuff it up and give it another coat. (but you will need to get every bit of that turtle wax off first)

HardlyDangerous
December 3rd, 2011, 12:29 AM
even in perfect conditions some dust an debris can and usually will find its way into and onto the paint. I wet sand and polish all my finishes not matter what it is. I finish wet sanding with 2000-2500 then polish with a polishing wheel and fine compound.
No way will you get a shine polishing after just 1000 grit. thats still way too heavy for a finish.



FWIW I usually clear or paint after 800. it leaves a smooth finish with enough bike for most paints. some hi build paint I apply after 600 but no heavier.

fretman_2
December 3rd, 2011, 09:12 AM
even in perfect conditions some dust an debris can and usually will find its way into and onto the paint. I wet sand and polish all my finishes not matter what it is. I finish wet sanding with 2000-2500 then polish with a polishing wheel and fine compound.
No way will you get a shine polishing after just 1000 grit. thats still way too heavy for a finish.



FWIW I usually clear or paint after 800. it leaves a smooth finish with enough bike for most paints. some hi build paint I apply after 600 but no heavier.

Will 0000 steel wool do better than the 1000 grit before going to the polishing wheel?

Tnx,

Sharp5
December 3rd, 2011, 09:43 AM
I would say we sand up to 2000. Then use a light compound followed by swirl remover.

Keyser Soze
December 3rd, 2011, 01:04 PM
Much depends on the particular product involved. Some polyurethanes never get hard enough to truly polish.

I'll second the approach of applying another coat or two. Since you have already levelled the surface very nicely go with light thin coats.

fretman_2
December 3rd, 2011, 02:40 PM
Much depends on the particular product involved. Some polyurethanes never get hard enough to truly polish.

I'll second the approach of applying another coat or two. Since you have already levelled the surface very nicely go with light thin coats.

Maybe that's it...never got hard enough to polish. I did make some headway wet polishing with 2000 then turtle wax polishing compound...then turtle wax itself. Not perfect...but acceptable shiny.

HardlyDangerous
December 4th, 2011, 05:32 PM
a good polishing compound will do wonders.
the cheapest stuff I would use is Swirl X or scratch X.
I used turtle wax polishing and rubbing compounds years ago. They were garbage IMO.
I use a machine and machine compounds but a foam pad on a drill with scratch x or swrirl x works decent.

2000 is the minimum for polishing. for black or candy surfaces I use 2500

JDolan121
December 6th, 2011, 01:05 AM
3M Trizact system (available at auto parts stores) sand out to 3000 grit and polish. I do it every day on polyurethane and it looks fantastic (but it ain't cheap).

Nick JD
December 6th, 2011, 02:35 AM
I've found that often the secret to finishing is to stick with one brand from start to finish (heh) if you can. The whole system is worked out.

1 paint manufacturer; 1 paint finishing system. No compatability issues; money well spent because you feel satisfied not frustrated. You want to finish a guitar, not dread it! :grin:

744UtkzXdM8

Jawknee5
December 8th, 2011, 02:54 AM
I'm getting ready to wetsand and polish a body I refinished(sprayed clear today) in Minwax "fast drying" polyurethane from a rattle can. I selected it because if its ment for hardwood floors, so its GOTTA be tough enough for a guitar. I wanted an extremely durable finish.

Im unsure about cure times and all that stuff, but I'm waiting at least 3 weeks before I do anything to it. That's just an average of what I've read online. Just to be safe.

This is my first refinish, so I'm pretty clueless about getting that nice shine... Any tips for Wetsanding the curves of a guitar?

I just want it to stop stinking...


How long until it stops stinking?!

fretman_2
December 8th, 2011, 10:17 AM
I rough sanded the finish and then put another coat of polyurethan on. That went on pretty smooth and glossed right up. There were a few areas that needed tending to so I let the coat dry for 4 hours (the can says 3 to 4), then hit it with 220 as on the instructions. I cleaned up the dust then put the next coat on and, as it dried somewhat, it looked rough...as if the grain was raised. I know that can't be because there are way too many coats on the thing to have sanded down to wood. WTF!?!?! I sanded it back this morning and put on another coat that went on smooth. I was thinking I had this thing licked then it went rough again!

I'm about to give up...LOL. I'm thinking that now that I can build a guitar, I'll never be able to properly finish it!

I think I'll give the poly a day or two to cure, then sand it back level and try again. Maybe the Minwax brush on poly just isn't my thing.

JDolan121
December 8th, 2011, 01:03 PM
I'm getting ready to wetsand and polish a body I refinished(sprayed clear today) in Minwax "fast drying" polyurethane from a rattle can. I selected it because if its ment for hardwood floors, so its GOTTA be tough enough for a guitar. I wanted an extremely durable finish.

Im unsure about cure times and all that stuff, but I'm waiting at least 3 weeks before I do anything to it. That's just an average of what I've read online. Just to be safe.

This is my first refinish, so I'm pretty clueless about getting that nice shine... Any tips for Wetsanding the curves of a guitar?

I just want it to stop stinking...


How long until it stops stinking?!

3M makes a foam block (about 3"X5", maybe 1/2" thick) that works great for wet sanding. Some tips: It takes a lot less water than you think. Wipe the water off often so you can really see what you've already sanded. Use a really good, bright incandescent light (doing it outside in sunlight is better). Fluorescent light can make your eyes overlook some very bad things. Don't oversand. If you think you're gonna cut thru the finish, you probably already did. Stop and apply another coat.

Also, you probably don't need to wait 3 weeks. A couple days should do it. Try to scratch an inconspicuous area (like under the pickguard) with a fingernail. If you can't see the scratch, it's ready...

JDolan121
December 8th, 2011, 01:06 PM
I rough sanded the finish and then put another coat of polyurethan on. That went on pretty smooth and glossed right up. There were a few areas that needed tending to so I let the coat dry for 4 hours (the can says 3 to 4), then hit it with 220 as on the instructions. I cleaned up the dust then put the next coat on and, as it dried somewhat, it looked rough...as if the grain was raised. I know that can't be because there are way too many coats on the thing to have sanded down to wood. WTF!?!?! I sanded it back this morning and put on another coat that went on smooth. I was thinking I had this thing licked then it went rough again!

I'm about to give up...LOL. I'm thinking that now that I can build a guitar, I'll never be able to properly finish it!

I think I'll give the poly a day or two to cure, then sand it back level and try again. Maybe the Minwax brush on poly just isn't my thing.

4 hours was probably too soon. What you most likely did was "curl" the ends of the sand scratches. Let it cure for 24 hours, and hit it again with 400 wet/dry using water with a couple drops of dishsoap in it (acts as a lubricant) and see if that doesn't work. The 220 is too aggressive for what you're doing, anyway.
By the way, I just live over in Fairhope. PM me if you ever want to get together and play...

fretman_2
December 8th, 2011, 01:20 PM
4 hours was probably too soon. What you most likely did was "curl" the ends of the sand scratches. Let it cure for 24 hours, and hit it again with 400 wet/dry using water with a couple drops of dishsoap in it (acts as a lubricant) and see if that doesn't work. The 220 is too aggressive for what you're doing, anyway.
By the way, I just live over in Fairhope. PM me if you ever want to get together and play...

Cool...glad to see a TDPRI'er lives close by. I'll send a PM your way.

HardlyDangerous
December 8th, 2011, 09:32 PM
220 may be ok for fixing but too heavy to finish over with a clear. you will see the difference between the sanded and non sanded areas as light hits it with that heavy of a paper.
800 is what I normally clear over however if I have to sand one area for a repair I will sand the entire surface so you dont see that repaired area.

when sanding to ready for polishing stay away from the edges until your on your finest grit then lightly sand the edges checking often. Only remove just enough to flatten/level the surface.

Colt W. Knight
December 9th, 2011, 01:57 AM
No way will you get a shine polishing after just 1000 grit. thats still way too heavy for a finish.



Depends on what rubbing and polishing compounds you use.

Nick JD
December 9th, 2011, 03:36 AM
Depends on what rubbing and polishing compounds you use.

I polish after 1200. Have done after 800.

HardlyDangerous
December 9th, 2011, 08:40 AM
Why waist time and money on compounds and polishing pads cutting a 800-1000 grit sanded surface to a mirror shine when for $3 you can grab a package of 2000 grit and have a fine finish ready for a fine cut polish. After 2000 you can do it by hand with mild polishing.

just because you can does not mean you should

braderrick
December 9th, 2011, 09:54 AM
I think our "Bucko" Steve only sands to like 800 or 1000 doesn't he? He sure gets some great looking results to me. And I only remember him using one or two at the most polishing compounds. If I remember correctly that is.

HardlyDangerous
December 9th, 2011, 06:22 PM
I've sanded my polyurethane coat with successive grits to 1000 and went straight to turtle wax to no avail...still that dull sheen that was present after the 1000 grit. Do I need a polishing compound next.

I tried the turtle wax with a cloth...not a polishing pad on a drill.

Tnx,

you guys will argue about anything.
hand polishing with turtle wax after 1000 grit.

yeah its going to be dull.

Polish anything long enough you will eventually smoothen it then burn the surface or remove it.
Im a professional painter. Custom paint is what I do, sure I could spend hours polishing out heavy grit swirls and curly q's with heavy compounds and elbow grease. But why? they make finer grit paper for a reason.

fretman_2
December 9th, 2011, 11:16 PM
Well...the initial coats were oil based minwax poly. They've had a month or so to cure and were very hard. The surface was orange peeled so I sanded back to level and applied a coat of gloss minwax poly. The first coat went on smooth with the exception of some pooled areas. I sanded with 220 after four hours like the can says. Apparently there were some areas under the surface that hadn't quite hardened enough and were milky in appearance after sanding with 220. The next coat looked like it raised the grain, but of course it had not.

Tonight I sanded and scraped those final (mostly soft) two coats away...down to the fully cured area. Apparently 4 hours isn't nearly enough drying time and I need to wait 24 hours before sanding and applying another coat. Apparently the finish gummed up on top of the fully cured finish. I had sanded the fully cured finish lightly with 1000 grit before applying the new coats. Maybe I should have sanded with 220 instead of the 1000 to give the finish something to adhere to.

Now I'll be holding my breath when I apply the new coats again.

Tnx,

HardlyDangerous
December 10th, 2011, 12:25 AM
Be sure your humidity and temps are correct.
Not just air temps but work surface temps.. spray light coats . too heavy or uneven paint/work surface temps are the major causes of blushing. Not so much humidity. In fact high humidity is often ideal for some paint applications. However a 10o difference in paint and work surface temps can cause paint to orange peel, blush, etc

1000 preped surface should be ok to clear over.. its far better then a shiny surface if its past its recoat window. use light coats following mfg's recoat/flash over instructions. Remember these recoat windows are based on light coats. If you spray a med/wet coat instead of a light coat your 10 minute or what ever window you have will be GREATLY affected. Only your last coat should be a wet coat.

Colt W. Knight
December 10th, 2011, 01:36 AM
Why waist time and money on compounds and polishing pads cutting a 800-1000 grit sanded surface to a mirror shine when for $3 you can grab a package of 2000 grit and have a fine finish ready for a fine cut polish. After 2000 you can do it by hand with mild polishing.

just because you can does not mean you should

Why spend all that time hand sanding and hand polishing when a buffer can do it for you?

Colt W. Knight
December 10th, 2011, 01:37 AM
I polish after 1200. Have done after 800.

I generally polish after 1000 or 1200. If I do a good job spraying, I can hit it with once with 1000 grit, and then buff it out.

HardlyDangerous
December 10th, 2011, 02:42 PM
cause hes not using a polisher machine.

hes said he did it by hand using turtle wax

im not saying you cant polish out 1000 grit with a machine and quality polishing compounds, im saying its a hell of a lot easier when doing it by hand to have a scratch free surface . the more fine the surface was sanded the faster and easier it is to polish.
custom paint shops never polish after 1000 grit.
If you know how to spray you start wet sanding with 1500 or finer just to level the surface.

musicalmartin
December 10th, 2011, 02:55 PM
I use chroma 1500 .Its a US product specially designed to finish 2K poly.Basically a 1500 grit .Its the only stuff apart from micro cloths that get a perfect high gloss shine .I use it on model racing cars but I have also used it on guitars .Its meant to be buffed on but I just polish it with a cloth .My model racing cars have to be perfect with no blems anywhere as they are sold to customers .

braderrick
December 10th, 2011, 03:28 PM
you guys will argue about anything.
hand polishing with turtle wax after 1000 grit.

yeah its going to be dull.

Polish anything long enough you will eventually smoothen it then burn the surface or remove it.
Im a professional painter. Custom paint is what I do, sure I could spend hours polishing out heavy grit swirls and curly q's with heavy compounds and elbow grease. But why? they make finer grit paper for a reason.

Wow a little full of ourselves are we? All we are saying is the OP says he sanded to 1000 grit and is wondering if he can get the shine from there. The fact is HE CAN and people do it this way. Sorry if some self proclaimed "professionals" don't do it this way, I'm just saying it can be done and many do it this way.

I bought my polishing compounds as a kit and it came with 4 different levels and honestly there is no reason for me to sand any further than 1000-1200 or so.

Its not that big of a deal, you can do it either way, sand to a finer grit and use less buffing compounds or not sand to a finer grit and use more buffing compound.

Either way if you don't have a buffer, you're gonna have to use a little elbow grease and time either sanding or buffing. And you'll have no more chance of burning through the finish while buffing than you will sanding through the finish while sanding haha...

onenotetom
December 10th, 2011, 03:50 PM
The unfortunate thing about the internet is that you always have to decipher who is giving good advice and who is not. Had the OP followed this advice I believe he would have been done.

I would say we sand up to 2000. Then use a light compound followed by swirl remover.

Yes, other systems work but for the inexperienced that is doing it by hand the above is hard to fault.

braderrick
December 10th, 2011, 06:38 PM
I agree 100% and you're right too just as they say "theres more than one way to skin a rabbit" or is it a cat? I think thats how it goes.

fretman_2
December 10th, 2011, 06:44 PM
The unfortunate thing about the internet is that you always have to decipher who is giving good advice and who is not. Had the OP followed this advice I believe he would have been done.



Yes, other systems work but for the inexperienced that is doing it by hand the above is hard to fault.

I did up to 2000 and rubbing compound then polish (both turtle wax) on the cured finish. It never glossed out...only a satin finish.

Colt W. Knight
December 10th, 2011, 06:52 PM
I did up to 2000 and rubbing compound then polish (both turtle wax) on the cured finish. It never glossed out...only a satin finish.

Can you describe your wet sanding and buffing technique?

onenotetom
December 10th, 2011, 07:05 PM
Can you describe your wet sanding and buffing technique?

+1

I did a custom motorcycle tank and fenders for a guy one time. Sent it to him in California for him to do the final wet sand, buff then install. He had the same results. As it turned out, the compound he was using was the white compound that he got at the auto store that was way too course. Once he got the right compound the tank came out perfect. Took quite some time over the phone to find out what he was doing wrong.

Nick JD
December 11th, 2011, 04:36 AM
cause hes not using a polisher machine.

hes said he did it by hand using turtle wax

im not saying you cant polish out 1000 grit with a machine and quality polishing compounds, im saying its a hell of a lot easier when doing it by hand to have a scratch free surface . the more fine the surface was sanded the faster and easier it is to polish.
custom paint shops never polish after 1000 grit.
If you know how to spray you start wet sanding with 1500 or finer just to level the surface.

Easy to tell everyone they're doing it wrong. Harder to show them how to do it right.

Sounds like you'd be the kind of guy to show everyone how it's done with lots of pictures. I look forward to it. Start a new thread called "How to finish a guitar correctly".

HardlyDangerous
December 11th, 2011, 04:08 PM
Nick JD. im in the middle of a build doing a fuax wood grain transparent job. I will do a step by step on the entire process.

Fretman 2
Get rid of the rubbing compounds. rubbing compounds are for heavy damage and oxidization on painted surfaces. were not repairing paint we are polishing paint.

I said in another post the turtle way compounds are really not that good. Ive used them before and even had people in my shop who have used them and ruined the finish and had me restore it.
If your looking for a hand use paint polish on the local shelves go to pepboys or autozone and grab some Meguirs polish. I actually used to be a dealer for Mothers products but prefer meguires.
Or if your using a machine grab some Meguirs Machine polishes.
The meguires deep crystal system will still work well with a drill/foam polishing pads or by hand with polishing buffs/pads.
step 1 is a heavier compound for removing a dulled finish and swirls
step two is a sealer/glaze
step 3 is a wax
After wetsanding 2000 grit and u are sure you have a perfectly flat surface...use the step 1 with hand polishing pad (not a rag) or foam pad in a drill.
Your going to continue polishing with this first step until ALL the sanding marks and swirls are gone and u have a super high gloss finish. Only after the finish is perfect then move onto step 2. If you still have dull areas keep polishing with the step 1.
Step 2 is a sealer /glaze. The sealer glaze puts natural oils back into the paint and gives the finish that wet look. Its a very fine compound and will not remove much but the very finest swirls and marks left by the step one compound. Then last apply the wax.

I dont have pics of step by step polishing only finished results.

I understand there are other ways to do it and many ways that will work. polishing out sanding marks left behind by 1000 grit or heavier will take 2X longer and a lot more work then a finish thats finely sanded with 2000.

fretman_2
December 11th, 2011, 09:12 PM
I purchased a Harbor Freight random orbital sander with 220 grit and in less than 20 minutes took the problem finish right down to the older cured finish. I then applied another fresh coat of oil based poly and, so far, everything looks good. It's not perfect, but it's shiny. I was very surprised at how fast the ROS works! I'm not saying that I'm going to use poly again, but at least this is workable now.

fretman_2
December 13th, 2011, 11:32 AM
After sanding back to the original cured poly, the new coats of poly worked like a charm.

105537

flyingbanana
December 14th, 2011, 07:01 AM
Easy to tell everyone they're doing it wrong. Harder to show them how to do it right.

Sounds like you'd be the kind of guy to show everyone how it's done with lots of pictures. I look forward to it. Start a new thread called "How to finish a guitar correctly".


"In as many words as possible." :lol:

nadzab
December 15th, 2011, 09:35 PM
Sand to 1000 (1200 is better) then use an orbital buffer with fine-cut polish, then a glazing compound. You'll have a glassy-smooth finish in minutes.

fretman_2
December 16th, 2011, 10:19 AM
Sand to 1000 (1200 is better) then use an orbital buffer with fine-cut polish, then a glazing compound. You'll have a glassy-smooth finish in minutes.

Cool...can you give me an example of a fine cut polish?? An orbital buffer is next on my list.

tnx,

nadzab
December 16th, 2011, 05:46 PM
Cool...can you give me an example of a fine cut polish?? An orbital buffer is next on my list.

tnx,

Sure:

http://www.autogeek.net/3mperllrubco.html

I used "polish" incorrectly in my previous post; you want a compound like the 3M stuff, then use a polish/glaze after that.