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PostPosted: Wed Apr 22, 2009 4:27 pm 
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Walnut
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I am finishing my latest ukulele and I am doing a shellac finish. Here is my finishing schedule:

sanding sealer
light sanding
zpoxy
sanded down to 220
sanding sealer
light sanding
6 coats of shellac
I went straight to wet sanding with 600
was possibly going to go through micromesh 1500-3500
should I have skilled 600 and went straight to the micromesh?

After wiping off any slurry and drying it off I noticed a bunch of (flecks?). It almost looks like glitter in the finish. Do I respray it or do I just keep sanding?

any help would be appreciated.


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PostPosted: Wed Apr 22, 2009 4:58 pm 
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Walnut
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first, replace the word "skilled" with "skipped"

second, after the 6 coats of shellac i had a slight orange peel which is why i sanded. could i have buffed the orange peel out?


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PostPosted: Wed Apr 22, 2009 6:13 pm 
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Koa
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Shawn,
I typically sand the bare wood to 220 or 320, then apply z-poxy, then brush on shellac straight from the can, directly to the zpoxy. I use the Bullseye Wax free sanding sealer as my shellac. I would apply 2-3 coats a day about 2-3 hours apart. After 2 days of this, let it sit for 10 days, then come back and level sand with 600 grit all the way to 2000 grit wet/dry. You could go to 600 grit, then go to micromesh 3400 on up to 12,000 if you want, then use some plastic polish #2 to hand buff it out. If you are doing a satin finish, then just level with 600 grit, then 0000 steel wood and some renaissance wax and your golden.

If I had flakes in my finish, I'd sand back and start over. I had the same problem on my last, even using Naptha to clean when sanding, and it still left some slurry marks. A few is okay, but if you have a lot, then you will need to sand back until they're gone. Good luck!

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PostPosted: Wed Apr 22, 2009 9:46 pm 
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Not that I want ot highjack this thread, but I'm currently trying stuff with shellac these days. I am trying out brushing on shellac with a 2lbs cut. I was wondering if a thicker mix would work better?

Thanks!

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PostPosted: Wed Apr 22, 2009 10:32 pm 
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Brazilian Rosewood
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A couple questions...

1. How long did you let the shellac dry before sanding? It skins very quickly, but 6 coats can take a couple weeks to really dry hard depending on how thick they were put on... especially if brushed.... If you waited an hour or two or overnight... it was still way too soft. You will end up with pills and weird globs stuck in the finish. You can test it with your fingernail. If your fingernail indents... it needs to dry more.

2. What did you wet sand with? Hopefully NOT water.... Paint thinner is the traditional wet sanding medium for Shellac. I am sure Naptha or pump gas would also work well enough.... but paint thinner is Cheap cheap cheap. When the shellac is still a little wet (See #1) -- the alcohol in it will absorb water and suck it into the finish and make it hazy or milky. Caveat..... Extremely flammable. Don't do dumb things that would cause you to burst into flames.... like smoke.... or use an electric sander.....

Personally, what I would do at this point...

Hang it up someplace indoors where it will get some air circulation.
Let it dry for a week... Resist the urge to fool with it any more tonight..... Resist I tell you.... BE STRONG!
Next Tuesday or Wednesday.... Wet sand with Paint thinner and see how you are doing. Use LOTS of paint thinner. Keep that sandpaper wet and use light pressure on pills and such. It will probably cooperate enough to get it sanded down and levelled out.... unless you start sanding through in spots.

Be very careful with it after that wet sanding..... it will still probably be soft enough to mar..... Then you can hang it up for ~1 month... and watch your beautiful mirror flat finish suck down and show the grain lines in the wood.

Good luck

John


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PostPosted: Thu Apr 23, 2009 5:44 am 
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"watch your beautiful mirror flat finish suck down and show the grain lines in the wood."
Thanks for that! gaah


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PostPosted: Thu Apr 23, 2009 7:12 am 
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Brazilian Rosewood
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Finishing is the hardest part of this process. We all want to finish it overnight but it takes time for a good result. I use both shellac and nitro. Both need a good amount of curing time. I also will fill between seal coats. The only woods that I don't fill are Maple and cherry. I spray but I don't think it matters that much.
You cannot buff out orange peel. You need to level sand. One thing I learned is that you have to look at finishing in 3 separate parts. Seal and fill as the first part , this is the foundation of what you will see as the end result.
2 nd the base coat , this should be a build of about .012 to .016 . Let this cure and level sand using up to 800 grit. Let cure about 3 weeks
3 rd finish coat , this is a build of 2 to 3 coats . This should be more level after cure time and you can start leveling off at 600 wet sand and go up to 2000 , then buff and polish.
If you don't allow a cure time you will see the finish pull into every little void and grain line

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PostPosted: Thu Apr 23, 2009 12:01 pm 
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Walnut
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i guess im trying to speed up the process. im way overdue for a delivery.

i will slow down and adhere to the processes mentioned. am i able to use zpoxy after i have already applied my initial coats? i noticed some slight grains still showing. -shawn


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PostPosted: Thu Apr 23, 2009 12:15 pm 
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Koa
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Shawn,
I also had some grains showing after applying 3 coats of zpoxy, and had about 3 FP sessions of shellac on it. I decided to use medium viscosity super glue and used my finger with a rubber glove to get it into the pores. Just before it started to harden, I wiped off with a thick paper towel. Waited about 15 min, then sanded level. I did this in small sections, and it worked great! Good luck!

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