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UkulelesRcooL
05-28-2016, 07:26 PM
Seems the top of a Padauk Uke is getting cloudy as the polish is being applied.
The alcohol spirits off as the rubber moves in circles and overlaps on the uke but their seems to be a cloudiness to the finish now.Not like it was in the beginning, Not sure what is being done wrong. Im not applying the the polish but if I were the same thing may be happening.
Any suggestions would be appreciated..
Thanks

sequoia
05-28-2016, 08:25 PM
This is usually caused by a humidity/moisture problem. Water and shellac do not mix = cloudiness. Seeing where you live, not surprising. Fixable. Don't despair.

Michael Smith
05-28-2016, 08:48 PM
Is your alcohol pure enough. It can pick up water if exposed to air.

UkulelesRcooL
05-29-2016, 06:22 AM
The alcohol is 190 proof....kept in a mason jar.. I believe my friend has kept the top of the jar on it... Ive been away for the last two weeks and hes been working
on the uke during that time. I know that the shellac has a shelf life too so I wasnt sure if that maybe that was the problem as its over 3 weeks since we mixed it.
Im just going by what hes told me.. He was thinking it could be that hes used too much oil..
I will see him today and can ask him about the cut being exposed to the air.
That totally makes sense now that I think about it.. the same thing happens to nitro... it gets cloudy with too much moisture..
Thanks Sequoia and Michael for your responses...

UkulelesRcooL
05-29-2016, 08:14 AM
Fixable. Don't despair.
Heh... ok... what would be the fix for this?
Sanding? wiping down with straight alcohol? Im not sure how to go about getting it on the right path.
Despair hasnt set in yet.. but.. Im sure its right around the corner.. ;)

Also I was wondering about finishing the polish... Level sanding Im thinking with 600 grit sand paper and then applying another coat of shellac and letting dry then spiriting it off..
that would be finishing it wouldnt it?
Or would it be more of what is done with Nitro.............. 600, 800,1000, 1200 or 1500 then 2000 and buffing...
Really.. Im going to get a book or something on this... watching videos online and reading bits here and there arent cutting it..
Thanks for any help..

sequoia
05-29-2016, 07:01 PM
If moisture (from very high humidity) is a problem clouding the finish, you can try using a hair dryer to gently try and drive off the water. Gently. Try a small area and then wait... wait.
See if it starts to clear.

I've used shellac that is a year old and never had a problem... Here is the thing though, you didn't do the finish and your friend did and you were not there so who knows what happened. And then there is the issue with the too much oil. This could be the problem and that is not good. The whole issue is becoming cloudy. Of course you can just take the finish off and start over. Sometimes that is the best way to go. Just sand it off and try again.

Michael Smith
05-29-2016, 07:30 PM
If you are starting at 190 proof you still have 5% water. I suggest going to a product that is close to 100%. You can buy isopropyl that is 99% or shellac thinner that is close to 100% alcohol. The only advantage of using Everclear 190 proof grain alchohol is that you can pour a little in your orange juice to make the french polishing chore go a little easier. But you can do that anyway and use the water free products for your finish.

Allen
05-29-2016, 08:03 PM
The thing with French Polishing is that it's very thin as far as finishes go. If you start out sanding P600 and working your way through the grits, I'll bet the farm that you cut through to the timber, and then you're back to square one.

If you don't know how much oil was added to the mix, and was a bit more added for subsequent sessions? How much was used on the rubber when applying......well then you really are better off to suck it up and strip that finish off and start again.

Michael N.
05-30-2016, 02:46 AM
It's impossible to get 100% alcohol and it's probably difficult to get 99% alcohol too. I know that they sell it as 99% Iso (I buy the stuff) but I suspect that it's a little less than 99% by the time that we use it. I doubt that it's the strength of the original alcohol that is causing the issue but it could be that polishing in a rather high humidity could be trapping moisture, coupled with the oil and it will form an emulsion. I'd try the gentle heat advice, often it will drive off the moisture.
Even a non drying oil will form a gummy deposit if (a) too much is used (b) the oil isn't removed between polishing sessions. If that happens you usually see witness lines when trying to rub it out, similar to using an oil varnish. That's why it's always important to remove as much oil as you can. You can gently mop it up with kitchen absorbent paper or even baking flour, then spirit it off in the normal way. If you use very little oil there really isn't a need to use the paper or the flour.
The highly processed shellacs (dewaxed blonde/platina) have a relatively short shelf life in the dry state. Waxy types seem to last decades. Once mixed you might get 4 months or so out of the dewaxed, bleached varieties. They slowly lose their drying/hardening ability. Again, waxy types have a shelf life a little longer, maybe 6 months or more. A lot depends on local conditions and how fresh the dry shellac was in the first place. I've never seen old shellac cause the cloudiness issue though, usually old shellac is difficult to dissolve in alcohol or it doesn't dry/harden very well.

UkulelesRcooL
05-30-2016, 04:29 PM
The only advantage of using Everclear 190 proof grain alchohol is that you can pour a little in your orange juice to make the french polishing chore go a little easier. But you can do that anyway and use the water free products for your finish.

Too funny... and thanks for the info.. my friend got this stuff from a friend of his that made it.. so I think its has a bit more kick than everclear and I got the opportunity to taste it.. Very nice.. but I dont think I want to make a habit of it even if it was some of the smoothest stuff Ive ever had..

UkulelesRcooL
05-30-2016, 04:37 PM
If moisture (from very high humidity) is a problem clouding the finish, you can try using a hair dryer to gently try and drive off the water. Gently. Try a small area and then wait... wait.
See if it starts to clear.

I've used shellac that is a year old and never had a problem... Here is the thing though, you didn't do the finish and your friend did and you were not there so who knows what happened. And then there is the issue with the too much oil. This could be the problem and that is not good. The whole issue is becoming cloudy. Of course you can just take the finish off and start over. Sometimes that is the best way to go. Just sand it off and try again.

Well noted... Thank you for your advice and time...
I will pass on the info to my friend and also Ill keep it in my own notes... and maybe after Ive done this a few times Ill actually have it in my head...
I really appreciate you all taking time out to answer my questions.. thanks.!!
Im finding I actually learn more when I fail... or someone that I know does... It really sinks in...

UkulelesRcooL
05-30-2016, 04:39 PM
The thing with French Polishing is that it's very thin as far as finishes go. If you start out sanding P600 and working your way through the grits, I'll bet the farm that you cut through to the timber, and then you're back to square one.

If you don't know how much oil was added to the mix, and was a bit more added for subsequent sessions? How much was used on the rubber when applying......well then you really are better off to suck it up and strip that finish off and start again.

I agree..... sometimes sucking it up is the best way..
Hopefully we wont have to do that but Im prepared to if needed...
;D

UkulelesRcooL
05-30-2016, 04:41 PM
It's impossible to get 100% alcohol and it's probably difficult to get 99% alcohol too. I know that they sell it as 99% Iso (I buy the stuff) but I suspect that it's a little less than 99% by the time that we use it. I doubt that it's the strength of the original alcohol that is causing the issue but it could be that polishing in a rather high humidity could be trapping moisture, coupled with the oil and it will form an emulsion. I'd try the gentle heat advice, often it will drive off the moisture.
Even a non drying oil will form a gummy deposit if (a) too much is used (b) the oil isn't removed between polishing sessions. If that happens you usually see witness lines when trying to rub it out, similar to using an oil varnish. That's why it's always important to remove as much oil as you can. You can gently mop it up with kitchen absorbent paper or even baking flour, then spirit it off in the normal way. If you use very little oil there really isn't a need to use the paper or the flour.
The highly processed shellacs (dewaxed blonde/platina) have a relatively short shelf life in the dry state. Waxy types seem to last decades. Once mixed you might get 4 months or so out of the dewaxed, bleached varieties. They slowly lose their drying/hardening ability. Again, waxy types have a shelf life a little longer, maybe 6 months or more. A lot depends on local conditions and how fresh the dry shellac was in the first place. I've never seen old shellac cause the cloudiness issue though, usually old shellac is difficult to dissolve in alcohol or it doesn't dry/harden very well.

thanks Michael for the info... I didnt know that shellac lasted as long as that... I thought once I mixed it I had 3 weeks... which if you think about it would really suck...
I really have to get some reference books on this process... you guys have been a great help..

Allen
05-31-2016, 12:48 AM
I would highly recommend Tom Billis' video tutorials on French Polishing if you are wanting to develop this skill.

They cover all aspects of materials, and techniques. Video is very good, and commentary describing the process guides you through from start to finish.

http://theartoflutherie.com/french-polishing/

UkulelesRcooL
05-31-2016, 08:28 AM
I would highly recommend Tom Billis' video tutorials on French Polishing if you are wanting to develop this skill.

They cover all aspects of materials, and techniques. Video is very good, and commentary describing the process guides you through from start to finish.

http://theartoflutherie.com/french-polishing/

Thanks Allen!!

kkimura
06-01-2016, 03:25 AM
Naphtha (lighter fluid) also works to clean French polish finishes.

Sven
06-01-2016, 04:44 AM
I will watch the video Allen linked to, I'm always looking for more information and inspiration. I found this article very good a while back. I had struggled with French polish for a while and the article / tutorial really helped me take a leap forward. I have now adapted the techniques to suit me better but I did follow it closely at first, getting better and more consistent results than before.

https://www.guitarsint.com/article/Introduction_How_To_French_Polish_Classical_Guitar s

Michael N.
06-01-2016, 02:23 PM
There is another way, which is brushing the stuff on. Half the time but requires just as much skill, perhaps more. Believe me, the results are just as good. In fact I doubt that anyone can tell the difference. I can't.

Sven
06-02-2016, 12:20 AM
For my modified process I too brush the first coats on. After levelling with scrapers and steel wool I switch to the pad. I only use oil as lubricant for the last layers.

sequoia
06-02-2016, 05:53 PM
Yes, yes. I too use brush on the early stages then switch to the nose/cloth thing as the layers start to build. The problem with brush applied at the later stages is the dreaded "little ridges" that can form. I hate the little ridges. Fixable of course, but lots of wet sanding recovery. I've pulled it off before, but it gets tricky and one must be almost an artist to lay it on. The perfect stroke. It works but maybe not for the neophyte tyro.

Michael N.
06-02-2016, 11:26 PM
Yes, yes. I too use brush on the early stages then switch to the nose/cloth thing as the layers start to build. The problem with brush applied at the later stages is the dreaded "little ridges" that can form. I hate the little ridges. Fixable of course, but lots of wet sanding recovery. I've pulled it off before, but it gets tricky and one must be almost an artist to lay it on. The perfect stroke. It works but maybe not for the neophyte tyro.

It's more usually termed spirit varnishing but I guess it depends on how much you put on with a brush and how much you put on with the pad.
The method for spirit varnishing is to brush all the coats on, can be as many as 16 or even more. Watery thin shellac. Seems like a lot of work until you realise that one coat takes less than 5 minutes to put on. You don't even need to clean or wash the brush. It's all left to harden for a couple of weeks or so and then you go through the grits and polishing compounds. You can get it looking like glass should you wish. I don't do that because I'm not fond of that glass like look, it's a bit too hard and cold looking for my tastes. I get all the coats on and rub down with something like 600 or 800G. That's it, just the one grit. Of course it leaves all sorts of scratches in the finish which is where the pad comes in. Very thin shellac padded on in very straight lines, probably over a couple of days. The shellac fills in all the scratches and the cloth leaves very feint but straight lines in the polish. Just enough to knock off the edge and avoid a very glassy looking surface. Takes a bit of practice but it's a pretty quick way of finishing an instrument to near full gloss.
The modern method of French polishing also seems to go through all the grits. It's not really how it was done in the classic method. They would finish with the cloth too, not polishing compounds and buffing. I guess it all depends on what type of look you want to achieve.
This is just about my limit, glossy but there's a touch of softness to it.

http://i56.photobucket.com/albums/g193/mignal/100_0204.jpg (http://s56.photobucket.com/user/mignal/media/100_0204.jpg.html)

Sven
06-03-2016, 12:26 AM
Michael, fanx for the run down. Do you glue the bridge after finishing? I glue mine before because I don't like scraping off the finish, but the bridge being there complicates polishing a lot. As does the fretboard.

Michael N.
06-03-2016, 03:03 AM
After. I go around with bridge with the scalpel, then scrape it off. I find that easier than trying to polish around a bridge. Except when I'm using a wipe on oil finish, it's easy to polish around a bridge with an oil finish, gives you so much more time.

sequoia
06-03-2016, 07:54 PM
Yes, thanks for the rundown Michael. Whatever works. I like the picture of the finish. I'm a sucker for shiny myself. I do however agree that it can reach ridiculous lengths of glossiness. I mean, is it necessary to sand to 100,000 grit? I don't think so. I have settled on about 3500 and I'm good with that. The question to me is not how shiny the finish is, but how thick the stuff is. Anybody can slather a thick armored coat of shellac on and polish it to mirror brightness. The challenge to me is keeping it reasonably thin and yet bright and protective. Below pix polished out to about 3,000. Not to buffed and it is quite thin. I'm happy and the ukes sound great.

91686

91687

Michael N.
06-04-2016, 10:51 AM
Yes. Many think it's the absolute height of F'polishing, rub it down and buff it until it's good enough to see Pluto. It's pretty easy if you put enough stuff on in the first place. Hard to see how it can go wrong. It's much harder to finish with the cloth and produce a good finish though. Somehow it's seen as being inferior and showing less skill. It's the other way around if you ask me. Then again I was taught by an old school French polisher who decried the abrasive polishing method.

UkulelesRcooL
06-27-2016, 02:57 PM
Update on the Cloudiness....
He sanded it and rubbed it down a couple more times and it took care of it...
It looks great now.. very nice.. Thanks for all the input...