| Official Luthiers Forum! http://www.luthiersforum.com/forum/ |
|
| Need French Polishing advice - please. http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=23393 |
Page 1 of 1 |
| Author: | Ray Pepalis [ Tue Aug 11, 2009 5:04 pm ] |
| Post subject: | Need French Polishing advice - please. |
I'm french polishing my first guitar (Cedar top). The back and sides were Z-Poxied, and had a nice glossy surface before FP, and are becoming pretty glossy with FP. The top, was given a light coat of shellac prior to FP, BUT does not seem to be leveling out very well. It looks like what some people call "orange peel". Shall I try to level the top with abrasive paper? Any suggestions will be greatly appreciated. Thanks, Ray |
|
| Author: | David Newton [ Tue Aug 11, 2009 7:24 pm ] |
| Post subject: | Re: Need French Polishing advice - please. |
It's pretty! Just keep polishing. Has your arm fallen off? Stop when it does. |
|
| Author: | SStallings [ Wed Aug 12, 2009 8:24 am ] |
| Post subject: | Re: Need French Polishing advice - please. |
I'm far, far, far from being an expert but I've had the same experience, i.e., that the top is "rough" while the backs and sides are "smooth" and it used to drive me nuts. Keep putting on the FP the same way and the top will come around, at least in my experience. |
|
| Author: | JJ Donohue [ Wed Aug 12, 2009 9:15 am ] |
| Post subject: | Re: Need French Polishing advice - please. |
Hi Ray...I've done a few things to get it smooth when I've felt that the surface was irregular. First, I make sure I'm doing the spiriting off with a DA pad only...and pressing harder as the trail starts to fade. This seems to help dissolve the high areas and level out the surface. Second, I've been successful in sanding with 800 grit and a small amount of olive oil. Then follow it up with more spiriting to remove the oil and grit. Having done this for awhile taught me the merits of proper spiriting off which led me to end up doing the spiriting off process properly on the first place. Learning to press progressively harder as the pad dries out and the vapor trail becomes less visible seems to be my key observation. |
|
| Author: | Michael Dale Payne [ Wed Aug 12, 2009 10:39 am ] |
| Post subject: | Re: Need French Polishing advice - please. |
You can not get orange peel when doing a Fp finish. You can get ridging caused by the weave of the muneca material and the figure eight motion of the body session. But orange Peel is spits of finish caused in a spraying session. I suppose some may call ridging orange peel as a generic term but in truth they are different things. The key to building a smooth Fp finish is in the second process of a body session. The spirit-off. Now I do not recommend using a pad with nothing but DA to spirit off with. This will pull shellac off the surface into the pad and will likely lead to sticking or unlevel build issues. The second process in French polishing (spiriting off) takes care of the unevenness of distribution of the previous body session if done correctly. If you skip this second process between body sessions then you tend to build unlevel causing your self more work down the line. The object in spiriting off is to melt over the high spots. Use the muneca that you body with . The residual shellac in the inner pad is important during all Fp process. Your load when spiriting off should be one to two drops of shellac to keep the muneca wicking, four to six drops of alcohol to be your high solvent load and one drop of oil smeared over the muneca face just to prevent the pad form sticking when you first touch out on the body. The motion spirit off motion is like buffing a shoe. The spiriting stroke should be done in straight lines moving from one end to the other end without stopping. It should be a glide on and glide off. The pressure should be firm but not hard. You will have to reload often but never hit the surface really wet. Always tap your muneca after every load to properly distribute the load. Over lap your strokes by approx half the muneca width and work from the center of the body to the edge for one half of the body width then from the center to the other edge. This distributes the meted shellac evenly as you spirit off. |
|
| Author: | Michael Dale Payne [ Wed Aug 12, 2009 10:49 am ] |
| Post subject: | Re: Need French Polishing advice - please. |
I noticed on close inspection that the roughness you are seeing is exactly along grain lines. this means that either prior to or during your seal coat somthing caused the grain to raise and as you bodied and built up this film you replicat these ridges. this is a prime example why I size tops with egg whites and smoth sand prior to sealing. |
|
| Author: | Ray Pepalis [ Tue Aug 25, 2009 1:19 pm ] |
| Post subject: | Re: Need French Polishing advice - please. |
Thanks, Michael and all who offered suggestions. I paid serious attention to the "Spitriting Off" step of the procedure, and it really helped. Thanks to all, Ray |
|
| Author: | SteveCourtright [ Tue Aug 25, 2009 1:30 pm ] |
| Post subject: | Re: Need French Polishing advice - please. |
Big improvement, Ray. That looks great. We would be interested in more detail on your process to correct the ridges. |
|
| Author: | Ray Pepalis [ Tue Aug 25, 2009 3:56 pm ] |
| Post subject: | Re: Need French Polishing advice - please. |
I made a different style of "Muneca" for the "Stiffing" and "Spiriting" steps. I used two 1 1/4 dia. pcs. of 1/8" thick cork material layered together and wrapped with three thicknesses of T-Shirt material. This "Muneca" is stiff enough and flat enough to help level the somewhat soft shellac film. Since it dosen't have the "Wool" reservoir to hold shellac, it needs to be recharged and oiled carefully to avoid sticking. This type of "Muneca" seems to reach into the body/neck juncture on a Classical guitar better that the conventional "Muneca". This is my first guitar, and I am very grateful for all of your posts on this forum. Thanks again, Ray |
|
| Author: | JJ Donohue [ Tue Aug 25, 2009 4:28 pm ] |
| Post subject: | Re: Need French Polishing advice - please. |
Wow, Ray...that looks superb! Nice save. I also use a pad specifically made for spiriting and it really made the difference for me as well. I know this goes against everything Michael et al have taught but you can't argue with the results. |
|
| Page 1 of 1 | All times are UTC - 5 hours |
| Powered by phpBB® Forum Software © phpBB Group http://www.phpbb.com/ |
|