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In the moment I am finishing a cypress Blanca using French Polish technique. I have FP more than 10 guitars up to now. This is my first cypress guitar. After the bodying process some "stripes" occurs in the finish. I have Sand this away with micromesh 1500 und to the bodying once more. The stripes occurs again. I use fresh shellac solution every time and the same muncea cloth. The bare wood was perfectly smoth. Did anyone ever hade this problem?
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RE: French Polish problems never had... (in reply to Vince)
Keep going with not so much sanding. Looks like the alcohol might be raising the grain as you go.
You may have to let it rest a few days and let the shellac get harder, the layers are tender when you lay them down. If you sand too much it makes the layers real think and the alcohol re wets the grain and it raises. Or that is my guess by looking.
Rosewood does not do this as much, but I run into the situation with Cypress.
RE: French Polish problems never had... (in reply to Anders Eliasson)
The Back was sanded to 400 grit perfectly. I have the same problem now on the Top and the Top became an egg wash between sanding. The weather changes in the last days. I have finished sanding during nice Weather with low humid. Now we have rain and high humid.
RE: French Polish problems never had... (in reply to Vince)
Ok I will wait for a view days and try again with very light sanding and bodying again. In case this stripes occurs again, what is the best way to strip down al the finish? Spirit with a cloth,sanding or scraping?
RE: French Polish problems never had... (in reply to Vince)
Sanding with 400 grot doesnt do anything. Anything more than 220/240 is a waste of time. You cant see the difference. And if you have some deeper marks. They could be from a drum sander, it takes a LOT of hand sanding to get it away and it wont get away with anything finer than 100/120 grit. And it may look perfect before the FP goes on and then its not. I´m not saying that is your problem. I´m only saying that it happens very often. The good thing is that you dont have to remove the FP. you can scrape, sand pad. what ever and continue from that. Just start with a thin wash coat and be carefull not to get any oil into the wood. If its very humid, wait with the FP.
RE: French Polish problems never had... (in reply to estebanana)
Thank you for your answer!!
Maybe it's the drum sander! I was really sure that the surface was nice and smooth without sanding marks! But nobody and "no body" is perfect! So I learn with every new Project.
I read in Romanillos new book about the egg wash! So I have decided to try this and see the benefit by myself. In conclusion I cut not see a benefit for me and I will never do it again.
So I have decide to sand the FP and the irregularities away and start the finishing again!
P.S I like this forum al lot, you are nice guys. You and my "try and error" system are the solution for a lot oaf problems! ( Sorry for my English, I'm not very experience in writing in a foreign language)
RE: French Polish problems never had... (in reply to Vince)
Kitchen products are common in violin (cello) building, where eggs, sugar and other bakery stuff is being used by some builders, but I´ve never heard it so often in guitar building. If what you have are sanding marks, dont sand it all away. A couple of thick coats with shellack where you use a good amount of oil, so that you can really polish and push for a long time will fill some of the marks. When you use the pad, you actually fill gaps. the shellack stays in the deep parts and you polish the shellack away on the plain spots. But you cant fill deep scratches that way. When the shellack hardens, it schrinks so you have to find the limit. A classical one is filling rosewood pores with shellack and no pumice. It looks great and half a year after you can see the pores again.
And please dont excuse yor level of english. Its nice that I´m not the only "foreigner" around and everyone should have their place here.
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Joined: Jan. 29 2012
From: Seattle, Washington, USA
RE: French Polish problems never had... (in reply to Vince)
Yes. It's funny, the more you FP the more strange problems you will encounter that you never had before. One solution to avoiding this problem might be to dampen the wood before finishing and then resand lightly after it dries. Or you can just keep bodying until those grooves are filled in. Sometimes stripes occur after finishing cypress due to resin being exuded by the wood, but they are raised stripes not grooves.
For stripping shellac, wet sanding using 400 grit and olive oil as the lubricant works surprisingly well.
One solution to avoiding this problem might be to dampen the wood before finishing and then resand lightly after it dries. Or you can just keep bodying until those grooves are filled in. Sometimes stripes occur after finishing cypress due to resin being exuded by the wood, but they are raised stripes not grooves.
Yes exactly if you use cypress good idea to raise the grain once even twice and the resand it. If I have any wood that could bleed, like rosewood I use a water, if I don't think any wood will bleed then alcohol. The alcohol evaporates fully in less then 10 minutes and raises the grain. This reveals deep primary sanding patterns that are parallel to the grain.
Egg white painted on spruce automatically raises the grain and sets the hard a soft grain at different levels. Like gluing them in position with raised grain.
I've tested this several times, egg white is called 'glair' in the art terms dictionaries you can look it up. It makes the hard grain lines turn more brown and creates a stronger difference between the color of soft and hard grain to emphasize the grain lines. It's not really what you want under shellac because it raises the grain and holds it stiff. Then you have to cut down through the raised hard grain and this causes a difference in color and hardness in the wood surface.
Egg is mainly used as a barrier for heavier varnishes or gessos to keep them from sinking onto the wood. French polish does not have that problem, you don't have to put a ground coat down to keep it from penetrating. The egg white painted on guitar tops is a waste of time in my opinion and Romanillos mentions it more out of historical curiosity than as practical modern method.
RE: French Polish problems never had... (in reply to Vince)
Babies and Gentlemen I am new here . Jim Frieson , a builder living in Hokkaido ex of Canada . I used to ( french) polish for a living , restoring antiques off and on for two decades , now I just do my guitars , and usually only the tops . But I have sure polished a lot of cipres blancas since the 70s ...and just about every wood you can name . I offer the following observations One : Prep . When preparing a back or top or side , after planing scraping or thickness sanding , lay it on a flat platen , never use a machine to sand , and use a block of hard flat wood to sand , sand thoroughly down to at least 220 with the grain . Wet with not soaking rag , and then resand if desired - I usually don't bother .The raised grain could have been there from the start , just not observed until polished up . I have seen this effect so very often in the finishing work of inexperienced builders ( hey no offense at all intended ) Two : Micromesh works well , but it will not flatten anything , it will just make hills and valleys more smooth . If Micromesh is preceded by 2000 or 2500 , well folded to ensure production of flatness and not just one thickness under the hand , then Micromesh takes out the 2000/2500 wet dry scratches admirably . Three: Pumice will tend to level finish pretty fast , but never use pumice if there is shellac in the rubber/pad or you will see it after the finish has dried down . Four : Pad on a bit more lac than you think is just right before leveling , because with shellac on bare wood , grain will always telescope to some degree . You can , however , get it flat . Hope of use Cheers Jim Frieson
RE: French Polish problems never had... (in reply to Vince)
I have fixed the problem! In my opinion it was the rapid change of air humid between last sanding and first bodying. I have scraped al finish of and do the process again! After the first glazing attempt it looks better!
Thanks for your help!
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RE: French Polish problems never had... (in reply to Vince)
Congratiolations on a great looking guitar!! Your soundport looks really nice, did you use some kind of reinforcement on the inside? How does she sound?
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