Rosewood guitar...

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Rosewood guitar...

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prd1

Posts: 206
Joined: Jul. 11 2007

Rosewood guitar...

Hello all,

I'm ready to polish a spruce/rosewood guitar. I don't want to use a thixotropic grain filler - nasty stuff...any ideas if it is possible to fill the porous rosewood with shellac or do I need a more drastic line of attack?

REPORT THIS POST AS INAPPROPRIATE | Date Feb. 18 2009 16:36:18

aarongreen

Posts: 367
Joined: Jan. 16 2004

RE: Rosewood guitar... (in reply to prd1)

You definitely want to fill the grain with something other than just shellac. I have tried just about every filler out there and they all have major drawbacks. My least favorite one is having to re-prep the guitar surface after scraping and sanding off the filler. This is pretty much a given with almost all methods except for an old school pumice fill.

My filling method is as follows. Before I finish the prep (rosewood guitars only) I flood the back and sides with superthin superglue. This is a preventative measure to take care of any hairline cracks that may have otherwise gone unnoticed and it also provides some measure of filling. Scrap and sand and finish prep. Then I give the back, sides and neck a coat or two of shellac. From there I put some pumice on my pad along with some walnut oil and shellac. The motion for filling is more of a circular one than straight lines. If I notice any lumps or bumps of pumice building up I switch out the shellac for pure alcohol. It takes me a few hours to fill the back, sides and neck but when I am done the guitar looks like it is ready for a final rub out of the finish. The next day it doesn't look nearly as good as the pumice shrinks back a lot. I let it sit for a few days before going back at it. It usually takes a few pumice sessions to get a really good fill job (better than I ever got with paste filler or epoxy) and from there you can go straight into french polishing.

The thing I like about this method is there is no separation between the filing and finishing. It is all one process. It is non toxic and from a visual point of view it looks better than any other filler, certainly any paste filler out there. The refraction of the pumice fill is exactly the same as if the pores were filled with nothing other than the shellac and as such it doesn't kill the depth of the finish, like paste fillers tend to do. Physically it is a lot of work so another positive attribute is you will end up with a forearm that means business. I suggest though you get good at filling with either hand, otherwise it may just look like you are really lonely.:)

Good luck!

aaron

REPORT THIS POST AS INAPPROPRIATE | Date Feb. 18 2009 16:58:48

TANúñez

Posts: 2559
Joined: Jul. 10 2003
From: TEXAS

RE: Rosewood guitar... (in reply to aarongreen)

quote:

another positive attribute is you will end up with a forearm that means business. I suggest though you get good at filling with either hand, otherwise it may just look like you are really lonely.:)

I hear Popeye was one hell of a French polisher.

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REPORT THIS POST AS INAPPROPRIATE | Date Feb. 18 2009 17:17:02

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: Rosewood guitar... (in reply to prd1)

quote:

The thing I like about this method is there is no separation between the filing and finishing. It is all one process. It is non toxic and from a visual point of view it looks better than any other filler, certainly any paste filler out there.

Well, the superglue bath is about as toxic as it gets.....
I do more or less like Aaron when using pumice but no superglue.. I to like the fact that its one proces and that its easy to go backwards. Epoxy works well, but if you mix wrong it doesnt dry well and its nasty and frustrating to remove.

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REPORT THIS POST AS INAPPROPRIATE | Date Feb. 18 2009 23:31:09

aarongreen

Posts: 367
Joined: Jan. 16 2004

RE: Rosewood guitar... (in reply to Anders Eliasson)

Hi Anders,
Not sure I agree with you on that. Cyano was developed to be used on humans. While this alone certainly does not mean it isn't toxic I have yet to see any actual medical information showing that it is. Have you? Seriously, I am very interested. The fumes when it kicks over certainly are irritating but since how it works has to do with the ph of the wood (or whatever you are gluing) I always assumed it was related to that.
I certainly think wearing a respirator is worthwhile though. I imagine that considering the oils and silica in rosewood amount to biological warfare (to keep critters from eating the wood) wearing one is pretty much a good idea during many guitarmaking operations. I recently invested in an air filtration system as well as a 2 micron bag for my dust collector.
As I said the superglue bath is mostly to stop any hairline cracks that might even think of forming. Not that that happens too often but I did have one appear once when I was rubbing out the finish. That was a major drag, easily fixed, and so far, 5 years later, no reports of cracks but I could have done without all the backtracking.

REPORT THIS POST AS INAPPROPRIATE | Date Feb. 19 2009 3:14:40

Armando

Posts: 302
Joined: May 27 2005
From: Zürich, Switzerland

RE: Rosewood guitar... (in reply to prd1)

Hi all

By my own experience i have to be with Aaron. My Romanillos rosewood guitar from 2006 is still not ready because of the polishing. I have tried to do the job by myself and i quickly realized that french polishing a rosewood guitar is quite a hassle. The main problem i faced was the filling of the pores with pumice without messing up the maple purflings. To be honest, i messed it up. When i asked Liam Romanillos how he does the job he said he is using thixotropic filler. O.k, i tried to get that stuff but there's no way for me to get that, because the stuff is flamable and therefor prohibited to ship. So there is no other choice for me than using some strange unflamable grainfiller stuff which i'm not convinced of, or otherwise remain with the pumice. I desided to stay with the pumice, but how to avôid messing up the purflings? I've done some tests on testing material using superglue to cover the purflings before using pumice and it works. The superglue is not alcohol solvable and therefore protects the purflings during the pumicing process. To use superglue on the whole surface, didn't came to my mind due to the fact that it is toxic and it has heavy solvent agents which may affect the health. I'm almost sure it works as a sealer on the whole surface but i wouldn't use it as i find it to be to harmful. On top of that it is rather expencive. 10ml cost like 10 dollars or something. How much would be needed for a whole guitar?

I don't find it to be necessary for the filling of the rosewood. For me, superglue is just a sealer for protecting the purflings.

O.k. the Romanillos guitar is still not done, not because it doesn't work but because of lack of time.

Regards

Armando

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REPORT THIS POST AS INAPPROPRIATE | Date Feb. 19 2009 11:43:28

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: Rosewood guitar... (in reply to prd1)

Aaron, I trust my senses more than some report saying that a chemical is not harmfull. Look at history and you´ll see thousands of storys.

My own rection to it is very direct. My nose starts running and my eyes gets irritated.

Cyano is a fantastic product and I use it during a lot of processes. The brush on is very effective for sealing purflings just like Armando says etc.

Armando, when having problems with purlings getting bleeded when pore filling, it can be because you havent sealed enough and thus you are sanding rosewood with the pumice and the alcohol bleed the color into the purfling. Make sure your pumice is very fine (D*ck.biz has a good one) and do a couple of sealer coats before. I do 3 myself

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REPORT THIS POST AS INAPPROPRIATE | Date Feb. 19 2009 23:24:52

aarongreen

Posts: 367
Joined: Jan. 16 2004

RE: Rosewood guitar... (in reply to prd1)

Hi Anders,
Well I can't argue with you there. I took it upon myself though to do some research on the web just now. I looked at medical reports as well as some other related sites. It appears that the fumes are not toxic per say but irritating and could cause allergic reactions in some people. Irritation can over time lead to other issues though so it is advisable to use a mask or at least have good ventilation. This is just a good idea in a workshop anyways.

Back to porefilling. I forgot to mention that I use pumice on my tops as well as the back and sides of blancas as well. Obviously there is not pores to be dealt with but what it does is get you to the point where the finish is building up much faster and it fills in the rosette, it can be a real drag when your top is totally done and the rosette isn't. Also when using this method on a blanca your bindings and backstrip are filled (re- your other topic Anders). The pumice fill on the top also helps maintain the evenness of the color of the finish, if you are using dark shellac. However for the pumice fill operation it is better to use superblonde shellac.

I find the pumice method does not stain the purflings or maple bindings. Since I am using superglue as a first step that seems to be giving some added protection. However on my blancas I don't do that and still I don't end up with any issues of the rosewood bindings staining the purflings. I think the seal coat of shellac before I start in with the pumice may be the reason there but I am not entirely sure.

REPORT THIS POST AS INAPPROPRIATE | Date Feb. 20 2009 4:00:23

TANúñez

Posts: 2559
Joined: Jul. 10 2003
From: TEXAS

RE: Rosewood guitar... (in reply to prd1)

I have never tried this method but Robert O' Brien uses drywall compound with some coloring. He also goes over the purfling with a bit of lacquer and thinner to keep the purfling from getting stained. Thoughts?

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REPORT THIS POST AS INAPPROPRIATE | Date Feb. 20 2009 5:22:15

aarongreen

Posts: 367
Joined: Jan. 16 2004

RE: Rosewood guitar... (in reply to prd1)

It might be worth a shot. Drywall compound isn't toxic (unlike oil-based pore fillers) so thats a plus. It looks like a fair amount of sanding though. I know a number of luthiers who like water based pore filllers, which is what this is. Years ago Tom Humphrey told me he was putting on the filler before binding the guitars. The idea was by the time he was finishing the guitar the pore filler had shrunk back as much as it would and then he would sand it off. Seems like it would be messy as hell when gluing on the bindings so I have never tried it.

REPORT THIS POST AS INAPPROPRIATE | Date Feb. 20 2009 5:37:41

jshelton5040

Posts: 1500
Joined: Jan. 17 2005

RE: Rosewood guitar... (in reply to aarongreen)

quote:

ORIGINAL: aarongreen
Years ago Tom Humphrey told me he was putting on the filler before binding the guitars. The idea was by the time he was finishing the guitar the pore filler had shrunk back as much as it would and then he would sand it off. Seems like it would be messy as hell when gluing on the bindings so I have never tried it.

I use water based fillers on the back before gluing on the braces. That way it's flat when you're sanding it and you expose fewer pores. It always needs additional filling after assembly but this method allows extra time for shrinkage and speeds the final filling. Never tried it on the sides since I use a bending iron and suspect the moisture and heat wouldn't work with the water based filler.

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REPORT THIS POST AS INAPPROPRIATE | Date Feb. 20 2009 6:09:34

prd1

Posts: 206
Joined: Jul. 11 2007

RE: Rosewood guitar... (in reply to prd1)

Hi all,

Many thanks for the replies.

I've previously tried to fill the pores of a guitar with Wenge back and sides by sanding inbetween coats and leaving the shellac dust to reconstitute when more alchohol solvent was applied - seemed like a good idea at the time but the Wenge was like the surface of the moon. I stripped this off and sealed with epoxy then sanded back...took forever and I went through a mountain if clogged sandpaper. I'm not too keen on this method but it did leave a good finish. I'll try filling with pumice this weekend.

As for superglue...I've not got a good track record with this stuff. I used to coat my finger nails with it but after a bit of a heavy night out in Madrid I fell asleep in the process and spilt a whole tub of brush-on down my shirt...didn't suffer from any allergic reactions but had a job cutting/shaving the shirt off.

REPORT THIS POST AS INAPPROPRIATE | Date Feb. 20 2009 6:24:34

Anders Eliasson

Posts: 5780
Joined: Oct. 18 2006

RE: Rosewood guitar... (in reply to prd1)

quote:

didn't suffer from any allergic reactions but had a job cutting/shaving the shirt off.

Thats a good story. I´m sorry, but I had to laugh. So you came home after a heavy night with the need of doing a bit of manicure...

If you use epoxy, its a good idea to scrape before sanding.

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REPORT THIS POST AS INAPPROPRIATE | Date Feb. 20 2009 23:27:19

HemeolaMan

Posts: 1514
Joined: Jul. 13 2007
From: Chicago

RE: Rosewood guitar... (in reply to prd1)

put a cork in the sound hole, and get a giant vat of poly and dunk the sucker.

= PORES FILLED! lol, then sell it as a toy because it wont sound like much after that lol.

oh wait, im sorry that's the industry standard method.

You mean you want it to sound good after? what for? lol

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REPORT THIS POST AS INAPPROPRIATE | Date Feb. 21 2009 8:50:37

Stephen Eden

Posts: 914
Joined: Apr. 12 2008
From: UK

RE: Rosewood guitar... (in reply to HemeolaMan)

hey petey how many guitars have you made now?

out of all the grain filling options i have tried i would suggest using a finishing resin.

Z-poxy by Zap you can get this from axminster i believe. this is pretty good stuff you dont have to put alot on which is a bonus because you dont have to scrape so much off. you can thin it with alcohol so you can seal the sound board too. i havent tried but i have heard that you can polish on top of this resin!

REPORT THIS POST AS INAPPROPRIATE | Date Feb. 22 2009 2:20:24