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Anyone ever try to pore fill with Zinser pure shellac(from can)?

I was thinking of trying to add some silica I have, originally to mix with epoxy, to the shellac to thicken it a bit, and trying to pore fill with it.

Can I learn from anyone out there who may have tried this?

Thanks

Sean

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I have read in a furniture finish book the concept of mixing shellac and pumice to make a slurry, that is pushed into the pores and with spreaders. I never tried it. I have done a more traditional French polish fill using pumice and shellac. I little pumice on a muneca with some shellac working it in to a small area. This fill came out very nice. It was a lot of work, so I switch to Zpoxy.

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This is how you pore fill with shellac, you use pumice. It's kind of hard to perfectly fill the pores with out a lot of experience IMHE. Egg whites are a great alternative because they are non toxic, inexpensive, readily available, and fool proof to apply.
http://www.milburnguitars.com/fpgraincontents.html

Pre-filling shellac doesn't work...believe me...I've tried every kind of filler in every unconventional way to fill pores. The main difficulty is getting the material down into the pore and getting it to stay these once its in there. Adding fillers tends to reduce surface adhesion so the bond inside the pore is suspect even if you do get it down and in there.

Shellac needs to stay liquid enough to be able to burn into the previous coat. The reason pumice works as a filler in shellac is because it is gradually deposited into pores while the shellac stays open (liquid). Liquid shellac burns into the old coat....filled shellac? Not so much.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Pumice isn't really the "filler" - it's an abrasive that cuts a slurry of the wood that you are filling and the shellac is the binder. Hence you end up with wood pores filled with wood - some pumice will be in there but you want mainly wood. Egg white is the same principle - sandpaper makes the wood slurry and the albumin is the binding agent.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

220 sandpaper with egg whites or finer?

A tutorial using eggs whites would be great - although admittedly I did not check to see if one exists.... I am just dropping by today - on hiatus on building till I build my new workshop in a new house.

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I know a couple of very experienced French polishers who do an initial pore fill with a shellac-pumice slurry. They add a lot of alcohol to the shellac, and work it into the pores with a pad. Let it dry for an hour or so, and sand back to bare wood. It works well for them, and they have many techniques for dealing with pores that aren't filled. They do beautiful work. I've studied their techniques closely, and tried to do the same thing myself. It doesn't work for me. (Or I can do it, but it takes me longer than the gradual pore fill I'm used to.)

Sure it is...unless it gets removed somehow from the slurry it's certainly going into the pores as a filler....and quite a bit of it too But I take your point. Of course there is wood dust produced as well.

I was really only trying to convey the idea that the surface of the previously cured shellac washcoats must be broken down by any subsequent coat in order to achieve any kind of result when using a pumice fill method. The alcohol does this...picking up shellac from the previous wash coats and mixing it with the pumice and wood dust. Packing shellac with fume silica reduces its ability to break down a previous washcoat. Trying to pack fume silica filled shellac into fresh, unsealed pores....I doubt you'd get much adhesion at all.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Stuart,

Pumice in it's original usage is an abrasive/polisher before the days of sandpaper - that's why you have to frequently change the municea cover as it gets abraded during the process. I said in my reply that some pumice will be in the mix, but the majority of the filler imho should be the wood. Yes you need a thin coat of shellac there as that becomes the binding agent and you don't need much, plus there is almost no shellac added to the municea during the process, mostly alcohol - at least using the Milburn's method. You don't use lots of pumice either - just enough to abrade a wood slurry.

Horses for courses though - Eric describes another method and I'd be interested to hear how the shellac/pumice slurry s created in this one.

All methods of pore filling take time effort and patience if you want a perfect fill.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

I would have said too most of the fill is pumice. Initial shellac coats are gradually dissolved and acts as a binder, while the alcohol extracts color from the rosewood. There is some abrasion happening, sure, but not that much as pumice is weak. Usually it is very hard to remove even the slightest scratch remaining from older sanding, even after minutes of rubbing, while big pores around it might be filled after just 5 sweeps.

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Build log

Alex,

You've done more FP than me - I've only pumice pore filled three EI Rosewood b/s guitars - so I'll bow to your experience. I'm still a little surprised given the minimal amount of pumice required and how quickly you get through the spit shellac coats to "feel" and see the wood as you grind through with the municea but I've been wrong before.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

I'm with Dave on this. A common mistake is too much pumice ....it fills the pores & you think ..great!
'Till time passes & everything cures & you see all the pores under your beautiful finish show up white! Just enough pumice is required to abrade the wood & previous shellac & jam it into the pores. Takes some patience & practice to get it right.

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Dave
Milton, ON

I'm with the Daves. The biggest mistakes people make with pore filling using pumice is to use too much shellac and too much pumice. Dave W is quite right, the pumice is there to act as an abrasive, the alcohol reactivates the very thin spit coat of shellac and the pumice abrades to make a shellac/wood slurry which the muneca works into the pores. Obviously some pumice ends up in the pores, but shouldn't be the main filler.

I must've done 30 or so instruments this way, but now by far prefer the much older egg white method.

Colin

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Before now I have not paid much attention to discussions about egg white pore filling as I don't French polish, or at least haven't. Is the egg white method used only under FP finishes or does anyone use it under more traditional SS finishes like nitro or varnish?

One problem is that we can't really relate well to each other. How can one tell another is using too much pumice without sticking close to the other seeing what he does?

Basically I am trying to stick to the Milburn too. An initial three heavy wiped coats of shellac. No shellac after, the muneca is loaded with alcohol only, then I slightly grab a bit of pumice from a plate, wipe the eventual excess with my finger, so what is left is only what sticks in the cloth texture. Then I use it for as long as it works (hear grinding, see progress, still wet) perhaps a fifth or quarter plate then refill. I clean excess pumice by changing the cover very often. I used to keep it until it felt to pieces but no more. As soon as it gets extra dark with color and soiled, I change it. Soaked, clean cloth removes excess pumice buildup very easily, worn cloth does not.

I spend about 30 mins to 1h a day for about 3-5 days. Most pores are filled in a day or two, but the remaining ones are stubborn, especially on Madagascar rosewood. After 2-3 days, the initial shellac is pretty much all used up, the few left over pores are not getting filled, I see no polishing effect, so I start loading the muneca with some shellac only as needed.
What I see happening is: first, grinding. The alcohol grabs some shellac and color, pretty soon one gets the required fill paste. The paste is spread in the pores and around them, additional rubbing starts to polish the wood. When I'm done filling the rosewood almost looks like it has a half satin, slightly glossy minimal finish.

So far I made 5 in EIR, 4 in Madagascar, 1 in Amazon. Oldest is 4y and I see no white pores or any noticeable shrinkage...All in all I have no reason to change my method yet. Basically we were arguing about how much pumice and how much wood is in the mix. I felt/imagined there is a lot less wood than pumice but oh well, maybe I am wrong. I still feel I am not using too much pumice (too much makes a mess or makes white pores) and not too little (when not enough, nothing really happens...you rub for nothing)

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Build log

Filling pores with pumice won't cause problems down the road. White pores are caused by the pumice not being wetted with shellac. They don't show up later. (You may notice them later.) How do I know? I've seen the work of French polishers who have finished thousands of guitars, who fill the pores with pumice.

I don't have any problem with each finisher having his own idea on the right way to pore fill. I have my own ideas too. Alexandru is right that we're mostly talking past each other here, and need a chance to to see what's really going on in each others' shops. I don't know how to make that possible. Maybe we will meet at shows, where we can at least compare our end results. I don't go to many shows, but I have plans to be better about that. ( I also have plans to learn Cantonese, paint my house, and start running again. Don't hold your breath.) I missed the latest Healdsburg show, but a guitar I French polished was there. (I'm reminded of a Gary Larson cartoon: a crowd of fascinated patrons crowded around a beautiful painting in a museum. From the back of the crowd, the proud mother, "My boy made the frame.")

Hmm, that gives me an idea... anyone tried taking a jar of pumice and sanding dust from the wood you're going to fill, pouring thinned shellac in and stirring until you get a paste, and then mashing that into the pores? Seems like it might be a good head start on pumice filling, at least. Pretty much the same as the LMI micro bead filler, but with shellac as the binder so you can use a muneca and alcohol to push around the filler that isn't in the pores, to clean it up and/or top off any pores that need a bit more. Micro bead has worked well for me in tests, but I'd rather have a filler that doesn't involve sanding back to wood after applying.

I read a Jeff Jewitt finishing book and he showed mixing 4F pumice and shellac into a paste and spreading it on to the surface to pore fill.

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I brush very liquid hot hide glue on the rosewood, then a coat of plenty of shellac. When dry, I use a ball of cotton soaked in alcohol and pumice, and rub it on the surface. When the pumice abrades the surface, you obtain a mud that fills the pores. After sanding, the surface is ready to french polish (if not, repeat the rubbing).

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What Dave White said...

Pumice and shellac abrade the surface of the wood very finely, releasing not just micro wood fibers, but also the color of the wood, if like EIRW the color can leach out. The slurry created by the use of shellac and pumice then fills the pores nicely. It's very hard work, but can work nicely.

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If you have a little pumice on the cotton and touch it with a drop of oil the pumice turns from grayish to clear. Then no white pores. It's described much better in the 2nd big paragraph here:
http://www.milburnguitars.com/fppumice.html
I haven't gotten good at fp, but I don't get white pores, so I think this works.