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frustration with pumice pore fill
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Author:  Bart [ Wed Jun 30, 2010 11:54 am ]
Post subject:  frustration with pumice pore fill
I wanted to try a 'traditional' pore fill method on a guitar than I'm finishing so I though I'd try pumice. I first read all of the tutorials and past postings on this subject that I could find.

At the risk of sounding like a complete idiot, duh , I'll admit that I've spent a good part of 5 days trying to fill pores with pumice and at this point only the shallowest pores are filled. The wood in question is Madascar rosewood and Spanish cedar. The Mad. rose has pores that make the Grand Canyon look like a minor erosion problem, and after a couple days I realized that I was getting nowhere. I thought I was making progress on the Spanish cedar neck but as soon as I started to apply shellac it revealed that most of the pores were not filled.

I have tried every combination of more/less pumice, more/less alcohol and more/less pressure along with various padding patterns. My guess is that I'm going through a cycle of depositing some pumice in the pores, and then removing it in the next application, rather than building on top of it to get a completely filled pore. [headinwall]

I've given up on pumice with the Mad. rose [uncle] and will try something else, but I'm still trying to get the neck filled with pumice. The problem is that the neck, too, has some very deep pores that I'm not getting anywhere with.

So, my question is: does anyone have advice for getting pumice into deep pores, or is the best advice to give up on the pumice?

Many thanks,

Bart
Author:  evanmelstad [ Wed Jun 30, 2010 12:04 pm ]
Post subject:  Re: frustration with pumice pore fill
Did you spit coat the guitar with shellac first?
Author:  Stephen Boone [ Wed Jun 30, 2010 12:08 pm ]
Post subject:  Re: frustration with pumice pore fill
I did not see anywhere that you are using any shellac in the mix. When using pumice to pore fill I generally use mostly alcohol but with a small amount of shellac as well in the pad. I use dropper bottles to dispense the various liquids into the pad. For pore fill my mix is usually something like 10-15 drops alcohol with 3-5 drops shellac. This creates a very thin cut of shellac. You need the shellac to act as a binder with the pumice and hold it in the pores. The pumice acts as an abrasive and creates "sawdust" from the wood being filled. Make sure you use no oil at all until there is an obvious coating of shellac on the wood or it can cause blotchiness. After that a little oil can help. I find that usually the pores are not completely filled until later in the actual French polish process.
Author:  Bart [ Wed Jun 30, 2010 12:26 pm ]
Post subject:  Re: frustration with pumice pore fill
Thanks for the response guys. I began by following the Milburn FP tutorial. I have no doubt that method works for them, but it didn't work for me. They begin with 3 spit coats of shellac, and do not use any shellac from then on in the pumicing process (in fact they make a point of saying you should 'lose' your shellac at that point). So when I started applying the pumice it dissolved the shellac on the wood and created a mess. I ended up sanding back to bare wood and starting again with one thin spit coat of shellac. That was much better, but still only the shallow pores got filled.

Stephen - your point about using some shellac with the pumice makes sense (as opposed to Milburn technique).

As for a different approach, I have Jeff Jewitt's French polish video, and his technique for filling with pumice is to create a slurry of 8 lb. cut shellac with pumice, and then trowel it on. I'm almost tempted to try that on the Mad. rose.
Author:  enalnitram [ Wed Jun 30, 2010 12:28 pm ]
Post subject:  Re: frustration with pumice pore fill
I'm with you Bart. I'm a first time finisher, just completing it last week, actually. I FP'd a mahogany guitar, and I definitely would've gone mad doing pore fill only with pumice. I used tinted pore-o-pac.

I'm sure that it's possible to make pumice work, but I have to question some aspects of the traditional process. this is the 21st century. It's like walking 30 miles when you could've biked it.

I gave up on the pumice and tried to put pore o pac on top of my progress to date, which was a mistake. I stripped it all and then started with a shellac seal and then on to pore o pac. then stain on top of that. it worked great.
Author:  enalnitram [ Wed Jun 30, 2010 12:36 pm ]
Post subject:  Re: frustration with pumice pore fill
Bart wrote:
So when I started applying the pumice it dissolved the shellac on the wood and created a mess.
Did you load the pad only from the inside, and use oil? It sounds like your pad was much too wet.
Author:  WaddyThomson [ Wed Jun 30, 2010 12:57 pm ]
Post subject:  Re: frustration with pumice pore fill
The wool inside of the muneca should be loaded with a saturation of shellac, then squeezed out until it won't drip, then left to dry over night in an open container. The next day it should be about the consistency of taffy, but pretty much dry. If it is hard, add a few drops of alcohol and get it to the taffy consistency. Then wrap it with linen or muslin or whatever you are using, those are best, and use only alcohol and pumice. The only shellac that should be needed comes from the reserve in the pad, which wicks into the alcohol pumice mixture and combines with the shellac that is removed from the instrument, and is deposited into the pores. From what I have read, when you are finished pore filling with pumice, there isn't much of the spit coat left on the guitar. It has mostly been ground and melted off and forced into the pores. Big pores do take a long time to fill.
Author:  CWLiu [ Wed Jun 30, 2010 8:04 pm ]
Post subject:  Re: frustration with pumice pore fill
Use very light pressure.
Try not to overlap the area that has just been worked.
Small circle fills faster.
Add some alcohol when there's too much pills on the surface or your muneca(I use folding cloth) becomes too sticky. After adding that I beat the cloth to the back of my palm a few times.
Thciker shellac tends to grab thinner shellac, so be careful when you really have to add more shellac to your muneca. That's when there's almost no shellac on the surface, btw.

I recon that pumice pore filling is harder to leard than bodying session, but it can be done.
Author:  Bart [ Wed Jun 30, 2010 8:33 pm ]
Post subject:  Re: frustration with pumice pore fill
Waddy and CW: thanks very much for the advice, it's given me a few things to try.

Martin: This will be the 4th guitar that I've French polished and I feel like I'm getting better at it, so I thought I'd try the pumice. My hope was to do a complete finish (including pore fill) with NO sanding. You can read all there is to read, but pumice filling and French polish are skills best learned in the presence of someone who knows how to do it properly, and very difficult to learn on one's own.

Bart
Author:  Stephen Boone [ Wed Jun 30, 2010 10:39 pm ]
Post subject:  Re: frustration with pumice pore fill
It is obvious from this thread that there are many ways to approach this thing. One other observation on my end is that less pumice is better than more. With too much pumice things get lumpy and ugly pretty fast. I just got done with my fifth french polish and it actually looks pretty nice. It just takes time and work. I highly recommend the Ron Fernandez DVD on the subject.

http://www.fernandezmusic.com/FrenchPolishingDVD.html

Ron is a nice guy and I re-watch this video from time to time and it really helps.
Author:  Alexandru Marian [ Thu Jul 01, 2010 2:33 am ]
Post subject:  Re: frustration with pumice pore fill
I don't use any shellac or oil when filling and it still works fine. Shellac can be replaced by a couple eggwhite coats if you want. I like the muneca to be pretty wet, much more so than what is needed for actual FP. Madrose can have huge pores indeed, so you will need to use more pumice. I just did a madrose guitar yesterday and it took me about 3 hours to fill and another 1-2 h to clean the goo left all over the guitar. I clean by softening the extra filler piles with a soaked muneca then rub it off with the finger. Once in a while hit everything with 600 and 1000 grit. When you are done the wood should shine pretty nicely almost like a satin finish.
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