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Thread: wet sanding shelac

  1. #1
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    wet sanding shelac

    Ok so I ventured of this am to try my hand at wet sanding shelac on my saw handle.HAAHAHA I got quiet a mess going the shelac gumed up pretty fast and my handle is a mess im thinking that this is part of the prossess but I wondering if I thined this shelac if I wouldnt get better results? Im using the zinssener amber in the can? any thoughts?

  2. #2
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    If it's giving you grief, you can always pad a couple of coats on, wait for it to dry, then sand it and do the same.

    I haven't tried what Klaus suggested yet, either, i've always had a bear of a time sanding shellac that isn't dry, but I'm inclined to try it, too.
    Unleaded tastes a little tangy, supreme is kinda sour, and diesel tastes pretty good.

  3. #3
    How long did you let it dry for? Shellac takes a good long time until it's rock hard (a week...maybe two depending on how you finished it). Once it is, I sand it dry with 3M Frecut Gold sandpaper and it basically just powders off for me. The trick is to keep it cool. Once it heats up, and it doesn't take much, it will start to melt, get gummy, and will just make a mess.

    This is just what works for me. I'm not a finishing guru.

  4. #4
    I wouldn't wetsand shellac.

    The good news is you can probably just let it dry now, and wipe it down with a DNA moistened rag. The goal isn't to remove the mess, but to smooth it all down. Then let it dry.

    Then DRY sand it. Dry ssanding shellac means take 400 or 600 gt sandpaper and lightly wipe down yr piece; it'll get chalky and white. That doesn't matter; you just want it smooth.

    Then resume applying shellac. The easiest way on something like a handle is to squirt some shellac - don't dip - into a shoptowel, and then wipe it - swiftly and once. Don't try to keep going over it; it dries too fast. Let it dry for 10 mins to 30 mins, then apply another coat this way.

    If it feels 'dusty' or 'nubby' when dry, then wipe with 600g DRY. After the sheen is smooth and even, then stop. You don't want to build it up.

    Due respect to John below, but in my experience, shellac doesn't require long at all to sand. It might require a couple days MAX before final rub out, but it's usually 'denubbable' within an hour.

  5. #5
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    Another option is to apply it french-polish style, but I think for something as small as this, just padding a few coats, letting it dry and then doing it again should work fine.

    You can also wetsand it with naptha or mineral spirits if you have W/D paper handy. But I would guess you'd still want it to dry for that, and I think that also wouldn't be any less trouble than just padding it and sanding it.

    We have an advantage as hobbyists in that if it takes a couple of days of off and on fiddling to finish the handle, you can just set it aside while it dries - no big deal.
    Unleaded tastes a little tangy, supreme is kinda sour, and diesel tastes pretty good.

  6. #6
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    Quote Originally Posted by Robert Culver View Post
    Ok so I ventured of this am to try my hand at wet sanding shelac on my saw handle.HAAHAHA I got quiet a mess going the shelac gumed up pretty fast and my handle is a mess im thinking that this is part of the prossess but I wondering if I thined this shelac if I wouldnt get better results? Im using the zinssener amber in the can? any thoughts?

    You don't really need to wet sand french polish. Here's some info I've sourced from another site for you. It was already written and I can't honestly improve upon the methods described;


    French Polishing with Michael Payne


    Introduction

    First a little about my self before we get started; I grew up in my grandparents care. My grandfather was a master carpenter by more than just title. Meaning during his life he served an apprenticeship and worked as a journeyman, under the tutelage of master craftsmen. He opened his own cabinet shop and put 40 plus years into his craft. During my teenage years and beyond, I worked under his supervision. This is where I learned to French polish. My methods with the exceptions of pore filling and my choice of solvent are for the most part unchanged from what I was taught.

    My methods are very traditional. I hold on to some beliefs that may be controversial to some about what produces a good hard finish. Nevertheless my technique is proven and provides a smooth, hard and durable finish worthy of a fine instrument or piece of furnisher.

    What is French polish?

    French polish is a technique of applying shellac to form a single continuous amalgamation or film. Shellac is applied in steps called sessions. A session may be one process or a series of processes. To truly understand this technique, do not think in terms of coats. The term “coats” implies applying one layer over the next. In French polishing we will build one continuous amalgamated film in a series of processes preformed in a series of sessions.

    Not counting the pore filling process - for which there are a myriad of media and techniques that are acceptable to French polishing - the three basic process to French polishing are known as Bodying, Spiriting-Off and Glazing.

    Here is a brief explanation of each of these processes.

    Bodying

    Applying shellac via a muneca or two piece pad in overlapping figure eight or circular motion; this process is much like applying past car wax to a car or paste shoe polish to a shoe. This process builds the majority of the films thickness but does not provide the finish sheen.

    Spiriting-Off

    This process is done with a moderately high alcohol load with very little to no added shellac other that the residual shellac already in the inner muneca. This process is a glide on glide off straight stroke buffing like process done to melt down and level out riding and high spots and to remove lubricant oil left by bodying or glazing.



    Glazing

    This is the application of a more diluted cut of shellac in a straight or buffing motion that adds a high gloss to the film.


    Supplies

    There are many acceptable substitutes for some of the supplies. However, I will only mention the ones I use.

    100% de-waxed shellac flakes or a pre mixed shellac such as Zinsser’s Bulls Eye Seal Coat 100% de-waxed shellac.

    Denatured Alcohol, denatured with no more than 5% methanol or 180 proof Pure Grain alcohol from a liquor store.

    4 or 6 oz of 100% pure Walnut oil or Extra Virgin Olive oil

    Eight to ten 4” x 4” well worn non-dyed Muslin or linen squares (Outer muneca or outer pad)

    A couple feet of non-dyed 100% wool roving. (Inner muneca or pad)

    Three 2 or 4 oz plastic bottles with caps (bulk shellac and oil storage)

    Three eye dropper bottle with eye dropper (one for 2# shellac, one for 1# shellac and one for the lube oil. used t store shellac and oil for loading the muneca)

    Small natural bristle artist brush

    Available supply of 8.5 x 11 printer paper

    A good med high intensity work lamp

    A lint free work pad like a well worn folded linen sheet

    Several pair of nitryl gloves


    Last but not least…….. A good bit of patience and determination.


    Preparation of the finish media.

    If you are making your own cuts of shellac you will need to make up two different cuts or mixes of shellac. You will need a 2# cut for sealing and bodying, and a 1# cut for initial seal coat and glazing. I use Zinsser’s Seal Coat or Liberon’s Pale French polish pre mix because they are quite good off the shelf French polish shellac mixes. I like the slight amber tint that the Zinsser Seal Coat provides. Its colour is a 50% blonde and 50% amber or garnet blend. It gives a nice warm vintage but not dark tint to the wood. If I want a less tinted appearance then the Liberon’s Pale French polish would be my choice. both come as a 2# cut straight from the can. I cut that with 25% per volume with to achieve a near 1# cut. I make up 2 oz at a time and store in the plastic 2 oz squirt bottles I mentioned in the supply list.

    Preparation of the Muneca.

    Make up at leas 6-8 outer pads 4” x 4” square from well used white muslin or linen for the outer cover. You want this material clean and well worn. If new wash at least 10 times before using to remove any loose fibre. T-shirt material is often suggested and will work well but I find it causes unneeded ridging during bodying due to its 3D stretchable weave.

    I prep my inner muneca a day in advance. These are made from 100% non-dyed wool roving and enough to make a tight golf ball when dry. To prepare I first set the ball of wool roving on a piece of wax paper in a bowl and saturate them with 2# cut of shellac. I then allow it to stay in the open air bowl for about 2 hours. At this point I put on nitryl gloves and roll the ball in the palm of my hand over the bowl till no shellac drips from it. It should be about the size of a ping pong ball or slightly smaller at this point Then place the ball into a zip lock bag with the seal half open over night or until the ball is the consistency of soft taffy then seal the bag air tight. At this point the inner muneca is ready to use. It’s important the inner muneca be at this viscosity for the muneca to work properly. If the inner muneca is too wet it will not form the proper wicking channels between the inner and outer muneca. In fact if the inner of outer muneca are too wet they may remove shellac rather than apply it.

    Once the inner pad is ready to use wrap it in one 4” x 4” outer pad bundle it tight as possible and secure it with twine or a rubber band. Keeping in mind that you will be changing the outer pad every so often so you want to be able to remove whatever you use to bind the muneca.

    NB A little note of interest the word muneca is Italian for rag doll in reference to the pad having the appearance of rag dolls head.

    Preparing the work surface;

    Naturally you will want your guitar body or other type of work surface to be prep sanded, pore filled, grain raised and sanded back ready to seal.

    If there are any coloured purfling that need sealed to protect from bleeding woods this should be done first with 1# cut of shellac and a fine artist brush before the seal or spit coat is applied. This way if during the application of the seal or spit coat; any bleed over occurs it can be scraped off with a razor blade or small cabinet scraper then resealed with shellac. I seal or spit coat in this order; purfling, top and then back and sides.

    The initial spit coat is applied much like body sessions will be later but a tad wetter. After any purfling has been sealed with a brush; if needed, load the muneca up with 4-5 drops of 1# shellac, 3-4 drops of alcohol and 1-2 drops of lube oil the tap one time on a sheet of white printer paper. The forces the alcohol and shellac into the inner pad stating the wicking process of the residual shellac in the inner pad. Start on the top and cover evenly the top with short figure eights until the top is evenly covered with shellac be sure to reload the pad as soon as you start to feel drag. You do not want the pad to ever stop or slow down as you working. If it does it will stick causing a lumpy build-up. After the top do the back, one side then the other allow about 10 min of cure time before moving on to another surface.

    This spit or seal coat is the foundation of the future body sessions. It went on wetter than the body session will and is done so that the dryer first body session have a base to melt into. The spit coat does not need to be very thick at all. It just needs to cover the entire surface area.

    Bodying:

    First let’s start with a brief understanding of what boding is and is not.
    Bodying is the application of the residual shellac contained in the inner muneca transferred on to the work surface by means of melting apportion of this residual shellac with a fresh load of shellac and alcohol to the outer pad that is then taped on a piece of paper causing the newly loaded shellac and alcohol to be forced into the inner muneca partially melting the residual shellac of the inner muneca thereby creating a wicking channel for the melted residual shellac to flow from the inner muneca through the outer muneca and on to the work surface.

    Bodying is not the application of a wet fresh load of shellac loaded on to the outer muneca and then painted or ragged over the surface. In fact that is exactly what we do not want.

    The reason for not wanting to apply the shellac as a wet film has several reasons. First is that a wet media migrates. It wants to flow until it thickens enough to overcome the flow. This means that you would likely end up with thicker film at the ends of the flow than at the centre. Second is the fact it is harder to control the application thickness of a media that is low viscosity as apposed to a higher viscosity.

    Tell tale signs the muneca is properly loaded:

    There are two key tell-tale signs if one you have the muneca properly loaded and if the wicking is happening.

    1. The fist sign to look for is right after you load the muneca with a new load. This load should be 4-5 drops of 2# shellac, 3-4 drops of alcohol and 1-2 drops lube oil. Then tap the newly loaded muneca on white paper till the stain (referred to as “report” from here on in this tutorial) is spotty not solid. This is the first tell-tale sign. It ells you the muneca is loaded and prepped for boding.

    2. The second tell-tale sign of a properly loaded muneca is displayed during the bodying process. This sign is the vapour trail of alcohol appearing and rapidly disappearing behind the muneca as you body. For an example of this next tell-tale sign; take your safety glasses off and breathe on them. Notice the water vapour from your breath appear and disappear quickly on the lens. This is water vapour flashing off a dry surface. As we body we want to see the alcohol vapour of the new load doing the same thing as the muneca moves along the work surface. Seeing or not seeing this sign tells you really several important things. One; that the wicking action is of is not happening. Two; it tells you if your load has too much or little shellac or alcohol. Be aware the vapour trail is a fleeting thing. It will last only a brief fraction of a second at any given point and you should be watching for it at all times. It should extend for about ¼” to ½” or a little more behind the muneca as you body.

    If there is no vapour trail but there is a thick wet trail behind the muneca that does not disappear quickly as the muneca moves this tell you that you have loaded the muneca with too much fresh shellac.


    If you see a thin wet trail that does disappears fairly quick but not as nearly as quickly as I described above; this tells you have loaded too much alcohol. This will lead to a messy pushing of previously applied shellac forward of the path of the muneca and thereby a very uneven surface.

    If there is no vapour trail and no wet surface behind the muneca then you have too little alcohol in the load. This will likely lead to the muneca sticking as you body.

    Do not confuse wet shellac as a vapour trail. Once again the vapour tail will appear and disappear just like the fog you see when you breathe your safety glasses.

    --------------------------------------------------------------------------------------------------

    Before we go into how to do the body process I would like to discuss first how the inner muneca works for us when boding. Recalling the inner muneca prep that I gave earlier, understanding why and how the inner muneca works will greatly aid you in noticing how well your body session is going and help you reason out many difficulties you may face when boding.

    Think of the inner muneca as a reservoir of shellac. It is this shellac that is to be applied to the surface during both bodying and later glazing processes. Each new load to the muneca you add during boding does two things. First and foremost a new load melts residual shellac in the inner muneca and primes the muneca to allow the meted residual shellac to wick through the outer pad and on to the surface. The shellac that is wicked is of higher viscosity than liquid 2# cut straight from the bottle because it is partially set up or gelled.

    During bodying we want the shellac being applied to the surface to be pretty much the constancy of a soft past car wax. That is somewhat of an exaggeration because shellac has a tack to it that past car wax does not. But it is a good mental conception of how applied shellac should be thought of during the bodying process.

    Waxing a car is also a good description of the application technique. When you apply car wax you apply it in overlapping figure eights so that you spread it evenly over the surface. The same is true for the application of shellac during the bodying process Keep your circles or figure eights tight and overlapping by about half the muneca diameter.

    I find it best to body from the edge at one end and work towards the opposing end migrating one hale the muneca diameter until you reach the centreline of the surface then do the same for the other side. You can if you wish work from the centreline of the surface towards an edge if that is your preference. But in either case work the surface as two halves. This intrinsically leads to building a more consistently level surface that going willy-nilly all over the place. Also pay close attention to the edges. This is where you are most likely to miss in your coverage. Beware that dependent on the size of the surface you are bodying; you will likely have to reload the muneca several times in one session. As soon as you start to feel the resistance between the muneca and the previously applied shellac build up to the point you think the muneca may stick or if you stop seeing the vapour trail behind the muneca it is time to reload.

    After each body session; I recommend you allow the surface to set for 10 minutes or till dry to the touch. After the surface has dried to the touch I also recommend a spiriting off session and allow to dry to the touch again before moving on to the next body session. This provides several beneficial outcomes. First and foremost it melts over any ridging left behind during the previous bodying session which if done after every body session will greatly aid in building a level film as you body. Also spiriting-off will remove the oil used to reduce the surface tension from the previous body session. For info on how to spirit-off see the “Spiriting-Off” section.

    You will in most cases wan to build a film thickness between 3-5mils thick. Normally this is done in six to eight body sessions.

    Spiriting-Off:

    Spiriting-off is the process of melting down ridging and high spots and or wiping off oil from the surface of bodied or glazed surface. Spiriting-off uses the same muneca used in bodying or glazing. The load how ever is much different. When spiriting-off your load will be mainly alcohol with only one drop of oil added to break the surface tension. Because the load is mainly alcohol the residual shellac that will wick through the muneca will be of a far lighter viscosity in fact the viscosity is so light that very little shellac will be transferred. Because the new load will have much more solvent than shellac the way the stroke happens must be altered from the previous boding stroke. The Spiriting stroke is a glide on glide off stoke that is quick and slightly firm If the stroke is slow and deliberate we would end up melting too much of the previously applied shellac and end up dragging a groove in the film. Instead we just want to melt the shellac that is higher than the base thickness and wipe of the oil.

    The stroke starts by gliding on to one end of the surface and end by gliding off the opposite end in a non stop quick motion each pass of a given spiriting-off session should start at one given end and end at the other each pass should over lap by half the muneca diameter. Never repeat a spiriting-off pass in the same place twice in a given spiriting-off session. This will lead to over melt of the film. Always work for the middle of the surface and work your way towards the edges. This avoids over melting the edges which would lead to a excessively thin film at the edges.

    You can alternate which end to start at; every other spiriting-off session to insure building a level film. Here again, depending on the size of the surface you will likely have to reload the muneca several time to complete a session. I always wipe the muneca with just a small drop of oil at each new load. this is only to prevent the muneca from sticking as it first touches the dry to touch film from the previous body and or glazing session.

    Most other French polishing tutorials recommend spiriting-off every third body session. Those same tutorials lead you through an abrasive sand paper film levelling process between the bodying and glazing process to insure a level surface. I do not teach abrasive levelling, though it is and acceptable process. I teach building a level film as you build the film thickness. Regular spiriting-off sessions is key to building a level film as you go and will eliminate having to wait for the film to cure out then sanding to level.

    Glazing:

    Glazing is the process that refines the film and polishes (actually burnishes) it to a desired sheen. Glazing is much like spiriting-off with the exception of additional 1# shellac added to each load. Using thee same muneca as before but with a lighter cut of shellac work from one end towards the other in a straight line with the grain is preferred. Work from the centreline of the surface and work towards one edge then again from the centreline towards the other edge. The stroke for glazing needs to be quick and deliberate.

    The typical load for glazing is 3-4 drops of 1# shellac, 3-4 drops of alcohol and 2 drops of oil. Glazing is slightly wetter process than bodying. But not by a lot just a little.

    The intent of glazing is to refine and polish the surface of the film. Work with a work lamp mounted at the opposite end of your workstation than you are standing at. Direct the work lamp so that you can see the reflection of the lamps bulb on the surface you are glazing. As you glaze you will notice the reflection of the work lamps bulb slowly come into focus. The more detailed the focus the higher the state of the sheen. You need to move the work around to see the reflection at all location on the surface. The clarity of the light bulb image on the surface will be your key indicator as to how far along in the glazing process you are at and any given location. The idea is to bring all areas to the same sheen.

    You can pay more attention if need to troublesome areas if needed.

    Whenever glazing, I like to spirit-off after every other session for the first 4 sessions. Then eliminate spiriting-off the further along I get. To continue to spirit-off beyond the first few session can lead to dulling of the polishing you have accomplished. Keeping in mind that you are adding some oil at each load up there will be a build up of oil on the surface of the film after you stop spiriting off. This is a good thing. Oil will always rise to the surface and aid burnishing to the high gloss or sheen you desire.

    Once you’ve achieved a desired sheen everywhere, take a lint free cloth and wipe off the remaining oil. Allow the surface to harden for 24 hours and then wipe using a lint free cloth lightly dampened with alcohol to remove any remaining oil and double check the reflection of the work lamp on the surface to confirm desired sheen.

    After a week of setting up you can compound polish or machine buff if desired but the truth is you can get to as high of sheen as you may desire by glazing more.

    At this point you have completed my traditional French polish process. You now have a very durable finish that should last a life time. Now this is a shellac finish. It will scratch. It is susceptible to solvents degradation; alcohol based solvents in particular. If by chance an alcohol accident or scratches happen; you can always repair the finish by following the process described above.



    Best Regards

    Gary


    If it aint broke, don't fix it

  7. #7
    There´s nothing happened, Robert. Just let it dry and sand it off. The wet sanding has to be done immediately after applying the shellac on a piece of the tote. After a few strokes you will see the sanding mudd, then only 3 or four strokes rectangular and the mudd fills the pores. That´s it. Please avoid it to continue the sanding when you notice that the shellac begins to get hard. Then it will get very quick a gummed consistence. But that is no problem either because after the drying the proper surface comes back after sanding it.

    The best and fastest result you will get when you sand just small areas so quick that the shellac still is thin fluid when you are finished with sanding it in.

    I did the other way, too. Giving at first a coat of shellac, letting it dry and sanding then. It works - but very slow. You need probably 4, 5 or more coats until the grain is closed. So I prefer the wet sanding. You get better results very quick. Like all things it´s a matter of practice.

    Klaus

  8. #8
    This is a grain filling technique? So instead of pumice, or some other filler, you sand when the shellac is wet, get that mixed with wood dust, and fill the grain like that? I'd never thought of that. You better be quick with that sandpaper!

    Klaus:
    Have you tried using shellac like we normally would with water, i.e. dip wet/dry sandpaper into the shellac and then sand with that?

  9. #9
    In my experience if you want to fill the grain, yr better off either letting the shellac dry, then sanding it back dry to remove everything but what's in the pores. Repeat.

    If this were a table top then perhaps a proper french polishing with grain filling is called for. But this is a saw handle f'cryinoutloud.

    Anything north of "moisten a rag with shellac, wipe it on, let it dry, lightly sand, repeat until you like the look/feel" is bigtime overkill...

  10. #10
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    Quote Originally Posted by Klaus Kretschmar View Post
    There´s nothing happened, Robert. Just let it dry and sand it off. The wet sanding has to be done immediately after applying the shellac on a piece of the tote. After a few strokes you will see the sanding mudd, then only 3 or four strokes rectangular and the mudd fills the pores. That´s it. Please avoid it to continue the sanding when you notice that the shellac begins to get hard. Then it will get very quick a gummed consistence. But that is no problem either because after the drying the proper surface comes back after sanding it.

    The best and fastest result you will get when you sand just small areas so quick that the shellac still is thin fluid when you are finished with sanding it in.

    I did the other way, too. Giving at first a coat of shellac, letting it dry and sanding then. It works - but very slow. You need probably 4, 5 or more coats until the grain is closed. So I prefer the wet sanding. You get better results very quick. Like all things it´s a matter of practice.

    Klaus
    Secret's out, start sanding before it begins to dry and tack. That's smart!
    Unleaded tastes a little tangy, supreme is kinda sour, and diesel tastes pretty good.

  11. #11
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    I've never tried to wet sand shellac, but I have created a mess with the stuff! A little alcohol will strip it right off and you can try it over again.
    The Plane Anarchist

  12. #12
    I wet sanded a knob once and it exploded being shipped to the far noth during winter.. Buyer said it looked like it was shattered ice cube..

    I thought with several coats of shellac the wet sand paper would noy effect the wood but I guess it did..

    What I find is if you have several different grits to paper and move up coat after coat works best for me..
    aka rarebear - Hand Planes 101 - RexMill - The Resource

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