deglossing shellac

[vbw]

I'd like to reduce the gloss of a shellac finish to more of a satin appearance. I heard there was a product available but have not found anything. Does anyone know of a product or can recommend a process that may be the answer.

Thanks for any help offered

 

[Andreas Preuss]

Silica containing minerals or wax can create a less glossy surface when blended into shellack. But there is a limit to the proportions.

I used often for this purpose ‘Kieselerde’, a product available in German drugstores for strengthening bones in humans. It’s basically silica dioxide and might be sold under other names. A too high proportion makes the varnish blurry.

Wax is more efficient, but makes the varnish too soft. However I never tried carnauba wax which seems to be much harder. 

Otherwise the raw shellack still contains its own wax, but also all the dirt with which it collected. 

Maybe this gives some directions. The rest is up to experimenting anyway to find the right degree of desired ‘satiness’.

[FiddleDoug]

Silica will reduce the gloss. There is, or was, a product called something like "Matt Lacq". It's basically colloidal silica in solvent. In the "real world", colloidal silica is used as a filler for epoxy resins in fiberglass repair. You only need a little, so you may be able to get it at a boat shop. If you're buying, something like this:

https://www.amazon.com/Boating-Accessories-Colloidal-Silica-System/dp/B0000AY1OC/ref=asc_df_B0000AY1OC/?tag=hyprod-20&linkCode=df0&hvadid=312168100217&hvpos=&hvnetw=g&hvrand=8690365460863979607&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9005591&hvtargid=pla-569061977759&psc=1

[Mark Norfleet]

2 hours ago, FiddleDoug said:

Silica will reduce the gloss. There is, or was, a product called something like "Matt Lacq". It's basically colloidal silica in solvent. In the "real world", colloidal silica is used as a filler for epoxy resins in fiberglass repair. You only need a little, so you may be able to get it at a boat shop. If you're buying, something like this:

https://www.amazon.com/Boating-Accessories-Colloidal-Silica-System/dp/B0000AY1OC/ref=asc_df_B0000AY1OC/?tag=hyprod-20&linkCode=df0&hvadid=312168100217&hvpos=&hvnetw=g&hvrand=8690365460863979607&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9005591&hvtargid=pla-569061977759&psc=1

I buy the West Systems colloidal silica at my local hardware store.

 

[Christian Pedersen]

[Don Noon]

2 hours ago, Mark Norfleet said:

I buy the West Systems colloidal silica at my local hardware store.

 

You can also search around for cabosil, aerosil, or fumed silica. All the same stuff.

[donbarzino]

Gloss can also be reduced after the finish is dried by rubbing with a very fine abrasive

or with steel wool.

[vbw]

7 hours ago, Andreas Preuss said:

Silica containing minerals or wax can create a less glossy surface when blended into shellack. But there is a limit to the proportions.

I used often for this purpose ‘Kieselerde’, a product available in German drugstores for strengthening bones in humans. It’s basically silica dioxide and might be sold under other names. A too high proportion makes the varnish blurry.

Wax is more efficient, but makes the varnish too soft. However I never tried carnauba wax which seems to be much harder. 

Otherwise the raw shellack still contains its own wax, but also all the dirt with which it collected. 

Maybe this gives some directions. The rest is up to experimenting anyway to find the right degree of desired ‘satiness’.

 

[Mark Norfleet]

1 hour ago, Don Noon said:

You can also search around for cabosil, aerosil, or fumed silica. All the same stuff.

Agreed, but I have noticed some difference in fineness in products from different sources.

[The Violin Beautiful]

I bought some silica in powder form from a museum conservation company a few years ago and have been using that as a matting agent ever since. 

[Jeffrey Holmes]

I don't use Shellac alone (I add others stuff to it when preparing it) for touchup, as it tends to harden a bit too much with time (and it's quite glossy by nature), so my touchup is a little less glossy to begin with... but I do use a matting agent (silica) as well as occasionally a bit of wax when appropriate.

Several in restorers Europe (especially the UK) I know stock Jenkins matting varnish (Link) in their shops as an additive. I never made friends with it personally, but I can attest that a good job can be accomplished with it by those who have.

[Don Noon]

5 hours ago, The Violin Beautiful said:

I bought some silica in powder form from a museum conservation company a few years ago and have been using that as a matting agent ever since. 

I also have some silica in a fine powder form, which is 5 micron silica, or ground glass.  Definitely a different animal from fumed silica, where you get it in a large container that you'd swear is empty when you lift it.  The 5 micron silica is fairly dense.

[Richard4u]

22 hours ago, vbw said:

I'd like to reduce the gloss of a shellac finish to more of a satin appearance. I heard there was a product available but have not found anything. Does anyone know of a product or can recommend a process that may be the answer.

Thanks for any help offered

 

This is just an afterthought.  My experience has been that young players (elementary and middle school age) LOVE new and highly gloss violins.  But high school and up want the antiqued look to their instruments.  Has anyone else found this to be true?

[FiddleDoug]

13 hours ago, Don Noon said:

I also have some silica in a fine powder form, which is 5 micron silica, or ground glass.  Definitely a different animal from fumed silica, where you get it in a large container that you'd swear is empty when you lift it.  The 5 micron silica is fairly dense.

Yes, the fumed silica is around 0.15 microns, and will float in the air. Be very careful when handling it!

 

[vbw]

Thank you to all who have offered such suggestions and shared their experience.

It seems that many have suggested trying a silica in some form.

It so happens that the fellow in a neighboring shop is an amateur boat builder and offer some cabosil  he buys from West Marine to try.

So it looks like I'm in for some interesting experimentation time.

One thing I should have mentioned is that I  started this finish as french polish so I wonder how this will effect the process. I'm pleased with the results but not the gloss. Should I continue with the french polish process with the added cabosil or or try another means of application

Thanks again to all who have joined this conversation and I will follow up with a report of whatever results develop.

[Michael Richwine]

Don't use any flattening agent in anything but your final coat, and if you're going to rub it out at all, you don't need any flattener; you'd be working against yourself. Flattener in under coats just reduces transparency. Flattener is really most suited for spray finishes, IMHO, (Based on thousands of gallons of experience).

I refurbish and restore a lot of old violins with deteriorated finishes. I use a spirit varnish made of dewaxed blonde shellac, mastic, and sandarac, applied with a French polish technique over 2400 or 3600 micromesh prep sanding. This has worked well for me, and once the scant amount of paraffin oil lube dries, the vanish dries with a satin finish that is pretty satisfactory. I find that if I want a high gloss, I either have to "spirit off" the final hardened coat with alcohol and oil, or polish with rottenstone or something similar. Just my experience. I'm not generally looking for a high shine, so it hasn't been a bother to me.

[vbw]

21 hours ago, Michael Richwine said:

Don't use any flattening agent in anything but your final coat, and if you're going to rub it out at all, you don't need any flattener; you'd be working against yourself. Flattener in under coats just reduces transparency. Flattener is really most suited for spray finishes, IMHO, (Based on thousands of gallons of experience).

I refurbish and restore a lot of old violins with deteriorated finishes. I use a spirit varnish made of dewaxed blonde shellac, mastic, and sandarac, applied with a French polish technique over 2400 or 3600 micromesh prep sanding. This has worked well for me, and once the scant amount of paraffin oil lube dries, the vanish dries with a satin finish that is pretty satisfactory. I find that if I want a high gloss, I either have to "spirit off" the final hardened coat with alcohol and oil, or polish with rottenstone or something similar. Just my experience. I'm not generally looking for a high shine, so it hasn't been a bother to me.

Ok thanks, I'll try that before the cabosil. Is there a formula with the mastic and sandarac you'd be willing to share? 

Thank you for sharing your experience

 

[Michael Richwine]

2 hours ago, vbw said:

Ok thanks, I'll try that before the cabosil. Is there a formula with the mastic and sandarac you'd be willing to share? 

Thank you for sharing your experience

 

My touchup varnish is 50 gm dewaxed blonde shellac flakes, 7.5 gm sandarac, 7.5 gm mastic, added to 190 proof grain alcohol to make 8 oz. I grind the dry ingredients in an old high speed blade type coffee / spice grinder to help them dissolve faster, and test the batch pretty carefully after six months if I haven't used it up, to make sure it's still drying hard.

[Toby Newell]

Jenkins LT12 matting agent is the best although this is only really for maximum matt, ie virtually undetectable <3% sheen. You mix it 1:1:1 with meths and pale transparent shellac (roughly 2 to 3lb cut - ie 2 to 3lb shellac per UK gallon)

Best to apply via brush (zorino mixed hair or squirrel). If you wipe on use a clean, new, wet fad, you cannot use a rubber (or you will have streaks) Only use for the final coat, it's quite weak, overcoating may cause it to pull.

 

Mylands do a satin wuncote shellac and Jenkins do a range of satin and matt shellacs.

If you want a fine and traditional finish then you cannot beat a wire and wax finish.

The clue here is to let the final shellac / shellac varnish dry for a few weeks, wet and dry sponge sand with a P1500 or similar, then carefully wire with fine 0000 wire wool, with or without pumice / rottenstone and a good beeswax and canauba.

This takes a bit of practice but looks great. Perhaps the biggest advantage is in the feel. A satin or matt shellac with additives will look slightly cloudy and feel slightly grabby, where as a wired satin matt finish will look lustrous and feel like silk.

[bick]

On 1/19/2023 at 10:29 AM, donbarzino said:

Gloss can also be reduced after the finish is dried by rubbing with a very fine abrasive

or with steel wool.

7 hours ago, Toby Newell said:

This takes a bit of practice but looks great. Perhaps the biggest advantage is in the feel. A satin or matt shellac with additives will look slightly cloudy and feel slightly grabby, where as a wired satin matt finish will look lustrous and feel like silk.

Is there a benefit to using a flatting agent as opposed to knocking down the gloss with steel wool or fine abrasives suggested above? I've used the steel wool method plenty with success, but never was compelled to try a flatting agent. I am curious on the thoughts of others.

[donbarzino]

Sanding or rubbing creates a smooth flat surface, erasing or blurring the small textural details,

while using a flatting agent allows the natural, untouched  texture  to be preserved.

[David Burgess]

On a varnish with a lot of texture, using abrasives to reduce the gloss can leave the low spots shiny, resulting in a very unnatural look. Using the end of a stiff brush to grind a powdered abrasive onto the surface can help reach into and dull these low spots.

[Michael Darnton]

If you use an airbrush you can spray not very much too-highly dilute spirit varnish from too far away, sprayed almost dry, and the result is a lightly frosted appearance that rubs out nicely with the palm of the hand to give a very natural look.

The matte surface remains in whatever low spots you can't reach and the hand "polish" is like the healthy glow of a well cared for old violin that hasn't been aggressively polished.

You can achieve anything from the look of limestone gravel to glass this way if you aren't careful; experimentation and experience help a lot towards achieving the best look and consistent results. It works best when you are adding the absolute minimum material so as to not change the underlying texture at all.