# Shellac cure time



## CharlieButterworth (Feb 21, 2015)

I've applied around five coats of the Zinsser (sp?) shellac to my new speaker cabinets according to instructions on the can. There are brush strokes evident in spite of using a china bristle brush and my best abilities.

When it comes to rubbing out, there seem to be a number of approaches. I was thinking of using a series of grits: 500, 1000, 2000, etc. with soapy water as a lubricant, maybe mineral oil.

As I understand it, each subsequent layer of shellac dissolves and blends into the previous layer resulting in what would effectively be a single, thicker layer of shellac.

So, would using a 220, 500,........ Series allow me to minimize brush marks and achieve a gloss?

FINALLY...... What sort of cure time should I estimate? I am in Colorado, so the humidity is around 20% with my garage/workshop between 75 and 85 F????

Thanks,
Charlie


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## Al B Thayer (Dec 10, 2011)

For one your going to have to use a block of some kind to remove the ridges from the brush strokes. Maybe a rubber pad. Otherwise you just sand the low areas too and it will go from brush strokes the waviness. 

If it were mine at this very point. I would flatten it out with a fine sandpaper on a stiff pad. Then go to a French polishing application. Flat surfaces are the easiest to learn on and you really can't do it any harm in the process. The results are more suited for fine speaker cabinets than an application with a brush. 

BTW all coats of shellac become one. The meld together as they are applied.

al


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## CharlieButterworth (Feb 21, 2015)

I was thinking of using a random orbital sander letting only the weight of the sander rest on the wood.

Charlie


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## Steve Neul (Sep 2, 2011)

First of all shellac is a finish that should be sprayed. It dries so fast it is nearly impossible to eliminate brush marks. If you use a random orbital sander on the finish it would scratch the finish so badly it would be necessary to put another coat on. 

As far as the cure time if you allowed a day drying time between coats of shellac it would cure enough in a week to rub out. If you applied all five coats in one day I believe I would give it two weeks to rub out. If you start with 500 grit paper I think you can expect a lot of elbow grease to polish out. 500 grit is too coarse for that purpose. I know you need to get rid of the brush marks but if you sand with paper coarser than 1500 grit it takes a lot of sanding with finer paper to get rid of the scratches the 500 grit makes. If it were me I would attempt to sand out the brush marks by wet sanding with 1500 grit paper with water and a hard rubber sanding block.


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## lwp99 (Jul 4, 2008)

I just joined so no credibility established. Coincidentally, I'm also working with shellac refurbishing an old cedar chest - the originally applied finish. After cleaning/removing the old shellac, I began applying new coats. In an attempt to hurry the process and build up the surface, I used a brush with undiluted shellac (Zinsser amber) which resulted in having brush strokes and large areas with no shellac for unknown reasons. Patience is required.

To correct the problem by sanding, after trying 320, I went to 220, and finally to 120 sandpaper. NO pressure applied - just moving it across the shellac surface until it looked "more smooth". After a vacuuming and a wipe-down with turpentine to see how it looked, I moved back up the sequence to 220 and 320 with the vac and turp steps. All sanding is with almost NO pressure applied on a cushioned sanding block - you want to avoid scratching the wood and starting over. Each sanding sequence gets washed with the turpentine rinse to remove all the waste.

Because the wood is cedar with lots of knots, the surface will never be "flat" - but "smooth" is very acceptable for my project. I've begun building coats using a "staining pad" dipped in a 50-50 mix of shellac and denatured alcohol. The pad is dipped in the mix, then applied VERY LIGHTLY using a circular motion VERY RAPIDLY across the surface. The "why?" for the LIGHTLY and RAPIDLY... the alcohol will dissolve the underlying layers. By moving lightly and quickly, you avoid both long and heavy contact with previous layers which would disturb (move) them. 

After each coat you will see the marks (ridge) caused by the edge of the wet areas, but because the ridge isn't high, subsequent coats will help to dissolve them into the overall finish. It is important to vary the direction of applications to average out the coverage over the entire surface. Eventually, the surface should begin to look "uniform". Try a 320 or 400 grit using a block - just floating over surface - to evaluate the process, only knocking off the dust and high spots. When the results are "almost there", the French Polishing can begin... or use 0000 steel wool with mineral oil depending on the finish you want.

Hope this helps... the one thing I've learned... you can't rush the shellac process. I'm in AZ with temps in the 100's and humidity in single digits. Fortunately, my home shop has A/C.


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## b.hog (Jul 19, 2015)

I have best results using the sponge brushes when brushing shellac. Remove excess, then quick long strokes and after hitting an area leave be.



Sent from my iPhone using Tapatalk


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## epicfail48 (Mar 27, 2014)

Like Steve said, shellac should be sprayed. It dries so fast that brush marks don't have enough time to level out. But, that doesn't really help you too much now I suppose...

Anyway, leveling a finish is really easy, shellac particularly. First off, shellac doesn't really "cure". Its a solvent based finished, so once the solvent evaporates its done, vs something like a urethane which relies on a chemical reaction to develop its strength. What's this mean to you? Means that once shellac stops smelling like alcohol, its good. As far as time goes, its pretty quick. I've seen guys who rub out almost immediately after applying the final coat, but personally I like giving it a day or so. 

Onto the actual act of rubbing out! First off, stay away from machines. Way, way to easy to o right through the finish when using a power tool. Stick to hand sanding. Secondly, make sure your sanding block is flat. If it's not the finish will look... Bad. Okay, now, take that sanding block and affix a sheet of 320 grit wet/dry paper. You could start at 220 if you want to level the finish faster, but its a little riskier. Anyway, take the block, spray down the surface with some lightly soapy water and start sanding. Let the weight of the block do the work, don't force it, and keep all strokes in the same direction. Keep sanding with the 320 until the entire surface is uniformly matte. If you see any shiny spots, you still have low spots, which will show up badly once final polish is achieved. Don't get lazy, keep sanding until everything is nice and level. It takes some time, but this first sanding it the most critical part. 

Now, once everything it nice and uniformly matte, with no ununiform areas, clean all the sanding crap off the piece, switch to 400 grit paper, rotate the piece 90 degrees and repeat the process. Now that the surface is uniformly level, the next grit won't take any time at all. Keep going with the 400 until you can't see any more marks from the 320. One you hit that point, switch to 800 grit paper, rotate 90 degrees, sand, 1000 grit paper, rotate, 2000 grit. 

Once the sanding is all nice and done, congrats. At that point, you'll have a nice matte finish at 2000 grit. If mattes what you want, stop there. If you're going for high gloss, head to an automotive store and grab a bottle of automotive rubbing compound and a bottle of polishing compound. Start with the rubbing compound, get your karate kid on and wax on/wax off grasshopper. Same deal as the sanding, go over the entire surface until everything is uniform. Repeat with the polishing compound and boom, perfect high-gloss shine!

What's that? You wanted semigloss? Wow, you're impossible to please. Fine, grab some 0000 steel wool nand a can of paste wax. Dip the wool in the wax, go over the surface with the waxy wool, buff off the remaining wax and boom, semigloss


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## CharlieButterworth (Feb 21, 2015)

EpicFail,

So you're implying that I can get the brush marks flattened using hand sanding and patience?

If so, I'll plan on getting going. However, since the brush marks are only visible under raking light, I installed the speakers into my audio room as I was having some music withdrawal since moving my old speakers to the TV room.

Thanks for all the replies, this whole process has been quite a learning experience.

Charlie


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## epicfail48 (Mar 27, 2014)

CharlieButterworth said:


> EpicFail,
> 
> So you're implying that I can get the brush marks flattened using hand sanding and patience?
> 
> ...


Not implying, I'm flat out saying you can


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## CharlieButterworth (Feb 21, 2015)

Thanks for confirming that. My wife really likes the speakers as they are, so I am going to wait a while until I have plenty of time to not rush the finishing.

Charlie


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## epicfail48 (Mar 27, 2014)

CharlieButterworth said:


> Thanks for confirming that. My wife really likes the speakers as they are, so I am going to wait a while until I have plenty of time to not rush the finishing.
> 
> Charlie


Good idea, rubbing out is really not something you want to rush. It's a nerve wracking process as is, worrying whether or not you'll go through the finish


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## sancho57 (Oct 23, 2011)

Since shellac melts into itself and it is alcohol base, I would get me a better quality brush or shellac mop.
They are not cheap. They will run you about $30-$40. Dip in alcohol and try to smooth out the finish, then let dry, 
Lightly, very lightly sand with a block or Mirca sanding pad the can be hooked to a vacuum, gently lightly sand, then rub on a good wax like Bri Wax then using a 0000 Steel wool,or synthetic pad rub the wax into the finish, next buff out with a soft brush . Just finished this wine rack. It was supposed to have been a antique, kind of beat up, but a different looking wood turned it upside down and found a made in India sticker on the bottom . Realised the wood was Indian Rosewood(sort of crap looking )

So I just refinished it to make it useable and at least presentable. Kept the dings, dents etc so it would have a antique sort of feel to it.


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