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Buffing shellac debacle

R

Raif Harik

Joined
Jan 14, 2020
Messages
275
Likes
100
Location
Austin, TX
Hi,
I've been using shellac as a finish, and I thought I was really liking it. I'm using a 1lb cut from flakes.
Today I went out to buff a few pieces. I use the beall 3 wheel system. First wheel is some kinda weird red stuff if that matters. I set the wheel at about 1600 rpm which is slower than a slow speed grinder and I think they show it being used with just a regular grinder so I don't think it's too fast.
So as soon as I put the wheel to the piece it starts ... Rolling up a layer of finish. Idk quite how to describe it, just all this finish starts moving up and I have to sort of herd it up and off of an edge. I have included a pic. I tried applying very little pressure but that just made a blurry mess.
I mean I guess I must be putting too much shellac on? But ... It didn't seem that way to me. In the picture you can see the unbuffed part of the bowl as well.
Any help would be greatly appreciated.
Thanks
Raif
 

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Does the shellac powder when sanded? Thats the best way to check that it is fully cured. Is the shellac rough to the touch? The picks look as though it could be fabric fibers from the wheel, similar to cleaning a buff wheel with sand paper. If so sand the surface with hi grit to make smooth, or “french polish” after application to smooth.

I have buffed shellac but not with the typical Beal type compounds. I used automotive polishing compounds, and sanded or french polished the surface smooth 1st.
 
It most certainly must be the heat then. Heck it's about 167 degrees in my shop as it is!
That was a complete debacle.
@Dave, do you routinely use your beall wheels on shellac? I mean, are you saying that if needed to you would do it at 900 or are saying that is part of your process. I guess I'm asking how well that slow speed works, if it's still a big pain, or if it's a good process.
Thanks
R
 
If it's that hot in your shop, what is the humidity. Humidity dramatically slows the curing of shellac. I used to make hundreds of Christmas ornaments every year and they all were sprayed with shellac and buffed. In my shop the buffing is done very delicately. Just barely let the mops touch the wood, and not shove it in hard enough to melt the finish.
 
Humidity isn't great here around 50-60% It's not really 160 :) but you know the outside temp is ~100 and I just have a couple of fans. But when I was applying the piece to the wheel it was getting pretty hot.
Question about shellac, is it ok to put on 3, 4 coats in fairly rapid succession? like over 2 hours? Or does each coat need to cure?
Thanks
 
Really - my remarks are kind of a summary of all the above:
1. Allow shellac to cure for several days. A week is better. Thin coats applied at least one day apart for any kind of film build.
2. Don't risk power buffing unless you have experience with such. Low speed - VERY light touch is o.k. - French polish by hand, may be better to prevent damage.
3. Though you can....I never use shellac for a finish. If I apply shellac - I think of it as a barrier coat or a primer/mid-coat in preparation for lacquer.
4. There are so many gloss levels of lacquers that you may find no need to buff them. BUT....similar to shellac - allow plenty of cure time before you attempt buffing. 5. And - if you choose to buff....low speed, LIGHT touch.
 
I agree with the above. I use 4" wheels at about 1200 rpm so the surface speed is far slower than what your using. Canned shellac melts really easy. Mixing your own the shellac is fresher and usually easier to buff. I still had problems occasionally. Enough that I quit using it as a finish.
 
john lucas said:
I agree with the above. I use 4" wheels at about 1200 rpm so the surface speed is far slower than what your using. Canned shellac melts really easy. Mixing your own the shellac is fresher and usually easier to buff. I still had problems occasionally. Enough that I quit using it as a finish.
Click to expand...
I've been using the Beall 4" buffing wheels mounted in a reversible drill since 1998. Many advantages beyond the slower surface speed that John mentions. Easier access to tight areas and bowl interiors. Most important - I always mount the piece on the lathe (tenon, vacuum, or other method), run lathe at a slow speed while buffing. The wheel is never in the same spot long enough for any burn through, and you will never have a piece pulled out of your hands (I'm sure everyone has had that happen at least once! :( ). With this method you don't have to wait as long for the finish to cure. This worked so well that I bought three drills dedicated for buffing. Haven't used the large wheels in several decades.
 
Tim Tucker said:
Really - my remarks are kind of a summary of all the above:
1. Allow shellac to cure for several days. A week is better. Thin coats applied at least one day apart for any kind of film build.
Click to expand...
Tim I have to disagree. When doing a French Polish you only have to wait for the shellac to dry to the touch before doing the next application. Note all applications of shellac , like lacquer, meld together to make one coat. Each application does make the coat thicker.
Have never tried to buff shellac but would think waiting several days and slow speed would apply. As Doug stated I have used automotive compound and polish to finish lacquer and think it would work on shellac.
 
Gerald - fair enough.... the context of my post was if he was going to power buff. With a French Polish - aren't you doing that by hand? In extreme humidity like I have here, I have to be cautious about solvent entrapment - which happens because a finish "skins over" before the solvent in the coating can evaporate sufficiently. That is what the OP's photo looked like it could have been caused by, hard to tell. When I say extreme humidity...knowing you are in Miss. - let me be literal. I live at about 3200 ft. above sea level - deep in the Blue Ridge Mountains. I live in a micro-climate, even for this region. I had 107 inches of rainfall on my property last year. ( Take THAT Seattle!) And - it is not uncommon for us to awake at sunrise and find temps. in the 60's - but dew point in the 80's. It burns off as the day warms up. But I have to really take note of the humidity before even spraying lacquer - or it will blush and be cloudy. Thus my precautionary advisements to Raif...being pretty new to turning.

And, agree that shellac has similarities to lacquer in that they meld together...but one major difference is that shellac is alcohol based, and lacquer - using lacquer thinner. Lacquer thinner has a much higher KB value - or "power of solvent" rating. Generally speaking, in coatings - those requiring a hotter or higher KB value solvent - are "tougher" coatings. We know that lacquers were used as automotive finishes for a long time, but shellacs, never. Just my thinking about use of lacquers as a topcoat for turned objects that could be handled much. Hard to argue with the beauty of a good French polish tho.....;)
 
Raif Harik said:
@Dave, do you routinely use your beall wheels on shellac? I mean, are you saying that if needed to you would do it at 900 or are saying that is part of your process. I guess I'm asking how well that slow speed works, if it's still a big pain, or if it's a good process.
Thanks
R
Click to expand...
I don't use shellac as a final finish very often. I used to, but not recently. I do use it as a sealer or first layer sometimes.
My 900 RPM process may well have started with a problematic shellac piece, I can't remember. But I do remember having problems with peeling finish, like what you described. Could be I was not waiting long enough (in fact, that's quite probable knowing my usual level of patience).
But slowing down the buffing wheels did help, so it's just my normal now.
 
Gerald - thanks for clarifying. I am always open to new methods. But, was trying to imagine a French Polish via machine....Sounds like a long term project with little reward huh?
I try to spray outside to keep my shop air clean as my shop is my basement - and my wife is 3/5 blood hound on her Momma's side....
 
Tim Tucker said:
Gerald - thanks for clarifying. I am always open to new methods. But, was trying to imagine a French Polish via machine....Sounds like a long term project with little reward huh?
I try to spray outside to keep my shop air clean as my shop is my basement - and my wife is 3/5 blood hound on her Momma's side....
Click to expand...
I have a side table by my chair and it was done in French Polish on Cherry . For 16 years it has been there and the finish has held up rather well. Now I may have to try it on a platter. Just thinking platters may be a great place for a french polish. The cool thing is if messed up it can all be easily removed with alcohol.
 
Tim Tucker said:
But, was trying to imagine a French Polish via machine....Sounds like a long term project with little reward huh?
Click to expand...
French polish can be done with the project spinning on the lathe, so it is by machine. My preferred method is to spray the shellac to suitable film thickness, remount on the lathe, and french polish the finish from there.

Havent used the method in a few years as lacquer is better to work with IMO.
 
Gerald Lawrence said:
I have a side table by my chair and it was done in French Polish on Cherry . For 16 years it has been there and the finish has held up rather well. Now I may have to try it on a platter. Just thinking platters may be a great place for a french polish. The cool thing is if messed up it can all be easily removed with alcohol.
Click to expand...
It is a beautiful finish on nice furniture. And - you are right...I think on a decorative platter it would be great. But....about that alcohol....How much is required to get one in the mood to scrub off the shellac? Do you prefer Kentucky or straight white liquor?:p:D:cool:
 
Raif Harik said:
Humidity isn't great here around 50-60% It's not really 160 :) but you know the outside temp is ~100 and I just have a couple of fans. But when I was applying the piece to the wheel it was getting pretty hot.
Question about shellac, is it ok to put on 3, 4 coats in fairly rapid succession? like over 2 hours? Or does each coat need to cure?
Thanks
Click to expand...
Kinda depends on how fresh the shellac is, but no 3-4 coats in 2 hours is too much too quickly. It will feel dry, but that's different than cured.
 
Tim Tucker said:
Doug - I am assuming very low speed of rotation while polishing the shellac on the lathe?
Click to expand...
Dependent on dia, ~100 rpm for say ~14” up to ~500 rpm for finials. Give it a try, and try different speeds.

If you havent done so, look up Capn Eddie Castelin and OB shine juice - the Capn will entertain you if nothing else.
 
Doug Freeman said:
Dependent on dia, ~100 rpm for say ~14” up to ~500 rpm for finials. Give it a try, and try different speeds.

If you havent done so, look up Capn Eddie Castelin and OB shine juice - the Capn will entertain you if nothing else.
Click to expand...
Thanks Doug! I do know of Capt. Eddie...need to look up his shine juice...Shellac based?
 
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Tim Tucker said:
Thanks Doug! I do know of Cat. Eddie...need to look up his shine juice...Shellac based?
Click to expand...
It is equal parts of de-waxed shellac, boiled linseed oil, and denatured alcohol.
 
I use Capt Eddie's shine juice sometimes. It's great for spindles, finials, and pens where the surface area is small. But, I've found that on larger projects it takes too long to build up a shiny layer all over the turning. For me it builds up kind of patchy at first. Keep applying and you do get a beautiful finish. But as I said: way too much work. I do use it regularly as a sand and seal undercoat. Great for that with just about any top coat. Lacquer is difficult for me due to high humidity, and when not humid it's usually too cold in my shop. On the rare occasion that the "weather" is right, I will use lacquer sometimes. My go-tos now are wipe on poly, minwax tung oil finish, and true oil with a wax overcoat. I'd like to try waterlox but haven't gotten around to it yet.
 
> I believe zinsser Bulls Eye in the can is waxed 3# cut, in rattle cans is dewaxed cut unknown
> Zinsser Sealcoat is dewaxed 2# cut
> For larger items they can be sprayed with shellac 1st to get a build then mounted and shine juice or thinned shellac applied
> Dont recommend shine juice with oil under another finish. Just use dewaxed shellac at whatever cut, I use ~1# cut. Reduces cure time before other finish can be applied.
 
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