We have bought pine (white) panel doors for our new house and wish to use Zinsser Shellac (Amber 3 lb. cut) straight out of the can. Is this a good idea? We do not want solvent based products due to severe allergies to them and continued off gassing that goes on for months.
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3# cut is too thick for best brushing or spraying. 1 1/2# - 2# is the best brushing cut. I would cut it about 35% - 50% with alcohol.
If you've not used shellac before as a finish, I strongly suggest you practice on some scrap to learn how to handle it. It needs to be flowed on with minimal back and forth "brushing".
By the way, if it's only the odor that you are concerned about with other finishes, you might want to try using a waterborne clear acrylic finish. It has very low odor while applying and virtually no odor once it dries. It's dry with a few hours.
Interior doors I hope? shellac is not a good finish for outside, it won't last more than a few days outside..
Do not use shellac out of the can! Shellac starts to dry nearly instantly and so putting on a streak free finish is really hard..
I had a lot of problems getting a smooth coat untill I went to over thinning the finish.. There are several advantages to that technique.
first it is extremely fast, second you wind up brush mark free and run free.
Third it dries much faster that way. Straight from the can will take hours to dry. I've let it sit for 4 days and it was still soft.. Cut it with one gallon of denatured alcohol and you still have to be a pretty decent painter to get a decent finish plus it will take 4 times as long to dry..
What I do is pour 2 gallons of denatured alcohol together with one gallon of Zinsslers and the first coat is dry in 15 minutes..
Then I sand all the little nubs off with a 220 3M sponge (it takes about a second to a second and a half per square foot).. don't try to get the finish smooth because the next coat will melt the first coat and you'll have wasted your time.. just sand off the nubs that get raised untill they are smooth.
The second coat will dry in 30 minutes and the third coat will dry in an hour. Double the time for each coat.. Too thick is bad!
When you brush the shellac on , just flood it on. try to cover as much area as quickly as you can.. Neat doesn't count, speed does.. Do Not go back over anything.. if you miss an area keep going and get it with the next coat. (remember new melts old and makes invisable repairs)..
The brush you use very sensitively affects the look of the resulting finish when using a fast-dry film finish like shellac or laquer. A normal "universal brush" (that is, for latex and oil-based paints) will give you a fair amount of brush marks, even with a heavily thinned shellac finish. Some consider this desirable, so it's a matter of preference.
Using a very fine haired "flagged" artist's brush will greatly minimize brush marks with a 1 lb. cut of shellac, though it will not eliminate them entirely. The ones I use are Cotman artist's brushes for watercolors. These are incredibly fine and made of Taklon artificial fiber. They are not inexpensive in the larger sizes, but since shellac will re-dissolve repeatedly in denatured ethyl alcohol, a brush should last you practically forever. One source is Jerry's Artarama.
If you want even less brush marks, it's possible to wipe on a shellac finish by using a "rubber". These are typically used for the French Polish method of applying shellac, but they will also work well for just applying shellac. To make one, buy some lamb's wool from the drugstore (it's sold for relief from foot problems), make a ball with it, and put it inside a pure linen cloth, then twist the top closed so there's no folds on the bottom (applicator) part of the rubber. You can tie it off with thread, though I sew it shut. It's important to get the real deal linen - not the polyester/flax combo that's sometimes sold as linen. Note that linen is not made of cotton - you want the genuine article made of flax. Cotton-based linen look-alikes are not good - you will drag some of the cotton fibers out onto the wood surface as you wipe, which will lead to a lot of fuzz that you have to then sand off.
Soak the rubber in denatured ethyl alcohol, wring it out, and apply about a 1/4 teaspoon of a 2 lb. cut of shellac to the bottom, and squeeze it to distribute it into the lamb's wool. Thereafter, use an eye dropper to dispense fresh shellac onto the bottom after about every 2 or 3 strokes over the wood's surface. If the rubber grabs on the wood's surface, add about 2 drops of linseed oil to the bottom, again squeezing it to distribute the oil.
Before you use the rubber, brush one coat of a 2 lb. cut of shellac onto the wood - most of it will be absorbed, leaving a matte surface. However, this first coat will seal the wood and prevent sap from the pine from messing up your shellac rubber.
Generally speaking, you want to go over your doors with the rubber 3 or 4 times, waiting 15 minutes between applications. The rubber's action builds the shellac coat and also smooths out the brush marks from the initial coat. More coats will build a very thin, high-gloss finish on the wood.
Hey, Thanks! I didn't know that about linen. Last time I tried to French polish I simply went to a cloth store and asked for linen. I didn't bother to check if it was the real deal.
That could gave been the reason it was so darn much work. (and I mean an insane amount of work)..
There's no doubt that a true French Polish finish is a great deal of work. That might have been why there was specialization of cabinetmakers vs. finishers in the Federal period (about when French Polishing came onto the scene). But there are certainly ways to short-cut the process and still get a lot of the benefits. One way is to skip the "build" step with the rubber, and just brush a lot of coats of shellac on, then hand-sand with 400 grit stearated paper and then 600 grit.
That'll leave a matte finish with lots of sanding scratches, but the scratches are small enough so that you can use the French Polishing rubber with alcohol/shellac to smooth the finish out. It usually takes me about 3 times going over the entire surface with the rubber to get a nice, semi-gloss sheen that can then be left as-is or further polished with polishing compound or rottenstone to achieve a high-gloss finish.
Still a lot of work, but the result is an absolutely flat mirror that you can see your reflection in, and it's very difficult to achieve that with spray finishes or varnish.
What I do is short cut that step.
I build up the finish with 3 sometimes 4 coats and then sand block starting with 400 grit and working all the way up to 6000.. at that point I take out my buffer and polishing compound. When I'm finished. the finish is nice and shiney deep but not plastic looking.. Then I rub a nice coat of wax on it to protect it..
It sounds slow but I bet it takes me 1/100th of the time french polishing does.. heck maybe 1/500th!
Yeah - But I despise sanding. ;-) That's why I do the 3 or 4 coats with a brush and lightly sand it with 400 grit - often I skip the 600 grit and just go straight to the rubber. Generally speaking, the scratch marks are gone after the first hit with the rubber, the next couple of passes are just refining the finish.
If you don't like sanding, you might be interested in Minzerna's polishing compounds:
http://menzernausa.com/
I've their pre-polishing, polishing, and ultra-polishing compounds. The pre-polish will take out 600 grit scratches from laquer, shellac and polyurethane, so a heck of a lot of sanding is avoided. One good thing about this stuff is that it can be thinned with mineral spirits, so the consistency can be changed to suit the method you're using (power buffer or by hand).
I used to use Meguir's polishing compounds when polishing up laquer and shellac, but the Minzerna stuff works far better. I suspect the Meguir's was a bit too fine for the purpose.
What cut do you use for the coats (base and finish)?thanks,
---mike...
For the base coats, I use a 2 lb. cut, but that's simply because making a 2 lb. cut is a good compromise between having a decent solids content and waiting for the shellac to dissolve. I've seen others use as much as a 4 lb. cut on the initial coat to build the base quicker.
I use the 2 lb. cut with the rubber as well, but the procedure is putting 5 or 6 drops of shellac on the rubber that's been pre-saturated with DNA and then wrung out, using it for 4 to 5 strokes, then adding about equal numbers of drops of 2 lb. cut and alcohol thereafter to re-charge the rubber. On the last finishing pass, I typically use 100% DNA on the pad - that last pass is just to remove as many brush marks and sanding scratches, if any, as possible.
There is a lot of personal preference involved in choosing the lb. cut. for shellac, and also very little reason to be very precise about the mixing. I tend to like about 2 lb. cut for brushing, perhaps a bit less for padding. For wash coats 1 lb. or a bit less works fine, but I would find padding or brushing shellac that thin very slow. Under one pound cut each new coat would almost completely redissolve the earlier coats, making building the finish very very slow. Of course, all shellac coats dissolve sufficiently into each other that there is essentially just one melded layer in the end. That also means the choice of pound cut is only relevant to the application process. The final finish doesn't really care how many "coats" it takes to get there only how much shellac ends up on the surface.
I like the Taklon gold watercolor wash brushes, such as Winsor Newton 580 series. These do carry very little shellac, so on the down side, they need to be dipped often, but on the plus side they give very thin smooth and even applications. Others like large capacity brushes with very fine bristles--mop brushes like Winsor Newton 140. In either style, very fine soft bristles work a lot better for me with shellac that coarser china bristle sold for oil based paint or synthetic bristle brushes sold for latex paints.
For the covers on pads fine woven fabric--such as handkerchief linen works well, but well washed 100% cotton such as percale sheeting works ok too.
"I like the Taklon gold watercolor wash brushes, such as Winsor Newton 580 series. These do carry very little shellac, so on the down side, they need to be dipped often, but on the plus side they give very thin smooth and even applications. Others like large capacity brushes with very fine bristles--mop brushes like Winsor Newton 140. In either style, very fine soft bristles work a lot better for me with shellac that coarser china bristle sold for oil based paint or synthetic bristle brushes sold for latex paints. "
One thing to realize if you're buying a shellac brush sight-unseen over the internet is that there is a large variety of bristle sizes in gold Taklon fiber - some of them are quite coarse. You're pretty safe with brushes intended for water colors, as these typically require a very fine, flagged tip to work well with water color paints. One note about the Windsor Newton brushes - they cost a bit more, but they are very well made, and will stand up to repeated cycles between shellac/alcohol and dishwashing soap/water (what I use to clean them after getting as much chellac as possible out with rinses of DNA). Here's a link to the W/N from one vendor:
http://www.jerrysartarama.com/discount-art-supplies/Brushes-and-Palette-Knives/Watercolor-Brushes/Winsor-and-Newton-Water-Colour-Brushes/Winsor-and-Newton-Cotman-Water-Colour-Brushes.htm
I don't often clean brushes of shellac more than a swash in DNA to eliminate the heaviest of the shellac. It then dries hard, doesn't collect dust but the shellac softens quickly enough.
But, if you really do want to clean brushes after use, you can just use household ammonia. It too is a true solvent for shellac, every bit as much as DNA is (but cheaper) You do need to rinse it well before using again.
The Winsor Newton brushes are available fairly widely at local artist's supply stores in towns of any size. The Loew Cornell La Corneille line has some similarly good watercolor wash brushes. Once you can actually handle either of these you can then compare them to the less expensive watercolor wash brushes that these stores also carry, if you are more comfortable at a bit lower price range.
For starters shellac is alcohol based so it has solvents. If you use Zinnsers, use a 1 lb cut for brushing. You will need about three coats of course to attain the same thickness as the product out of the can. Try it on scrap pine boards first,you'll soon find that a three lb cut will be difficult to brush without brushmarks.
mike
I just finished a job using Zinnzer Amber shellac on pine. I cut the 3 lb by about 25% and sprayed it on. 2 coats sanded with 220 between. This gave me the color I needed to match. I then sprayed 4 coats of Minwax waterbased poly. Looks like skim milk going on but dries water clear. Matched the original cabinets perfectly!
Working with shellac takes practice to get the color even. DO NOT try this for the first time on your doors, practice on something else to get the feel.
Edited 7/7/2009 10:15 pm ET by paulbny
How about using the 1# shellac as a sealer then, as previously suggested, use a water borne product (Crystalac, Target, etc.) as the actual finish. I've sprayed on (dewaxed) shellac as a seal coat, then sprayed on Crystalac and been very satisfied with the results, and as for oder -- nothing from the waterborne lacquer. And the finish is dry in under 15 minutes.
GT
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