First of all, thanks to all who’ve answered my many questions regarding shellac over the past year or two… it’s become one of my favorite finishes — in warm weather.
Now I have another shellac-related question. Here are the facts, first: It’s beginning to turn cold here in Michigan. I heat my workshop with a woodstove. I don’t want to apply the shellac in my somewhat small, heated workshop, for fear the alcohol fumes will ignite if they come in contact with the fire in the stove. I can’t apply the finish in the house because my SO has forbidden all manner of solvents, etc. from entering the front door (although I do sneak in a winter finish job occasionally, when I’m on my own).
So, if I were to apply the shellac in my unheated worshop (current outside daytime temperatures range from 40 to 55 degrees on average, nighttime temps in the 30s — the shop doesn’t get quite as warm or quite as cold), would the shellac still cure/dry? Is shellac curing/drying related only to the evaporation of the solvent (denatured alcohol), or is there some other chemical process that occurs? Will lower-than-70-degree temperatures affect the quality (hardness, adherence) of the dured/dried shellac, or simply slow down the process (in other words, instead of curing in a half-day or overnight, it might take several days)?
Thanks in advance for your help.
David
Look, I made a hat — Where there never was a hat!
Edited 10/28/2002 4:55:58 PM ET by davamoore
Replies
I think you're wasting a good worry over nothing. You're not spraying the stuff at the stove, after all. Lower temps slow the cure on most finishes, so that part of your thinking I'd have to go along with. Not to be an "anti-safety" freak but how much alcohol do you really let flash off in one project? A couple of ounces, a cup? Disperse that over the space in the shop and I don't think the opportunity for spontaneous combustion is there. You'd have to be using a substantial amount and putting it in the air with some concentration to make me concerned. (This is where everyone who wants to flame me tells about the time a thimble of lacquer blew up a city block) If you really are concerned, heat the place to comfy, kill the flames, put on your finish. Twenty minutes later it will be dry enough to move around, the fumes will be gone, start cooking again.
I'm certain someone who knows more than I will correct me if I'm wrong, but I think Shellac is an evaporative finish. I don't think temperature is going to play much of a part. The only way it might effect finishing is that a colder environment tends to be dryer and for that reason it may cure faster. Although we are talking about alcohol evaporating off and not water. Still, I think it would have to be well below 40 degrees to substantially slow the evaporation of the alcohol. After all, its freezing point is well below water and you will be spreading it out thin.
Just thinking off the top of my head.
-Craig
"a thimble of lacquer blew up a city block"
You should wear a bicycle helmut ...that will keep you safe from just about everything....:)
I'm using Shellac for the first time on the new workbench (Rich Rose is gonna kill me). I'm getting some dark streaks..I've gone to a lower pound cut..is this the right thing? Thanks
BG, if you're using a heavier cut, the dark streaks may be where your brush strokes are overlapping... sometimes, if you're working on a large piece and you're moving completely across the area with one or two strokes, then coming back again for the next "row," you get overlap where the shellac in the first row has already started to set up. I tend to be a bit non-traditional when I've applied shellac, and have had no problem using the tips of the brush bristles to work out those overlap marks before they've had a chance to set. After the fact, they're a pain to sand out. A thinner cut will give you a bit more time to work, but you'll need to apply a few more coats to get the same build as with heavier cuts.
As for the rest, thanks for your advice re: shellac, cold and woodburning stoves. Since I tend to be one who usually leaps first, thinks afterward, this was a nice exercise in advance thinking... and since it's only been a few months since my last emergency-room visit -- I'm not stupid, just a klutz sometimes -- I figured I would play it safe this time. (Actually, woodworking IS one area where I generally play it safe... too many opportunities for accidents.)
DavidLook, I made a hat -- Where there never was a hat!
I've used shellac over the years to refinish gunstocks. I had the pleasure of knowing a fellow named Joseph Schober when I was a kid growing up in East Texas. Joseph was a master gunsmith and had served His apprenticeship in the 20's in Germany. He used a mixture of orange shellac and boiled linseed oil 50/50. You first apply a coat of boiled linseed oil daily until the wood can't absorb any more. Wipe off the excess, apply a coat of shellac mixture let dry, buff with fine steelwool, apply next coat. You fill the grain building the surface until it's level, apply a coat of floor wax and you have a very durable surface. I've always found this to be one of the easiest most forgiving finish I've ever applied (except for pure Tung oil).
This finish was probably used out of necessity for lack of options, 80 years ago there wasn't a lot of choices. I have used it on pieces other than gunstocks and was pleased with the outcome, I didn't apply but one coat of linseed oil .
Good Luck
les
Les,
The tales of use of Linseed oil are legion. I think you vastly improved Mr. Schober's finishing method by using only one application of Linseed oil.
Rich
"I'm using Shellac for the first time on the new workbench (Rich Rose is gonna kill me)."
Geees! What do you think I am some kind of authority about this stuff? My pants have 2 legs just like yours. I love shellac. It is God's gift to woodworking. Do a great job!
R
I dunno, Rich. Pants might have 2 legs, but those tall black leather biker boots at the end of 'em kind of intimidate some folks. :-)
RW,
Aw, shucks, blush. You noticed. You don't think they make me look fat, do you?
R
Well, the boots dont. . .
Dammit,
I knew it! I told the hairdresser not to punk me out too much!
Never had problems with shellac in cold weather. Unless it's cold AND humid. But, if your heating your shop, then humidity will not be a problem. Keep your shop nice and toasty with your wood stove and go ahead and use your shellac. But, don't spill any near the stove and don't spray it on. Direct an air stream from a small fan onto the work during and after application.
PlaneWood by Mike_in_Katy
PlaneWood
Mike, thanks for weighing in with your thoughts. I'll follow the advice I've received here and go ahead with the shellacking (sp?) -- except not today... I've been boiling water to bend the sides of oval Shaker boxes and my shop is a bit steamy.
DavidLook, I made a hat -- Where there never was a hat!
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