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Shellac

Hand Lettering topics: Sign Making, Design, Fabrication, Letterheads, Sign Books.

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Mike Jackson
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Shellac

Post by Mike Jackson »

Old Forum Posts: on Oct. 17, 2001

Moderator:
Topic: Shellac. The stuff is a great barrier material. It doesn't attack undercoats and most paints will stick to it. Any cool uses? Anything to watch out for?
Janette Balogh:
Last summer I tackled gilding on cast concrete finials ... my first time. The job turned out superbly, and you could see those balls for blocks, especially on a sunny day, or at night when the headlights of cars shone on them.

A few months later something went terribly wrong.
The gold started flaking off all over the place.
It kind of blistered, and you could literally blow on it and the gold would fly all over.

We had had plenty of rain in the summer months, and the humidity down here in itself is gastly, so I suspected some kind of moisture problem.

Called Rick Glawson, and explained the situation
at length ... from start to finish.
I found out that the person who had sealed the finials, before I had acquired them, used a waterbased primer. (Kilz) Apparently this is a "no-no" as the moisture from within the concrete seeps thru. As a side-note here, I'll say that I had gold on other areas of the sign, that remained unscathed, and that it was only failing on the concrete surfaces. In this case being the finials.

As per Rick's instructions, I sanded each finial down, and sealed them with shellac. I was told that it would stop moisture in it's tracks.
I bought the canned stuff, and sprayed a couple light coats on each finial.
Then proceeded to size them with a slow french size this time (had used a quick size before)

Last Saturday, after a week and a day, these finials were ready to gild.
It was somewhat of a windy day, so there I was on a ladder, gilding away under a heavy cloth sheet.
Folks probably wondered what that "ghost" was doing to their signs under there.
I was confronted by a cop while on the last finial,... right about sundown. A neighbour had reported that "someone was stealing the gold off the balls" I informed him that I was actually putting the gold back! :)

I'm keeping my fingers crossed that the gold stays put this time around.

Thus, another good use for Shellac.
Ain't learning fun?
Bruce Jackson in Response to Janette:
Another note on gilding on concrete. The cement component is highly alkaline. If you gild or paint straight onto it with oil-based paint or size, the lifespan will be shortened. It might go a few years, but it isn't good practice.

Remember how to make soap? Alkali eats oil.
Janette in response to Bruce's response:
They were sealed with a waterbased primer (Kilz Latex).

I went by them today, and noticed that they were failing again, after only a week.

Rick Glawson suspects those finials are contaminated somehow. After some discussion we guessed that the concrete may not have been cured when they were sealed.

My ideas as a recourse at this juncture is to replace them entirely with gilded HDU finials.

Some concrete (no pun intended) answers and solutions for me right now would be wonderful.
In other words ... what WORKS ... not what doesn't (as I'm only too familiar with that already) or what "might".

At my wits end.
Sarah in response to Janette:
As Mike mentioned shellac is not a waterproof coating. I wonder if this wont give you problems in the near future too?
Janette to Sarah:
OH GAAAAWD Schwartzie... I hope not!!!!
I just don't wanna be making a career outta these finials!

They still looked good today.
:)
Sarah again to Janette:
Careful Janet or you will be the first one banned for cursing, LOL

Im only familiar with shellac in woodworking and finishing. Heres what one of my books on finishes says:

Pros:
Excellent resistance to water vapor exchange
Excellent barrier to stain and silicone penetration
Dewaxed variety has excellent clarity and depth
Orange variety adds warmth to dark woods
Good rubbing properties
Less harmful to breath and to the environment than other finishes

Cons:
Weak resistance to heat, water, solvents, and chemicals
Only moderate resistance to wear
Short shelf life.
Carol C to Janette's question:
I've been thinking about the ... finials. I just hate to revisit jobs. But I was wondering if moisture is the problem, perhaps the cement needs to be covered with something like pool paint or that rubber stuff you dip tool handles in. Then size and gild. Or depending on the dimensions of the finials you could replace them. I've seen bowling balls used as finials.
Keep us updated on this and I'll in turn let you know when the banner with Smith's cream finally dries. lol
Bruce Jackson to the origina question:
A few years ago I was painting lots of theatre banners using a flexible acrylic banner paint on vinyl.

Because they were huge and expensive and short term, we used to re-use them for each new promotion. Some of the colors were fugitive and would bleed through when recoated. Especially white on top of red.

We started using shellac as a barrier. It worked OK but it also became a weak layer. If the banner got soaked with several days of rain, then folded up for a while, the layers would start to lift off.
http://www.goldreverre.com/gallery/banners.html Photos of Banners

Rick Sacks to Bruce:
Bruce, We used tio always use shellac to spot prime over red on signs we were repainting with different copy. It worked better than block out white. We also use shellac to spot prime knots in boards to prevent them popping later when in the sun.

Do you find newly discovered uses for shellac?
Kent Smith to Bruce:
I have often used shellac as a barrier between coats of Japan colors on glass. I have been experimenting again with this old reliable. Over a color panel which gold will overlap, it will help eliminate burn-thru of the gold. I know this would have helped Mike on that one you had difficulty on years ago. It also helps to eliminate lifing when using over-the-counter type gel super glue for applying pearl and abalone.

Dad used it for the things rick mentioned and more recently I have substituted waterborne acrylic.
Vance Galliher to Bruce:
hi bruce...........good to hear from you again....the point that struck me most about your post is .....", then folded up ....." banners should always be rolled with face out,.....never folded !!.......however, the more repaints and the more rolled, the thicker the paint, the heavier the banner.....it will crack !.....i onced worked at a shop where in a two year period we repainted a 4'x20'canvas panel at least 30 times !!god it got heavy !!!! haha..........also, i'm not sure shellac has much elasticity......?.vance
Bruce to Vance:
Hi Vance, Your right of course, they shouldn't have been folded. I didn't do the installs/removals. We had other guys do that stuff with a crane.

To be fair to them though. They were very big (70'x20') and VERY heavy. You simply couldn't roll them up.

Image
Mike Jackson:
Hi Bruce, Rick and Janette,
When we were screening some of the picture/drawings on our glass pieces, we often used Dekor gloss ink. One of the problems with Dekor was it was subject to self solventing when brushing across it with another color. In other words, if we brushed across the roof of this piece, it would cause the screened lines to disolve a little and streak. To solve that problem, we used clear shellac as a barrier layer. The alcohol based shellac never broke down the solvent based Dekor. After the shellac dried, we could brush and blend away.

In some of the later signs, we switched to regular NazDar screen ink for the pictorials when possible. It saved the shellac step, but the lines created by the NazDar was not as tough as the Dekor.
Other photos: http://www.goldenstudios.com/indexglass.htm
Mike Jackson / co-administrator
Golden Era Studios
Vintage Ornamental Clip art
Jackson Hole, WY

Photography site:
Teton Images
Jackson Hole photography blog:
Best of the Tetons
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