clear coating over gold...........

[vance galliher]

normally something I would never do, but this carved bird is going to be handled by a few hands before it get to its final perch atop the exterior totem pole in Lake Tahoe. And I have also used multiple karats of leaf so it really needs to be cleard to prevent tarnishing. The automotive paint store said that if I sprayed their catalytic clear it would lift the solvent based size. What about one Shot uv acrylic 4005 ...will that hold up ? Open for suggestions....thanks

[Billy Pickett]

...I advise you to NOT clear coat it. Carefully wrap the gilded parts w. tissue paper or bubble wrap held in place w. tape or string. And instruct the groping 'handlers' to remove it ONLY after the thing is installed. Naked gold leaf will last indefinately (or as long as the structure under it). Once exposed to sunlight, ANY clear will eventually break down and cause varing degrees of regret for everybody concerned.

[Mike Jackson]

I wouldn't put a clear over it either.
M. Jackson

[vance galliher]

Thanks for reply Billy Bob.... I agree that the "handling"issue could be resolved with a wrap of some sort, but I think the main issue here is that leaf less than 23K will tanish outside because of the silver content..there is no doubt about that.........and so this piece has to be cleared. I'm caught between the rock and hard place with this one..........it is either going to tarnish w/o being cleared, or it will eventually fail because of being cleared. Sepp Leaf and Butch Anton just suggested FrogJuice....I'll spray a few coats of that and wait a few years til I hear from the architects about the problems..........

[Doug Bernhardt]

Yes....I've heard the many complaints about clears over the years but I'm a strong believer in the Star coatings which I get here in Canada from Canadian Signcrafters. I've used white and green(16K) gold many times over the years, and never had a breakdown or tarnish problem yet. The secret would seem to be the acrylic factor. I've also used frog juice but never over gold and wouldn't dare without a test first. It smells very similar to one of the old Chromatic clears used some years back and it was self solvent. A little turps spill and there were heartaches. It couldn't be thinned AT ALL or it would peel bigtime which means no spraying if that is in the offing. Would really like to see this job when you're done Vance. You do terrific work!

[vance galliher]

Doug.............now you're scaring me !.........thought i had it all figured with the frog juice thing.....i called pete and lee in portland and they like the juice... plan to spray monday..and now maybe not...........pete mentioned something about not being able to to brush back over, as in"self-solvent "....... but folk at frog juice say...."SPRAY AWAY" ? I'll check with Lettrhead Sign Supply about Star. Do you srray it Doug ?

[Doug Bernhardt]

Hi Vance.....I do spray ClearStar from time to time with an HVLP but mostly brush on the flat. I was also thinking back and if memory serves me right (wouldn't be so sure of that) the "Boss" used Frog Juice over copper leaf. So Pete also mentioned it (FJ) being self solvent? I was thinking of the Chromatic as that.....I was doing a job, 15 or so years back, and wanted a tracing of the completed letters to keep for later. I took the long dry and Chromatic Cleared job to the bench and put a paper over it for tracing and wiped on thinner to see more clearly through, have done this hundreds of times, and couldn't get the paper off. It fused to the finished panel. Was a devil of a time trying to get it all off without having to redo the whole thing. Since then I've been using several types of acrylic clears and am really happy with the Star stuff. It has it's issues when sizing over it (another discussion) but the extra life is obvious. West facing signs just stay nice longer.

[Tony Segale]

Vance...

gilded this bear about five or six years ago ...no clear coat. It was quite a community spectacle, special dedication, wreath around it's neck, pretty scary all these city officials wanting to touch it before it went back up on the mission style arch. Still looks as good today as it did then. Rooster weather vane, no clear.
hI've gilded two exterior cut-out lettering jobs I did clear, two jobs I re-gilded for nuthin.

I've gilded a lot of letters for the Cheesecake Factory restaurants in the last three years...no clear coats on the 23K jobs,
clear over the copper jobs...Chromatic Clear Overcoat Varnish. So far, all is well.
I recommend no clear coat.

[Kent Smith]

There is an amazing amount of disinformation about paints and varnishes. First and foremost, ClearStar coatings was created by Steve Berman who was Chromatic. He has taken his original ideas for clear coats under the Chromatic flag and upgraded them.

Fact: most single component coatings of any type are somewhat self-solvent. Lacquers, shellacs and Japans have always been self solvent but with the specific solvent from which their resin is compounded. This is significant because it does not necessarily include a tail solvent nor solvents added in the field for improving application. For instance, lacquers are typically fabricated from acetone but the blended lacquer thinners which have other solvents in them may not rewet cured finshes. Japans are made with a pure naphtha type solvent but often will not be rewet by common mineral spirits.

The acrylic clear coats like we developed at Chromatic are similar to lacquer and others in that they are resins, reduced in a specific solvent which when it drys, the coating is cured. If the same solvent is introduced to the coating or another coat is applied, the surface will be rewet. This is significant for proper adhesion of multiple coats. The Chromatic acrylic clear could be rewet with acetone or toluene but not effected by turpentine, mineral spirits, citrus turpene nor water. It also did not have a sulfur based solvent so it would not tarnish composition leaf nor variegated much less gold that is of lesser than 23 3/4 K. The ClearStar acrylic has been improved in that it is more resistant to a wider range of solvents and "cures" more like varnish but still can be self-solvent.

The waterborne clear acrylics we developed were specifically compounded so that they could be overcoated with alkyd enamels. Eventhough they were waterborne, they were only self-solvent with the acetone that the resin was compounded in. This means they were a good primer as well as an acceptable topcoat for many purposes. They were sold as Ti-cote, UV Clear and in pigmented form as Universal Primer and High Build Primer.

Alkyd enamels (lettering, bulletin and background) and their family inlucing Clear Overcoat Varnish are not immediately self-solvent. This is because they actually "cure" over a 14 day period using ambient oxygen as their second component. Having said that, if they are satuated enough and left with a wet surface long enough using either turpentine or mineral spirits (not to mention stronger lacquer type solvents) their surface may become quite tacky. It does require a stronger solvent to rewet them to their base and cause them to be removable however.

There are some other finishes that use ambient oxygen or ambient humidity as their second component, much like a single stage epoxy, but because of their caustic properties, have not been popular.

The only finishes that truely are not self-solvent, nor can they be removed by any solvent, are the true two-component finishes. These are two-compnent urethanes, two-component acrylics and their cousins. We think of these as being a resin base with a catalyst but many are two resin bases which requre a solvent to activate them, a resin base with an activator, or a premix which only reqauires agressive agitation and oxygen to start the cure process. All paint manufacturers make two component finishes which vary widely in their compounding and hence their adhesion, curing and durability properties. (or is that vary wildly? maybe)

So, what would I suggest using? Hmmm...depends upon the application. That is to say, what outside factors will the piece be subjected to? For general purpose applicaitons where they are not subject to close contact (abraision) I would use an acrylic, either solvent or waterborne. For applications subject to washing with water or mild detergents, second surface glass, I would used the alkyd. For applicaitons subect to abraision such as low mounting where people will touch or lean against or for vehicles, I would use a two component acrylic urethane.

I hope this helps to give you all an idea of what there is to choose from. I also hope it is not too technical as there is a great deal more formulary information to add to my opinions. Additionally, forgive me for a one sided view but after spending 17 years with Steve, I learned a great deal about all of the competitive products and the chemical compounding in order to create products that fit our special needs.

[vance galliher]

beautiful gilds Tony.........and if my piece were 23K only, I also wouldn't consider clearing...but it's not, it is a mixture of 24K and lesser karats ....23, 22. 18, 16, 12 and aluminum (all the lesser kararts have varing amounts of silver....... which will tarnish) .
Thanks Kent for the information. From what you said perhaps one shot uv acrylic clear would work in this application. For one, I have it on hand, and two (and I'm assuming this bird will have to be recleared every few years) it would make it easier for whoever has to do it to simply put an extension ladder against the totum pole, climb up, clean the bird off, and brush on a new coat with a product that is readily available and easy to apply.

[Kent Smith]

Vance, I think that may be the answer especially with multiple Karats of gold. Using the acrylic would ensure recoatability. I would guess two to three years with the UV clear. Having said that, a two component might last longer but if it is only covering the gild, it is possible for the clear to cure in such a way that it would pull the gild right off the size.

[Doug Bernhardt]

Just a last note to all that is above....Tony and Vance...I'd never gold overcoat unless necessary as it is with this case, and have had, as mentioned, no problems with the acrylics over lesser karats to date, not so with varnishes although I've never really tried an actual experiment. The acrylics worked well right off the bat and so never bothered. Kent....I'd heard that the Star Coatings was somehow connected to Sikkens but had no idea how....interesting discussion. Have to add that they seem to remain sensitive to water and it'self for only a day or two and any fogging disappears quickly. I think the interesting part of this all is the inevitable..."To clear or not to clear....that is the question" A little homage to Shakespeare was in order right?

[Kent Smith]

Doug, I am not sure the Bard would approve but it had to be said. Only related to Sikkens as they bought Chromatic under the AKZO label before they sold it to 1-Shot (Spraylat). Your experience with acrylics mirrors mine and as it should be. I have always said don't clear...unless specific limited circumstances are evident.

[Tony Segale]

clearly stated, Doug and Kent...

clearly a weak pun intended

[Kent Smith]

I am glad that is cleared up

[Dale Feicke]

Whew, I'm glad that's cleared up.....in more ways than one.

As a new poster here, and since we are on the general topic, I need some clarification on clearcoats.

Quite a few years ago, I used a clear from Danacolors called Crystal Clear, and acrylic clearcoat.

Over the years, I got away from it; but more recently, have been trying the OneShot UV Clear and Frog Juice. I would swear both of these were identical to the old Dana.....same smell, same consistency, same drying characteristics.

And, they all seemed to work pretty well. Is it indeed the same stuff?

[Kent Smith]

Short answer: no........or at least not exactly. All are a formulations of clear acrylics and are more similar to lacquers than to varnishes as they dry more than they cure. Each has it's own blend of solvents plus various levels of either UV absorbers or UV inhibitors. Charlie Dana told me some years ago that he formulated his acrylic clear to have a compatible solvent which would not rewet or dissolve either bulletin enamels, finishing varnish or pictorial oil colors while providing the protection and high gloss of a "modern" acrylic. It was formulated as a final topcoat for bulletin pictorials or for protective coatings over flourescent colors. Frog Juice was originally a similar and competitive clear from Matthews Paint in their bulletin line which has a type of urethane/UV absorber added from their extensive technology in polyurethane two component compound coatings. The 1Shot product is the result of formulations from Chromatic clear acrylic topcoat, Dana clear and their own acrylic topcoat. Since all of those products are now under the 1Shot (Spraylat) umbrella, they have taken the best of these formulas to make the UV clear which has a UV inhibitor in it. Most of these were originally created in response to advertisers on bulletins (billboards) wanting them to be high golss shinny on Sunset Blvd. in Hollywood, for the entire life of the ad.

The variables are mostly related to how much UV protection each provides. An acrylic of and by itself will provide some protection from fading. For instance, laying a piece of clear acrylic sheet like Plexiglass over a surface will reduce its fading by 10 to 35%. The same is true of liquid adrylic coatings.

When a UV absorber is added, UV rays are absorbed by the clear which gradually breaks it down while it protects the undercoat. This type of coating about doubles the life, whatever that would be. The theory is that this coating would be cleaned off and replaced once it has broken down halfway so the life of he original finish will last much longer.

When a UV inhibitor is added, UV rays are bent or reflected away from the surface which extends the life of the surface about 1 1/2 times that of the clear with the absorber.

All clears breakdown, their role is to breakdown instead of the surface that they protect. How quickly they do so and what they look like as they breakdown is dependent upon the resin itself. Acrylics and acrylic urethanes tend to stay more transparent during the process than aklyds or spars do. They also are typically not as flexible as either alkyds or spars so if the surface has a tendency to extreme expansion/contraction, they will crack which can cause early failure. Alkyds and spars do not protect themselves from UV breakdown and tend to powder out and cloud up as they deteriorate.