Question about clears over acrylics?

[joe cieslowski]

I haven't tried this but I understand there are several shops that will paint images or reliefs using artists acrylics and then clear coat.

Does anyone have experience with this? Does this hold up in the long run? What kind of clearcoat should be used? 1Shot UV Acrylic Clear?

If this works, it opens a lot of options.

Thanks in advance,

Joe

[bob gamache]

Joe
I don't know if this will help but I do a lot of airbrushing on bike tanks etc. in body shops.
Sometimes I'll shoot artist acrylic paint (liquitex)...........The body shop then clearcoats the job with automotive urethane clear. It will not attack the artwork and holds up big time. If need be you can actually apply automotive clear urethane with a brush too. I do it all the time when surface gilding trucks and boats. You have to be quick though. Don't try it over 1 shot, it will attack it.

I would make a test piece and run it over to the nearest bodyshop and have them clear it.

[Kent Smith]

A few issues should be considered when using waterbourne acrylics for exterior. First is that because of pigment loading issues in a water resin, not all colors are very lightfast. This makes them degrade faster even when UV protected. Second, the 1Shot UV clear typically will double the life, whatever that might have been. It is the same with both solvent and waterborne varieties. Third, not all two component(automotive) clears are UV inhibitave so be certain the one you pick has that capability. Having said that, the clear itself gives some natural inhibition just as a clear acrylic does. Fourth, two component UV clears will triple the life, whatever that might have been and of course have a much tougher topset.

[Doug Bernhardt]

Joe......we are thinking along the same lines it seems. Have myself been looking for something to stand up better than artist oil and alkyd colours I've been using. While in Wales several months ago I dropped i on Dave Kynaston and saw some of his work. He is using one shot for his illustrations and using the 2 part top coats Kent has mentioned. Between his quite incredible ability and a good sound method/technique it makes for a delight to see. I have several photos of his work and will try and get a few here later in the weekend.

[Kent Smith]

A couple other random thoughts. Adding the 1Shot hardener to the alkyds gives them a harder topset and longer gloss hold-out which gives them better durabilty. You then may use a hardened clear or two component clear over them. This also holds true for the mixing varnishes you use with pictorial oils. Again, the oil colors are not all as light fast as they were 50 years ago because so many of the toxic pigments are no longer mined.

[Doug Bernhardt]

Kent......am not sure how the hardener would be but I do know they warn "vigorously" about the use of driers in artist oil/alkyd colours. In fact any kind of drying agent including a hair dryer. I have seen the results from turning heat on oil colours and it ain't pretty. It changes the chemical structure and it is no longer actually "paint"

[Mark Summers]

I (may) have a simple solution here.
Artist acrylics, I use Golden fluid acrylics. After a good number of years
at 9000 ft. Golden I've seen has really stayed color fast. If there is any
way I would go acrylics rather than 1-Shot.
For the clear I would go Ronan Aquathane U.V., two coats. Flat or gloss
I mix 1 part flat to 8 parts gloss. Ronan's Aquathane U.V. really stands up.
Acrylics expand and contract over the years and enamels go hard,
fade and crack.
My 2 cents.

Mark

[Danny Baronian]

Well, I'd have to disagree on the aquathane. I have a quart the my shelf, tried it and it didn't hold up well in northern California where the weather is mild year round. It may work in some areas, the best way is to do a test. But in Florida and California.

A friend in Florida made 20 - 4' x 20' HDU panels w/ 2' h letters carved and gilded on each panel for a shopping center. It was his intent not to clear, but at the customers insistence, his painting contractor said to use rhonan aquthane. This was from a job about 4 years ago.

He cleared the panels only after the customer signed off that he, the customer take full responsibility for failure of the clear coat.

Six months later they were back in his shop. The clear looked like crackalure. Sanded the clear off, re painted, re gilded and re installed every sign at the customers expense.

The second answer on this thread, for me, is the best answer to date. The only clear I've seen hold up outside is 2 part auto urethane clear. Next best is what Doug uses and seems to hold up well in Canada, but - Doug or the customers regularly maintains the signs. But Doug could address that better than I.

Danny

[Mark Summers]

Danny, are you talking about Aquathane U.V. over gold leaf?
Not sure if that's what I was reading.

Mark

[Danny Baronian]

Hi Mark,

aquathane UV over everything, gold and paint. The friend never clear coats gold, and was doubtful of it's durability period. The results after six months was not pretty. The gold and the paint re do, over the years still look fine.

The friend was smart insisting on a signed disclaimer, it was a costly re do the customer was responsible for. I believe that we're all trying to produce, providing the customer with a product that will withstand the elements for years.

It's not a quick answer, but the only way to really know is to do a sample note all the specifics, and attache it to a 'sample wall' outside your shop and watch it over time.

I'd like to think by now, in light of the paints that are being banned, someone would come up with a reliable water based clear, but not yet. The best I've seen is water based floor clears, both in satin and gloss. The gloss is very good, as we've had that on our home floors for over 10 years,the gloss is still great after a lot of use.

Time for a test...

Danny

[Mark Summers]

I think I get the picture now. Gold leaf is a whole different arena.
Kent Smith is probably the authority on clearing gold.

The thing with Aquathane and enamels is that the enamels have to be
cured and dead dry before application or you will get wrinkle city and
I guess failure. I have even used with success putting Aquathane on
Dupont acrylic enamel. I put a 1000 grit sandpaper to it first.
Entirely I have gone through about a half dozen gallons of Aquathane
over the years

The one area where I have ease of mind is the Golden fluids and
Aquathane. You can apply most any time after dry to the touch.
They play well together.

Good point on the weather sample board. Point it south. Date the
sample and the application.

Happy Thanksgiving everyone!
Mark

[Kent Smith]

Aquathane, Chromatic Ti-Cote or UV Clear, Clearstar acrylic clear etc. are much the same animal. What their actual components are, I don't know because they don't share anymore with me. When we first fomulized these waterbornes at Chromatic, they were a pure acrylic resin with a water carrier, what the percentage of resin or base formulation is of the other brands I do not know. As pure acrylics they adhere well to many surfaces like raw wood, galvanized steel, vinyl, HDU etc. They do not adhere well to slick surfaces, as most coatings don't, and those surfaces must be abraided for good adhesion. Examples of those surfaces are cured two component, two week cured enamels, Lexan, or smooth metals INCLUDING LEAF. Note that enamels that are dry but not cured yet will have good intercoat adhesion with the acrylics. The big advantage of these acrylics is that ALL types of paints and coatings will adhere to them because of their specific surface tension.

Clear...over gold? Not......or at least only in limited severe applications. Those subject to abrasion, frequent washing and similar abuse. The only true tested clear coat currently available is one of many two component urethanes.