Friday, March 21, 2014

tute: Varnishing Polymer Clay with Rustoleum Varathane ©; also introducing my new shiny Red Dangling Cherries Faux Bakelite Bracelet

Ever since I caught my first glimpse of vintage Bakelite Dangling Red Cherry jewelry on PBS's "Antiques Roadshow" I've been hooked and in love with them. The first piece I saw was a Red Cherries Necklace, followed by a Red Cherry Bar Brooch and bracelet, all incorporating red plastic chain links into the design and all with the most spectacular of SHINY finishes on the dangling cherries that caught the light when they moved.
My faux vintage Bakelite inspired Red Cherry Bracelet and other faux Bakelite cherry jewelry pieces including both Short Stem and Long Stem Necklace versions and various color chain options, earrings, and Cherry Bar Brooch are available for sale at MelodyODesigns at Etsy
When I decided to design affordable reproductions of these pieces for sale I set out to find a varnish that would produce similar levels of shine on polymer clay. Like many polymer clay artisans of the time I ended up selecting Flecto Varathane, a glossy, very low odor, safe to use, scratch resistant, very transparent WATER-BASED (for indoor use only) polyurethane with easy cleanup that provided a fabulous shine when applied to polymer clay in a very specific way. I used it for fifteen years, using it primarily with PREMO brand polymer clay to create surfaces that have been mistaken for shiny Murano art glass.

Unfortunately, Flecto Varathane was purchased by Rustoleum© and the specific product names of their Varathane line changed, causing some confusion in the polymer clay community. I started to do a little research on my own by contacting an extremely helpful and patient customer service specialist, Ryan, at Rustoleum.  He explained to me that the product I was looking for was now called "Varathane Crystal Clear Water-Based Polyurethane HEAVY USE" in the GLOSS formula. The manufacturer's number is 20041H. UPC code is is 026748200045. It retails for around $15-16 a quart and can often be found at Home Depot (they can also order it for you), Walmart, Ace Hardware and other hardware stores that carry Rustoleum© products. It is also available internationally

Even though the old can label says IPN and the new say "Polyurethane", they have the same UPC code, look the same, smell the same (hardly any smell!) and seem to work the same. Ryan told me that if the formula had been changed it would have received a different UPC code.

"Varathane Crystal Clear Water-Based Polyurethane Heavy Use Formula" comes in a choice of Gloss, Semi-Gloss and a Satin (somewhat matte) formula. The labels look VERY similar, so make sure that the UPC code matches what it listed above if you are looking for the GLOSS formula.

FYI: Just to make things a bit more potentially confusing when selecting the proper varnish at the hardware store, there is also a WATER-BASED "Varathane FLOORS FINISH High Traffic Formula" that has a bit of flexibility built in and is probably not a product of interest to clayers. However, there is another WATER-BASED product called "Varathane SPAR Urethane U.V. Protection Formula" that is supposed to provide excellent UV and weather protection and could POTENTIALLY be useful for protecting polymer clay pieces designed to be left outdoors (suggest one tests it first). All the products mentioned above have very similar looking labels.

Minwax©'s "Water-Based Polycrylic Protective Finish" (in  Gloss, Semi-Gloss and Satin formulas) is a liquid acrylic finishing product that is sometimes used on polymer clay. I've read mixed reviews about it. I haven't had enough experience using it to form a definitive opinion, other than Minwax Polycrylic and Varathane are NOT the same thing!

I didn't always love using Varathane. It was only after the the basics of effectively using it on polymer clay were initially so generously shared with me by polyclay artists extraordinaire, Sarajane Helm of and Elaine Robitaille of that I began to understand how to make it work for me.  I've adapted their techniques over the years to meet my own specific needs and will share the updated directions with you a bit later in the article. 
I think the key to successfully using Varathane to create a shiny surface on polymer clay lies in applying it in many VERY THIN coats that are each heat set to cure and also applying it with a moistened foam makeup sponge that has been well wrung out. I will be using the terms Varathane and varnish interchangeably in this article. 

The majority of my varnished pieces are made with PREMO brand polymer clay, so my suggestions are primarily meant for using with PREMO, though I think they also work on most other brands. However, because Varathane is water-based and Kato brand polymer clay is hydrophobic (tends to repel water), I have not had as much success using Varathane on Kato. I have read that giving Kato pieces a "wash" with alcohol first and then letting it dry before applying the varnish seems to increase the success rate a bit. However, I'm sensitive to alcohol, so I haven't tried it.
For ease in pouring out just small amount of Varathane, I periodically fill several smaller snap top glass or plastic bottles with varnish from the "mother can" using a small ladle or plastic scoop.  Some plastic prescription bottles with snap tops work well for storage. This helps keep the "mother can" cleaner, easier to seal, and prolongs it's shelf life substantially. Remember to VERY GENTLY stir the Varathane in the "mother can" first. Vigorous stirring can cause bubbles. Once the metal can cover has been replaced and hammered tightly closed with a rubber mallet I cover the top of the can with two layers of Glad Press'n Seal© plastic wrap. The smaller first layer helps protect the top of the can from accumulating dust that could  contaminate the varnish when the can is opened. The second larger layer helps provides an extra seal. I'm still using the last of a quart can of Flecto Varathane that I purchase 15 years ago, so perhaps the idea of that extra seal does prolong the shelf life.

Directions for varnishing polymer clay with Varathane:

For the most glossy and glass-like finish I recommend first sanding through grits 500, 1000, 2000, 4000, buffing, and then washing and drying the the polymer clay piece first to get rid of any dust or sanded clay residue before applying varnish.
Dip a foam makeup sponge (I use a wedge shaped one) into water and it wring out so that it's damp, but not at all dripping. I keep a water-filled bowl on my work table for easy access. Wait a few seconds after wringing out the sponge before dipping it into the Varathane, so that at least some of the bubbles can disappear from the sponge before dabbing onto the piece. 

GENTLY stir the Varathane in your small plastic bottle or just GENTLY invert the closed container once. Vigorous stirring or shaking causes bubbles that are difficult to remove. Pour a generous thumbnail-sized amount of Varathane onto your palette. I use the top of a plastic food tub as a palette. 

Dip the makeup sponge into the Varathane numerous times getting until the entire "generous thumbnail size" pool of Varathane on the palette is absorbed into the sponge. Then use the sponge to make numerous dabs (energetic dabs!) of varnish onto a section of your your clay and then lightly draw (i.e.,lightly drag) the sponge over the surface of the same section several times to the spread the varnish. The goal is a VERY thin and even coat (with subsequent additional thin coats). "Dab, Dab, Dab" and then "Draw, Draw, Draw" leaves many less air bubbles and adheres better than just drawing the sponge over the clay surface. I think that perhaps the varnish might adhere better with the dabs because the dabs break up the surface tension. I've noticed that applying it this way seems to improve the way the Varathane grabs the surface and diminishes the tendency for the varnish to bead up or give spotty coverage, especially in  subsequent coats. In subsequent coats it can also be helpful to "Dab, Dab, Dab", WAIT 30 seconds, and then "Draw".

I've also noticed that if there are hundreds of tiny little "spots" of Varathane that are visible on a piece AFTER the "Dabs" but BEFORE the "Draw", then the mix of water and Varathane on the sponge is perfect and coverage is likely to be good. The absence of tiny little "spots" can be a clue that the percentage of the water to Varathane might need to be improved. Too little moisture makes for thick and heavy coverage, in which case add a tiny drop or two of water to the Varathane on the palette or initially wring out the sponge a bit less. Too much moisture and the Varathane won't adhere or coverage will be spotty and bare spots will be visible, in which case add a bit more Varathane to that already on the palette, or initially wring out the sponge more. 
I use nitrile gloves to prevent potential skin irritation. I periodically add several drops of water into the varnish on my palette if it no longer seems to apply smoothly. I like to work with only a small amount of  varnish on the palette at a time so that it doesn't dry out before it's applied. 

I live in a dry climate where it generally takes about 10-15 minutes for the varnished piece to dry to the touch. If it takes a lot longer to dry than this it could mean that it had been applied in too thick a coat, or one may simply live in a very humid area. I've found that using this method of application provides a very smooth and clear surface with no visible brush strokes.

Inexpensive foam makeup sponges seem to work fine and when they start to shred just discard them. If your sponges seem to shred very easily you could try adding a drop or two of water to the varnish on your palette. 
Varathane that is used fresh out of a can should be close to the consistency of slightly thicker than whole milk. Once the Varathane meets the slightly moist makeup sponge, the varnish applied to the surface of the piece should end up with an approximate  consistency halfway between water and whole milk. The varnish in the can can thicken over time, especially if the top of the can is dirty or not properly closed. If it's thicker than whole milk, one can try increasing the percentage of water in the sponge or add a few drops of water to the varnish on the palette.

Once a piece has been varnished and is dry to the touch I briefly heat-cure the varnish to make it shinier and decrease the drying time. To do this I let the varnished piece air dry to the touch first and then cure it in the oven 205-215F. (96-101C.) for 15 minutes. I let the piece air dry first for 10-15 minutes for several reasons. I don't want to risk marring the finish if I bump it getting it into the oven.  I use a convection and am worried about any PC dust blowing inside might mar the still-wet varnish. I've also had some pieces that seemed to develop surface imperfections when prematurely heat cured.

If applying multiple coats of varnish I recommend letting each coat TOTALLY COOL from the oven curing first and then apply another THIN layer of varnish, heat cure again, etc. I've had some pieces develop an "orange peel" finish after varnish was applied before they were totally cool. I've read that without heat curing it can take up to a week for Varathane to reach maximum hardness.  I usually use 2 (VERY THIN) coats of Varathane, heat setting after each coat, and 3-6 (VERY THIN) coats for pieces that require depth to the glossy shine, like the cherries. 
You might also enjoy reading my following two articles on “My 25 Favorite Polymer Clay Studio Tools + Gadgets + Glues Part 1         and Part 2

Ginger, of The Blue Bottle Tree, has written an excellent article entitled "Varathane-The Best Polymer Clay Sealer." I highly recommend reading it.