Sunday, July 18, 2010

Pouring Resin-like finishes

How do you get that surfboard finish so popular on paintings? You know, that super clear, glossy, smooth top coat. The best results can be obtained using commercial resins. They come in two parts – a resin and hardener. They are, however, very toxic to work with. I prefer to use acrylic non-toxic fine artist alternatives that may not look as perfect, but will also last without yellowing or cracking.

My favorite technique is to lay the painting flat and very level, and propped up on containers to get it lifted off the table or floor. By the way, it is easier to work with rigid surfaces like panels. If you are using a stretched canvas then you need to prop up the center of the canvas to keep it from sinking downward while laying flat. I then pour Golden's GAC800 without diluting it with water onto the painting’s surface. I spread it out evenly with a plasterer’s knife, and then immediately spray lightly with isopropyl alcohol to eliminate any bubbles. This takes a day or two to dry but has a smooth glossy finish.

The GAC800 is the only pourable acrylic that I know of that can be poured in deep layers without crevising. So you can also take duct tape and tape around the outside edges of the painting creating a wall that stands out from the top surface of the painting. By applying a small amount of a thick acrylic gel where the tape and painting meet you can keep the pour from later leaking out. While the gel is still wet pour the GAC800 into the pool or well that’s created by the tape. You can get a very thick poured layer this way. The thicker the pour, the longer you need to keep the painting level and flat while drying – which may take weeks if it’s more than an inch thick. When the GAC800 is used thickly it will appear slightly yellow and cloudy, not really visible in a pour with no walls or duct tape, and is favored by artists that like the "wax" or encaustic appearance.

If you don't like the cloudy look of GAC800 you can use other pourable products but you can't pour them thickly in one pour, or they might crevice as they dry. Instead pour several thin layers. My favorites for these are Golden's Clear Tar Gel and Self Leveling Gel.



Anonymous Anonymous said...

Thank you for this entry. I have been curious as to how this was achieved. Am I correct in assuming you would only do this over acrylics and not oils?

September 4, 2010 at 2:53 PM  
Blogger Nancy Reyner said...

Yes, acrylic will not usually adhere to an oil painted surface, so this technique is meant to be applied to surfaces primed with acrylic gesso, and/or painted with acrylic paints or products.

September 6, 2010 at 1:09 PM  
Blogger Jan Heigh said...

Would self-leveling clear gel work as well or would it not be able to be put on as thickly? I think GAC 800 may not be as clear as the self-leveling clear gel?


October 11, 2010 at 3:13 PM  
Blogger Nancy Reyner said...

Hi Jan,
Self-Leveling Gel is very clear, while GAC800 has a slight cloudiness to it that is not easily visible in thin pours, but looks almost wax-like in thicker pours. Unlike the Self-leveling Gel, however, GAC 800 is made specifically for thicker pours and will not crevice. If you want a thick pour with self-leveling gel you would need to slowly build up using multiple thin layers. Another idea is to use a thick gel like Heavy Gel Gloss which goes on thickly by knife (not pourable) and you can apply an ample layer of this first, then after it is dry "smooth" it out by applying a thin layer of the GAC800 as a last layer which will fill in any texture made by the knife application of the Heavy Gel.

October 11, 2010 at 3:51 PM  
Anonymous Iskra said...

I recently purchased your wonderful book. This blog is just wonderful, so full of useful technical info and inspiration!

I have been trying the tar gel coatings for work on paper mounted on panel. I would like a thick depth and clarity that I can't get from the GAC. I tried brushing it first with no added water, and had no crazing, but also it dried too quickly to be perfectly smooth--the brush strokes got gummy even on a small panel of only 10 inches square.

I next tried two coats, the first brushed and a day later a second coat of tar gel poured (diluted with half water). Disaster! The pour is crazing and cratering.How do you know how much to pour? And if you start at one edge, with the panel tilted, there is always more at one end. It seems the cratering may have been caused by setting the panel back down flat and the backflow--?

I also tested the alcohol spray. I misted the first dry coat before pouring, and it got tiny crackles where the alcohol was a little heavier. After the pour I misted very lightly again over a few bubbles. They immediately went away, but I'm wondering if the alcohol could have had an effect on the crazing. I use alcohol for image transfers so I know there are many kinds. I used the 70% rubbing alcohol--was this the right kind?

This is all so tricky, it seems like I will have to practice many times before getting it right and there may always be a risk of ruining the art. My goals are twofold: I want to be able to work on paper on panel and show it without glass, both for economic reasons and because I don't like how glass distances you from the surface. I also want to create very deep-space collages with skins overlayed, and use a a final bath of translucent gel to encase the whole.I don't like the brush strokes of matte or gloss medium over collage, it tends to distract from the underlying textures of the edges. But perhaps tar gel is the wrong medium--?

I'd love any thoughts you have on this!

November 10, 2010 at 12:31 PM  
Blogger Nancy Reyner said...

Hi Iskra,
You are right - getting a smooth even glossy finish is a bit tricky, but can be easily obtained with a little practice. Try working on small "test" surfaces (that you don't care about) until you get it right. You will get different results with pours depending on the climate. The easiest one to use is GAC800 - as is described in the blog post. If you use the other 2 I mentioned (Clear Tar Gel and Self Leveling Gel) you need to practice. For what you are trying to obtain, both these gels should not be brush applied, but mixed ahead of time with 20% water (not 50% as you did), left overnight to de-bubble, then slowly poured over the surface. You can gently spread it out evenly with a large spatula. Spray with alcohol very lightly and immediately. This all needs to be done fast, so pour and spread within minutes, then spray the alcohol before the top paint skin sets - that's probably all under a few minutes. So you need to have everything easy to grab fast. Do not spray the alcohol BEFORE the pour - spray immediately afterwards. I use the higher percent alcohol (90 something...). Unless you use the GAC800 for a pour you need to pour out a thin layer (maybe 1/16").
If this all sounds too difficult here is another idea for you. Apply a thick (any thickness but at least 1/2" more than your thickest collage item) layer of any gloss gel (start with the Regular Gel Gloss). Let this dry a few days or more until clear. Then pour a thin layer of the GAC800 on top to smooth out any texture.
I hope this helps.

November 11, 2010 at 8:10 AM  
Anonymous Surekha (Sue) said...

I wanted know if yellowing is an issue with GAC-800. Also, does one need to varnish the painting after the coat of Gac-800 is applied & set?
Basically I want to know about the longevity of the artwork, if GAC-800 is used as a topcoat.

March 7, 2011 at 8:53 AM  
Blogger Nancy Reyner said...

Hi Sue,
Yellowing is an issue with any acrylic paint or product, when water soluble impurities come up through the surface into the acrylic layer. This will usually happen, unless you first apply a stain sealer such as GAC100, Polymer Medium Gloss, or a commercial stain sealer such as Kilz. The yellowing becomes most visible with thicker applications of clear gels and mediums, or white pastes.

A varnish is the best way to protect a finished painting, and has nothing to do with what acrylic paints or products you have used in the painting. A varnish is the last layer you apply, and a varnish is removable. This means that if you (or anyone else) ever wants to clean the accumulated dust off your painting, they can remove the varnish layer that collects the dust, and replace it with a clean varnish coat. This is the only way to clean a painting. If your last layer is GAC800, which is not a removable layer of acrylic, it will not act as a varnish. Only products called varnish that mention how to remove it in the label will work.

Longevity is obtained by using as many archival processes as you can. The most important ones are (1) apply a stain sealer first to eliminate yellowing (2) apply a good quality coat of gesso on top of the stain sealer to help adhesion (3) use quality paints, and select colors that have a good lightfast rating (4) apply a good quality varnish that has UV protection - and apply it over an isolation coat so it can be removed if necessary for cleaning. (5) wait 2 weeks to allow the painting to fully cure before wrapping it in plastic or storing it without access to air.

Please note I wrote a blog article November 8, 2008 called "Making your artwork last" that has more details on this topic. Here is a link to it.

March 7, 2011 at 9:47 AM  
Blogger Unknown said...

I have been having difficulty with my GAC 800 pour yellowing after several months. I adhere a photo on top of a wood panel, then cover that with a thin coat of heavy gel and paint washes over that. Then I pour GAC 800 to give depth and a resin like finish. The problem is after a few months, there is sufficient yellowing which is ruining the piece. What to do? Thanks.

March 30, 2011 at 3:29 PM  
Blogger Nancy Reyner said...

Hi Adele,
Yellowing will occur two ways: the GAC800 has a slight yellow and cloudy appearance to it. When it is poured thinly this is not noticeable. When you pour it thickly (1/4" or more) it is noticeable, and is often thought of as desireable by artists replicating a wax or encaustic effect. I like it too. Once it dries, though, it shouldn't yellow more. I am thinking that in your case, the yellowing is occuring from impurities in the bottom layers coming through the layers and creating more yellowing. The best way to solve this is to apply a transparent stain sealer (like Golden's GAC100) over your photo, before you apply the gel. There will still be some yellowing, though, if there are any impurities in the photograph you have collaged. The best thing to do would be to stain seal the wood, then gesso, then apply your photo printed onto a clear acrylic skin (see Golden's site for Digital Mixed Media) and then keep applying the layers as you have. This way there is nothing that may have impurities that are applied after the stain sealer.

March 31, 2011 at 8:41 AM  
Blogger Brittany Lembke said...

I am painting a table top that I want to finish with a resin about 1/4 inch thick that will look and feel like glass. I want it to withstand the kitchen life of a large family for many years. I
am not familiar with the product you are describing here. Do you think it would work for that?

April 24, 2012 at 5:01 PM  
Blogger Nancy Reyner said...

Since you are looking for a hard wearing protective layer for a functional surface, I would not use a fine art product. Instead I would go to a home improvement store like Home Depot and find a polyurethane or other finishing product made especially for daily wear and tear. Fine art products are meant for long lasting but not daily use such as on a table.

April 27, 2012 at 5:15 PM  

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