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MITRA Forum Question Details

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  • Preparing An Ideal Rigid SupportApproveRejectUn-ApproveSubscribeUn-Unsubscribe
    Question asked 2018-09-30 19:16:31 ... Most recent comment 2018-10-01 07:49:02
    Rigid Supports Flexible Supports Oil Paint Grounds / Priming Sizes and Adhesives


    I'm trying to find the best way to prepare my supports so that I can have the longest lasting paintings possible. This is my current process, I use commercially made birch plywood panels that are cradled with basswood. These are the ones I use

    This is my current process

    1.    Sand the panel to make it smoother using fine or extra fine grit paper (usually 220). Wipe off dust or vacuum the panel to get rid of any debris. (I use a dry cloth because I don't know if it's okay to get it damp)

    2.    Apply 1 coat GAC 100 to the front and sides, and let it dry enough that I can turn it over without it sticking to anything (usually 20-30 minutes roughly)

    3.    Coat the back and inside edges of the panel, then let it dry with the back facing up for 2-3+ hours (I use a smooth but semi-firm nylon brush to apply the GAC 100, it helps minimize brush strokes)

    4.    Repeat the process above to coat the front and the back again, but this time let it dry for 3+ days

    5.    After 3+ days I apply acrylic gesso with a very soft camel hair brush or a soft nylon brush. If the gesso is thick I use a stiffer brush or water it down. I apply 2 coats but if I water it down I add more to compensate, usually only 3, sometimes 4. I wait the around 4+ hours between new coats depending on how cool to the touch it feels.

    6.    I let the gesso dry for 72+ hours before painting because I've seen that recommended by a few companies/artists including Golden. Then I start painting

    I do want to add a few steps to help my paintings be more archival. First I want to start mounting cotton canvas to the panels using BEVA film, before the gesso step. I would then use GAC 100 x 2 coats to help block oil penetration to the canvas. After that I would continue with the gesso step, but this time add a third layer. The third layer would be clear so I can draw my design on the second layer with pencil first and then seal it, to avoid having any graphite transfer through to the paint. Finally I would finish by using a 50/50 mixture of Galkyd Lite and Gamsol to thin out a colour I want to use for the ground layer, and then paint it over the gesso and wipe away the excess to leave an even tint. I was told this is a good way to increase adhesion for future oil paint layers, especially if you do heavy impasto which I want to explore more.

    I'm using those specific wood panels because they are the only ones I can access easily where I live in Canada, and I'm using 10oz cotton duck canvas because I can't afford linen (yet). I'm an art/design student, I don't have a big budget. 

    One thing I saw mentioned in another thread here was that GAC 100 is really bad as a moisture barrier, so I was wondering how much this matters with the panels I use since they are 3 ply and cradled? Do I need to do the priming method listed here instead? - if so, how would that change my current method? Also how much ventilation would I need because I don't have anywhere to work with a ventilation system. I do all my work in my room and avoid anything with fumes, or do it right by the open windows.

    I havent painted much all year cause I've been fixated on solving the issue of "what support is best?" and I know that's a subjective topic so I'm hoping someone with proper expertise here can help me out. Thank you for taking the time to read this

Answers and Comments

  • EditDeleteModerator Answer

    I have often worried about how our work on this forum and a general obsession with “proper technique” could hamper young artists before it is really even an issue. This seems to be more of an issue with artists with more of a conservative bent on art that those who are more contemporary in their world-view. Most of our early work, even that we felt was our exemplary pieces, we will find inferior in maturity. It is most important to practice and experiment early on, far more that trying to create eternally archival works that we may throw away in a few years. Please paint even if you cannot afford to do so in the most “permanent” manner.

    To your question, as I have stated on MITRA previously, I am very dubious of any plywood used as a rigid support if they are going to receive a ground without a fabric interlayer. You seem aware of this and hope to incorporate such a layer in the future.

    However, you may be over thinking the need for linen. Linen is a far stronger fabric than cotton and is preferable for use as a flexible support. Chemically, however, they are very similar (composed of cellulose) and the only benefit of linen is its longer fiber length, and therefore strength as a flexible support. This is meaningless if it is adhered to a rigid panel under layers of ground. The only reason to use linen in this instance is if you want to retain the “organic” texture of linen. Covering this completely with a ground, which will be sanded smooth, negates any reason to use the more costly fabric.

    What do you mean by moisture barrier? First, I am not sure that this is true. It would certainly be better at stopping the diffusion of water the animal skin glue and acrylic dispersion mediums tend to be better than PV(ac) layers in this respect. As a dispersion, it is inferior to simple solutions of resins like B-72 in solvent but this is overthinking the issue. The back of the canvas is readily accessible to moisture in the environment and this is more of an issue than what you describe.

    Anyway, kudos for worrying about thes issues of longevity, but the essential thing is to paint, paint, and do more painting. If you do so on more permanent supports, all the better.

    Brian Baade
    2018-09-30 22:04:18
  • ApproveRejectUn-ApproveUser Comment

    ​Hi Brian, thank you for your response. Yeah you're right, I should just keep painting and not worry about the durability of the early work as much since I'm so caught up in it right now. 

    Yes I want to add a canvas layer so I can retain the rigidity, but also so if the rigid support ever fails or is broken in an accident, the fabric can be removed and placed onto a new panel. 

    I see your point with the cotton vs linen on a rigid panel debate. I will most likely stick with cotton, but one of the reasons I wanted to use linen is that if I ever work with super heavy impasto layers and the painting needs to be taken off the rigid support and put onto stretchers, I've seen many people say linen will support heavy impasto way more then cotton. If it's glued to a rigid support it doesn't matter, but if a conservator ever needed to switch it I would want the fabric to be agreeable and not sag. However none of this matters unless I'm selling enough to justify the price difference, so I gotta start painting again.

    Regarding the moisute barrier, what I meant was I saw Sarah Sands from Golden mention in another thread that GAC 100 is a terrible moisture barrier for wood, and that wood should be sealed using the methods here - I am just trying to figure out if there's a way to seal wood from moisture (I live in a high humidty area), that I can do safely in a low ventilation area. I've heard of B-72 before but have no idea how it works or if it's something I should try or can safely use in my work environment. 

    2018-10-01 07:49:02

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