Re: Wood panel preparation (Keith?)
Well, here is where we may go our separate ways, because we are meticululous and me?... not so much! Sizing Strength: I don't actually know. I use a half tablespoon of Jelatin (Toz - no idea of the bloom) to 450 ml water to which I add about 3 ml Gluteraldahyde. Coating: I'm using two surfaces at present. MDO is a very smooth plywood used for signs and for boatbuilding, but I'm not sure if it is actually "marine grade". MDF is a heavy pressed wood. MDO is very smooth so it takes three coats of the affore-mentioned gesso. MDF requires only two. I'm sure a roller would be great. I prefer a big rough brush, as I like the brushstrokes. I do not sand, as this provides a surface that is too smooth and perfect. Something tells me this is the method you will prefer :) - When I did sand I just used a rough screen - the type used for smoothing drywall plaster, or a 3m scotchpad green thing - sandpaper made a big mess - the pumice powder got into everything. 2009/2/24 Loris Medici <mail@loris.medici.name>: > Thanks Keith! As I understand it, I need to increase the whiting amnt. in > my preliminary formula, since I choose to mix equal *weight* of acrylic > gesso with whiting (50g gesso + 50g CaCO3), but you say equal *volumes*... > That was good to know. Thanks for the info about sizing. > > Few more questions: > - What is your sizing solution strenght? > - What is your coating method? (Detailed description please; how much > layers? exact application method and procedure? - crossing fingers: I want > to be able to coat with a foam roller...) > - Do you sand the acrylic gesso before sizing? If yes, how? What is your > exact procedure? > > I feel like leaving the "traditional gesso" plan behind, it's too much > complicated for my liking -> I may resort to it if everhing else fails, > but I'm afraid it has its own problems as it looks like a method that > should be mastered - painfully! > > Thanks again & regards, > Loris. > > > 24 Şubat 2009, Salı, 4:22 pm tarihinde, Keith Gerling yazmış: >> Hi Loris! >> >> The #1 formula you present is very similar to the one I use with great >> success: 1:1 Liquitex acrylic gesso to water and then to that 1:1 >> dilute gesso to pumice by volume. That produces a surface that acts >> very similar to paper, so I size it with gelatin and hardener. This >> mix is very good for coating porous surfaces such as wood, plaster >> (spackle-ed wood) and old gumprints on paper. For surfaces such as >> aluminum and glass, bubbles of water tend to form between the surface >> and the gesso with long soaks. For these surfaces I do not use >> acylic, preferring to mix up a concoction of gelatin, pumice and >> marble powder. I haven't used this in a while and I haven't reduced >> it to a recipe, but essentially it is a gelatin mix (the same as used >> for sizing paper) with 50% pumice and marble. It produces a surface >> that is so hard that it is actually very hard to remove even with a >> belt sander! >> >> Hope this helps >> >> >> >> On Tue, Feb 24, 2009 at 2:30 AM, Loris Medici <mail@loris.medici.name> >> wrote: >>> I will try to print gum on wood panels (marine grade plywood). I will >>> try >>> two different grounds: 1) Acrylic ground + whiting (I presume that's >>> what >>> you do Keith?) 2) Traditional gesso ground... >>> >>> 1) Keith, what is your acrylic formula? I plan to dilute acrylic gesso >>> 1:1 >>> with water and then add equal amnt. of calcium carbonate (marble dust) >>> and >>> some white pigment into it. For instance: 50g acrylic gesso + 50ml water >>> + >>> 50g calcium carbonate + 10g titanium dioxide (titanium white -> purest / >>> brightest white pigment). >>> >>> 2) Traditional gesso: 100ml water + 10g hide (or rabbitskin) glue (high >>> bloom gelatin) + 60g calcium carbonate + 12g titanium white. >>> >>> I need a good working recipe and application (and finishing) procedure >>> for >>> #2. BTW, traditional gesso is a PIA! (Have to keep it hot + it doesn't >>> set >>> quickly, so takes awfully long to complete 4 - 6 layers...) >>> >>> Another questions: >>> >>> 1. Do you harden the traditional gesso ground? >>> >>> 2. Do you add a hardened gelatin layer on top of the acrylic (or >>> traditional gesso) ground? >>> >>> Thanks in advance, >>> Loris. > >
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