Re: Wood panel preparation (Keith?)
Hi Keith, Yes, I'm a little bit meticulous because I have little time devoted to printing, therefore I don't have the luxury of trial and error, without risking motivation loss that is... ;) That sizing seems pretty weak. (My usual for paper is 3%) Will calculate by measuring the weight of half tablespoon gelatin -> that should be pretty close since we have the same stuff. What if I don't size? (I'm pretty sure you have tried this.) Will that work also? I was afraid of long soaks therefore I ordered marine grade plywood (which is very resistant to water - no warping, no veneer coming apart...), it's not expensive (considering the material) -> I ordered 25 13x17" sheets, it will cost me only USD 48, including cutting the huge raw sheet to size. (Makes less than USD 2 per sheet, and that's cheaper than fine quality watercolor paper!) At your printing size smoothing actually takes something (tactility?) from the prints but I prefer to work on smaller scale which makes a smoother surface a necessity. See the aluminum sheet I just finished to gesso here: http://tinyurl.com/dl5wnu It was shot under oblique incandescent light, exaggerating the texture. (The field of view is something like 4x6" - just to give you an idea of the magnification. 4 layers of acrylic gesso with calcium carbonate, applied with a foam brush.) Ground formulation as following: 40g gesso + 80g CaCO3 + 80ml water. I like the texture, will sand half only of the sheet and see how each side behave... The surface is very nice, feels very absorbent and soft to the touch -> very similar to an eggshell. (That's fine I presume...) Scotch pad idea is great -> will try that first. Yes, I'm concerned about the dust -> I don't think Elif will appreciate it! :) Thanks again, Loris. 24 Şubat 2009, Salı, 5:40 pm tarihinde, Keith Gerling yazmış: > 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.
|