Dear MITRA people
I have some acrylic primed artist grade polyester canvas that I find objectionable to use because it has very little texture or tooth (unlike another brand I tried that was lovely to use). The surface is rather slick. I have tried experimenting with home made grounds made of acrylic primer plus marble dust or calcite as well as acrylic primer with pumice but the first 2 gave too little tooth and the last one (because we can’t get ultra fine pumice in Australia) was far too coarse. I recently found some Liquitex brand “Natural Sand” acrylic gel, and put a thin coat of it over the original priming on the polyester canvas. It definitely gave a good degree of tooth. Is it relatively sound to paint over this in oils? I will be adhering the canvas to a board first as I always prefer a rigid support.
Thanks Brian and Matthew. I’m relieved that the commercial product with sand should work OK and will certainly follow the steps and precautions you recommend. Cheers, Jenny
That should be fine. As the surface of the current canvas is slick, I would probably use 220 sandpaper on the existing ground to ensure that there is enough mechanical tooth to hold the ground. I would also wipe the surface with OMS and allow that to dry to make sure that you remove any greasy material that may have come in contact with the surface. Acrylic dispersions are great adhesives so it may not be necessary, but I can see no reason to not give it a preliminary cleaning and light sanding.
Acrylic-based mediums and grounds with pumice and garnet texture additives generally will accept oil paint in thin to moderate applications. The weight of these products can make lighter or larger canvases sag, so in my opinion, using a rigid support as you suggest is a good idea. If you are able to find a factory-prepared product that satisfies your process, I think that would be better than experimental DIY solutions which can’t easily be tested to the standards of the industry. It’s easy to add too much solid filler to acrylics without realizing at first that film strength has been affected; factory-prepared mediums, by comparison, are formulated with the benefit of performance testing that gives assurance that the film will not be crumbly.
Matthew, I was responding to his use of the commercially made product. I do agree that it is east to add too much additional material and create an underbound layer. Additionally, due to acrylic dispersion medium’s rapid drying, it may be difficult to properly disperse the amendment into the medium at home.
Brian, I’m afraid I was still writing while you were posting. Sorry to step on your reply!
It is best this way as we tend to cover the things that the other did not think of.
