Post by kashirigi on Sept 28, 2011 11:24:53 GMT -5
I posted this message on another board, but I thought it might also be of relevance here.
I have been working on some terrain pieces that are glued onto masonite, which I haven't much used as a basing medium. One of later steps involved the usual gluing sand/flock to the base, something which I have done hundreds of times over the years.
I followed my usual procedure of watered down acrylic gel medium, much like the model railroading procedure:
1. Apply diluted gel medium/white glue/soap mixture
2. Apply ballast
3. Spray with diluted gel medium/white glue/soap mixture until soaked
4. Let dry and move on.
This time, instead of my usual result, I found that nothing stuck. I may as well have sprayed sugar water on the ballast. What's worse is the masonite started warping, too. Luckily I caught it as it began, and a couple of extraordinarily heavy books on top while drying flattened it right out.
I tried applying more slightly diluted glue to the ballast to make it stick. And I mean lots of glue. Still, no result. The ballast flaked off at the lightest touch.
At this point, I got angry and made an experiment to see what would hold sand onto a piece of masonite:
1. Diluted gel medium with soap as a wetting agent, applied before and after the ballast -- no.
2. Diluted PVA glue with soap as a wetting agent, applied before and after the ballast -- no. (note, this is basically the same as 1. The A in PVA is "acrylic".
3. Diluted gel medium with soap as a wetting agent, applied before and after the ballast. Then, the whole works was soaked with Future floor polish, which is again a clear, shiny acrylic. I've used Future to glue windshields into model vehicles with out issue. Result -- no. Actually, I might as well have just poured water on the whole thing.
4. A layer of gesso painted on the masonite, then 1 - 3 above: Success!
5. Gesso mixed with ballast and applied directly. Great success! This stuff is never coming off. Unfortunately, it's now white and needs to be painted.
This is what I learned from my experience:
1.The "wetter" something is the worse it is for adhesion to masonite. The material is sucked directly into the masonite without enough of the adhesive left on the material to be glued. Future was the worst, then soapy glue, then diluted glue. Any of these methods resulted in failure. To make it worse, the use of a wetting agent will cause the masonite to warp. Severely if you're using lots of adhesive.
2. "Dry" viscous material works like a charm. The best results were achieved with gesso mixed with ballast. Straight white glue worked reasonably well, but not as well as the gesso, and it was harder to apply. Warping was minimal or non-existent. Gesso acts as an impermeable barrier (within reason) when dry, so it's perfect for the highly absorbent masonite. I expect this would work perfectly for MDF, which is much more porous than masonite. There was basically no warping.
Of course, none of this really helps me as my project is covered with a layer of partially adhered fine ballast that I need to remove somehow. If I find a way to remove it easily, then I'll be set.
The moral: At the very least, apply a layer of gesso to masonite before doing anything on top of it. This goes double for MDF.
I have been working on some terrain pieces that are glued onto masonite, which I haven't much used as a basing medium. One of later steps involved the usual gluing sand/flock to the base, something which I have done hundreds of times over the years.
I followed my usual procedure of watered down acrylic gel medium, much like the model railroading procedure:
1. Apply diluted gel medium/white glue/soap mixture
2. Apply ballast
3. Spray with diluted gel medium/white glue/soap mixture until soaked
4. Let dry and move on.
This time, instead of my usual result, I found that nothing stuck. I may as well have sprayed sugar water on the ballast. What's worse is the masonite started warping, too. Luckily I caught it as it began, and a couple of extraordinarily heavy books on top while drying flattened it right out.
I tried applying more slightly diluted glue to the ballast to make it stick. And I mean lots of glue. Still, no result. The ballast flaked off at the lightest touch.
At this point, I got angry and made an experiment to see what would hold sand onto a piece of masonite:
1. Diluted gel medium with soap as a wetting agent, applied before and after the ballast -- no.
2. Diluted PVA glue with soap as a wetting agent, applied before and after the ballast -- no. (note, this is basically the same as 1. The A in PVA is "acrylic".
3. Diluted gel medium with soap as a wetting agent, applied before and after the ballast. Then, the whole works was soaked with Future floor polish, which is again a clear, shiny acrylic. I've used Future to glue windshields into model vehicles with out issue. Result -- no. Actually, I might as well have just poured water on the whole thing.
4. A layer of gesso painted on the masonite, then 1 - 3 above: Success!
5. Gesso mixed with ballast and applied directly. Great success! This stuff is never coming off. Unfortunately, it's now white and needs to be painted.
This is what I learned from my experience:
1.The "wetter" something is the worse it is for adhesion to masonite. The material is sucked directly into the masonite without enough of the adhesive left on the material to be glued. Future was the worst, then soapy glue, then diluted glue. Any of these methods resulted in failure. To make it worse, the use of a wetting agent will cause the masonite to warp. Severely if you're using lots of adhesive.
2. "Dry" viscous material works like a charm. The best results were achieved with gesso mixed with ballast. Straight white glue worked reasonably well, but not as well as the gesso, and it was harder to apply. Warping was minimal or non-existent. Gesso acts as an impermeable barrier (within reason) when dry, so it's perfect for the highly absorbent masonite. I expect this would work perfectly for MDF, which is much more porous than masonite. There was basically no warping.
Of course, none of this really helps me as my project is covered with a layer of partially adhered fine ballast that I need to remove somehow. If I find a way to remove it easily, then I'll be set.
The moral: At the very least, apply a layer of gesso to masonite before doing anything on top of it. This goes double for MDF.