Was going back over one of Dave Frary’s scenery books and noticed something I don’t remember hearing of before. He indicates that when he mixes the matte medium with water he lets it sit for a week to let the solids settle out, otherwise it can leave a white residue on the layout. Have any of you encountered this problem? He does suggest that better quality matte medium does not have as much of a problem as cheaper brands. Wonder if all brands have done away with the ingrediant that caused the problem?
I use Liquitex Acrylic Matte Medium, and I have used it for years with excellent results. I consider Liquitex Acrylic Matte Medium to be a high quality matte medium which is available in art supply stores.
Traditionally, I have mixed this matte medium with water in a 50:50 ratio.
However, last year, when landscaping a new portion of my layout, I had to order a new one gallon jar of Liquitex. When I applied the traditional 50:50 mix, it did just what you said, it left a white residue similar to egg white.
So, the next time I applied the matte medium, I mixed it with water in a 2:1 ratio, that is 2 parts water to 1 part matte medium. The results were much better, similar to what I had experienced in the past, and without the white residue.
Incidentally, I did not leave the mix sit before applying it. I applied it immediately. I have never heard of setting aside mixed matte medium. So, I will be interested in others responses to this issue.
I had the same thing happen once as well. Usually I mix it 1 part matte medium to 2 parts water. I mixed it 1/1 and got similar results. I have some old W/S Scenic Scenic Cement bottles, and I noticed I had a full one and any empty one in the kitchen later! I remixed and then it went on fine. I had to ‘re-ballast’ about 15: of the ballast shoulder where it got ‘white’. This 1:2 ratio seems to match the W/S stuff pretty close. BTW, I have been using Galleria Matte Medium form the local Hobby Lobby(quite inexpensive when using the 40% off coupon). I comes to something like $5.40 after the coupon discount.
I use a 1:4 ratio of matte medium to water for scenery / ballast. I have also gotten the white film, but I attributed that to insufficiently wetting the scenery so the the solution sat on top instead of wicking in.
I’ve never let it settle, either. In fact, I usually mix it in an old 1 qt pickle jar, and store the extra there between sessions. It does settle,but I think the solids are part of the adhesive materials, so I shake the jar until the solids go back into solution before I use it.
Oft times we tend to assume that every useful thing was designed for use somehow, somewhere on our railroads. Might be vanity, maybe not. matte mediums were originally formulated for use by artists. The idea was to prepare a surface so that paints and such would not soak into the pores of the surface. To do this many of the mediums had various fillers, fine ground clays and suchmixed into the product. Naturally, when those products were thinned with water, gravity would take hold and all of the clays and such would settle out of the mixture. Since it does not take a great deal of adhesive strength to hold ballast in place, loss of the non adhesive fillers was not a big deal.
Clever chemists have now found that with the proper resin emulsions they could get a film to form over the top of paper stocks, canvases, and the other surfaces that those who enjoy painting use, without so much of the filler type materials. This is the why of the white residue that you are seeing. The cure is also quite easy: when thinning this type of product for scenery work, be sure to add just a bit of a wetting agent…personally I sneak in about a percent of my dear bride’s favorite dish detergent, so that all of the thinned medium soaks in below the surface of the ballast, dirt, scenic foam, etc.
I don’t disagree with your comments about the origin of matte medium, but I do disagree with your “cure”. I have always added some liquid detergent to the matte medium/water mix to facilitate the absorption of the mix into the ballast, dirt, scenic foam, etc. But, in my most recent purchase of matte medium, I noticed the white film that the OP indicated for the first time, and it leads me to believe that something has changed in the formulation of the product. A higher proportion of water to matte medium seemed to solve the problem.
In the scenery book I am reading, Dave suggests that it talc is the filler used.
He suggests a mix of 1 part matte medium to 3 parts wet water. After it is throughly mixed, he puts it in a wide mouth jar and lets it sit for a week, undisturbed. He then pours off the liquid and discards the sediment.
Sounds like several of you have encountered the problem, regardless of brand. May be that this is a solution (pun intended) to solve the problem. It does make it a little slow, just plan ahead.
Precisely what I do. Never a problem. After sitting a few days there can be a quarter inch of white material at the bottom of a quart jar. Decant carefully into another jar and go to work. You can let the residue dry out and dump it. I use quarts of the Dick Blick house brand. It holds well and is much cheaper than scenic cement etc.
This thread just goes to show that even a relatively old hand can still learn something new here. I’ve always been very careful to mix the solids back in. I’ll try leaving them out and see how it works.
Makes sense that talc would be used, though, as it would add to the smooth appearance of paint. Contrary to the “origins of Matte Medium superheros” above, though, the “medium” is just what it means: a carrier. It is added to paint to enable it to flow more smoothly and brush better without leaving streaks, not to prepare surfaces (although it may at one time have been applied separately).
I won’t attempt to reinterpret their extensive discussion of the product; however, it appears that it is the solids that produce the dull finish (and possible white residue) and one use is indeed to prepare surfaces.