Before all you psychiatrists start getting comfortable, I better explain.
I’m working on a small sectional layout and my experience is very minimal. I decided to cheap out and make my own ground cover out of dyed MDF sawdust. Looks good and is very easy to make (in my profession as a carpenter). The issue I have is making it stick to the layout. For hills and such I’m using a combination of medium density foam, high density, and paper towel soaked in diluted drywall mud. Once I’m ready to add the ground cover, I’ve painted the “bare ground” with beige latex paint then sprinkled the ground cover on. That only provides a partial covering that sticks. I tried spraying a mixture of 50/50 white glue with a touch of dishwater soap but that only blows the cover all over the place into gooey clumps.
Another method I’ve tried was brushing on a heavy coating of that glue mixture and then added my ground cover. But that gives me a ton of loose cover that blows away. I’ve read that the spray bottle method with the mixture works, but I can’t see how. Maybe the MDF dust is too light. Has anyone else used this stuff before? If so, how did you make it stick?
Never have used MDF, but it does sound like it is light weight, but so is WS ground foam.
A few things I see, in my limited amount of scenic work that might make a difference. I do put my first layer onto the wet paint and had good luck. Don’t put it on too heavy or it will not all make contact with the paint. When using a sprayer, mist it over the area, don’t spray directly from close range, just let it drift down onto the surface. The other thing is that most folks use a wetting mix as well as a glue mix. It helps the glue penetrate the materials. Wet water (water with a few drops of dish soap) or an alcohol mix. Also, many prefer to add the glue and wetting agent using a dribble method from a pipette or other slow release bottle (I use an old Elmer’s glue bottle, not fully open). When I put my second layer of color and texture onto the layout, the glue and wet water caught any of the material that had not stuck to the original paint layer.
The fumes from the MDF glue would be enough to give me a headache [banghead], but I doubt that the sawdust is lighter than ground foam. [swg]
If you use a brush to apply full strength white glue to the landforms, simply sprinkle the sawdust onto it, then use a good-quality sprayer (one capable of delivering a fine mist) to saturate the area with “wet” water (water with a few drops of dish detergent added - if your water is especially hard, 70% alcohol may work better). Aim the first few spritzes upwards and let it fall like a gentle rain, then, after the surface has been wetted somewhat, you can spray more directly. The wet water has a very low surface tension, and will penetrate right down to the level of the glue, drawing it upward through the sawdust. Don’t skimp on the water and don’t touch the area while it’s wet. It may look pretty disgusting, but it will improve as it dries - this may happen overnight, but I’ve done areas on my layout (using ground foam and other commercially available products) that took up to a week to dry. Once dry, the material should look as if it’s loose, but will be bonded solidly to the terrain.
If you want to use dilute white glue as the bonding agent, apply the sawdust dry, along with any other material you might like to include, and use a soft brush to arrange it to your satisfaction. Next, spray the entire area with “wet” water, using the same technique as outlined above - I have found that it’s almost impossible to apply too much, but it should at least penetrate right through the ground cover and down to the base. Next, using a dropper bottle of some sort (some use a mustard or ketchup squeeze-type dispenser, but anything which holds a respectable quantity of dilute glue and will dispense it as controlled drops will suffice - an eyedropper will work, but it’s much too small for any area larger than a postage stamp) to apply the glue mixture. Each drop will spread so
Allow me to offer a couple of thoughts that may well help you get better results. Instead of a heavy coating of undiluted glue, try brushing on your 50/50 mix thinly and then sprinkle in your sawdust mix. Key step is to dust the sawdest mix onto the glue and let it settle in place, without touching or fussing with it. When I use this technique, the glue is absorbed upwards by whatever i am using for ground cover. In most cases you will not need a bond as strong as what you might want in a carpentry application, as sawdust and other ground covers are very light in density and are rarely put under stress after the glue is dry.
Thanks for the tips guys. And Wayne, very nice photos. Maybe the MDF dust isn’t too light but rather my application of it was too heavy. I was only doing one layer of it. Tomorrow I’ll do 2 or maybe even 3 and see how it goes. I really like how the MDF dust looks and for me it’s a never ending supply. The only cost is the food coloring.
I don’t know for sure,havn’t checked, but they used to make, a powered glue,that you would,mix in with your,ground texture ingredients and then, spray,or mist the area, pour on your mixture and spray,or mist again,to soak in. I used that years ago,with good results.
I remember a few videos on the MRR site were they brushed on white glue on top of the paint (like you were applying a second coat of paint, and then apply the saw dust, and follow the steps in the post above. I have a old MRR issue around my house somewhere, were it described this only they diluted the white glue, the artical was about a grainery? I will find that issue tommorrow.
Two ways to “make it stick”… Paint the surface with latex paint and sift the ground cover on it while the paint is wet (of course), OR, mix a batch of 50/50 white glue & water and paint over the colored surface and spread the ground cover on that.
Don’t fret over the sawdust… I still have coffee cans of the stuff from many decades ago, and it still works (but ground foam is preferable).
I use a cheap Dollar Store brush to apply full strength Elmer’s white glue to the surface. I sprinkle my ground cover onto that. I then wet the area thoroughly with wet water. While wet I then dribble on top, a mixture of 50% Elmer’s and 50% alcohol using an old Elmer’s bottle. As long as the area is wet, it wicks out to cover well.
I have never had much luck trying to spray glue, and pipettes have insufficient volume for anything but spotting problem areas.
I’ve never been a fan of the spray technique for applying glue or “wet water.” Instead, go to the drug store and get a big bottle of 70% or 90% rubbing alcohol. Get a pipette from a craft or hobby shop. Use the pipette to drip on the alcohol, straight from the bottle. I use white glue mixed 1 part glue to 3 parts water, which I keep in an old Elmer’s Glue container. The container lets me drip glue on directly.
I would venture to guess that the MDF sawdust is heavier than Woodland Scenics ground cover. So, what works for ground cover should work at least as well for MDF sawdust.
After I paint the surface, in small areas at a time to prevent premature drying, I quickly sprinkle the ground cover lightly, and most of it sticks. Then, after the area is dry, I apply a second coat of ground cover, spray isopropyl alcohol as a wetting and absorbing agent, then use a pipette to apply the glue/water mix.
I like that pipette idea. I’m going to try that later today…assuming my truck will start. Got pretty cold last night and forgot to plug the truck in. Ya, in my neck of the woods we use block heaters to help with the cold temps.
So, on my shopping list today is 70-90% alcohol and a pipette. I used a few of the methods you guys mentioned, my mistake was sprinkling on too thick of a ground cover coating initially. I really like brushing on the glue. more of a controlled application.
Thanks again guys. Very much appreciated. Once I get a few more things worked out on my layout, I’ll post some pics and show you our progress. (I’m the only one doing the physical work on the layout, but only with your help. That makes it ours in my book).
You will bury a LOT of MDF sawdust in thickish glue, no matter how you apply it.
What I would try is that 3M Product 77 in an aerosol can. Or, just cheapo hair spray. It’s what those of us who make our own trees use to adhere the flocking and ground foam mixes onto the branches of our home-made trees.
Gel medium would work painted on with a brush IF you can find it in matte.
When I have to apply ground foam to a near-vertical surface, and it happens all the time on my layouts, I wet the surface well, spray a suitable adhesive, and then use a half-folded sheet of paper or cardstock to BLOW the product onto the sticky surface. Blow doesn’t mean sneeze or gale force winds. It means a gentle blow with pursed lips held close to the material on the cardstock. Puffs at first to get the feel for the process.
Note that you can vacuum up what doesn’t stick. Just have a clean container to recover the material, or use a bit of panty hose taped over the mouth of the inlet to catch the stuff you’d rather not waste.
You need a generler spray so that it does not blow the material all over, and also try an initial spray with 70% isopropyl alcohol as a wetting agent. Then drip on a glue/water mix - or glue/alcohol. That water with a drop of dish soap method NEVER works for me, the water in my area is very hard (generally don;t drink it, or use it in coffee makers) and all I ever get trying that way is the glue forming a crust on the outside. Since using alcohol, it penetrates the whole way, for ballast and other secenery materials.
Also, instead of relying on the latex, I’d spray that initial coat with glue, then sprinkle on the next layer, and finally do the alcohol and glue.
Another tip on using straight-from-the-bottle alcohol. Don’t really use it “straight from the bottle.” Instead, pour it into a small, clean cup or bowl. It’s easier to fill the pipette that way, particularly when you’ve used enough alcohol that you’re down a few inches. Then, put the top back on the bottle so you don’t knock it over and spill it. You can put any unused alcohol back, if you only use that bottle for scenery and wheel cleaning, like I do.
I agree. I never used sawdust but it sounds like you might just be trying to put everything on too heavily. Suggest you think more in layers.
I’ve been working on developing my methods this year and very happy with where ground texturing has ended up. I actually quit using wall paint to seal my pink foam, instead now I just go over it with thinned raw umber acrylic to get a reasonable base shade for the area I am working on. Then brush on a 50/50 mix of white glue and water and a light layer of sandy dirt or base ground foam. Then brush another layer of 50/50 glue for wherever I want to add thicker grasses- foam and/or static, and maybe a pinch of fine foams on top here and there just for added coloring. By applying light layers the thinned white glue soaks up and through, and holds everything in place. There are spots where a misting of scenic cement over the top is needed to completely seal it but most of the time its not really necessary. As long as I can lightly vacuum over it without picking anything up I am happy.
A gallon of white glue is cheap and will go a very long way. Add water to a point where it still has some body (not too runny) but is thin enough to soak up into your ground cover. 50/50 is about right most of the time but don’t be afraid to adjust to find the optimum ratio for your sawdust mix.