Hadn’t really thought about drywall mud being different than Hydrocal or molding plaster as far as its solubility. I think, just to be on the safe side, I’d still not wash it down the drain unless it was with large volumes of water. This is especially true for my case since my waste lines run into a septic system which doesn’t like a lot of extraneous things put in to it.
Bob
Thanks for the info guys. Have over 100lbs of the stuff left, so providing it “keeps” until I am ready, should provide a decent start. Still wondering if sheetrock mud would work better of wire mesh or foam? Those are my prefered choices because I have both of those on hand as well.
Another question, would any old fabric sheets work? You can probably tell I will be trying to keep the expenses down and use everything I already have.
[C):-)] Rob
I use plaster cloth. Or more accurately plaster gauze. Woodland scenics sells gauze already impregnated with plaster in 10sq ft rolls. All you do is wet it to to activate the plaster, set it on your under-structure (bumpy side up) and smooth out the plaster.
I twist and wrinkle alum screening, then to prevent the mud mess, spray with adheasive (eng gasket spray) outside, then staple and hot glue in place. Drywall mud thinned down a bit ( as like a thick milkshake) and brush on a light coat, next day another to cover the mesh. I also use Bragdons geodesic scenery alot as in this pic. I always use wash coats to get my rock colors 
…John
You know, I listened to the wisdom of this John, who, in my opinion is as smart as the St. Johns. I did what he says, and am so amazed at the results one gets. When I started, I thought, I hope I can do something similar to John and remain so pleased with the effects.
Do yourself a favor and go to trainboard, rail images and look at his work there! U will be glad U did!
Joe
PS, Thanks again and again for the expert advice John!
Thank you for your kind words Joe…Not use to that LOL. I think the best way to do anything concerning this hobby is to learn the different ways and come to the type of operation or methods that fits the modeler. Havent posted pic over on the railimages for some time due to some glitch. On Photo bucket “FeatherRiverRoute”. Gads havent heard from you in a long time Joe, I still visit your blog, is fantastic…Take Care my Friend…John
I may well have seen your work already, don’t remember. Is there a link to the Feather River Route? Thanks for all the excellent suggestions.
[C):-)] Rob
Concerning keeping plaster, if it is completly airtight, it will keep. A pin hole in the bag will eventually turn the who bag into a block.
Concerning Drywall mud, if it drys, it is not plaster and can be washed down a drain. I do not know about a septic system. Plaster does not dry, it cures and will cure underwater and will clog the trap every time. You can tell, if it turns warm when it cures it is plaster. if it turns cool it is drying and not plaster.
This is a small but VERY important difference when dealing with it, if water will disolve it later. As I said earlier, fine detail work, carved into drywall mud will disolve when painted with water based paint.
NEVERMIND…just found it! Right off the bat, the rocks arount that bridge with the semi on the road is incredible. Will study these closely. Thanks again! [C):-)] Rob
I never use plaster for scenery. It is much easier, cheaper, and cleaner to use extruded foam. One $18 sheet purchased several years ago was more than enough to build all the mountains on my 10’x11’ around-the-wall layout. The mountains are hollow and lift off the layout for access to tunnel tracks. I use Sculptamold over the foam to carve rock formations. It makes a very realistic scenery that is very light and easy to move. Another plus to this scenery is that soaking it with detergent/water loosens it and makes it easy to remove when I change my mind about something.
$18 for a sheet of foam?
I wish it was that cheep here! I was at a home improvement place yesterday, and looked at the price of foam and 2 inch 4x8 sheet of polystyrene was $28 and 1 inch urathaine foam was only a little less!
I’ve tried ALL of the methods posted above. I like the ease in carving foam when modeling sheer cliffs, covered with a thin layer of plaster. For rolling hills and mountains, I’ve used shop towels (the blue ones), dryer sheets, and regular paper towels dipped in plaster. My favorite method is to cut paster cloth into strips and lay in place on the layout. I then spray the strips with wet water. A little smoothing into place, and about the only mess is a little plaster on my fingers. I’ve found that when you dip the plaster cloth in water, it turns into slime, wanting to fold over on itself. It’s easier to push a chain. Once the plaster cloth sets up, you can either brush on a thin layer of plaster over it, or rewet the plaster and sift dry plaster over it. It’s a great way to give your plaster texture.
I’m building a new mountain now. If interested, click this page ===> then on the tab ‘photo’ and watch a slide show of 12 pics…
http://home.mchsi.com/~ironmaster1963/wsb/html/view.cgi-home.html-.html
…just one of many ways to build mountains and cliffs…
I used drywall mud “full strength” (undiluted) over fiberglass window screen. To support the screen I “roughed in” my hill with blocks of white beadboard foam blocks (Salvaged packing material from RTA bookcases and a treadmill). I applied it by hand and smoothed the contours.
Having tried all the listed methods, except the WS plaster stuff [wayyy too expensive for what you get], I can state without reservation that drywall mud works best FOR ME.
The stacked foam works great also, and when applied over said stacked foam, drywall mud makes superb mountains\hills. Some methods won’t work for some people, so you can’t say ‘‘Do this and ONLY this’’, you have to experiment and see what you like and what works best for you.
Drywall mud is NOT plaster, its gypsum, and when washed down the drain [something I personally wouldn’t do] it won’t harden and block the drain, it just dissolves. It does crack when applied too thickly but a skim coat fixes that right up. As for it loosing its texture when you paint it, nope, only if you paint it while its still wet and with water based paint, let it dry…say, a week for thick applications,2 to 3 days for thinner coats, and you can paint it with whatever you want, BUT, painting it isn’t even nessecary, mix some latex paint in it when you’re stirring it and you won’t need to paint, or, use the WS method like I do…a spray bottle, some dye [ I use RIT brand and mix my own colors] and a good imagination.
When I apply the mud I sculpt textures into it like cracks, rock faces, layered rocks and crevices, on areas I want to be smoothe, I use a damp sponge to texture it when it’s almost set up, like say, 2 hrs after I put it on.
Let the mud dry, mix the dye to the color you want, browns, reds, grays and tans are good for rocks, then start lightly s
Excuse me, but this is the SECOND time in this thread someone has ‘informed’ us that drywall mud is not plaster. According to dictionary.com and the US Gypsum company at plaster.com, you guys are sadly and totally mistaken.
plas·ter plas-ter, plah-ster] Pronunciation –noun
| 1. | a composition, as of lime or gypsum, sand, water, and sometimes hair or other fiber, applied in a pasty form to walls, ceilings, etc., and allowed to harden and dry. |
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| 2. | powdered gypsum. |
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| 4. | a solid or semisolid preparation spread upon cloth, plastic, or other material and applied to the body, esp. for some healing purpose. |
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–verb (used with object)
| 5. | to cover (walls, ceilings, etc.) with plaster. |
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| |
| |
Slow Down, and Take A Breath.
No offence intended, but, Joint Compound ( AKA Dry Wall Mud ), is not a plaster of any type ( either lime or gypsom). http://en.wikipedia.org/wiki/Joint_compound
Modern joint compound is a mix of water, finely ground limestone, a polymer, and a magnesium aluminium phyllosilicate ( otherwise known as Palygorskite, a naturaly occuring mineral ) and in the case of light weight joint compound it also has expanded perlite in the mix.
That is not to say plasters ( lime or gypsom ) have not been used as joint coumpound. OTOH, normal gypsom, that has not been fired, to drive out the water ( to make plaster of paris ) Does Not Harden When It Get’s Wet**,** and so it can be used as a filler to make joint compound, much like limestone.
Only when gypsom has been fired and the water driven off, or limestone is fired to drive off the CO2, do they make plasters, That Will Harden When They Get Wet.
Lightweight Spackling Compound will be difficult to get to stick to smooth bare foam.
We use rough carved foam, then two layers of plaster cloth, then a thin layer of spackling compound. All mountains over track (currently 5 seperate sections) lift off, and are very light, even including paint and trees.
It’s probably not the least expensive method, but I did a paper mache layout when I was 14 and wouldn’t touch that stuff again with a ten foot pole. If you consider the cost of the carpet under the layout, this may be the least expensive method available to us. Because all the foam we used on phase 1 was scrap, leftover from other projects, there was less expense than usual.
I’m very careful in how I use and apply the spackling compound. We buy 1 gallon buckets ($13), open the near or now empty 1 quart bucket first, then the gallon, use a putty knife to pack the quart full, and close the gallon bucket first, to keep it from drying out as long as possible. When applying spackle to the layout, I use the putty knife to pack a small styrofoam coffee cup half to three quarters full from the quart (working) bucket.
To make smooth rolling surfaces, thumb sized gobs of spackle are “smear pasted” onto the plaster cloth, then tamped with clean dry fingers to flatten them, and then brushed with a 1" brush after dipping it into clean water, to give final smoothness. Care is necessary here, too much water will wash away the spackle.
To make rock walls, thumb sized gobs of spackle are smear-pasted onto steep plaster cloth, then tamped around the edges to fix them solidly to the cloth, again, with clean dry fingers, then edged and carved with a butter knife, usually from the top down. Finally, vertical cracks are cut with the tip of a bamboo skewer, and as many “sharpies” (little points of raised plaster that make it look like plaster and not rock) are tamped down. Rock layering schemes are planned out in advance, and created with a little extr
Greg,
You are the one shouting, not me. Drywall mud is a plaster. It may indeed be a different type of plaster, but it is still a p l a s t e r. And I’ll stick with the dictionary, Wikipedia is as reliable a source of information as a prarie dog is a watch dog.
And to the casual reader, I’ll repeat, flush wet or dry plaster of any kind including drywall mud down your drain at your own risk. I always recommend and do every thing I can to avoid putting any kind of plaster down the drain.
Joe
Sorry, but, I’m afraid that I have to tell you this, but that the prarie dog you were refering to, just bit you where the sun don’t shine - US Gypsom, agrees with the definetion