Drywall Mud

[Anonymous]

Crazy question but can the drywall mud be used over styrofoam or plaster cloth in place of moulding plaster? I've got quite a bit left over from doing the basement and was hoping to use it.

[Medina1128]

I don't know it drywall mud dries hard enough to withstand "Ooopses"...

[UNIONPACIFIC4018]

http://www.terrorsyndicate.com/Terror_Syndicate_Monster_Mud_Recipe.html


Look here and see what this guy did with it

[ARTHILL]

I use lightweight tapping compound over everything. It can be put on with a bru***o be a base for dirt, it can be spooned on to makes rocks. It glues rocks and trees in. and Its CHEEP. Takes a couple days to dry, but so does WS foam. Hydrocal is better but costs way to much for me. It paints with WS paints and artist colors. I have not tried to mould it, but that is what WS hydocal is for.

[howmus]

Absolutely! I have used it for years. It is actually stronger and easier to work with than hydrocal and many other common plasters. I dilute it to the consistancy of pancake batter and brush on several layers. It does not take Woodland Scenics rock paints as readily as hydrocal and may need a few more coates or a darker mix, but it paints well. Try it. I think you will like it.

[CBQ_Guy]

Definitely. It's all my LHS owner uses on his home and store layouts.

In fact, he has given NMRA Division Meet clinics on using it right over foam.

[jwar]

Ditto to all the above. If you ever apply it on alum screen, spray an adheavise over the back of the screen, then apply a plastic kitchin wrap, makes it a no mess application if you ever use the screen/plaster method....John

[MisterBeasley]

It's heavier than hydrocal, if that's important.

[Anonymous]

Yeppers! I use it too. Over Spray foam. Over extruded foam. Over wood. Works great! I have found on occasion that a crack will appear on the side of a hill as it dries, but the cracks can be filled before or after grass et al are installed.

Trevor

[Seamonster]

I've used it for both scenery and roads. The only problems I've had with it is that it dries slower than plaster and shrinks a bit when drying (that's why drywall installers use multiple thin coats of the stuff) but both problems can be overcome by not applying it too thickly. It does have the advantage of being ready to use and you don't have to mix a powder and water. I had some left over from basement wall work and had some problem storing it for a long time. It was recommended to pour a little water over the top of it in the pail and pour off the water before using it. That seemed to help keep it from drying out, but eventually it started to mould and smelled bad so I had to throw it out.

[electrolove]

Can someone please point me to a picture of this miracle medicine? I want to learn what this is called in Sweden.

[MisterBeasley]

electrolove - This is the stuff that is used in construction to fill the cracks between sections of drywall. In the US, this is a common method of building interior walls, particularly for homes. The house is first "framed" with 2x4 lumber. The wall sections are 4x8 foot sections of drywall, which is a gypsum material, sometimes called sheetrock. It is like a big piece of dried plaster with a paper layer on the outside. After the pieces are all up, you put drywall compound, or "mud," between the cracks and generally put a piece of paper tape or plastic gauze over it. Over the next couple of days, as the mud dries, you slowly put on a couple of additional coats and smooth the edges.

[electrolove]

MisterBeasley:

So what's the difference between this and pathing plaster?

Is this what you call drywall or sheetrock?



And this?

[selector]

Yes, we are all talking about the same thing, Electrolove. The mud is the stuff that makes the light patch lines between the drywall sections in your lower photo.

[electrolove]

selector:

Ok, we call these drywalls 'gipsskivor' in Sweden. If I try to translate 'gipsskivor' it will be something like plasterplates or plasterboards. Not easy to live in Sweden with all these strange words...

Maybe you can tell me the difference between drywall mud and pathing plaster?

[ARTHILL]

There is not much diference. Patching plaster is designed to fill holes and mistakes. Lightweight drywall mud can be purchased premixed in Minnesota and is a nice consistancy to finish scenery. Patching plaster may be better for forming rocks, but I use plaster of paris or hydrocol for that. If this is all new to you, get a little of it and see what it will do. You will find fans of all the materials on this forum, including stuff not yet mentioned.

[Medina1128]

I can buy a 20# bag of molding plaster for $7.99 at Ace, compared to $8.99 for plaster of paris. It molds nice, and has a nice hardness to it to make it durable. AND it takes staining great!

[bogp40]

The only problem I have with joint compound, is that it dries very slow, when dry is still soft, shrinks and cracks when appied thicker than 1/8", and is water soluable- can turn to putty if ever wet. Even when I use it for it's intended purpose, I will only use it to skim the seams after first applying Durabond 45 or 90.
I have the best luck with using veneering plasters over an initial layer of plaster cloth, whether on wire screen or foam. Hydrocal is saved for castings or soupy mix w/ paper towels. I feel you will end up with a better quality base for your scenery with plasters rather than a frail layer of mud. Bob K.

[selector]

Bob, my experience is limited to plaster cloth, overlayed at angles at least once for toughness, and then covered with plaster of Paris rocks glued with Hyrdrocal.

I would think that joint compound or Pollyfilla type stuff would be okay for molding rock faces, but it would be best to use it in thin layers, spraying the dickens out of each preceding one with liberal quantities of water so that the new layer doesn't get dried prematurely by the older stuff, beneath, wanting to wick the moisture away.

[Anonymous]

The difference between plaster (patching or any other kind) and drywall mud is that plaster undergoes a chemical reaction to harden. Drywall mud dries out......This means that the mud is water soluble and plaster is not. I don't use mud because I don't like the shrinkage and I tend to soak areas later with stains and glues and I don't want the base to dissolve. I also find hydrocal to be hard as stone when it sets. Mud is quite a bit softer and I tend to err on the tuff side.

My suggestion would be to track down some hydrocal or casting plaster at your local home center that sells plaster and lathe materials to contractors. Give it a try to see if you like the stuff. Don't buy the Woodland Scenics Light Hydrocal, it is expensive and doesn't set up as tough..

Sounds like other have had good luck with the drywall mud...who knows maybe you will decide its for you...

[electrolove]

Does that also mean that patching plaster is a powder where you must add water yourself, and drywall mud is premixed with water and ready to use right away?

[Anonymous]

Yes,

Most drywall mud is ready mixed.

[gjvjr50]

not sure about the "patching plaster" but the "mud" yes is premixed from ether a pint/quart up to arounh 5 gal buckets   but you can get it in 25 lbs bags or so and mix it up yourself

[LD357]

 I've been using drywall mud on dioramas and layouts for years. I think it works better than plasters because it doesn't dry in 5 mins. and you can work with it.

  Once it's dry you can paint it or use Woodland Scenics approach and spray dyes or thinned paints on it to color and stain it to simulate rock faces or outcroppings or you can mix paint [acrylics or dyes] into the mud before you apply it.

 If you want smooth, flat fields it's very easy to achieve them with drywall mud and a wooden roller, [just make sure the wife doesn't find out!! LOL], just apply a thin ,1\4 inch or so ,coat and roll it out. The results are very nice and it dries pretty fast.

  At $12 for a 5 gal. bucket you'd be hard pressed to find a better deal, and if you need time to work in your contours and shape your landscape you can't beat drywall compound, plaster will dry so fast you won't have any time to work with it.

[Autobus Prime]

Folks:

In case anybody wants to know (nobody asked, true), drywall mud is basically clay, a vinyl polymer (I'm pretty sure it's the same one used to make hot glue sticks and some foam rubbers!) and fillers.  It dries, and does not set up into "stone" like plaster.  Some patching plasters are similar, made of glue and fillers.  Others are just gypsum plaster with retarder added.  To complicate things, there are also powdered setting-type joint compounds sold.

I have used premixed paste joint compound for mountains on screen wire.  It's pleasant to work with, but stays soggy a much longer time than plaster.  It's more resilient and rubbery when dry than plaster is.

I've often thought that joint compound could be used with paper towels in a revival of the old-fashioned texture-paint method -- texture paint was glue and fillers, and the properties seem similar.  I haven't tried it yet.

[Tamvalleyrr]

Sure - it will work.  It might crack if you make it too thick but I've put it over styrofoam. I use an old paint brush and jab it with the bristle's to add texture.  You can use a damp sponge to smooth it.  When its dry just paint it with some latex earth or rock colored paint.

 

Duncan 

[ldrake26]

If anyone is concerned about the dry time of joint compound, use a faster setting mud.  You could use mud with a dry time ranging from 20 min. to several hours depending on which type is used.  The only drawback is that it comes in powder form so you would have to mix it.  It will also be harder to sand and will require a little more effort to smooth out, but again it hardens much quicker