streams and creeks and rivers, oh My!

[SteamGene]

It's obvious that using any liquid to make a body of water on the layout, one needs to have a waterproof streambed.  Any suggestions to cope with "subflooring" that is not continuous?   I'll have one run (as in Bull Run for those not familiar with Central Atlantic dialect) and one "river" - the South River, which is really the South Fork of the Sheandoah River, but shortened by the locals to South.  Mickie's Run will have a waterfall.  South River will have a trout fisherman - an anachronism in 1957 as the river was highly polluted then. 
Gene

[TonyD]

Paint or detail the underside of plexiglass, can be just thin stuff, any length you can afford, and it's washable.

[Jim Banner]

Gene, I assume you are making your river out of a liquid, like Envirotex, which sets up after pouring.  I usually use Plaster of Paris for leveling lake, stream and river bottoms.  For leveling, a rather thin mix will level itself.  For shaping rough water, a thicker mix will hold its shape as it dries.  If the base below the plaster is made of multiple pieces of wood etc. and there is any chance of relative motion, tack down a layer of 1/4" hardware cloth to serve as a reinforcing mesh.  Then add enough plaster to completely imbed the mesh.  The longest river I have done this way is about 15 feet long and crosses a number of joints in the plywood support beneath.  After 15 years, it shows no signs of cracking, either in the plaster below or the Envirotex above.

If the liquid you plan to use will stay a liquid, then Plaster of Paris is not a good choice.  There are plasters available for casting outdoor statuary that might work, although they are not recommended for continuous underwater use.  Tile grout, one form of which is Portland cement and very fine sand, can be worked like plaster, and it you get the type that is made for grouting swimming pools, will stand up to being continuously immersed.  It would probably take a reinforced layer 3/4" to 1" thick to avoid cracking and leaking.   Regular concrete would probably be cheaper than grout, but does not take as fine a detail and usually requires much heavier reinforcing and layers at least 2" thick.  And suitable benchwork to take the weight.

A different approach is to not rely on any sort of masonry for a seal but to line your river channel with butyl rubber sheet.  This is the stuff sold for heavy duty, permanent garden ponds.  You can use grout or mortar to level and/or shape the inside, and even add small stones as it is setting.  If cracking occurs, it is usually not too noticeable and can be patched.  But most important, any leakage through the cracks will be retained.  This is a method that is used successfully to make concrete lined outdoor creeks that last for years, even in areas with frost heaving.

Yet another method is to build up your river to almost final shape using plaster of Paris or other material and then fibreglass the inside.  If the polyester resin usually used with fibre glass is to is too smelly, use a two part epoxy finishing material instead.  Circa 1850 (the paint stripper people) produce a two part epoxy finish.  Just make sure the fibreglass cloth is well overlapped at joints.  A second layer of the same material will stick to the first layer and can be used to hold sand, gravel, scale boulders etc. in place. 

I am not sure what liquid you wish to retain, so you might check on its compatibility with the suggested materials first.  For example, Butyl rubber doesn't like petroleum based oils while polyester is not compatible with various alcohols.  Epoxy is compatible with most liquids at room temperature so may be the best choice in spite of its price.

I see Tony D has posted while I have been writing.  His comments suggest another solution for making a stream bed for retaining a liquid that stays liquid.  And that would be thin sheets of PVC, either clear to show the details below or grey if you wish to paint details on the surface.  PVC can be heat formed to fit your stream bed using an electric heat gun or a propane torch with a flame spreader.  Joints can be glued using a PVC backing strip for reinforcement, or better, can be welded.  I would suggest keeping a fire extinguisher on standby although I have never had to use one when hot working PVC.  PVC would be cheaper than fibreglass if you have access to the welding equipment.

[grumpy]

If using two part epoxy use the longer setting type. Mix it up and then warm it up- this makes it more pourable by lowering the viscosity. you can even paint with it. During the 80's this was a method of applying a finish to larger wingspan model airplanes that would represent metal.
Don

[Yampa Bob]

Hi Gene
I will be adding a stream to my layout,  using Woodland Scenics water.  Their scenery manual says to use plaster cloth making sure there are no small cracks or holes, and dry the cloth thoroughly.  There are 5 pages devoted to water effects.

If you don't already have the manual, I would recommend it. 

Here is an article from MRR magazine:

http://trains.com/mrr/default.aspx?c=a&id=1126

Rick Inglis of the Northern Colorado Model Railroad Club has a 4 page PDF on "Modeling Rivers".  Follow this link, right click on the image and save target  as  "Modeling Rivers.pdf ".

http://www.ncmrc.org/joomla2/index.php?option=com_content&task=view&id=25&Itemid=27

Bob

[TonyD]

Hey Gene, sometime this week I will send you pics of my water scenes, so you don't have to put mining timbers under the layout. Mine is around the room shelfwork, so I keep things featherweight......and finished the basics in less than 2 years....besides, I had to do SOMETHING 21st century....Tony

[SteamGene]

Tony,
I'm going to have to give up model railroading to start pursuing radioactive hairless foxes and headless geese!
Gene

[TonyD]

Whoa! sounds like another cool hobby! What caliber do you use? I prefer an Ithaca model 37 myself...The season up here started yesterday.... I had no idea what you were on about till I read the other thread...yeah. Anyway, I will send some pics to your email sometime latter, I won't try on here yet...and don't know if it's worth the effort!!!! you can judge if my cheesey short cuts are worth it.....I far prefer reading the manual for the new camera than reading stuff on here......beam me up Scotty!!!!

[SteamGene]

Tony,
My real love is the old towed M101A1 105mm, but most of my career was with the M114 155.  With either, I'm deadly. 
Gene

[Jim Banner]

It's obvious that using any liquid to make a body of water on the layout, one needs to have a waterproof streambed.
Gene

I am still left wondering if the "liquid" you are concerned about is water or some free flowing substitute for same.  Using real water usually ends up in a stinking, slimy mess unless you dose it regularly with a fungicide/bactericide and then you risk poisoning the cat.  Substitutes can be quite expensive.  And even the most minor of leaks is a headache.

I see that everyone else has assumed your "liquid" is a thermosetting polymer, in which case the requirements are much, much easier.  Just fill the major leaks.  If you lose a few drops of polymer through minor leaks, so what.  Just make sure it doesn't drip on the rug (or the cat!) 

[r.cprmier]

 With either, I'm deadly.

You sound as bad as my son and that damned cow!!!!

Rich

I got to fire a BAR up at the East Range at Schoffield once.  Does that count?

[SteamGene]

Jim,
I have no plan to use real water.  I have some of the "melt it, pour it, let it harden" fake waters.  I remember reading several articles in MR about waterproofing the bed to keep the liquid in until it hardens. 
Like I said, were I to have opened the package first, I probably wouldn't be annoying all these innocent electrons.
Gene

[grumpy]

If you are going to use the melt it ,pour it,let it harden material move the pets and the wife out of the house, unless you are not too fond of your wife .Also use the next door neighbours oven . The odour is a killer.
Don

[SteamGene]

I've heard of an odor issue. 
Gene