I have an area that is to be a river. When I built the benchwork I used some plywood as a base lower than the roadbed and spanned it with a bridge with a pier in the middle. I had shimmed the pier and the bridge abutments to get it level which left a gap of about 1/8 inch.
It had been my intent to make a watery batch of hydrocal and pour it in to fill the gap and level the surface. To test how it would work I mixed a batch much thinner than usual when I was pouring rock molds. While it flowed easily and would work as a filler the surface was not as even as I want.
Is there a more suitable product for this or do I just need to get the hydrocal mix right?
Rick
I'd use floor leveling cement.
I'm not so sure about self-leveling cement for such a project as this, but maybe it would work.
It seems to me that the problem will exist on either side of the bridge piers as well as at the site of the bridge pier itself. How long and wide will this river be? And, what product are you considering for the pour?
I used Envirotex Lite on my most recent river project, and it could be your solution. It is thick enough to work with to allow you to at least create the appearance of a level surface to fill that gap under the pier.
As you pour Envirotex Lite, it will initially seek its own level. However, there is plenty of time to "play" with it with a wood stir stick in order to achieve the level effect that you seek under the pier while maintaining the proper and realistic appearance of the river on either side of the pier.
Rich
Alton Junction
Before I tried to pour anything, I would ensure that the area that will become the river is level. Once that is done, I'd use clear silicone caulk to seal the edges of the shore to the base of the river. I'd use plaster, patching plaster, whatever to seal the riverbed, especially if you are using foam. Bare foam can outgas, creating bubbles in whatever you use to create your river water. Now, paint the riverbed. Once the paint is dry, now would be the time to glue some stones, to the riverbed. Now's the time to pour/brush your water medium. I use glossy ModPodge. READ the instructions carefully for whatever you use to create your water. ModPodge specifically tells you to not brush on a layer thicker than 1/8th of an inch. Once each level dries, add another layer.
Marlon
See pictures of the Clinton-Golden Valley RR
I do intend to use Envirotex for the final pour. I am looking for something to put down first. I don't want to use drywall compound because sanding it will create a mess. Been there done that.
The hydrocal looks like the answer if I get the mix right. I'll continue to experiment as I make more castings.
hbgatsf I do intend to use Envirotex for the final pour. I am looking for something to put down first. I don't want to use drywall compound because sanding it will create a mess. Been there done that. The hydrocal looks like the answer if I get the mix right. I'll continue to experiment as I make more castings.
As I say, you can work it with a wood mixing stick to achieve the leveling effect that you want. At first, the pour will seek its own level, but then you have sufficient time to work it around the bridge pier.
I actually tried using Hydrocal at first to level the plywood surface and it was a mess. I scraped it all up and just relied on the Envirotex Lite pour.
Here are a couple of photos that show the scene before and after the Envirotex Lite pour. When I built the plywood base to span the open space between the two sides of the main layout, the result was a difference of about 1/8" from left to right with the right side being lower than the left side. When I made the pour, I just worked the epoxy with a wood stick to achieve the leveling effect.
The plywood I used is not as good a grade as you have. I need to prep it first.
I have the same two bridges and piers as you do. The area that I am working with is slightly larger than in your first photo. I had thought about using the floor leveling material but I need to buy a bag that is much larger than I will use. I have plenty of hydrocal so I was hoping that would work.
I have mixed a few more batches with an increasing ratio of plaster to water. I am very close to a mix that will work. What went wrong with your attempt at using the plaster?
hbgatsf I have mixed a few more batches with an increasing ratio of plaster to water. I am very close to a mix that will work. What went wrong with your attempt at using the plaster?
Yes, my plywood is cabinet grade. If your plywood has what I refer to as potholes, use a high quality wood filler to fill and smooth out the potholes.
I use Famowood Wood Filler in the blue labelled plastic container. It comes in many sizes and is inexpensive. I have never used a better wood filler. It can be applied thick or thin, and it is easily smoothed out. I use it to fill and smooth seams in the various pieces of plywood that I need to seal together for the river base.
I would not use wood filler, however, as a leveler. There would not be enough time to work with it before it starts to cure.
By the way, I was recalling a conversation that I had with a fellow model railroader about the blistering problem that occurred with the hydrocal.
Plywood does not readily absorb water to allow the hydrocal to bind with the plywood. Plywood doesn't necessarily repel water, but it is slow to absorb water. So, the hydrocal dries without bonding to the plywood.
Hydrocal is excellent for forming landscapes over wads of newspaper or strips of cardboard, but not for covering large expanses of plywood.
Some good points being raised here.
There are threads here about best ways to seal when pouring thin epoxy water that leaks through the tiniest places. Much of that advice may apply to 'self-leveling' plaster material.
I'd use an acrylic bonding agent on the plywood, and some in the mixed plaster. This should slso assist with making feather edges stronger and less crumble-prone.
i'd consider quickly rough-sanding the plywood and then soaking the resulting surface with 'wet water' or a thinned binder solution (analogue of the first thinned primer coat used in oil house painting on shingles) for at least a few minutes prior to the pour. This will only affect the face ply and shouldn't cause any serious buckling tendency in the structure, but still ensure the plaster won't delaminate as it cures.
I'm interested in learning what lastspikemike's father would have recommended for this application and its prep.
hbgatsf...I had shimmed the pier and the bridge abutments to get it level which left a gap of about 1/8 inch....
If I were you, I'd fill that gap, especially if you're planning to use a fairly clear product for your water...a pier that's "floating" likely won't look too convincing.
richhotrain...Plywood does not readily absorb water to allow the hydrocal to bind with the plywood. Plywood doesn't necessarily repel water, but it is slow to absorb water. So, the hydrocal dries without bonding to the plywood...
When I did my first experiment using Durabond patching plaster to represent the water, I pre-wetted the plywood (3/8" sheathing plywood) riverbed with "wet" water and the Durabond has stuck like-you-know-what to a wool blanket.
A couple of "before" views...
...and at least a couple decades later, it's still stuck solid...
Wayne
The idea to use a leveling product to fill the gaps was only part of issue. I also need to prep the plywood. I was hoping for a solution to solve both issues at the same time.
As has been stated I can hide the gaps with shoals or rocks after prepping the plywood. Maybe I need to rethink doing a skim coat and sanding it smooth.
Lastspikemike Something like shellac should seal up plywood nicely. It's methanol based so seeks out the tiniest cracks. Shellac is, or was, extensively used as a knot sealer for this reason.
Something like shellac should seal up plywood nicely. It's methanol based so seeks out the tiniest cracks. Shellac is, or was, extensively used as a knot sealer for this reason.
hbgatsf The idea to use a leveling product to fill the gaps was only part of issue. I also need to prep the plywood. I was hoping for a solution to solve both issues at the same time. As has been stated I can hide the gaps with shoals or rocks after prepping the plywood. Maybe I need to rethink doing a skim coat and sanding it smooth.
I am assuming that you are concerned about the less than smooth surface of the plywood when you talk about applying a skim coat. If you are hoping for a solution to solve both issues at the same time, the other issue being leveling, Envirotex Lite would solve both issues, but you better tint the mix, perhaps heavily, because otherwise the uneven surface below will show through the pour.
I pulled out the instructions from my Envirotex Lite box. Here are some relevant points, germane to this discussion.
Surface: Coverage will vary according to surface and method of application. The surface to which Envirotex Lite is to be applied should be dry and free from dust, grease, wax or oil. Level the surface.
The unique self-leveling qualities of Envirotex Lite can be attained only by using enough material to flood the surface. It is better to mix a little too much, rather than too little.
Mix only as much Envirotex Lite as you can pour and spread at one time. Unmixed components should remain in original containers. After pouring you have about 25 minutes working time before Envirotex Lite begins to harden.
As the instructions indicate, Envirotex Lite has unique self-leveling qualities. Also, as the instructions indicate, the surface should be dry and free from dust, grease, wax or oil.
I would be very skeptical of sealing the wood with something like shellac. Since a high quality wood filler will seal off off cracks, gaps, and other openings, stick with wood filler to ensure a good bonding surface for the Envirotex Lite. I have read where others ruined the pour because the mix did not bond to the surface.
Is Durabond essentially the same type of product as Quickset or Plaster of Paris?
I will repeat that if you need to seal gaps or cracks or whatever on the surface of the plywood, use wood filler. I speak from experience.
However, if you don't want to use wood filler, then apply a thin coat of Envirotex Lite with a brush over the entire surface of the plywood.
Here is what the Envirotex Lite instructions have to say about sealing:
Seal Coats: Open grain woods such as oak or walnut require a thin coat of Envirotex Lite® prior to flood coating to prevent air from escaping from the wood into the thick fluid. To seal coat something, just mix up about 1/4 the amount youwould use to flood coat, and spread it thinly over the entire surface, using a brush or scraper tool. This puts a thin film down over air passages, and seals them off. Occasionally two seal coats are required. Allow the seal coat to cure for at least 5 hours, and you are ready to flood coat the object.
hbgatsf Is Durabond essentially the same type of product as Quickset or Plaster of Paris? Rick
hbgatsfIs Durabond essentially the same type of product as Quickset or Plaster of Paris?
I'm interested in hearing the reasons shellac won't work as a barrier coat. The stuff I used as an undercoat with pourables was polyurethane spar varnish; there are two-part versions but I have not used them. (Incidentally you can 'officially' shellac over the Famowood filler -- at least the solvent-based formula...)
I always tried degassing the epoxy during the sweat-in period, before actually pouring it, just as I degassed things like RTV that needed extensive mechanical mixing with air present. Surprising how this reduced the need to run heat over the surface, breathe on the bubbles, etc. etc. etc.
Rick, I have a few questions for you.
hbgatsfThe plywood I used is not as good a grade as you have. I need to prep it first.
hbgatsfI have the same two bridges and piers as you do. The area that I am working with is slightly larger than in your first photo. I had thought about using the floor leveling material
hbgatsfThe idea to use a leveling product to fill the gaps was only part of issue. I also need to prep the plywood. I was hoping for a solution to solve both issues at the same time.
hbgatsf Is Durabond essentially the same type of product as Quickset or Plaster of Paris?
It would help if you could add further clarity to all of this.
Let me close with these thoughts. When I began my river project and decided to use Envirotex Lite to create the river, I was faced with the same issues that you are faced with. Like you, I needed to level the river bed, seal the plywood seams and prevent leaks.
I was concerned about whether I needed to use multiple materials for this purpose. Wayne had suggested Durabond to me, but my hesitation was that the Durabond itself would become the river instead of using Envirotex Lite.
I don't have Wayne's skills, and on a sample test, I concluded that pouring Durabond, then painting it and then sealing it would not give me the realistic look that I was looking for. My sample test looked like a painted blob of plaster.
So, I decided to try Hydrocal over plaster sheet. But that only led to my blistering disaster.
In the end, the one-step solution to all of my problems was the Envirotex Lite pour after first sealing any joints between the plywood sections with wood filler. That required minimal sanding which produced no dust, only sanded wood particles which were simultaneously vacuumed up with my Shop Vac.
The only reason that I suggested Famowood Wood Filler to you is that it would be a good solution to the need to smooth the surface of your plywood base if that is what you mean by "prep" the plywood.
My overrriding concern was the caution in the Envirotex Lite instructions that "the surface to which Envirotex Lite is to be applied should be dry and free from dust, grease, wax or oil".
Prior threads on this forum spoke of horror stories about failures of the Envirotex Lite pour to bond with the surface because the surface was not properly prepared. So, my primary objective was to do as little as possible to the plywood surface to ensure proper bonding.
I hope that all of this helps.
My Maclau River use a very large port .
Course to model such a surface of water some precaution were necessary.
I also ended with the fact the surface is not perfectly level and I can't change it
I seal the whole surface of plywood with a professional product which is used to seal the wood boat hull made by International.
All the edge of plywood were sealed using an acrylyc join filler with a brown color which is paintable .
The International sealer is not a varnish but a product absorbed by the wood which seal it.
The plywood was painted in the final color of water deep blue brown green all gloss colors.
I didn't pour resin in the harbor because the surface was too great, but I brushed it on the surface; I used simple translucide polyester resin used to build up polyester parts; cheap and esay to use and ended with three or four layers.
When the thin resin surface was completely dry, the surface was brushed with acrylic gel medium from Golden to simulate waves and rippled water.
After a few days the milky color of the gel has completely disseapper and the gel was translucide.
I come back with two brushed layer of polyester resin on the gel, which smoothed the waves and rippled water.
When dry I ended with a last layer slighly tinted with a blue green color.
It's take severals days to finish the harbor water because of drying time between resin layer, but I ended with a nice looking water effect and I have a full control of the process.
Making a new parts now of the harbor, it's has also the advantage to not have the need to finish the whole surface in one session, it's possible to continue to work the water surface later even months later.
Here a few pictures of the results on my N scale Maclau River layout,