First to start off, I am completely new to model railroading. I have been following advice that I have read from researching. I have my base with blue foam (bought from local hardware store). Glued foam to my base and then went over it with plaster cloth (I am using Woodland Scenics and also Activa Rigid Wrap. Both in differect areas). Within a hour I had bubbles from the plaster cloth lifting from the foam. So I started over. This time running some sandpaper over the foam to rough it up and tried again. This time it worked.
So I moved on to covering the plastercloth with hydrocal. Well lets just start the bubbling off of the foam all over again. It will not stick. I have read several people having a great layout with plaster cloth over foam. And that is the layout style I am trying to go for. It seems that everytime I introduce moisture into the plastercloth I release the bond to the foam and get bubbles.
My question is: What am I doing wrong? Any tips to help correct this issue?
Any help would greatly be appreciated. Thank you
Try painting the bare foam with acrylic or latex paint before doing the plasterwork
<<How hot does the plaster get as it is drying? Are you using hot water on the plaster?>>
To rephrase my concern, hot water is never used in humans for casting fractures as it would cause burns. Plaster gives off heat as it sets up. Starting with hot water would raise the final temperature. I don't know if it would be hot enough to give off steam but it might cause some off gasing of the foam.
Henry
COB Potomac & Northern
Shenandoah Valley
Knight94It seems that everytime I introduce moisture into the plastercloth I release the bond to the foam and get bubbles.
That´s the most likely explanation!
What I don´t understand is why you cover the foam terrain with plastercloth when you again cover it with Hydrocal in the next step? Try leaving out the plastercloth.
I have found temperature has a great effect on plaster, plaster cloth and hydr. I have found in my room, which is in a shop not controlled, using warmer water to mix helps sometimes.
NickyB
Knight94 -
First, to the forums!
Now, if I have understood correctly, your plastercloth is pulling off of the foam.
I would first of all, second the recommendation to seal the foam with latex paint. (And, always make sure the paint is fully cured before putting plastercloth over it!)
Also, make sure the temperature is not too hot, for the water to activate the plaster, as it might cause some unintended results, such as you are experiencing.
And, I almost wonder if the foam is not "cured" fully yet, but you have no way of testing that... Is the plastercloth new? Old stock plastercloth may not work quite right, so that could also be an issue, but both seem unlikely. (And, zero way to test for sure...)
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
I don't paint my foam before applying plast cloth, and I've never had your problems. When I wet the plaster cloth, I dip it in a shallow bowl of water so it gets covered, and then run the wet cloth through my fingers to squeeze out the excess moisture. Once it's down, it causes me no problems.
I used Gypsolite on top of my plastercloth. Hydrocal heats up as it sets. I like the much rougher look of Gypsolite vs. the smooth texture of Hydrocal.
It takes an iron man to play with a toy iron horse.
What you are discribing dose not make any sence, my whole layout is done with plastercloth over foam and I was always amazed at how well the plaster cloth held to the foam but then I use beaded foam as it dose not shrink one it has some age, thats why they use it for peir floats etc. in 1-1 life.
Thank you for all the advice.
Let me try and see if I can be more detailed now as I have read the responses.
As long as I have scuffed up the foam the plastercloth will stick fine. The only issue now is when I add the hydrocal afterwards (it bubbles in areas). As it was stated, I believe it is heating up (while drying) and causing it to lift. Usually I notice the bubbles about 40 min after they hydrocal was applied. So maybe some kind of sealant to it would be great before the hydrocal. Since I am new at this, I have read that you want your trackbed to be as flat as possible. So hence why I am using hydrocal to flatten the areas where the seams as such are. Maybe I don't need it as flat? But from what most say, it needs to be flat. I don't want any derailments.
I did a little test patch of foam with laytex paint that I had sitting around the house. So we will see how it works.
Again thanks for the welcome. Excited to see how this works out. It is a great hobby for my son and I to spend some time doing.
I have used this combo extensively myself first of all. I used the cloth over the foam period. I used a cheese grater to remove the bigger bumps plus sand paper,just be very careful to not cut through. I use every small bump etc as long as it does not cause derailments as rocks fascia etc and weathering. relax it might help your finished product.
Knight94 So I moved on to covering the plastercloth with hydrocal. Well lets just start the bubbling off of the foam all over again. It will not stick. I have read several people having a great layout with plaster cloth over foam. And that is the layout style I am trying to go for. It seems that everytime I introduce moisture into the plastercloth I release the bond to the foam and get bubbles. My question is: What am I doing wrong? Any tips to help correct this issue? Any help would greatly be appreciated. Thank you
It sounds like you solved the plaster cloth on foam part.
I laid Activa plaster cloth over carboard strips (old school) and that part worked totally fine for me.
However, where I did have issues was when I put a layer of plaster of paris over the dry plaster cloth - well, that part went semi ok but the Activa plaster cloth was dry and sucked the moisture right out of the plaster making it difficult to apply.
Solution:
The activa plaster cloth, once dry, is like a moisture trap sucking moister out of the plaster I was putting down. So what I did was first wet the plaster cloth with a spray bottle and then I used a soupier mixture of plaster. That helped the plaster go on.
When I got to the step to put a layer of latex on the plaster, again, I needed more moisture because the plaster of paris, after drying, is again a big moisture sink, sucking the moisture out of the latex paint.
1) I added some water to the latex so it was a bit runnier than straight out of the can from Home Depot, and
2), I sprayed water on the dry plaster of paris surface and wetted it well before painting on the latex base color paint.
So when using a more dilute latex in concert with a wetted plaster of paris surface, I was able to paint the latex on much better without it bubbling up or ending up with a rubbery skin of latex that just peels off. You do have to be careful not to paint over the same surface a lot as the paster can start to come loose - and you will see bare spots where this can happen. It's not the end of the world but you'll have to gently repaint over it.
The issue all along here is moisture, and having to add water back into the equation at both steps.
Rio Grande. The Action Road - Focus 1977-1983
I gave up on plaster or anything that had to be mixed and now use drywall mud. Never had an issue with either. Seams in foam were treated as a wall joint;taped and mud. On bare foam.
I have seen some foam come with a very thin sheet of plastic on it. Could it be that you might have some of this and not removed the flim?
Finally got it!!!!
Using laytex paint before i set the plaster cloth created a better bond than without. Plus the use of re wetting the plaster cloth before applying the hydrocal made it so there were no bubbles. Happy to finally move past this part and continue to the mountain I have to make.
Thank you all for the advice.
Knight94 Finally got it!!!! Using laytex paint before i set the plaster cloth created a better bond than without. Plus the use of re wetting the plaster cloth before applying the hydrocal made it so there were no bubbles. Happy to finally move past this part and continue to the mountain I have to make. Thank you all for the advice.
Knight94 Using laytex paint before i set the plaster cloth created a better bond than without.
rrebell Sorry but would have said something about wetting down the plaster cloth, for me it was a given.
riogrande5761 What do you mean using latex paint before you set the plaster cloth? How can you do that? Or are painting the foam and laying plaster cloth over the painted foam? If so, that seems like an unnecessary step - cause you going to need to coat the plastic cloth at minimum with a thin layer of plaster or something else to hide the plaster cloth and create a surface for scenery. The paint will completely be covered up making it superfluous. Or are you using the paint to bond the foam to the plastic cloth? I would have thought gravity would have been sufficient?
It may be an unnecessary step, but I am planning on this layout being portable. While in theory the plaster cloth sticks fairly well to the foam. I noticed with a little pull it will come up. So I wanted a solution that would make it stick better. The paint for me seems to work. Being this is portable I want to make sure while traveling, moving etc. Vibrations, heat, or cold does not affect the bond.
riogrande5761 Hah. Your answer reminds me of what one of my math professors would have said when I couldn't figure out how to finish a math problem. They just assume I would magically know the missing steps! I did a fair amount of asking and reading up on forums before doing my plaster cloth and EVERYONE made the same assumpsion, which I might add, caused me some grief, until I went back and reported the various problems I was having. SMH. It sure would have been a HUGE help if people would have included this "small" but extremely important step, liberally wet down your plastic cloth or plaster surface before for adding plaster or latex paint, repectively. Future noobs will be sure to thank you, hint hint!
Yes this is exactly true! I run into this alot with other projects and such that I do myself. Granted once I know what the solution is, and I think about it. It seems like common sense. But when first starting a project that I have never done before, I am trying to follow step by step from the videos or articles I have read. And of course, all of them miss that step. I am glad it is here on the forum now for other newbies like me that need to find it.
I don't use plaster cloth over foam. Only on open framework of cardboard strips. I use a soft Sculptamold directly over foam and save a step. I use Sculptamold over the plaster cloth to get a nice lumpy gound texxture and increase the strength of the cloth. Then I use latex paint for the basic scenery color. Staic grass or ground foam can be directly applied to the wet latex paint.
When dealing with plaster cloth on irregular surfaces, I run a bead of full strength white glue along the edge, then work the plaster cloth down into it. Once the glue dries, it stays in place. I use a 1-2" brush for the next steps. I cut my plaster cloth into strips to fit, then overlap the cloth enough so that when it's wet it won't fall through. Then, I brush the cloth with a wet brush, applying enough water so that there are no longer holes visible in the cloth. After the plaster cloth is dry (solid to the touch, I brush a thin coat of plaster of Paris over it. The solid layer of plaster aids in giving the surface some rigidity for attaching rock castings to it, or just paint over it in an earth color. Some people like to add some pigment to their plaster so that if it gets chipped, there's no glaring white spot.
Marlon
See pictures of the Clinton-Golden Valley RR
riogrande5761 Knight94 Using laytex paint before i set the plaster cloth created a better bond than without. What do you mean using latex paint before you set the plaster cloth? How can you do that? Or are painting the foam and laying plaster cloth over the painted foam? If so, that seems like an unnecessary step - cause you going to need to coat the plastic cloth at minimum with a thin layer of plaster or something else to hide the plaster cloth and create a surface for scenery. The paint will completely be covered up making it superfluous. Or are you using the paint to bond the foam to the plastic cloth? I would have thought gravity would have been sufficient? In my case, I used strips of cardboard with hot glue to provide a shape to lay the plaster cloth over, so no paint was needed until I wanted to create a base earth tone (sand color) scenery color on which to layer other things over. rrebell Sorry but would have said something about wetting down the plaster cloth, for me it was a given. Hah. Your answer reminds me of what one of my math professors would have said when I couldn't figure out how to finish a math problem. They just assume I would magically know the missing steps! I did a fair amount of asking and reading up on forums before doing my plaster cloth and EVERYONE made the same assumpsion, which I might add, caused me some grief, until I went back and reported the various problems I was having. SMH. It sure would have been a HUGE help if people would have included this "small" but extremely important step, liberally wet down your plastic cloth or plaster surface before for adding plaster or latex paint, repectively. Future noobs will be sure to thank you, hint hint!
rrebell And don't spare the water, spray it down good.
Yes, now that I've tried to put plaster on plaster cloth or paint plaster without wetting, I have learned, spray it down liberally; it is a necessary step not to be left out or the consequences are not good. I found out the hard way.
And don't worry, it will all dry out within 24 hours, as long as you have a reasonably dry environement.