Elastomeric coatings are a popular product in Scenic shops for coating styrofoam as well as other surfaces to create textures and durable coatings. Jaxsan is a popular product but for me in Alberta, Canada, it is sometimes hard to get in the winter, and shipping in a heated truck from Toronto or the eastern US gets very costly very quickly. So I’ve turned to a few other products that are closer to me and some of them are freeze/thaw stable, which will reduce the shipping costs in the winter.

The company that I buy from is Robson’s Thermal out of White Rock, British Columbia. They specialize in industrial coatings. They’re also open to creating new formulations depending on what you need. They’re pretty cool.

“Since 1992 Robson Thermal has developed over 300 specialty coatings, adhesives, sealants, and composites that apply to many industries including airports, marine, industrial plants, film and stage, water parks, hospitals, schools, office buildings, and commercial buildings.”

I use 4 different products from them. Some of them are listed on their website, some are not. So hopefully this information helps to give you some additional choices. I’ll start with the elastomeric coatings from thinnest to thickest, then move on to Robson’s Foam, which is an amazing product in a category all by itself.

RT-38

This product is a liquid elastomeric. I find it thicker than elastomeric paints that are available through Benjamin Moore (Super Spec) or Cloverdale (Towerthon). It is NOT freeze/thaw stable. It’s water-resistant, UV resistant, impact-resistant, stays flexible, and elastic at low temperatures. This is a good product to apply straight to styrofoam to do a light coating so that it will be easily paintable. It can be thinned, and of course, you can add whatever compounds to it to make a thin texture and it will take tinting. Of course, you can apply it to thin muslin or cheesecloth to make the surface more durable. Highly versatile. It is not sandable. I use this mainly to prepare a styrofoam surface for painting if I don’t need an overly durable coating.

RT-10

 

This is like a smoother version of Jaxsan. I have used it to coat raw wood, I’ve troweled it on a stenciled surface to create a texture that was then gold foiled. Use it directly on styrofoam to create protective skin, or add texture to this and apply that to your surface. This is freeze/thaw stable. If the contents do get frozen, let them fully thaw in the pail, then mix it up and use it. I have not experienced this product personally when it was frozen and then thawed, but I feel they can’t make that kind of claim unless it is in fact true. I have found that this product does tend to come a little thick, and it does thin easily with water and a drill mixer.

RT-29

Upon first glance, this product initially looks the most like Jaxsan, but there’s a couple of differences. It’s grey, and there are little fibres in it that make the surface more resilient when it’s dry. I have found that the amount of fibres does occasionally differ, depending on the batch, but I don’t really find them obstructive. I have mixed RT-29 with different-sized bits of cork to create texture – I did have to thin it quite a bit and it was still really resilient. I have mixed it with sand and sawdust to create a brick texture and the results were excellent and very durable. I have troweled it onto plywood flooring to create a thin skin so that we didn’t have to apply a hardboard surface onto the plywood. Doing this, the fibres did get a little in the way, so going forward I would likely do this with the  RT-10 instead. This product is also freeze/thaw stable.

Robson Foam

This is the neatest stuff. It’s super lightweight. It paints or trowels on easily. It is lightly sandable. It fills in holes in styrofoam. When you’re carving that bas-relief out of styrofoam and you cut in a little too deep. This is your product. It sticks effortlessly to styrofoam and you can cut it and sand it when it’s dry. It can withstand a small amount of flex afterward.

Our Props department has thinned this product down (doesn’t take much water) and made it more liquid to pour over top of a styrofoam cake to mimic Royal Icing, and it’s very durable.

This product will dry out over time, and looking at mine, there are a few clumps in it and therefore it’s been sitting for a while, unused (What?? There’s a pandemic and we can’t build any shows??). My solution to this is to add a few drops of water, maybe a tsp to a tbsp, and mix it up with a spatula or wooden paint mixer to fluff it up again. It really doesn’t need much water at all. This product is NOT freeze/thaw stable.


Now is the time to show you some photos of applications where I used these products.

RT-10:

Here’s our process using it on a stencil to create a raised texture. We created the stencil image digitally and then cut it out of vinyl using a die-cut machine (Silhouette). Plucked out the part of the image that we wanted to be featured, and then troweled on the RT-10. After it was troweled, we ran a texture roller through it and then removed the stencil when the product was still wet. We found this created the sharpest edges. We tried to keep the thickness relatively consistent around 3-4mm thick.

This is the surface after the RT-10 is done and the stencil is peeled off.

The whole thing ended up with a gold paint treatment, then we added an adhesive sizing to the texture and applied gold leaf to the textured areas, then finished with a light breakdown.

“Christmas Carol” Citadel Theatre Designed by Cory Sincennes

This last summer, a show that I was working on used a real tree fence, so I encapsulated the whole branch in RT-10 to make it durable, FR, and easily paintable. I thinned the RT-10 slightly so that it could paint on easily with a chip brush. This ended up being super effective.

RT-29

This is the product that I’ve used the most so far. One word of advice is that when you rinse your tools, etc. into your sink, make sure you have a screen on it made from window netting or the like. Because this material does have little fibres in it, I don’t want that to go down my drain, so the netting catches the bulk of it, then you can dispose of it into your garbage.

These are bricks that I created from scratch using a mixture of RT-29, sifted sawdust (sift your shop sawdust through a metal mesh strainer), and play sand. The whole area was measured and taped off using 3/8” masking tape, then the product was applied with a large trowel. To create texture, I used the trowel to punch into the material and lift it unevenly, followed by one smoothing pass to calm down any immense peaks. Like the RT-10, we then lifted the tape before the product was fully set. This was applied to lauan and then painted. Because the bricks didn’t have a huge amount of depth, we base coated with the mortar color, then reapplied another round of tape to mask the mortar, then we could paint the brick color very freely. No doubt the process was fussy but very effective

In the second photo, you see that we are applying the RT-29 with cork (1-3mm and 6-10mm cork were used) directly onto pink insulation foam which was carved. I made 2 batches with separate thicknesses of cork, then applied it with a chip brush. As you can see, we painted some plain RT-29 over the area and then added the textured ones afterward. Because the cork would absorb water, we found that thinning the RT-29 was important.

Once dry, we could paint as we saw fit. It received one base coat and 4 glazes.

 

For this show, our carpenters created a tree and some limbs out of pencil rod, ethafoam, and then bound it with Coban. We needed the Coban to be FR and then paintable, so we thinned the RT-29 slightly, then scooped it up with our hands and smeared it all over the tree. It made a very flexible and durable coating that was easily paintable.

“The Color Purple”, Citadel Theatre Designer: Brian Perchaluk.

And I’ve used it to create a flooring surface. You may need to thin it slightly and then apply with a notched trowel, I’m fairly certain we used a 3/8” notch. You don’t want it very thick. We applied this to 1” Good One Side plywood on a touring show because of the weight and space in the truck. Apply with a notched trowel, then a long, flat trowel to flatten. End result is that you want about a 2mm thick, even coating. Depending on your workspace (Alberta is VERY dry) you have to work quickly and clean your tools often. Luckily in theatre, you can usually work with inconsistencies in the material and it works into your effect. This stage floor was coated sheet by sheet, then assembled and painted.

“Peter Pan Goes Wrong” Citadel Theatre with Mischief Theatre (UK), designed by Simon Scullion.

RT-38

Admittedly, this is the product that I’ve worked with the least, but as I’ve mentioned earlier, it is very similar to both Cloverdale and Benjamin Moore elastomeric only slightly thicker. I have used it to do a light coating on styrofoam that doesn’t need a thick layer of protection.

This production, by Alberta Opera (now Alberta Musical Theatre Company), does touring shows to schools across the province. The houses in this set were made from pink insulation styrofoam and coated with a few coats of RT-38. To add durability, you could scrim with a thin muslin or cheesecloth.

Robson Foam

This stuff is really neat. It is light as air and I use it primarily to fill “oops” gaps when carving styrofoam. Apply with a trowel and let it dry and then it can be cut, sanded lightly. It wouldn’t hold well enough to attempt to do any intense carving of it afterward as you may do with Plaster of Paris, but this product will take a few cuts.

As an example for how you would use Robson Foam – let’s pretend that in this photo, our Friendly Neighbourhood Scenic Carpenter had an “oops” and took a chunk out of one of these styrofoam squares after he painstakingly arranged them and affixed them. I would use some masking tape to create a dam or wall and then trowel in some Robson Foam to fill in the chunk that was missing. Leave it for the day to make sure it’s set up (it doesn’t take that long, but sometimes in life, you have bigger “oopsies”). Then peel away and trim down as needed and then proceed as normal.

Our Properties department recently made some fake desserts where the Robson Foam was used as icing. I believe they may have also used it to make “mashed potatoes”.

  

 

 

 

 

 

 

 

 

 

 


Check out these other great articles written by Nicole Deibert!

Inlay Wood Floor – without the sawdust!

Painting Metallic Finishes


Nicole Deibert is the Head Scenic Artist for the Citadel Theatre in Edmonton, Alberta, Canada. Nicole has been painting for roughly 20 years, is member of IATSE Local 210, and has spent most of her professional career at the Citadel, with a short stint at the Shaw Festival in Niagara on the Lake, Ontario. Her other interests lie in photography and cooking. Instagram: @nixpaints

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2 Comments
  1. Sarathescenic 1 month ago

    love all the new products. One reason why I like jaxsan is because it has no ecotoxicity (won’t harm aquatic life) or carcinogens. Do you know the stats on any of these products?

    • Author
      Nicole Deibert 1 month ago

      That’s a great question. Looking at the MSDS for RT-38, it has no carcinogens but says to prevent going into open water. RT-29 does have some potential health impacts to fertility, but no carcinogens, and prevent going into open water. RT-10 has no carcinogens and also says to not allow into open water.

      I have definitely found that when it comes to any paints, Rosco or otherwise, there is typically a symbol on the can that says that the paint does have compounds that have been found to be carcinogenic. I’m seeing more and more on polyurethane finishes that they can affect fertility or damage to the unborn child.

      I have just reviewed the MSDS for Jaxsan, and while it doesn’t seem to be overly informative, it does claim that there are no ingredients in it that are currently known to be carcinogens, and it has “low toxicity contaminant to bodies of water with which it has contact”.

      Ultimately, it is up to you to choose which products you wish to use and for what reason. We have a stringent protocol with dumping excess paint products that get processed by a specific company and disposed of properly. Any product you choose will have MSDS and technical sheets available so that you can make informed decisions as to the product you wish to use, and with the standard finally being updated, reading the MSDS sheet finally makes sense and can be properly interpreted.

      Thanks for the great question!

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