I have decided to take on a project to scratch build a firehouse for my club’s holiday train display (WVMGRS at Brookside Gardens). (My first scratchbuild, btw)

I would like to build a core structure, and then cover the core with a brick texture. Using this handy ppt: (https://piedmontgardenrailway.org/wp-content/uploads/2017/01/BUILDING-OUTDOOR-STRUCTURES.pdf),

I decided that Coroplast or Sintra would be the best material(s) to use for the core, as they are easy to work with.

So my questions are:

• What are the advantages and disadvantages of each?

• Does one have advantages over the other?

• What do people prefer, and why?

Joe,

Sounds like a fun project! While I have just used generic PVC, I’m not sure it makes a lot of difference as none of them rot, plus they will be covered up anyway. I can recommend a good exterior paint for the brick. I’ve had very good luck with the custom samples you can get at Home Depot. (Don’t do Lowes as their samples are INTERIOR based). When I built my firehouse I just used some PVC sheets I bought online. Best of luck - I’m sure you will enjoy this!

I work in the sign industry and use these products daily.

COROPLAST (corrugated plastic sheet).

Sign industry uses both 4mm and 10mm thick sheets. 4mm is very easy to cut using a utility knife. If you are going to be cutting a lot, a Coro Cutter that has guides for the flutes makes it go fast. For 10MM cuts we generally use a panel saw as it is pretty rigid. For structure substrate, the 4mm makes for fast construction using simple tools. End result is very light and may require added weight. Gluing can be tricky. I prefer a good quality double faced tape (3M VHB if you can afford it) over glue for Coroplast

Lots of folks use it - search the forums. I think Ken Brunt has posted threads on methods.

FOAMED PVC SHEET (Sintra, Azek & Komatex are just a few brand names)

Available in many thicknesses. Sign industry uses 3mm, 6mm, 12mm, 19mm and 25mm (Roughly 1/8", 1/4", 1/2", 3/4" and 1") for various applications. For structures 19mm makes a very robust substrate. Cutting anything thicker than 6mm requires a saw. Cuts and drills with wood tools. Ken’s recent Mancos Depot thread shows his methods. All but the thinnest can take nails or screws. If you use screws, don’t over torque as the threads will rip out. Lowes sells an Azek glue. Works great but it’s pricey. A generic PVC Pipe cement costs a lot less and will work.

For outdoor use, I think I’d probably suggest the foamed PVC board in 6mm or thicker as the superior product, It does cost more . If you have a local sign shop, you can beg for scraps.

Ah, I stand corrected! It turns out I HAVE used coroplast, I just didn’t realize it. But, I wasn’t fond of it, as it required me to make the dimensions correspond to the "flutes’. So there’s basically a grain and if you need to make a cut diagonally or on a curve, it’s going to be a lot more difficult than using PVC - which, I don’t think really has a grain at all. Easy to work with to get the dimensions you really want - not dictated by the material. Jon has the right knowledge for this!

SINTRA…Much easier to work with and glue up. You can even carve and texture the outside to look like brick, or random stone, or cut stone. It is what I have used to make the master stones for the Mik’s build challenge cut stones.

Do a search for Ray Dunakin, and learn of the remarkable things he has done using it… Truly a master of the medium.

Dave

I got some large free Sintra scraps from a sign printer here, but I had a heck of a time carving it. If you or Ray would fill me in on the best way to carve it, I’d appreciate it.

Watching this thread hoping I may learn something.

I’ll wait for Jon R. to reply and clear this up for my mistakes…

But … There is variations of the stuff I (we) call Sintra, Azek & Komatex are just a few brand names. And I would be only guessing the difference in charistics between the brands.

All of what I call “Sentra” is of a uniform white composition all the way thru, and rather smooth on the surfaces . Fairly soft to cut and carve. I have also had some “Stuff” of the same like, that had a rather hard outer shell and fairly soft foamy inside that was used for signage.

Jon R, having worked in the industry would know better, and I hope that he chimes in and gives a better description of each product and such.

Ding Dong… Calling Jon R…

There are differing formulas to be sure. We get ours from 3 different suppliers. One brand, PA-Light is a very loose (larger bubbles) foam and has a somewhat pebble surface. Another brand, Komatex, is much denser foam and heavier. The surface skin is a very high gloss and the 48" tall sheets are actually over 49" with a formed semi bull nose edge. The third supplier we rarely buy from (higher price) shares characteristics of the other two; more dense like Komatex, but cut edges like PA-Light.

At the local Lowes they sell Azek. I’ve not used enough of it to recall it’s characteristics. I think they also sell Royal which has a slightly different surface texture. I’m sure there are even more brands with varying characteristics.

For use as a substrate for making vinyl signs the brand doesn’t matter. But for CNC cut letters and decorative details like post skirts, we prefer the glossy finish of the Komatex. For modeling, as a substrate, I would think the less shiny surfaces would take glue better. And if you are going to carve; you want the light stuff with larger bubbles. It bends easier, but cuts easier too.

I have only used coroplast for buildings. And for larger structures it needs some kind of internal bracing., It can bow or bend over time. I did use Axec square extrusions to make my bridge, and it is definitely more ridged, and glues up easier, but I cant say how sheets of it would work out since I haven’t used any of them.