The trouble with Trex is that it's a wet noodle. It needs much more frequent support than wood. That means it is not a unit replacement for wood. You would need to reengineer the support system to provide support at least twice as often. Nice as it would be for roof walk or deck boards, you'd need to add a bunch of supports and now you're deviating a fair bit from historic.

We tried 6/4 Trex to replace 2x6s on picnic tables, after just a few years they were so warped they looked like an impressionist art installation. It worked better when they were reinforced with aluminum or steel beams but that amounted to re-engineering the picnic tables.

It's a shame, there's an open-air gondola car that would work really well with it, but the seating would have to be rebuilt to provide the additional support.

The stuff that I used to redo my own deck was definitely 'soft', has held up well into year 4, but needed the additional support I put under it. Other than pressure washing, no maintenance at all. I also used some of the white PVC boards to construct a set of steps in direct ground contact that NEVER held paint and it's just amazing how it's held up.

But the stuff I'm seeing now - which is supposedly 'Trex' - the local Amish craftsmen are using like there's no tomorrow. Outside furniture, small buildings, custom work. It's pre-colored and much more rigid that the plastic material I used on my deck. It's weird to see a classic Adirondack chair made out of the stuff, but it impressed me. My father the lumberman would be appalled.

I also think one of the 'catches' is that it probably won't hold conventional paint, although I did read Jason's post. Maybe if it has a plastic adhesion function like the "Fusion" spray paints. I'd be more interested in hearing how people are painting it.

Well, I see I had most the posts in the original discussion, so let me update. The ten year old Trex deck boards I spoke so highly of are still there, now approaching twenty years in the weather, and don't look any different. In the intervening years I've had to replace red cedar fascia boards that are directly below the Trex because they rotted away, but the Trex remains unaffected.

In reference to a glue to be used with the composite materials, has anyone tried Leech's
F-26? I have yet to find a material that can not be used with F-26.

The only problem I have with most composites is that there is only one product I have found that has T&G material in floor boards (flooring - not decking) with the size of a 1x4 floor wood. That is AERATIS. (www.aeratis.com).

AERATIS does have dimension size material (S4S) from 3 1/8" to 5 1/5" plus a limited selection of trim and also beaded ceiling in 4 basic colors. According to the literature, AERATIS may be painted or stained.

I have not yet used this material but am planning on a porch replacement this summer. Any one else's experience with it will be appreciated.

The other problem with those picnic tables is that the ends of the Trex boards are unsupported and several broke off at the joints where they connected to the legs.

After about 15 years or so, we have learned the hard way concerning where and where not to use PVC. One of our early attempts was our Parlor car Marian’s letterboard. During the first winter after application, it broke (vertically) in three places. Lesson #1; PVC expands and shrinks a lot more than we thought. It turned out the material expands and contracts roughly 2 ½ to 3 inches over a 60-foot span! (hot weather vs. cold weather) Lesson #2; PVC doesn’t like to be “captured”. We tried using it for lattice at the window openings where it went against the sill and the letterboard. As soon as the weather got hot, it buckled and pulled through the finish nails. Lesson #3; there must be a moisture barrier between the PVC and the wood structure it is attached to. We started to notice moisture coming from behind tongue and groove siding. It turned out that condensation was forming because of the different temperatures and humidity levels between the inside and outside of the car. (plastic doesn’t breathe) In other words, the car will eventually rot from the inside out instead of the outside in!
We have been using plastic with good results in areas that can accommodate its tendencies. Examples are as follows;
Siding, if the bottom portion is not restrained and is allowed to move.
Roof molding, but it can only be used on the end of the car where there is an arc. It can also be used where the main and clerestory roofs come together. (another arc)
Screen boards, if an “expansion joint” is used between the panels. We use cooper flashing over the joints.
We have been using Trex on our car platforms with good success for many years.
While not plastic, we have been using Boral (http://www.boralamerica.com/TruExterior) for letterboards, lattice, and siding with good success. Like plastic and Trex, it has little strength, but it doesn’t expand or contract and is impervious to moisture. The cool thing about it is that is a major part of its make-up is fly ash. We are a steam railroad after all! The down side to that is it is tough on cutters because of abrasion.
We are always looking for better methods and materials, so we will continue to experiment with both. I have joked with a couple of the guys that we may soon need to change our proclamation of having 18 wooden cars to “mostly wooden cars”.

Rick

Gee Rick, your post and use of plastic really flies in the face of our policy of "mastery of archaic methodology". Next we will be using a laser to level the cars in the shop (oh, wait).

Another issue I've not seen addressed yet: durability in ultraviolet light, i.e. blazing sunshine.

Out here in the Southwest desert, durability to high-UV sunshine is a factor in building materials. I'm not the expert--my one brother-in-law is--but as I understand it, there are some "plastic woods" you simply do not use in full sunshine because they degrade even more rapidly than powder-dry wood.

Another issue is operational restoration versus static display. I would have no qualms slapping proper "plastic wood" on a static display, but plastic either doesn't flex and give the way natural wood does, or does way too much, as noted by the honorable Mr. Musser above--ironic when we note that it needs more lateral support!

I recall reading somewhere that the Colebrookdale railroad here in Boyertown, PA used "plastics" when doing the fancy-schmancy interiors like shown here in this car:



Whatever they used, it looks awesome!

I wonder how it would cut in a CNC water knife, which would remove the abrasion issue.. A water knife isn't something I would recommend to every shop but Strasburg would get good use out of it, I would think!!

expensive to maintain, and for what new ones cost you need to be constantly making money with it in order to justify the expense. Cleaning out the tank on a waterjet is an experience not for the faint of heart and takes a good work day of at least 2 people.