Thanks for all the further ideas and comments guys. I sure appreciate being able to chat with you about the pro’s and con’s of materials and techniques. Even though it takes time, at least I’ll know that I did my homework and received solid advice. So thanks for your patience.
Cliff Jennings said:
I’m toying with the thought of bagging all this, and 3D-printing the whole dang trestle. Would require maybe 20 or 30 sections, who knows, printed from a common parting plane of indeterminate location, upwards and downwards from that or those. Maybe bents can be printed vertically (as they stand), but would look much better built flat. So, another 40 sections. And probably with all the stringers as add-on bits of styrene or something.
Why not cut them out on the laser as planks and use brass screws to hold the pieces together. I know that acrylic may yellow and turn brittle, but the laser can also cut corian, which is far more durable and can be worked like wood. You can drill it without special regards and it has color/pattern all through so wouldn’t even need paint if you found a suitable color.
Hi Todd, good to see you!
The main members are 3/8", and they’re all over the place. I actually looked at Corian earlier (and Formica, and phenolic, Starboard, many others), and thought that Corian was only available in thin sheets. So you made me look, and I see it’s available in up to 1/2" sheets. But I don’t see it in any “wood grain” pattern, in 3/8". And it’s very expensive. I’m sure willing to do some experiments with you though, for generic building purposes, if we can find affordable stock.
For this project, I think I’m hitting pay dirt with a hybrid of laser-cut cedar, stick cedar, and laser-cut acrylic. More on that later.
Thanks again Todd,
===>Cliffy
Just a note …acrylic is UV treated and is fine if it stands upright however it does not like to lay flat and will warp.
Your digging into all the materials Cliff and once again I’m digging this thread and YOUR findings …keep digging!
The mine structure is still on hold until Saturday, so the following is in regards to its waste trestle design.
This has always been the biggest “how the heck am I going to do that?” part of the mine project. But since it’s a huge part of the mine’s appearance, and since the other mine structures I hope to build also have these waste tramways, I decided to bite the bullet and focus on this aspect during my limited weekday design opportunities.
As of yesterday, the materials have finally been settled upon: NWP agrees to supply 3/8 x 2" x 24" cedar sheet; and I now understand acrylic to be the best plastic for both laser & outdoor uses. Starting yesterday, I’ve been able to fully proceed on this trestle design.
I’ve covered the bents already, but will mention that they will utilize all-cedar stock. The main 3/8" thick parts will be cut from lasered patterns, but the thinner pieces will probably be manually cut. Something I’m not good at, but we’ll see.
The most challenging & perplexing thing to replicate in this odd prototype has always been the trestle’s superstructure. But after much emailing and phone calls to vendors, and conversation here, I’m reasonably confident in a approach that I can use to build the components, replace damaged parts as needed, and apply to other designs.
There will be an acrylic core to provide registration of all the cedar superstructure parts above and the cedar bents below.
The core and handrails will be acrylic, but all else cedar.
The cedar will be a combination of:
- Laser-cut from sheet
- Laser-cut from stick
- Manually cut from stick
The cedar on the superstructure will be bonded to its acrylic core. And if someone wants to argue about differential expansion, I’ll say that a) I will use silicone, and b) challenge them to a literal physical test on any better approach.
Here’s an example of why I require this project to continue in the direction of laser cutting. These pieces have complicated notching which, for me at least, would be almost impossible to cut by hand. Why all those notches though? So that the parts are self-indexing, thereby speeding assembly.
The acrylic core is two layers. Some of the cedar parts index into it from above, but not all. The bents, however, index into the lower layer from below.
The two bridges will be stick-built add-on’s, basically 4 frames added to the trestle and resting on certain bents having elongated top sills.
More design to do on the railings and some joint details. Much more effort will be spent in translating this model into either drawings (to manually make the parts from) or patterns (to laser the parts from).
Thanks Rooster and others who may enjoy seeing the steps involved with this. It ain’t easy or pretty, but I wanted to document the story.
===>Cliffy
Cliffy,
If you don’t have one already, get yourself a 23ga Pinner to help you put that trestle together. Trust me, it will make your construction go A LOT easier. Also, get yourself a lot of sandpaper.
Be cool to see your trestles when done.
Chris
" Rooster " said:
Just a note …acrylic is UV treated and is fine if it stands upright however it does not like to lay flat and will warp.
Your digging into all the materials Cliff and once again I’m digging this thread and YOUR findings …keep digging!
Point taken Rooster, and thanks!
dupe post
Chris Kieffer said:
Cliffy,
If you don’t have one already, get yourself a 23ga Pinner to help you put that trestle together. Trust me, it will make your construction go A LOT easier. Also, get yourself a lot of sandpaper.
Be cool to see your trestles when done.
Chris
Hey Chris, yeah Dennis mentioned the Grex pinner, and that they even have self-gluing brads. Now that I’m going almost all cedar, I agree, I need something like that.
[edit] And thanks for your anticipation, and hope it turns out ok, and am finally thinking it will. BTW, you got me remembering that I’d gotten a pin nailer from Harbor Freight, but never used it and hadn’t seen it for years. So I tracked it down in the garage, but, it’s 18ga… bummer. I need 21 or 23, down to 3/8" length I think. Can’t do an expensive one, but you’re right, need something.
There are patterns of corian that would work, such as sorrel. But you are correct that it is expensive unless you find where someone is removing a counter top.
BUT!!! Have you looked into “laminate flooring?”
It comes in 12 mm and 7 mm thicknesses, so is pretty close to scale, a “yuge” assortment of wood colors, and the prices can be very competitive, especially for “removed” product. In those cases, could even be free if you are lucky!
Rick Marty said:
Cliff,
That bridge was sprayed with cheap auto primer and “Hammered Silver” and has lasted just fine.
If ABS has no RV resistance there are going to be a lot of disillusioned building department officials not to mention plumbing contractors around the country. There have been ABS plumbing vent pipes sticking out of building roofs for at least 30 years and you hardly ever hear about one of them falling apart and rolling off the roof.(http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-foot-in-mouth.gif)
Keep thinking on it
Rick
Rick, sorry for the delay, but wanted to comment. From what I gather, ABS (and other plastics) can have a UV inhibitor added to their formula, but it’s not always done, and its natural state isn’t UV tolerant. Unlike acrylic, which seems to be more UV resistant, either because of its chemistry or because they always put in the inhibitor, say, to make it useful for windows (that’s just a guess though).
I read somewhere that black pigment in plastic is, in itself, a protection against UV. If so, maybe that’s why DWV pipe (like you mentioned) is generally black. Again, just guessing.
Thanks,
Cliff
I’m up for experimenting with it Todd, especially since you can get the stuff in tiles, right? Might be good for siding, platforms, who knows?
For this waste trestle, the cedar’s been calling out to me, and I’m even bagging the acrylic handrails in favor of it. It’s been a matter of joint design, in view of which plane the laser is cutting from and what stock to cut from. So the bridge design is also looking better, and I’ll put in some tie rods to dress it up.
I’m very happy that a design solution is emerging. So thanks Rooster, Korm, Chris and others for pushing me to find how wood might work, and everyone for helping me think through all the plastic options.
===>Cliffy
Yesterday my good friend Jerry B. came over, bringing our good friend Dwight J. along, and we had a great time talking RR stuff, and going over the laser details. Thanks Jerry and Dwight!
Today I finished the sheathing, including the lighter material on the ore bin.
Also got the doors and windows painted.
Next will be corner trim, which involves literal trimming of the sheathing at the corners, spot-gluing if something isn’t fully adhered to the core, lasering the “trim boards” from an ivory-colored acrylic sheet, and cutting & gluing those into place.
The “ivory” acrylic sheet I bought doesn’t match the paint on the windows, but it was the closest match I could come up with. I hate to paint pre-colored acrylic (kinda obviates the point), but I’m considering using stock white styrene instead and painting that. Or, just live with the color difference.
Anyway, it’s been a really fun day wailing away at the sheathing again, but I’m happy that step is done.
Thanks for viewing,
===>Cliffy
Very nice!
Thanks Todd!
Hey Cliff
It was great fun visiting your shop the other day. You have developed a very impressive capabilities, with the new laser and the 3-D printer and that oh so organized work area, you are an inspiration! The mine building is just stunning, with the structure, sheathing, details, windows and doors, a master piece in the making. I look forward to a fall visit with the H&N in place on the layout, I will bring my live steam Forney for a run then
Jerry
Thanks for the thanks Rooster, I’m pleased that you’re enjoying this, means a lot.
Hey Jerry, that’s way generous of you, thank you. And yeah, that’s a good goal: finish this thing by the time you get back from your big trip. I have quite a long way to go on this project, but I’ll try. And thanks for coming over, it was great fun.
===>Cliffy
I experimented just now with lasering some 3/8" x 3/8" cedar (from NW Precision) that I had on hand, and learned quite a bit.
I don’t want that burnt look on the long edges of main beams, and that’s what I’d get if I cut everything from wider panels. (Yes, I’m slow). So the idea here was to set things up to cut mainly the ends and notches in a single 3/8" thick “timber”. Sort of like a mini sawmill, starting with pre-cut stock. So after more calibrating & jigging & test cutting, I tried a string of parts from one stick.
The charring was worse than I expected. That’s probably due to how slow I had to run (to cut all the way through) and maybe how soft the wood is. But it’s not too bad, and doesn’t go very deep. Good enough for this project I think.
===>Cliffy
Steve Featherkile said:
" Rooster " said:
Cliff Jennings said:
Thanks for sharing this build with me guys,
===>Cliffy
No… Thank You !
Suck up. (http://www.largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-laughing.gif)
Whiskey Tango Foxtrot, over.
Today the corner trim, windows and doors went on.
The corner trim involved final trimming and a little scraping of the sheathing, bonding on some painted styrene angle and, a little later, trimming it at the top.
Doors and windows just needed gluing down. A few of the double doors were warped, so needed weighting down some. Other than that, this step all went surprisingly smoothly, and was a heck of a lot of fun.
Randy, I wanted to put a light in it and take some pics, but ran out of time. Soon though!
===>Cliffy