The Western Maryland in Free-moN Modules

[PiperguyUMD]

@garethashenden - Wow! I don’t have the guts to tackle a skewed bridge! What did you use to attach the GMM bracing? It looks like you where able to use the CV parts for the vertical supports is that the case?

[Scottl]

On my Cisco bridge that I built for my last layout, I used a variety of parts including the GMM and CV cross-braces.  They attached to styrene strips quite well using CA and solvent cement, respectively.  I also used some HO scale ME parts for larger beams but I don't think that you would need them for yours.  The CV parts can be bought as a separate package from the complete bridge kit, which helps make the process a little more economical. 

To stiffen the styrene bridge beams, after advice here from @mark dance, I hid brass square tubing in deck structure and it give the bridge excellent support.  After 7 years, the bridge had no sag or distortion.

[PiperguyUMD]

They attached to styrene strips quite well using CA and solvent cement, respectively.

Which solvent cement did you use?

To stiffen the styrene bridge beams, after advice here from @mark dance, I hid brass square tubing in deck structure and it give the bridge excellent support.

I'd thought about laminating a brass strip to the inside of the styrene channel, but this sounds like a great idea! Would be easy to hide under the track.

[Scottl]

I used styrene solvent cement.  I think Tenax but honestly, anything like it should work.

[garethashenden]

@garethashenden - Wow! I don’t have the guts to tackle a skewed bridge! What did you use to attach the GMM bracing? It looks like you where able to use the CV parts for the vertical supports is that the case?

I think I used superglue

[Ed Kapuscinski]

Wow! Busy week! 25 private students plus rehearsals and performances of the sound track to one of the Harry Potter movies.

The BSO does those movie play alongs, they're really great! I hope yours went well.

[PiperguyUMD]

The BSO does those movie play alongs, they're really great! I hope yours went well.

It did, thanks!

After we destroyed the Sorcerer's Stone twice this weekend, I did some thinking in Sketchup. I think I'm going to try to build the top and bottom stringers from styrene and GMM webbing, and 3d print the vertical bracing. Here's where I'm at:



Looking at the bottom deck, the two center railings will be 1/8" brass tube, the outer beam which are lacking webbing in this shot, will be Styrene channel. All the miscellaneous bracing and patching on the bottom deck will be styrene as well.
 




As I was drawing place holders for the vertical bracing, I figured it might be worth a try to 3d print them. These will slip into place on the 1/8" tubing in a similar fashion to the CV valley kit. I am a little worried about tolerances but more so strength. Hopefully once all of this stuff is glued in place it will be strong enough. I've also be toying with ways to make this bridge removable. It will most likely be the tallest thing on this module, which would make it ripe to get waxed in transport. Every thing in this shot will be 3d printed. I'll make the remaining diagonal braces with styrene channel and GMM webbing.



Looks like I'm on my way!

[PiperguyUMD]

Long overdue update! This summer has been extremely busy! Most of my private students asked to continue lesson through the summer, and even went on to present two recitals! In addition to teaching, I was also invited to participate in conferences in Georgia and Kentucky, and gave two two solo recitals. BUSY!

While I was putting in all these miles, I came up with a way to print kit components for the 4th Canal crossing bridge. I've been running test prints and making fitment adjustments over the last few months. Happy with the last round of prints, I thought I would have a go at assembling my kit. Unfortunately when I had a chance to sit down and work on this thing, I didn't have the energy or time to document it, but it's basically what I outlined in my last post. 3D printed superstructure, GMM webbing, phosphor bronze handrails, and some styrene cross bracing.

The positives are

1. Nice rivet detail that I couldn't get if I used styrene.
2. Ease of construction.
3. Strength. To this point, I'm very surprised at how strong this piece is. Time will tell, but so far so good.

Negatives

1. Warping/Wracking. Some of this is in the larger 3d prints, but some is also the foreman's fault. I had some CA drama at some of the joints. I would clamp the joint and allow the CA to set. Thinking it had set, I would remove the clamp and move on, only to realize later that the joint had popped loose and the CA had set in the new position.
2. This coupled with a design mishap makes the hand railing wavy from certain angles. Its more noticeable in the unpainted glamour shots, but as I eyeball it in the paint booth, a coat of matte black hides a multitude of sins.

Having built one, I know I could do better on a second draft, but this bridge has been the bottleneck on building my next module. I'm anxious to start that process so I may move forward from here. I'm have some ideas for making its installation on the module semi-permanent so that if it's ever damaged, it can be easily replaced.

[Cajonpassfan]

Wow, that's coming out looking really good!
Nice job!
Otto

[wm3798]

I'll need to open the negotiations to acquire a copy of that.  It's not too far from my house, as you know...

Lee

[chessie system fan]

Looks fabulous! You have me thinking about B&O bridges now.  Studying yours, I wonder if for version 2.0 the GMM latices are worth it.  Maybe it's just the photos, but I can't tell a difference between the etched GMM pieces and the 3D latices at the top. If you 3D printed everything, the outside of the latices could be even thinner and more to scale, while the inside could be .5mm thick.  I bet you'd never notice the thickness, especially if it was painted black.  Plus, it would be less assembly work later. 

How long is the bridge?  I also wonder if it's possible to print it as one piece.  Fewer sub assemblies could help with the warping.  But this assumes the whole bridge would fit on a build plate.

[PiperguyUMD]

@wm3798 Absolutely! It’s the least I can do for the roundhouse! I’ll make a few more tweaks and I’ll get something headed your way.

@chessie system fan Thanks! The bridge is a scale 130ish’. I could print it in one piece only at +40 degree angle. The trick is getting supports where you need it. Some things printed beautifully, others not so much. But by the time you cut
Out all the supports it didn’t look so hot. I tried twice and moved on lol.

I thought about printing the webbing, but since I already had the etched parts I rolled with it. Adding the webbing to the prints as you mentioned would most likely work great!

[chessie system fan]

Supports would certainly take some planning and probably custom design.  I just did a quick test on my Photon M3 Premium software, and a bridge 135 ft long fits at 23 degrees (assuming 5mm height from the base).  I don't remember which machine you have. 

Another thought.  How are you curing it?   I got lots of warped prints when I just used sunlight.  When I started using the Photon wash and cure machine, all the warping went away.  I think the constant rotation and even UV coverage made the difference. 

[CNR5529]

I second @chessie system fan's observations regarding sunlight vs wash and cure machine curing. That was a total game changer for me.

[Lemosteam]

As for the gluing, please, just try it once. Either buy some resin glue, or you’re a small cap full of resin and buy/find/make a UV light pen or just buy some UV glue. I just don’t trust CA anymore, for the same reason you mention, and the 10 second curing lets me move on to other assembly processes without fear, as I progress through a build.