Sutro Tunnel Model

[Cliff_Jennings]

Bruce, for this model, mine will be like something between tall tree stumps and grains of rice I think, so yes, very un-super in the details!

A couple years ago I made human a figure for a model for work, close to this scale. I’d bought the “surfer” figure, and it was detailed down to the dude’s grin. But I learned that human legs, at 1:300 scale, don’t resist very much force. Especially when certain office staff can’t resist touching… I was asked to replace the tiny thing, which I did last November, after it laying on the (painted) water for a year…

But at least model this will have a cover.

[Cliff_Jennings]

I’ve been working today on structural model approaches. I want the rooves and windows to be nice and distinct, but without careful hand painting.

So on a test building I tried separate parts for all that. Doors and windows had a little trapezoid to plug into cavities in the walls. Here’s a sample window CAD model:

The separate roof went well, but my printer gave up on individual doors and windows. Way too tiny for my cheaper printer.

Changed horses, and worked up a bunch of windows and doors to be laser-printed onto “durable” label stock. These are off-white windows with gray glazing.

Here’s the 1st test building (well, 4th but don’t tell anyone).

Hopefully the final ones will have smoother walls, maybe rougher rooves, and a stack or two. But this test gives me reasonable confidence in the general approach.

As a last resort, there’s always Shapeways for better details… Yes, I’m trying to use my own tools, but in the end the product matters more. We’ll see.

Cheers,
Cliff

[Bruce_Chandler]

Cliff, you continue to amaze! Nice work!

[Cliff_Jennings]

Thanks very much Bruce, means a lot coming from you!

[Cliff_Jennings]

The computer modeling of the buildings is now done, so I’m very relieved!

Through the week I hope to do the check prints, debugging, and final prints.

Cheers,
Cliff

[Bruce_Chandler]

That is such a neat idea!

BTW, for those of you that have NEVER done any 3D printing - it sure looks easy, but there’s no feeling like coming down to check on your print after it’s been going for 20 hours - and all you find is a tangle of “string” where you expected a really cool object!

Cliff sure makes it look easy, but I can only imagine how many design & drawing hours went into those buildings! (Not to mention how many hours it takes to master the “stupid” drawing program! )

[Cliff_Jennings]

HahaHAA! Thanks very much Bruce! About the printing, yep, you said it brutha!!

And yeah, I admit I’m spending a crazy amount of time on this… Like I’ve opined before: it’s amazing what you can accomplish, once your priorities are sufficiently screwed up.

[Eric_Mueller]

Bruce,

Thanks for that reminder! I have been watching Cliff and others work magic with these machines, and the more I watch, the more I learn that this method of model building is as much an aspiration for me as making straight cut with a saw! There are many ways to be a master modeler, and 3D printing is certainly a path to that title!

Eric

[Cliff_Jennings]

I’ve been resin printing the building bits, with the usual amounts of mistakes and reprints, and am happy with the progress. I began yesterday afternoon with all the tall parts, because height determines the build time, so those need to print separately from short stuff. This is a 7-hour build, just out of the vat.

If you’re not familiar with resin printing, I’ll point out the major steps.

The model is printed upside-down on the “build plate.” Layer by tiny layer, UV light cures the resin that’s right against the bottom screen. It’s basically a dot-matrix video screen, with tiny pixels of UV light that selectively cure the resin right against it. After that, the build plate moves up, and the process repeats.

Here’s the same parts after some drip-drying.

Then comes washing in an alcohol bath…

And, after drying, final UV-light curing. You don’t have to have this “wash & cure” station, but it’s helped me a lot.

I’m now checking for parts fitting together, parts I forgot to print, and parts that could use a little model tweaking for a better print.

Cliff

[Bruce_Chandler]

Only 7 hours? (Makes my 45 hour printing seem “quick” - especially when I ran out of filament after about 15 hours and had to start over! - And, now that I think about it…it’s probably time to order another spool of PLA!)

[Devon_Sinsley]

@Eric_Mueller

Thanks for that reminder! I have been watching Cliff and others work magic with these machines

Just a reminder/clarification. The method Cliff is using is a quite different technology than that which Bruce is describing. Both are 3D printing but by a very much different process. The tangled mess of string Bruce refers to is from FDM or filament printing. The machine lays down pass after pass of filament thread melting each new layer to the previous one. What Cliff is doing is SLA or resin printing. The process uses liquid UV curing resin. Each layer is created by focusing UV light in a very narrow field to cure very small amounts of resin in a vat or tray. Each layer is placed actually under the previous one as the build plate moves up and out of the vat, curing the next layer of resin to the previous one.

In SLA while the misprints don’t end up as a tangled mess of string, prints can and do fail often and you end up with a blob on your build plate (or nothing on your build plate) and a blob of cured resin in your vat.

Each have there merits and their pitfalls. Resin is hands down the winner for fine detail but parts are fragile and brittle. FDM is way more cost effective for large projects and many of the filaments that can be used are very very strong. Like everything they are “fixing” the issues of each and FDM printers are getting much higher detail and they are creating many resins that are harder and more durable. Many people who venture down this rabbit hole end up wanting both types. Build the basic structures in FDM and the detail bits in resin.

[Bruce_Chandler]

Yeah, if you’re thinking of getting into 3D printing…it’s a DEEP HOLE! It IS very cool to be able to make your own stuff, BUT the learning curve is steep and it’s NOT inexpensive, either. Still, it IS fun!

[Cliff_Jennings]

Devon gave a very good summary on the differences between FDM and “resin” printing (SLA being the high end resin method, DLP being the low end method; here’s an article on the diff). I (and Devon) use DLP, but I think Al Pomeroy has a true SLA machine from Formlabs, IIRC.

Anyway, Bruce, even though that was a 7-hour print, I’m on my 3rd attempt of it! There’s a bit of nastiness I’ve not encountered before, but I think/hope I’ve found its solution.

However, for the sake of brevity, and the BD’s photo hosting costs, I’ve, um, not elaborated on those printing issues…

[Devon_Sinsley]

I don’t mean to hijack Cliff’s thread but he kinda already hijacked it himself. I want to add a bit to what Cliff is describing is all. IF someone is wanting to head down this path I think it should be real clear what all it takes especially with resin printing. It much different in process than filament. With filament you print and are pretty well done once you remove the supports. With resin it is a lot more messy. Since they are formed from liquid they come out wet and messy. To salvage the resin you let them drip. I personally leave them in the machine and let it drip back into the vat. others do it differently but basically to conserve product you want it to drip. Once that is done it requires removing the supports and excess uncured resin. Hence his alcohol. Most people use at least 95% isopropyl alcohol. During COVID it was somewhat hard to obtain at least in my neck of the woods. My printing mentor steered me to denatured fuel alcohol. Much easier to obtain and in my opinion works equally as well. However I am not sure what is going on but parts do seem to be stickier and can form a white residue. But beyond that I don’t see where they type of alcohol matters. Once dry completely the sticky goes away.

Final curing. This had me confused when I first got into it. But the printer only puts enough UV on the piece to solidify it. But in order for the next layer to adhere you do not want it fully cured. Epoxy only chemically bonds to tacky under cured resin (for the most part). Final curing means putting it in a chamber that floods it with UV light to fully cure the resin. This can also be accomplished on a long sunny day by setting the part outside but takes longer. A chamber is bought or can be made that has a UV light source either top mounted or side mounted. Many home brewed chambers have a reflective interior to bounce UV everywhere and a top mount light is sufficient. Almost all of them that you see have a solar powered turn table with a clear rotating plate. This all ensures that UV light reaches all parts of the piece. I have a low budget one now but I want to build a larger one with a mirrored interior and a side light and a top light. Probably over kill but they are cheap to make so why not.

once this whole process is done the part is ready for sanding and painting.

[Devon_Sinsley]

@Cliff_Jennings

I (and Devon) use DLP,

Even when I know it all I can stand corrected. I learned something today. I thought all resin printers were SLA. But thanks Cliff for correcting me. I can honestly say I have no idea what my machine is now. It is a resin printer for sure but now I wonder which type.

I use an Epax X10 which is DLP thanks Cliff for the education

[Devon_Sinsley]

Oh an BTW. . .Hey Cliff this project is awesome. I do like what you are doing with the buildings. When I first saw them I was down right impressed with your painting skills. Then I read on and I like the way you are doing the detailing. Great idea.

At first glance I thought you were making fancy monopoly houses and hotels.

[Eric_Mueller]

And this discussion is why this site is so valuable!

Eric

[Cliff_Jennings]

@Devon_Sinsley

At first glance I thought you were making fancy monopoly houses and hotels.

That’s EXACTLY what I feel like I’ve been making…

But heck, there’s a business idea for you: hi-end monopoly pieces, haha! Maybe N scale…

[Cliff_Jennings]

Eric, thanks!

I often wish this technology was around when my kids were young. Back then, they couldn’t relate to my 2D, and later 3D, CAD work; and I had no hobby then either.

If our family was young, it would be a whole different ball game, and they’d have picked up the 3D just for fun, and to make stuff. I’ll go so far as to say that the 3D modeling is so fun, that it can really take over. It’s been my main job since '97, and I still love it.

Nowadays, decent software can be had for free (there are two main kinds / approaches, but that’s another conversation). And a decent printer (FDM or DLP) can be had for a few hundred, rather than 10’s of thousands back in the day.

The software learning curve will always be a hurdle, but a manageable one. And the knowledge is easily transferable to a career skillset.

In short, with all your amazing family builds, it’s hard for me not to think of your opportunities, in view of all the above.

Thanks for letting me share, I needed to get that off my chest, haha!
Cliff

[Rooster]

3 color paint scheme at a minimum!