3D printing

[wefalck]

Another option would be 'bare metal' foil: https://www.bare-metal.com/index.html, but I did not check what colours they actually offer.

And another, completely different route would be have them cast in brass/bronze via a model in wax.

[wefalck]

A slight diversion: a couple of days ago I stumbled over a YouTube-video in which someone used the the printing-screen of a resin-printer to create the patterns for PCBs. The UV-sensitive coating is exposed to UV-light without the need for a mask. I gather this in essence what modern commercial PCB and etched parts maker do today, to digitally expose the coatings. That could be interesting added-value of having such a printer.

The guy also tried to do away with the UV-sensitive film/coating by printing a thin layer onto the areas not to be etched, but that was less successful.

I have contemplated to use my little laser-cutter for burning away a thin coating of black paint and thus expose the metal for etching, but not put this yet into action. The main difficulty will be to align properly the piece of brass sheet for doubled sided exposure/etching and to zero in the laser-head. This could also be the problem when using a 3D-printer screen, even though there you would only need to align to the screen properly.

[Iceman 29]

Yes, I saw this video as you did, it looks very interesting and quite easy to do with a little practice.

You can also recycle printers that you don't use anymore because they are no more as efficient in 3D printing.



And of course to create EP yourself in complement of 3D printing.



Author notes :Little corrections of used material: Not zinc sheet but a brass sheet
and not duct tape but packing tape

Here is my negative image for printing: https://www.dropbox.com/s/708fouiui893t ... 2.pdf?dl=0

hydrogen chloride solution 31%, hydrogen peroxide solution 30% and ferric chloride solution 40% and NaOH 10g for 1l water

[Fliger747]

A very interesting video on brass etching, looks very doable, though I have no idea where we would find the chemicals, at least here. When I was a kid we could buy what we needed at the drug store to make rocket fuel for home made rockets. They didn't go very high, but lots of fun.

[NavyShooter]

Well, after some initial frustrations, I found a couple of good youtube instructional videos and have spent a few more hours fiddling about with Designspark.

Here's my first 'project' at Version 1. The Crash Barrier support arms.

The design is based off the screenshot from a youtube video showing carrier operations on a British aircraft carrier from 1975, and from the ship's diagram that I have showing an overhead view with both a long arm and a short arm crash barrier as shown in the image.

[Fliger747]

Those came out pretty well, though as I am sure you know, we can design all sorts of intricate things in scale that won't print successfully. Those look pretty straightforward. I think I remember you printing with filament, unfortunately I have no experience with this method wit regards to capabilities. Aside from the mess, a big disadvantage of SLA printing is a reduced print size.

DSM is a solid design program which has advantages and disadvantages. You are also designing the interior dimensions if there is one and to the degree an item can be hollow of solid. In the real world of printing this can be advantageous. Every program has it's necessary workarounds.

Keep plugging away. This may change the trajectory of you project because of what you can do!

Cheers: Tom

[NavyShooter]

Well, apparently this will take just 36 minutes to print. We shall see how it goes!

I have to say thank-you for pointing me towards DSM, it's got a lot going for it. I'm still at the point of figuring stuff out, but with some youtube tutorials going in the background while I'm puttering away at other things, I am seeing steady improvement in my skill, and this program is SOOOO much more capable than TinkerCAD.

I suspect you're right that this will take me to another level - I'm pondering re-drawing some of my existing models and having a go at re-doing them, but realize that can be a 'later' thing. For now, there is SOOOO much detail that I can add to an Aircraft Carrier, moving forward, it will be better.

[DrPR]

I have seen comments about "shrinking" and printed parts not coming out the correct dimensions. Has anyone done any experimenting to test exposure times with the final part size?

I have noticed that the default base layers in Chitubox for the Photon Mono printer and the standard gray resin (six layers at 40 seconds exposure) come out significantly larger than the "normal" layers above the base (exposed for 4.5 seconds).

I made a beginner's mistake of printing a part without any supports. It was a set of 14" bitts (1:96 scale) with a wide base and vertical cylinders that I thought wouldn't need any supports. It printed fine but the base layers came out 0.2675 inches wide, and the layers immediately above the base were 0.2335 inch. The actual dimension should be 0.229. Another part of the piece measured 0.1465 inch, and the actual dimension should be 0.1458 inch.

The base layers were 117% oversize, but the layers above the base were 102% of the correct size. The other measurement above the base was 100.5% of the correct scaled size. So the recommended exposure times for the gray resin produced very accurate dimensions, and the longer base exposure times produced significantly oversized parts.

So it would seem that layer exposure times may have an effect on the final dimensions of parts - at least for the "horizontal" dimensions parallel to the printing base. If you cut the exposure time to speed up the printing you may be causing undersized parts, or "shrinkage."

Phil

[Iceman 29]

I use only 3 primary layers since the beginning on the mono X, with 45 s, even with 3 it sticks hard to the plate. No worries.

[Fliger747]

Under "ya never know" heading: I tried printing the ribbed main deck ramp seen at the bows of LST's and it came out baggy/lumpy and too thick on the bottom. I tried something not recommended, I printed it right on the platen. It cane out perfect, flat and thin and easy enough to pop off the platen. Go figure?

Tom

[Fliger747]

Grabbed this one out of the spares box, MK 37 director with cupola. I did these appropriately with and without cupola for 1:192 Missouri and Alaska. Trying to do these (which I did) with rails and whatnot by analogue means is somewhat trying. These are done with Phrozen Rapid Black Resin, which I like for detail. It did leave some very minor stepping on the glacis. A soupier resin would not do this but would have less crisp detail. I did do a version of this with the officers hand slewing device (Phil would know the proper name).

Sitting on a 2 Ruble coin (worth about $.03 US). As these can be printed fairly thin walled, I did contemplate doing the interior.

Possibilities are endless.

Tom

[DrPR]

Tom,

The thing in front of the Director Officer was called the "slewing sight." We called the grips the handle bars - don't know if they had an official name.

If you pressed a key on the grip and twisted the handle bars the director followed immediately, and it could turn pretty fast. You needed shout "hold on" and be sure everyone was in a secure position (not sitting on top sunning) and you had to hope someone wasn't climbing the outside ladders. Binoculars fit into a mount on top of the sight. You swung the director around until if was pointing in the general direction and then used the binoculars and brought the target into the field of view. The target would then be in the Pointer and Trainer's telescopes.

I mentioned someone climbing the outside ladders. In 'Nam it was very hot in the summer, and on the gun line the director got very warm inside. We usually sat on top where it was cooler until we got a fire mission or we saw an incoming target. Because it was so hot inside the director and barbette we usually changed the watch by climbing the outside ladders. Besides instead of the center line ladder inside the barbette. It was easier to get into the director from the top than through the small hatch in the deck.

On one occasion when I was climbing the outside ladder to relieve the watch they started swinging the director. It was quite a ride!

Phil

[Fliger747]

Phil:

I remember that now, the slewing sight. The 5" mount gun captain had a similar control but just a bead and rung sight instead of binoculars. I did make a version of the MK 37 that did have the slewing sight. Yes I can expect it was an exciting ride.

Tom

[Fliger747]

Top is a quad Bofors that I printed for the APA (1:120). This could be printed with the barrel units on the trunions or separate. An advantage for separate is easier placing and removal of supports, disadvantage is some fussiness of assembly. There is also a shield that can be added as I did for the ARL. I printed a large number of these in 1:192 for Alaska, with shields and barrels in place.

The bottom two consider a 5" 38 open mount that I built for the APA (1:120). The original hand built which I replaced is for comparison to the 3D model. I printed these as separate barrel and carriage for the same reasons as the Quad Bofors. The one's used on the models have some additional paint such as deck blue, black Bofors barrel unit sections etc.

Tom

[wefalck]

Looking good. Still, personally, I would probably go for turned barrels in combination with 3D-printed parts. Rotation symmetric parts seem to turn out crispier that way.

[Fliger747]

As a note, the left barrel is turned on the handmade piece and the right barrel is printed.

Tom

[wefalck]

OK, didn't say anything ... the printed barrel actually looks rather good

[Fliger747]

I do agree that brass barrels turned by an expert machinist, such as yourself, are superior. I have a small lathe, but not a jewelers model and have turned some barrels, but I find such small thin, long items somewhat problematic and have a certain failure rate. Certainly I could not turn successfully 40 mm barrels in 1:192. With some forethought one could print a barrel and tune it up on the lathe. However such could not be attached to the receiver and would have to be separate pieces. For most of us, having a wide variety of techniques, each most suitable for the task at hand is best. For instance the Laser cutting seems like a good technology. In a somewhat similar manner I have used the stencil cutter for making masks for hull numbering and even some superstructure members that would have been cut from sheet metal. It does have the capability of cutting styrene and balsa but I have not experimented with this as yet.

Best regards: Tom

[wefalck]

I think the beauty of 3D-printing is, that one can design/generate complex shapes and surfaces that are difficult to produce by hand- or machine-tools, also at small sizes that are difficult to handle.

[Fliger747]

Well, yes, even if one could hand produce the small components, which must by necessity be separate pieces, the assembly can be formidable. Your gunboat project is a good example of this. I do admire the ability of yourself and EJ Foeth to produce very small items!

Tom