Process for 3D printing of carronade

[tkay11]

I would like to obtain a 3D print of a carronade in the UK, but don't know how to go about it. It would have to be at 1:96 scale (13mm long, 3mm barrel). I don't think I have the skills to make such a complex object at this scale, although I certainly could have a go. I had a search through the fora for hints about going to 3D print shops but couldn't find anything, perhaps because I didn't search correctly.

 

The idea is to find a UK supplier who would print out one of the carronade stl files that seem to be available for download. As I don't know whether you can specify sizes for printing or whether the files have a size embedded, it would be a great help if someone could offer me some advice as to how to specify such a 'thing' for printing.

 

It would also help if a particular UK-based 3D printing shop could be suggested, and whether having just two copies of such a small object would be both cost-effective and accurate.

 

With thanks for any suggestions or pearls of wisdom!

 

Tony

[henrythestaffy]

Tony, if you have a picture or pictures of the carronade you want I would be only too happy to create an STL file for you. The scale is unimportant at this stage as it can be adjusted prior to printing. You can also have a look on some of the sites that allow you to download files but you can not always find the one you want. This way if you have a particular gun in mind I can make exactly what you want.

 

Regards,

Paul

[tkay11]

@henrythestaffy: That's wonderfully generous of you, Paul, and I may well take you up on that. Before I do so, though, I want to be clear about the process of asking a 3D printing house how to generate the model at the correct size. Do I just specify the overall length, or is that something that should be done when generating the STL file?

 

Thanks

 

Tony

Edited June 26, 2022 by tkay11

[Lieste]

If I have a model loaded into my slicer it comes in at native size @100% (e.g. 1/600) - to reproduce it at 1/300 I would rescale to 200% and then print  - to reproduce in 1/1200 I would make a scratch calculation to retain full thickness of an extrusion/pixel at the printer resolution 'expand' horizontally the model elements (making everything a bit 'chunkier' to preserve finer details in 'some' form) and then reduce the 50% scaling by whatever proportion gives the proper width and length compensating for the expansion (*this will break most of the interfaces between parts which are supposed to fit together - some fettling will be needed, unless you "assemble" all the parts into a single solid.

This latter task isn't needed with resin printers or SLA types, which you would probably be specifying - but I have an FDM printer with an "0.4mm" nozzle and similar minimum line thickness for consistent printing, so when substantially reducing model scale (e.g. from 1/72 to 1/350) some compensation to preserve detail and/or structural elements is needed.

I've not used a bureau, but I would start with this definition, belt-and bracing with a 'dimension' for overall length or length between two landmarks and a suitable diagram to indicate where these should be.(e.g. if you note the length between breech ring and muzzle moulding, where the breech ring is, and where on the muzzle the moulding is measured (carronades can have multiple sets of mouldings ahead of and behind the sight, and a flash tube extending forward... overall dimension is more reliable, as it is less ambiguous.

You can download and 'play' with the stl in a free slicer (such as Chitubox) to get an idea of the required scaling amounts and overall dimension to specify.

[John Fox III]

Greetings Tony,

Are you dead set on 3D printing your carronades? I have made the 18 carronades for a 1:200 scale model out of paper and thin pieces of maple wood. The photo shows the final result, minus the trucks. If it is of interest I have a series of photos I could post showing the steps to create them.

Anchor's A Weigh!

John Fox III

[tkay11]

@Lieste: Thanks for that very detailed reply. I see that the accuracy would depend on the printer resolution. I attach a screenshot of the plans I am working on (traced from Boudriot's monograph of La Jacinthe) as well as a photo shown in that book of a model of a 12-pounder carronade of the same design. Do you think a FDM 3D printer could make a solid model of the entire carronade (perhaps without the supporting wooden blocks) at the scale dimensions I show in the screenshot? Although I have already separated components in the tracing for study purposes, I wouldn't attempt to have all the details of the revolving mechanism, just the curved base).

 

@John Fox III: That's an intriguing idea, to make it from paper. Having seen your excellent work on Polaris I am not sure I would be able to match your skills (even at the larger scale I am working on)but am open to all suggestions. It would be really valuable to a lot of people if you could share your methods as you suggest. I can certainly see the sense of your making the carronades simpler in construction as at that scale trying to detail them further would make little sense.

 

Thanks,

 

Tony

 

 

 

[John Fox III]

Greetings Tony & All,

Thanks for the kind words about my work Tony. The photos and text below show my process. Ready to answer any questions, if necessary.

 

The following photos show how I made the 12 pdr. cannon and 32 pdr. carronades for my 1:200 scale model of Niagara/Lawrence. Both barrels are made from paper tightly rolled around an appropriate sized drill bit shank, saturated with CA glue, then sanded to shape. Before sanding I used a fine wire to insert CA glue into the barrel, to harden the inside. After hardening the inside I used the drill to clear it out. To perform the sanding I slid the barrel onto a piece of drawn down bamboo that fit fairly tightly into it, swapping ends of the barrel to shape the whole thing.  It did take multiple applications of the glue, as it could only penetrate one or two layers of the rolled paper. I used standard inkjet printer paper, soaked in ink jet ink, I had a spare cartridge for my printer so used that for the ink. The carraiges and slides were made from maple.

 

Anchor's A Weigh!

John Fox III

[tkay11]

Very neat! Great ideas for the construction. Thanks!

 

Tony

[John Fox III]

17 minutes ago, tkay11 said:

Very neat! Great ideas for the construction. Thanks!

 

Tony

Thanks Tony! When you work on miniatures, especially ship in bottle or light bulb models, you learn to think outside the box.

Anchor's A Weigh!

John Fox III

[henrythestaffy]

Tony,

         I am not sure what printing companies do but I can tell you that I take the picture that you posted above and import it into Fusion 360. I then create the model and scale it down after I am happy with the end result. The screenshots show the carronade after I have scaled it down from the size it would have been when originally created, which is the size of the drawing. I then save it as a mesh and import it into my slicer where the supports are installed. That can be a bit of trial and error. The last shots show the end result. As you can see they are very small. The detail is there except for the thin handles on the screw.

 

Paul

Edited June 27, 2022 by henrythestaffy

[tkay11]

@henrythestaffy: Wow, Paul! That's simply astonishing! I had no idea you could do that from a photo. I'll PM you in case you're still willing to post the PST file. I suppose all I would then have to do is send that to be printed.

 

Thanks very much indeed for spending time on this. I can begin to see the magic and usefulness of 3D printing.

 

Tony

Edited June 27, 2022 by tkay11

[henrythestaffy]

Tony here is the finished model from the sketches. If there is anything I have missed or not designed correctly just point it out and I can adjust it.

 

Paul

[tkay11]

@henrythestaffy: That looks perfect, Paul. I wonder if you think it would be worth it to make a little log of the stages through which you developed this? Of course, it may be something that I am just behind the curve and don't know what so many others now take for granted, but if you think there are others who might pick up some tips as to how you did this, then it might prove enlightening for some of us who have yet to catch up.

 

In particular I would like to understand the process of converting photos and 2D drawings into 3D files for printing. So far I have only really used CAD for 2D planning.

 

If you think this is all too basic, I'd be glad of some pointers on the web as to how to learn. I've seen some tutorials for Blender and Fusion, but the ones I have seen don't seem to cover this initial conversion.

 

As with many others you have helped on this forum, I am very grateful,

 

Thanks

 

Tony

[tkay11]

@henrythestaffy very kindly sent me the printed version of these carronades, for which I am extremely grateful.

 

This has been a very useful conversation for me indeed. It enabled me to look at a number of options and interesting ideas, to learn about stl files, the 3D development process (especially the need for care with the supports) and more on how to use Fusion 360.

 

I can't afford a 3D printer yet, but I think I will shortly be able to send difficult parts to the printers for the time being, given my growing understanding.

 

So thanks to everyone for chipping in, and particularly to Paul who has been so generous with his time and the prints.

 

Tony