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9 Pound Naval Cannon (1786) by AON - 1:12 scale - Finished


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  • 3 weeks later...

It has been an exciting few days.

First I realized the Royal insignia was upside down.

Then I struggled to rotate it.

Then I managed to get the new file over to the local Library via the internet and they confirmed receipt.

Then they contacted me because the STL model was less than 2" long when it should have been 7-1/2" long.

Got that all sorted out.

Then at 3 PM I get a call that they are starting my print... but they were going to use the old original file.

Got that straightened out and just got back from watching the print process.

They added support ribs inside the bore to keep the barrel from collapsing on itself and a couple very thin supports under the trunnion to keep them from drooping the small amount between it and the machine bed.

I am hoping for a call tonight that it is done and ready to pick up.  Worst case I'll get a call tomorrow.

Here are a couple pics and a short video.

3d printing - 1.jpg

3d printing - 2.jpg

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Picked it up last night at about 8 pm.

Photos will be posted much later today.  I think I'll need to get out the real camera and ask the resident expert photographer to do this.

 

The finish is nothing like resin casting.  There are visible steps from the layers.  Makes the finish look like wood grain.

According to YouTube it can be dry then wet sanded from 80 to 4000 grit to get it smooth.

I will not attempt this until after our meeting this weekend so the club members can see it as is for now.

 

The muzzle end is warped upwards a wee bit on both halves but does pull down.  The plastic is at about 350°F when deposited so I imagine it happened when they slipped the spatula under it to separate it from the machine bed.

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Part of the texture issue may be the limitation of the printer. Ideally it should have been printed in one piece and done vertically. Obviously that printer couldn't 'stack' a piece that tall.

 

Could it be re-printed in vertical sections with the joint lines at the reinforcement junctions?

Edited by druxey
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Well, the batteries in the SLR are almost dead, so while they were recharging we tried with my wife's new fangled phone camera.  Following are some results.

 

I did not clean off any of the temporary printing supports so the fit in the carriage was not in anyway perfect.

 

I set the bottom half in the carriage and then placed the top half on it.

Both ends seem to bow away from each other but the good news is they pull together with very little force.

 

I also set the cannon balls on the rack.  They do not seat properly. The flat plastic foot seemed to have spread out a bit.  I measured the ball and diameter wise it is perfect enough but the flat bottom diameter measured larger than it should have been.  I will sand these down to fit.

 

You can clearly see the stepped layers in building the pieces.   Funny enough though, you only notice it when you get up quite close. Otherwise the look of it is beginning to grow on me.  If I were to sand the whole thing down it would be dimensionally inaccurate... and I might possibly ruin it.  The third photo shows the first layer being laid out as three outer strings and a wavey filler.  So if you sand it will there be holes?

 

I will leave it all untouched for now but I`ve found online (YouTube) that ABS glue works on PLA plastic, and this I have.  Apparently you can weld the parts together by brushing solvent (nail polish or acetone) and clamping them together.  I will leave it all alone until after our club meeting this weekend.

3 cannon layers.jpg

2 cannon ball layers.jpg

0 assy dry fitted.jpg

1 assy profile.jpg

4 cannon layers.jpg

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Batteries charged but the photos were surprisingly not much better.

The only thing that it caught that the phone wouldn't is the royal insignia.

 

I am considering having it printed a second time so I might try sanding one of them.

 

1 royal insignia.jpg

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50 minutes ago, druxey said:

I think that the printer used has too coarse a resolution for what you need, Alan.

Alan,

I agree with Druxey.  The resolution is too coarse.  Also, with the taper of the barrel you will get those steps in the barrel if you print it lengthwise. You might consider printing it in sections vertically.  It will come out better and you can glue the sections together with a dowel down the center of the barrel to hold everything straight. Then smooth the roughness with acetone and sand. 

 

You dont need to get the barrel perfectly smooth. Remember, these cannon were crudely cast and their finish was a bit rough on the outside. 

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Druxey and Dowmer

Thank you for the comments.

The printer was set at 1.5mm layer thickness and 20% fill.  I confess I do not know if this is good or bad.

 

Trying again vertically in two or three pieces might be worth trying.  The insignia could would be applied seperately.

 

I've been watching numerous YouTube videos regarding gluing and smoothing.

 

Thank you again.

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6 minutes ago, AON said:

Druxey and Dowmer

Thank you for the comments.

The printer was set at 1.5mm layer thickness and 20% fill.  I confess I do not know if this is good or bad.

 

Trying again vertically in two or three pieces might be worth trying.  The insignia could would be applied seperately.

 

I've been watching numerous YouTube videos regarding gluing and smoothing.

 

Thank you again.

I thought I would chime in here, because I actually have some 3D printer knowledge (one is sitting on my desk behind me). 

The layer height is way way too course for what you want.  I typically print with a height of 0.2mm. I'll attach a "poor" print with this layer height.  The infill amount is ok, and should be fine going forward.

 

You should also consider wall thickness, for your cannon, a 1-1.2mm thick wall should work well.   All this can/should be variables in the printer, limiting factors include nozzle size, print speeds, people making the print for you, etc.  But they should certainly be able to produce a better cannon for you without having to remodel it for vertical printing. 

 

Final thought: shorter print height will definitely increase the print time.  I'd guess, without running the model through my slicing program, each half would be 3-4 hours... max. 

IMG_20181206_095800.jpg

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Is there a university or trade school in your area that is more refined with their equipment and knowledge. Once had to go 150 miles to find a school shop that could drill a pin hole in a hardened hydraulic motor 1" dia. shaft, they kept it a couple of weeks, used it as a class demo., used their equipment to drill with electric spark etching, hole was perfect and it saved me a bunch of money. Think I would produce a well detailed and finished pattern, then cast your cannon, once the pattern is done to your liking, many casting methods are available to you. 3 D printing is still developing and skill in picking the subject, is probably more valuable than the printing method.

 

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Thank you for your coment Jud!

 

However, I feel that would be counter to my original intent.  Printed locally.  Our local College has a 3D printer but they will not compete with local businesses.  They cannot even offer to do a "one of" for free, even as a teaching aid.  It is against policy.

 

I am not looking for perfection. I have yet to create perfection. I see the beauty in the rawness of this piece's imperfection.

Having said that, I would not turn my nose up to something that was prettier!

 

I wanted a 3D printed cannon and that is what I got.  I think I will try to work with the library first before I might consider any other avenues.

 

I also want to say, you really have to get quite close up to see what shows up in the photos.  My display case prevents that.

Or possibly my eyes need a re-alignment / adjustment.

I will get feed back regarding the aesthetics from the club this Sunday.

 

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Jud

Thank you for the offer.

I will make up a short list and PM you before the weekend.

 

At the moment I do not know what accessories (i.e. nozzle tips) the library has or even if they are willing to make any adjustments at all.

I will contact them in a moment to arrange a meeting next week.

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Also... I typed 1.5 mm (0.059") but meant 0.15 mm (0.0059").

Yes... that is a huge difference.  I am not comfortable with SI Units.  Just barely understanding °C , forcing myself by having everything in the house display that way.

 

If I submit and print half the barrel (vertical or horizontal) at a time it could be saved with more detail to meet their 8Mb max limit.

They might adjust feed and speed but then they have a 5 hour max print limit.

 

A meeting with them should help me to understand this all better.

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34 minutes ago, AON said:

Jud

Thank you for the offer.

I will make up a short list and PM you before the weekend.

 

Wish I was in a position to make that pattern for you, I was intending to convey that if it were me making a cannon I would cast it using brass, Old Gunners like full length bore with a touch hole and cast on trunions. 

500125990_DIRECTFROMCEARCLICK462.thumb.jpg.e6ef90ca30729ae54efcb297eb38ec58.jpg

 

 

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Edited by jud
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I didn't expect you to know nozzle size, or some of the other details for that matter. It's something they should know, as it would go into calculating the right wall thicknesses to make number of passes an even number. 

 

0.15mm is much more reasonable. Yet you should have been able to get more/finer detail than you did, even under large zoom. And I will freely admit looking at a picture isn't the same as holding the part in your hand, it might not be a bad print at all. It'll be interesting to see what you learn from meeting with them. 

 

In the end, it comes down to whatever you are happy with, not everyone else's opinion. 

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Completely concur w/ the advice to print the barrel vertically, redesign the assy. to be 3-4 parts w/ interior lap joints (YMMV, but .3mm clearance should yield a press fit after a quick clean-up), size the i.D. so you can press fit the parts over a dowel and chuck it into a rotary tool--spin on slow speed while gently scraping w/ a blade to knock down the steps.  (I use a small Olfa blade in a pinvise)  --don't worry about getting too undersized--a coat of filler, primer and paint will make up the difference.  If the printer has a GUI like Ultimaker Cura, it's pretty straight-forward to change the settings to slower speed/max rez.  I would also turn off the auto supports and build them into the model only under the trunnion section; use about a 5mm raft under the barrel sections so everything sticks to the platform.  I would also do the logo as a couple-layer flat (make a few copies)  sand it to thickness and mount it to the barrel w/ epoxy...

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