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Author Topic: Drooping gun barrels  (Read 3103 times)

mudway

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Drooping gun barrels
« on: March 27, 2017, 09:21:41 am »

Iíve just received some 3D printed twin oerlikons and noticed that the barrels droop downwards.
My only thoughts are to stick the barrel ends in hot water, bring them out and while holding the barrels straight, put them into cold water hoping they will then stay straight.
Has anyone come across this before and have another solution?
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ballastanksian

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Re: Drooping gun barrels
« Reply #1 on: March 27, 2017, 10:08:16 pm »

What is the material they are made from? I found this online: https://www.shapeways.com/forum/t/unbending-warped-fud.17419/

And it looks like you can.
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mudway

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Re: Drooping gun barrels
« Reply #2 on: March 28, 2017, 12:23:13 am »

Thanks, looks like hot water is the go. I might try tap water first as our thermostat is set at 65 and they seem to recommend 80. Mind you, not sure what happens when it gets out into the Australian sun or sits in a hot car.


It is Frosted Ultra Detail.
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derekwarner

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Re: Drooping gun barrels
« Reply #3 on: March 28, 2017, 12:44:37 am »

After the straightening process [don't use the Microwave oven  >>:-(], insert a length of close fitting brass wire/rod from the breech to just inside the barrel end....that'll keep straight  {-)

Derek
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Derek Warner

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mudway

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Re: Drooping gun barrels
« Reply #4 on: March 28, 2017, 12:49:30 am »

Thanks, a nice idea but the barrel is only 2mm in diameter, a twin 20mm oerlikon in 1/35th scale. Worst case and i could chop off the barrels,  drill out the breech and insert small diameter brass tubing.
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derekwarner

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Re: Drooping gun barrels
« Reply #5 on: March 28, 2017, 01:28:30 am »

Yes...two sections of K&S telescopic brass tubing for each barrel/spring chamber would seem to be a perfect long term fix......

Nothing worse than painting the mountings and have the barrels re-droop   ;) on a hot summers day

Derek
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Derek Warner

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RAAArtyGunner

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Re: Drooping gun barrels
« Reply #6 on: March 28, 2017, 03:14:21 am »

Thanks, a nice idea but the barrel is only 2mm in diameter, a twin 20mm oerlikon in 1/35th scale. Worst case and i could chop off the barrels,  drill out the breech and insert small diameter brass tubing.

That would be better.

Some where on the forum is the same question, with the cause being that 'plastic' quality used is not suitable.
Might be in Shapeways postings.
It recommended  another 'plastic', (filament??) which is far stronger, no droopy barrels but is costlier.
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mudway

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Re: Drooping gun barrels
« Reply #7 on: March 28, 2017, 03:19:41 am »

Thanks, it only comes in Frosted Ultra Detail, no other options. Rummaging through my odds & sods of brass box now.
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tigertiger

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Re: Drooping gun barrels
« Reply #8 on: March 28, 2017, 04:39:05 am »

Drooping plastic was indeed covered in another 3D printing thread. As different plastics have different limits for strength, smoothness of finish (printing limits), and different prices. The good news seems to be that materials are rapidly developing in line with the technology.
An interesting aside on materials suitability.
I watched a vid on the new Corgi 1:72 Vulcan, https://www.youtube.com/watch?v=ne21Hq00KA0
Although the model is die cast, the wing surfaces were made of plastic, as the shape could not be effectively modeled in metal.
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gra2

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Re: Drooping gun barrels
« Reply #9 on: March 28, 2017, 06:52:07 am »

Hi I did mention this on forum last year replace with brass tube or wire.
I don't think they like the Australian sun.

Gra2
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mudway

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Re: Drooping gun barrels
« Reply #10 on: March 28, 2017, 09:26:20 am »

Thanks Graham. I'll email you and ask how when Telstra stops cutting off our internet.  :((
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mudway

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Re: Drooping gun barrels
« Reply #11 on: March 28, 2017, 12:06:03 pm »

Well the temporary good news is that hot then cold water did straighten them out. The not so good news is that, per the digital micrometer, the barrels are only 1.2mm thick.
The bad news will probably come tomorrow when it is forecast to be 30 degrees centigrade and one of them will be out in the sun to see what happens.
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ballastanksian

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Re: Drooping gun barrels
« Reply #12 on: March 28, 2017, 06:07:17 pm »

Even in real life the military have issues with drooping guns and in recent decades the armies of the world have taken to cladding tank guns in thermal jackets, so you are not alone in experiencing droopiness  :((
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mudway

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Re: Drooping gun barrels
« Reply #13 on: March 30, 2017, 08:07:14 am »

Even in real life the military have issues with drooping guns and in recent decades the armies of the world have taken to cladding tank guns in thermal jackets, so you are not alone in experiencing droopiness  :((
Well the hot water and cold water one survived 3 hours in the sun yesterday without drooping. Despite this, having found some 1.5mm tube in the bits box, the barrels of the other two were chopped off, new holes drilled and the tube inserted and super glued in.
Thanks for the help.
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