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Making cannons from non-traditional materials


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I have a daunting task in my very near future, and that is fabricating 100 plus cannons at 1:96 scale. Although metal ones would be preferred, I neither have the budget to buy or the proper lathe to turn them.

I have considered turning some from wood with a drill lathe, but even that will prove tricky at this small scale.

I am wondering if anyone out there has made cannons using non-traditional materials such as the polymer clays Fimo or Sculpey? I was thinking of starting with a finely detailed base cannon and making a mold from that and then mass producing the rest? Any thoughts on this or any other materials? 

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You can use tin as shown in the link below:

 

http://gabierschimeriques.free.fr/modelisme/canon.htm

In the articles section, there is a process of construction in resin:

 

http://modelshipworldforum.com/ship-model-casting-and-resin-techniques.php

In fimo or sculpey is very difficult to finish all equals
.

 

Belco

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Hey Sherry

 

Why not buy some wood dowel, same as the maximum diameter and file and sand them down with a drill...cut them 1/2" longer to fit into the chuck, If you make a stand for the drill that would give you hands free...and you could make the stand so that it has another centre with a pin to hold the other end of the dowel to hold it steady while turning...a Dremel might even work better....I'm kind of thinking as I type.

 

When the barrels are turned, then stain....

 

Just a thought...

Steve

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Sherry,

 

I moulded the carronades for my Stag (1:96) from resin.  I made a master from wood and copper wire and used that to make a mould - it worked extremely well.  I had never tried resin casting prior to this and found the whole process slightly messy, but very simple to do.  If you have 100+ cannons to make, you could probably make several moulds from your master and then go into mass production.

 

John

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Hey Sherry

 

If you want to go wood, another idea could be to purchase a small drill press for a hand drill. I used to see them on sale occasionally at Canadian Tire. You could use that to hold the hand drill and basically set it up as vertical lathe by fixing a centre pin on the base to steady while turning.

 

If you want to cast, I have done many moulds using RTV rubber purchased at local hobby stores for around $30. I would buy a barrel or carve one to use as the original plug. Cast as per Belco's posting and make a mould. You could either use metal or I would use polyester resin and cast as many as you need. That would be far less labour intensive than carving 100+ cannons. Buy a single 1/96 cannon barrel for around $2 plus shipping and use it as your plug.

 

Hope this helps

 

Steve

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I would agree the postings above this, and go make an RTV rubber mould and resin casting. I would only make the one mould for now, but I would buy several, around 5 canon  barrels and make the mould hold all five. Then you are only having to make about 20 castings. Tips when casting..You can vibrate the bubbles out of resin while in the mould if the mould is set vertically as the bubbles with rise to the top or make your self a homemade vacuum chamber using a clear fairly strong container that you can make a connection to your vacuum cleaner hose. This helps draw the bubbles out better than vibration. Having a clear plastic or glass (I used a large mason jar for mine attached to a refrigerator compressor with a surgical hose attached to a little pipe glued through the lid) having the container clear allows you to watch and regulate how long you need the suction. 

 

Steve

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Fort that many cannon, for consistency you really need to make one master and then a mold. Casting in resin as recommended is your best bet. It will guarantee that each cannon will be identical. There is no way that you could be consistent without a lathe set-up. Even then, it would be a long process!

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The easiest way to replicate them is to cast them.  Resin or pewter using RTV molds.  There are several tutorals for doing this.  Make up the master. then cast it.  Then use the master and the casting to make a 2 cannon mold then 4. You will then be able to produce all you need.

David B

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Thank-you to everyone for the responses and links!

 

John: What was the resin you used? I realize the product will be different here in North America, but it will give me an idea where to start.

 

Chuck: Good idea. I had thought about buying a few masters for the 3 sizes required on my model. I even stopped by your web store, but wasn't sure if any could be used at 1:96 scale? 

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Sherry,

 

The stuff I used is 'Pinkysil' two component silicone mould maker, and 'Procast' medium set rigid polyurethane casting resin.

 

These are both made by an Australian company called Barnes Products Pty Ltd.  Their local shop web site has a lot of interesting information on it -

http://www.barnes.com.au/catalog/index.php   They also have some helpful 'how to' stuff on you tube that can be accessed from the web site.

 

Hopefully this will give you enough information to atrack down what you need over there.

 

John

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Sherry, if you do go with the casting method going with steves idea for a vacuum chamber is well advised. just make sure your mixing pot is at least twice as big as the amount you want to mix. The whole mess will foam up and over as you apply vacuum, like pouring warm soda, especially as you get to the max that your vacuum will create. Its messy when it overflows. Not that I have ever made that mistake, nope not me! Never! :)

Sam

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John, I missed that and I commented right after you! Sheesh!  :huh:

Interesting, I wonder if the lower cure temp on your material has anything to do with it. I went over to the BJB site: 

( http://www.bjbenterprises.com/polyurethanes/castable/rigid/water-clear/ )

to look up some of the resins we use and none of the TDS showed an actual cure temp, just cure times at ambient temps and post cure oven temps. Most of the stuff we use gets pretty warm to the touch, I am guessing 125 F or greater. I am thinking the smaller parts cast here and the lower cure temp doesnt allow excess bubble to form?

Thanks for the info, something to look into.

Sam

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Hi.

 

For the people in the UK there is a very good resin for casting.

 

Black Fast Cast Polyurethane Liquid Plastic Casting Resin.

 

Made by DWR Plastics. They also sell on E-Bay.

 

This is a very thin resin and you do not get any air bubbles like other resins that are thicker.

 

Also it is a 2 part 50 50 mix . that is hard to get it wrong.

 

I used two syringes  to measure the resins and they were reusable.

 

Setting time is 90 minutes.

 

 

 

Regards Antony.

 

 

 

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Sherry,

 

 You can try to contact Polytek (www.polytek.com) and/or look at some of their Youtube videos.  We use several of their RTVs for making molds for our automated lipstick molding machines, and I also have purchased RTV's and casting resins from them in their Easy Flo line of products.  Great stuff.

 

Allan

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  • 2 weeks later...

I realize I'm late on this thread but might I suggest the Grizzly hobby lathe. http://www.grizzly.com/products/Hobby-Lathe-Disc-Sander/H2669

I have one and it's not a bad investment for the money and it does a descent job. It's 24 inches between centers and adjustable speeds. I have used for turning the mast's for my Enterprise and I have used for some other turning projects.

 

DSC02050_sm.jpgDSC02035_sm-1.jpg

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Sorry I missed this thread.....

 

Couple of observations...... Early in the thread it was mentioned to buy a few cannons and make molds and pour resin copies.....hmmm, even though you only intend them for your own use, and not for sale...it kinda takes away from the time and effort of the person or company who created the master in the first place.....no ?

 

Anyhow, since you have already chosen your materials, I won't go into those...let me offer some technique advice instead. Have some really fine cornstarch powder on hand. You will use that to 'dust' the interior mold cavity. After doing that, turn the mold (if single piece) upside down and tap the mold a few times with your hand to remove excess powder.

 

When you pour the resin, it helps to use a narrow rod...you hold that to the edge of the cup with the other end of the rod slightly inside the mold opening, then pour the resin down the rod and into the mold. After pouring the resin into the mold, give the mold a few gentle taps, then allow to cure.

 

I will tell you though that when you make the silicone molds, it is best to do a vacuum degassing of the material right after it has been thoroughly mixed. Then you pour nice and slow, Pouring a thin amount over your part, then moving off to neutral areas and allow the mold box to fill from the bottom up. Try not to introduce any bubbles when you pour.

 

Also, for general discussion......often times when you see resin parts that have voids or 'bubbles' , it is not that the part needed to be pressure cast or vacuum cast...I have cast thousands of parts right on the bench in normal atmosphere.....the voids you see are mostly due to either the wrong viscosity of resin, poor mixing and mostly, poor flow of the mold cavity. Humidity also has a big impact. Most of the poly resins are hydroscopic and the moisture absorbed then boils during the chemical reaction phase and wants to 'outgas' and gets trapped due to the quick curing process.

 

Your mix of A and B must be fairly accurate, and you want to try and find the lowest viscosity material so that it flows well and gets into all the detail. Mix in small batches, and keep the temperature on the low side of what the manufacturer calls for....this will slow the reaction down some and give you more time to mix and pour.

 

Silicones Inc, makes great mold making silicones for the hobbyist, and PolyTek and Alumalite make good resins for easy pouring.....there are literaly hundrds of formulas out there, and you can even make 'cold cast bronze' cannons. It involves mixing super fine bronze powder into the resin ( side A) then mixing that to B...and you pour that into a mold that has been dusted with the same bronze powder......resins can be colored also using dyes.

 

I started making molds and castings 15 years ago, and did a lot of production work for various companies along the way. At any rate, if anyone has questions about resin casting or mold making, feel free to ask. I will try to help if I can.

 

Joe

Edited by JPZ66
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Hi Belco,

I was very interested in the article at the http://gabierschimeriques.free.fr/modelisme/canon.htm link. Problem is my French is ... well, nonexistent. I used Bing to translate and it came out understandable.

 

There were some translations that were pretty funny, for instance "... A sleazy old made a makeshift cheap crucible..." But, still very understandable.

 

I am interested to see that compared to a resin method for cannon to see what I might try next. Joe, that's a another hint :)

 

On the other hand, I am not sure I could find any cannons better than Chuck's. That's 16 carronades. Not sure if Chuck also has the long guns, I did not see them on his site. Chuck.. What size carronades would I be using for the Syren?

 

Richard

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  • 1 month later...

I've seen the recommendations for dusting the mould cavity with powder, but, being totally ignorant, am wondering why the powder would not interfere with the surface of the mould. Is it just absorbed into the liquid as it is poured? And what is the function of the powder?

 

Thanks for any tidbits of illumination!

 

Tony

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I have been informed by a highly reputable source, that powder is better suited for metal castings so I will avoid that.

It was suggested that I use a combination of Vaseline and Isopropyl alcohol as a release agent. I am going to try this in the next couple of weeks and will report back with my results.

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Hi all,

 

Fine talcum powder or cornstarch powder will get absorbed in the resin. It is very important to dust the molds prior to casting resin. I use either a beat up old paint brush to dust the mold cavity or an old sock filled with powder. After the initial dusting, lightly tap the mold halves to get rid of the excess. What you want is just a really light coating of powder on the mold cavity surfaces.

 

Why is this important ? Surface tension. The Surface of a clean mold has a specific surface tension, and the resin has a surface tension. Without powder, the resin in the mold cavity behaves much like plain water on a waxed surface...it wants to bead up. In a resin casting that will likely mean areas of trapped air, creating voids in the casting. The powder serves to break the surface tension and allows the resin to flow smoothly against the mold surface.

 

Also, I am getting ready to make some molds and do some test castings, which is all I need to do to finish up my tutorial (so I can provide pictures of the complete process) the text of the article is finished. If anyone wants the text only version right now, PM me and I will send you a copy.

 

At any rate, if the molds are designed properly, your castings will likely come out 'ok' even without dusting the mold and depending on the complexity of the part, but I can assure you that dusting the mold first will make a great improvement in the final casting quality.

 

Joe

Edited by JPZ66
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