You know when you start scratching, the itch becomes worse Tom, you found it out the hard way, as for sitting back and learn, i'm starting to learn how to make molds and pour some resin, it will be a fun ride into the unknown, the masters are made and the silicone is poured, tomorrow i'm going to pull them out, and yes, it consumes time making posts, the main objective stays, show what you can do and how, so other builders can do the same trick.
Japanese Class A 1/16
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As promised some more pics from the cave,
This is the final result of building my two-shooter, still need to adress the firingmechanism, before i could even think about that, there was something else to do.
Took some pine-wood and started up the lathe, ending up with this, since drawings of this torp are rare, i eyeballed it to get it right.
Compared to one of my electric runners, which are scale 1:35. they look big!!! ( do i think live warhead?)
Can wait to see them running out like this in the future.
Before i could start with molding them i gave the masters several layers of paint and sanded them back each time, i wanted to get them a smooth as possible, this pic is the result of some weeks hard work, HURRAH!!!!!, finally my first born casts in resin, despite the fact i don't own that fancy vacuum stuff David and Bart have, they came out well with no airbubbles, used a makeshift vibrationtable to get those pesty airbubbles out.
Manfred.
I went undergroundComment
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So, the first pair was born, made a second set, i should have started earlier with making molds, this is fun stuff.
This was the goal, two identical torpedo's, and now i'm able to make even more.
While i was pouring those torpedo parts i took some parts off from the V80.
Making this mold learned me some things, NEVER!! i say NEVER!!! let the cat inside the cave when you make some, end of story was i forgot to add the mold release stuff when pouring the second time silicone rubber, i ended up with a solid block of rubber, had to cut it in half with a scalpel, i can hear David laugh all the way over the ocean.
Despite that setback the result wasn't that bad, next time make a better mold.
David, those are your problem now, send me a mail with your adress, if you dare!!, i'll pack them up and will send them over.
Manfred.
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Hold off on sending those parts -- the V80 at this end has been set way back. New Boss, and more work than I can complete in a day (a good thing). I'll let you know, Manfred. And thank you for the kind offer.
Yes, cats be dangerous animals around the shop. You found, by hacking the two halves of the RTV tool apart that you created a perfect keying/indexing system between the two halves through the ragged knife cuts. Of course, poking a sharp knife in there is not good for the masters, but what the hey?
The upper two pieces of this four-piece tool were slit with a knife, to prove the point.
DavidWho is John Galt?Comment
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OK i will hold them back, yell if you need those parts in the future, another question, how do you store those molds on the long term?, is ther any kind of deterioration which i have to account for?
Manfred.I went undergroundComment
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On the other hand, I have thirty-year old tools that are just as serviceable today as they were back when they were made. With those the only aging is caused by the polyurethane casting resins we use these tools to cast parts off. I get about a hundred cycles off of those type tools before the cavity faces start to crack. The metal casting tools (low temperature metal like lead and white-metal) however are as fresh after hundreds of cycles as they were for the first. I exclusively use the BJB brand platinum-cured type room temperature vulcanizing tooling rubbers.
The perfect part-release (and mold-release) agent is Mann 200, in a spray can. Using it will insure quick, clean, easy part ejection and minimal chemical activity between the rubber and casting material.
Storage is not a big deal -- most of my production tooling (tons of it by now) is stored in the sheds where temperatures range from blistering hot to freezing cold (and recently, under water). The rubber just don't care!
DavidWho is John Galt?Comment
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With the torps i ran into a tiny problem, the props i needed had to be around 20 mm, two times and fourbladed!!!, decided to get a run at this,
First i made this doomsday contraption with simple means, the result is a fourbladed prop with a moderate pitch, and yes, those blades have profile.
Making of the mold, placed some channels on top of the blades
Made the first silicone pour and turned the mold upside down for the second run with silicone.
Today i opened up the mold by splitting her, the propmaster was easely removed, have to clean out some flash, but they are in decent shape for a amateur like me, tomorrow pouring some resin.
Manfred.
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Tried several times to get me a decent propellor by using the mold, either the resin is too weak, or the dimensions of the propellor are too small, also tried to reinforce the propellor with a little brass frame inside, no succes yet, those blades just sheer off after some pressure.
David, is there some other stuff i can use for making the props sturdy and still flexible?, i allready made a second copper one with the use of my prop-jigg so i can keep progress in building the torps, takes about three hours to produce a copper prop, so time is not really the issue, and by using the prop-jigg it's the same as the first one.
Manfred.I went undergroundComment
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Tried several times to get me a decent propellor by using the mold, either the resin is too weak, or the dimensions of the propellor are too small, also tried to reinforce the propellor with a little brass frame inside, no succes yet, those blades just sheer off after some pressure.
David, is there some other stuff i can use for making the props sturdy and still flexible?, i allready made a second copper one with the use of my prop-jigg so i can keep progress in building the torps, takes about three hours to produce a copper prop, so time is not really the issue, and by using the prop-jigg it's the same as the first one.
Manfred.
Two wheels (different scales for the MONTANA). And one wheel for the bad-guy, 'AKULA' -- you can see a casting of that wheel spinning of stage-left as the AKULA implodes... Neat!).
If you watch the movie you will see the MONTANA screw at one point going ahead and turning clockwise, and in other shots, going ahead turning counter-clockwise. The second-unit was not paying attention to the story-boards, later compelling the post production guys in the Editing office to flop the film when printing for continuities sake. Bad Ju-Ju!
Notice that the AKULA wheel is a counter-clockwise rotating unit, and the American wheel turns in the more traditional clockwise direction.
Here's what you do, Manfred:
Strip carbon fibers from some sheet, their length about equal to the diameter of the propeller, lay them into the blade cavities of one-halve of the two-piece rubber tool -- the fibers running right through the hub. Pack them in there. Then assemble the tool and cast as you would using quick-cure polyurethane. But, you must pressurize the mix before it changes state as the fibers are bubble-grabbers.
DavidLast edited by He Who Shall Not Be Named; 01-11-2017, 05:39 PM.Who is John Galt?Comment
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Thanks for the advice David, i don't own a pressure pot, but that can be my next birthday-present, i've seen Bart made his own if She Who Must Be Obeyed starts rolling with her eyes on this strange request.
For now i´ll take a try with the copper one´s, did some testing to see how the thrust is, they produce enough thrust on low speed but not too much, i could only test with a drillingmachine, got one on my dremeltool to speed them up dry-running, the revs make the difference.
I´m going to use a single prop on each torpedo, sice testing revealed that the thrust did not ingreased that much with two props together on the same shaft, you guys have to wait for pics because it´s busy inside the cave, first finish them up.
One more question David, i´ve used the e-motor of my stripped 2 inch Kilo SD, do you know the brand or size?, i've notice you beefed up the shaft by shimming it, prefect for my purpose.
Manfred.I went undergroundComment
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It took some time to produce something, but the vid is worth it, later on i'll add the still pics from the build, enjoy
Manfred.I went undergroundComment
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Hey those screw terminal block on your jig look familiar…
The pressure pot I bought at
http://www.fribel.be/product.asp?Obj...&stoelen=false
Compressor and VAC chamber were DIY.
Just one more thing
NEXT TIME YOU'RE IN NEED OF SOME EQUIPMENT AND I HAVE TO FIND OUT BY READING IT ON THE FORUM….......I WILL COME OVER WITH MY TORPEDOMAN'S TWEEKER.
If you had sent me the parts I would have casted them for you.....the offer is still valid Manfred.
Grtz,
Bart
Last edited by bwi 971; 02-07-2017, 04:43 PM.Practical wisdom is only to be learned in the school of experience.
"Samuel Smiles"Comment
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Yup, i steal only from the best Bart, thanks for the link, now i know what to look for.
You are always wellcome to visit me, next time keep the letters small, still have the age that i don't need a magnifier to read the text.
As for sending the masters to you, that was a option, thanks for the offer, but now i know how to do it myself, a nice learningcurv added to my list,
Manfred.I went undergroundComment
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As promised the pics from the build,
The business end of my torpedo, shot this pic before i started to rework the rearpart, two little brass bearings, the shaft with the propellor and the disk that will be used as a base for the equipment attached to the e-motor.
The allmost finished rear-part, still had to dremel down those white notches, the black spot you see is a grubscrew which can be taken out to lubricate the shaft.
The first design with the internal rack which will hold all the parts like, timerswitch and batterypack, used that previous shown disk as a guide at the front.
The nose-cap on the real thing had netcutters, so the small one should get them too, used a flame to soften up a jewelerssaw, so i could bent it into the desired shape.
One finished, still one to go, at the background you can see the second front-cap in the buildingstage.
Since those torps are big enough i decided to add a timer for the runningtime, this one has a range from 3 sec untill 8 sec, as i know now 5-6 sec running time is more than enough to demonstrate the torpedo to the crowd.
Tom, this is the scematic you were asking for, a pretty simple transistor switch, you can use it from 4,5V untill 12V DC, showing it on the forum will be usefull to other people if they need it.
The complete finished inside of one torpedo, from left to right, batterypack 2S 200mA, timerswitch with reedcontact, E-motor 6V, by slightly overpowering the E motor you will get enough revs for a decent speed.
Next time some more info about the launcher, this item is still under contruction so it will take a while to show the finished product.
Manfred.I went undergroundComment
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