DIY Rotocasting

[Big Al]

How to build a DIY Rotocasting Maching Tutorial Part 1

I wasn't going to include this one because this article was posted in Sept 2010 and ther has been no follow up. so there is no part 2 as of yet. I have E-mailed the author but I have received no response.

This article started out very strong! it's very clean with good clear pics of his build. So I will post it and if you would like to pusue it that's up to you. Have a look.

The name of the site is Small Stuff and here is the link Diy Rotocast Tutorial

DIY Roto Machine Tutorial Pic 1

Pic 2

Pic 3

Pic 4

Pic 5

Pic 6

I hope this guy comes back and finishes the article. you can help by visiting the Link and leaving a comment like I did.

More to come !

[Big Al]

my question on the DIY Rotocasting Machine Plans on E-Bay,
is how does he keep the wire from the seconond motor from twisting and breaking after it passes through the shaft tube???

I have the answer for that .......it's a spinning electrical conector similar to a swashplate on a helicopter.

RotatingConnector.gif (37.77 KiB) Viewed 7456 times

RotatingConnector.gif (37.77 KiB) Viewed 7456 times

Here's the link for the company Mercotac

[Cylon-Knight]

So a rotomachine looks like it would be easy to make, but I'm still not clear on the "why."

Big Al... could you either make or find some sort of pros and cons for Vac Vs. Roto forming? It seems like Roto involves a lot more work on making your master/mold/negative and all that... am I understanding right? How is one better than the other, if "better" is the correct word that is... ???

[Big Al]

Commercial Rotocasting machines


Here are some examples of machines I found and once again, if you have the means you can just BUY one of these machines but they are a little pricey!


These machines are available from Environ Molds

Pretty nice machines and they start at $4,900,00

Here is their Link Environ Molds Rotocasting Machines

[groupleaderzeta]

Cylon-Knight wrote..
could you either make or find some sort of pros and cons for Vac Vs. Roto forming? It seems like Roto involves a lot more work on making your master/mold/negative and all that... am I understanding right? How is one better than the other, if "better" is the correct word that is... ???

I would say it depends on what you are molding, cost, and detailing needed.

If you were making detailing pieces that would be glued to a model, many would be made in a open mold (part that has a flat back).


If you were making a helmet to wear and need a hollow part then roto-casting is a great option. Roto-cast is simple in these terms, It casts a shell, like many kids ride on toys. The thickness of the shell depends on how much casting material is used, the more material, the thicker the shell and more durable the shell is.

[Big Al]

So a rotomachine looks like it would be easy to make, but I'm still not clear on the "why."

Big Al... could you either make or find some sort of pros and cons for Vac Vs. Roto forming? It seems like Roto involves a lot more work on making your master/mold/negative and all that... am I understanding right? How is one better than the other, if "better" is the correct word that is... ???

I'm not totaly sure on the pros and cons because I have never done any rotocasting. However I do know this is the way they have made helmets for a long time.

I believe the Don Post studios used this method for their productions to make Masks, helmets, props etc and it enables you to make parts with different materials such as Resin, Latex, or any liquid casting material short of molting metal.

Metal is cast this way too, but mold making gets alot harder because you have to make things that wont melt!

From what I have read, you can get better detail from rotocasting such as highly detailed model ships with great detail like wood grain in the wood planks for example.

That's not all I'm just grabing at straws for this one but I think mostly is because the vast kinds of liquid casting materials you can use and that you can vary the casting material with different additives making hard parts, soft parts, rubber parts. etc.

I also think you can achive great detail in the parts if you want to go with a thick set!

on a Vac machine, your material has to be relatively thin to heat and pull. This can result in a nice detailed but flimsy part. Thicker plastics, such as Kydex or ABS is normaly not done at home because you need alot of heat to form it and when they do it in an industrial setting they use a process that combines Vacuum and Pressure (Pressure Forming) to get what they want. The vacuum is an assist and the plug is pressed in the mold with great pressure as the vac assists.

A vac machine will only make parts just so thick. With a Rotocast, (Like my Darth Helmet.) you can cast with a liquid, and get the great detail, and depending on how you build your mold, (1 pc. vs. 2 pc.) you can get the thickness that you want without going industrial ...Depending on the material, when the liquid sets, you could have a part with the same strength and hardness as Kydex or ABS.

So the short answer is More part making material choices.


UPDATE: What I did forget to mention was that Rotocasting allows you to make 1 pc. Hollow parts! to make a hollow part with a Vac form, you need to marry 2 peices for a final product.

Rotocasting is also a great tool for making plugs for your vac form, Sculpt the master, pour a mold, cast a plug, pull many parts from vac machine.

Or Sculpt a master, pour a mold, cast a product, cast a product, cast a product. (repete production for casting)

If I were a betting man, I would say that some techniques that you would use in fiberglassing could be transfered here like the way paint is applied into a mold before the the fiberglass and resin are laid into the mold to form the part. thus achiving the gel cote paint job.

I beleive in some cases you can apply paint into your mold, then cast your resin thus giving you a finished painted part upon the removal from the mold.

I would never look at any of these processes as "One is better than the other" or "it's either one or the other" All of the processes have their place depending on what you are doing.

Those two phrases are marketing slogans for selling a particular product!.....You see them every day on tv. first they show you an over exaggerated demo of the old way of doing it (Usualy in black and white footage to make it look old and outdated anoying, and cumbersome.) then the new way! in bold vibrant color! then they tell you how much time you will save with the new way (Saving Time / Marketing Ploy)!....Then they tell you the secret technology (Secret Technology/Marketing Ploy), Then they tell you the low low price you can get the new way for (Usualy $19.95 Magic Marketing Number) and then they create a sense of urgency to get you to act now by saying somthing like "This is a limited time offer" (Limited Time/Marketing ploy) or "we are only selling 50 of these in your area as a test market" or this one has been used alot latley "If you call right now in the next 5 min, we will include a complete second set of the new one absolutly free just pay shipping and processing charges" then they put a count down clock up on the screen or a caller sold counter to get you to hurry up and order!

All bunk! It's never the old way vs the new way and there are no secrets!

Rotocasting is just as important as Vacuum forming, Hot wire cutting, Carving , Sanding or what ever

I own hundreds of sanding tools hand sanders and power sanders...and not one of them replaces any of the others. they all have their place.

All of the processes are the same in that it ends with a finished part and depending on the part your making will determine the process that you use!


Here are some samples of a helmet project done with Rotocasting

[attachment=3]3805817944_25ce21b885.jpg[/attachment]

[attachment=2]4833433042_b0e47a4ca0_b.jpg[/attachment]

[attachment=1]daftb.jpg[/attachment]

[attachment=0]daftfamilyportrait.jpg[/attachment]

[Huttman]

Ok first off, thanks for the kudos, and letting me know you were going to post that
Second, Rotocasting is an art in itself. You can build a machine in any way you can. Wood, Aluminum, Steel... But the key is, MATH.

I dont claim to be an expert, but I was mentored by one and I am very happy I was or I would have made some very costly mistakes.

Some of you ask "why". One reason is this, If I were to make my blasters simply by pouring the resin in the mold , wait, then pull it out, its too heavy to troop in, plus its costly. Resin is not cheap, and as of late the cost just went up.

I took my master and made a two part silicone mold which is held in place by a exoskeleton (or fiberglass jacket). I pour the resin in, turn on the machine and watch it go. the resin coats the inside of the mold until its hard. After you have a hallow piece which is light to carry, and light on the wallet. Another benefit is that you can add electronics to it, which you cant really do very well if it was solid. If you have trooped a parade like i have, even the lightest prop gets heavy after a while.

The most difficult part about building a machine is weight distribution. For each mold you need to find the center mass, and kind of go from there. The rotocast machine I really want is 3 grand, that kind of scared me to make my own lol. But by this time, had I bought it, It would have paid for itself a few months ago :-/
The great thing about the one I want, is that is has variable speed on BOTH frames.

Thats the key. Your outside frame can spin as fast or slow as you want, but how are you going to control the inner frame? If you go to fast, there wont be enough coverage, if you go to slow, the resin will harden quickly and make the walls uneven. When I first was dialing in my machine, I scrapped a few parts because my mold wasnt doing a complete 360 turn, which i thought it was!

How I changed the speed was changing one of my gears that controlled the inner frame. When it comes to making a helmet, im hoping that changed aids that as well.

I very much want to sculpt a cylon helmet and rotocast it. I plan on getting a helmet from CORA soon so that once its together, I can use it as a reference, with his permission of course.

Help control your re-caster population. Have them spayed and destroyed

The cylon rifles, I know they are not rotocasted originally, but I still think it would be cool to do one. I want to someday be a part of the army here that has something to offer to help us grow. I AM an arms dealer after all

Anyway, I hope that gives some insight, I left A LOT out because I cant cram a years worth of learning in one post lol!


Here is what my mold looks like opened up


cheers

[groupleaderzeta]

All the parts I have mold would be considered solid cast parts. The mold is a cavity that is filled with the casting resin. sometimes they are open, similar to a bowl. Others are 2 pieces that are clamped together and the hollow space inside is filled with resin.

[Big Al]

Ok first off, thanks for the kudos, and letting me know you were going to post that

Sorry I should have given you a heads up on the thread, but you had posted both of those links on a couple of other threads here so I didn't think it was classified

And second, I did this to flush you out and get you talking about this awsome subject and I know that you are indeed the resident expert on rotocasting.

You just proved that with your last post!

So please don't be shy and tell us more!! we are all ears! especialy ME!

[groupleaderzeta]

Huttman,

How would you deside on size to make the machine?
Most likely I would use it to make helmets or hollow backpacks.

I was thinking of a inner frame around 36 inches square. Or does it have to be square??

[Cylon-Knight]

Thanks for the info Big Al, Zeta and Huttman!

So, to sum it up for Rotocasting...
-You make a master prop, by any means
-You create a silicone mold of the master (A negative)
-You create a strong exoskeleton (a fiberglass jacket) to keep the silicone mode in shape
-You fill the mold with some liquid plastic
-You close it up tight
-You put it in the roto frame and sit while it spins
-*poof* a very detailed solid hollow 1:1 copy when it all drys and you open it up

Am I getting it right?

[Big Al]

Comercial Machines cont.


Here is a machine that is made by Stelter Creative I featured their Vac machines in the Vacuum Forming thread and they build very cool machines. They make several machines all different sizes.
their 2 X 2 Machine starts at $3300 their 3 X 3 Machine is $5100 and their 4 X 4 Machine is $6500


Stelter Creative Rotocasting Machine

Control Panel

Here is a video of the machine in action



Here is the link to Stelter Creative Home Page

More to come

[Big Al]

Huttman,

How would you deside on size to make the machine?
Most likely I would use it to make helmets or hollow backpacks.

I was thinking of a inner frame around 36 inches square. Or does it have to be square??

Huttman is your man for that question. But if it was me, I would say Yea....I would want a machine big enough to do my helmets and backpacks!....You also have to think about the extra size and weight that is added for the mold. I would say that a 3 X 3 machine would do that.

If you look at the post I just did on Stelter machine, they are casting someting in their 3 X 3 Machine so you can get a look at the size of such a beast! and I would say that it is probably sufficiant........I could be wrong ...so let's here what Huttman has to say.

[Big Al]

The Ultimate Rotocasting Machine!!!


I'm pretty sure this is a DIY machine but it's hard to tell. the coolist part of this machine is that it has 2 speed controls. (Inner Frame control seperate from outer frame control) I'm not sure what the advantage of that is, But there must be a reason they built it that way and if you look at all the machines in my past posts...they are single speed control units and the inner frame is geared to the outside (Except the 2 motor machines) but this is the first 2 motor machine that I have seen with the 2 speed control system.

Here's the Video




Here is the same machine refined with all of the motors and drives concealed also has a digital countdown timer and automatic shut off




This guy has about 8 videos on his youtube account and I think he is just a home machine builder, Nothing comercial but if you want to get in touch with him this is the link to his youtube account

Macleod Youtube Channel


More stuff coming!

[Big Al]

DIY Spin Caster Machine (AKA Centrifugal Casting)


Ok this is the first time I have seen one of these machines and I would like to know if anyone knows about this process and is it as good as Rotocasting? is it similar? is it garbage?

This one is a book and a plan from Cast Craft and looks ok but I'm just not sure what advantages or applications you would use it in???

Ok nuff said here it is

The Complete Handbook of Centrifugal Casting

centrif.jpg (6.84 KiB) Viewed 7446 times

centrif.jpg (6.84 KiB) Viewed 7446 times

Centrifugal Casting Machine

centrifbann.gif (7.4 KiB) Viewed 7446 times

centrifbann.gif (7.4 KiB) Viewed 7446 times

I will add more to this post as I find it so check back!

UPDATE: I found a build page on this machine check it out!!!

Building a Spin Caster & the fun that goes with it . . .


Spin Caster Build Page 1
Spin Caster Build Page 2
Spin Caster Build Page 3
Spin Caster Build Page 4


If I find more info I will post it here