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Discussion Starter #1
Does anybody make and sell resin wheels/tires? It would be a good way of making sure there was a good supply of harder to find wheels when people needed them.

If not would people be interested in them if I cast some? The casting would be easy enough and pretty inexpensive. I guess the hard part would be finding the original wheels to duplicate in the first place. I haven't planned anything yet, I was just curious to see if there is any interest.
 

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Discussion Starter #7
Resin is great stuff, it can get detail down to a fingerprint...really, I saw a guy who molded his hand and the fingerprints were clear.

I'm thinking of doing some 1/64 and 1/50 wheels for my own use if nothing else. I need a bunch of wheels for a dirt racing diorama I'm thinking of making and I hate the idea of buying a lot of expensive donors.
 

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:wave: Hi Sidewinder- Saw your thread and thought I'd add a bit for 'ya.
It is all great stuff, but if your plan is based on saving money, you might be in for a shock! Unless the wheels you want to reproduce really are difficult to get hold of I think going round all the fairs and buying cheap beaters as donors is gonna be way easier and cheaper!

The cost of the silicon rubbers, polyster and urethane resins is ridiculous, and theyre quite messy which could be a problem if you're doing it indoors. The rubber catalysts and the resins can be pretty nasty as well, so all need care and caution. An important thing to consider which is often overlooked is that you need to be prepared to experiment- there are countless variations of all of them not to mention differences between brands etc, and they all have specific characteristics aimed at specific applications. This often means yet more dosh and more time before you find the right combination and set-up that works best for you! How well a compound will work for molding and another for casting depends on what properties you want both the mold and the casting to have for the mold making and casting process. Some flow better than others for pouring, some are more elastic than others for taking undercut etc, some softer for tires and others harder and more brittle etc- I'm sure you get the idea. If youre making your own rims/hubs and only want to produce tires there are some good rubbers available but I found most are light grey and so need pigment to dye- Yet more expense and faffing around with mixing! I used a really good one for tires but it was white- great for chase style wheels for a General Lee but not much good for anything else! You might be lucky and find the right ones for your molds and castings first time, but from what I found from all my dabbling I think it'd be unlikely!

With small parts you can make a lot more of them for your money compared to casting large stuff, but with wheels and tires they're so small you really need to make a mold that casts 20 or 30 at a time for a mixed volume in order to make it worthwhile.

After loads of experimenting, I now only use the RTV silicon rubbers for metal casting, and mainly only for difficult parts like bodyshells, with all the smaller stuff I make aluminium molds and then injection mold plastic as long as I can machine the negative for it.
I found the hassle with resin and rubber for smaller parts that bit too much, allthough for making rubber tires I gotta admit they cant be beaten.

For me the reality was I can make 100 X more molds per cost using aluminium and without any of the hassle. No more mixing stinking gloop with vapors that send you to the moon and back, no more worries about the stinking gloop dripping over the bench and up your arm, no more binning molds because of deterioration from chemical build-up, and no worries about the stuff going off on the shelf either- Loads of the compounds only last 4-6 month. Now I use recycled plastic for everything-whatever the color I need, so I can do a run of 5 or 100 plastic parts and the materials cost is zero! :D

Dont get me wrong though- Casting resin and rubber can be great and it's amazing what you can do. Youre right in that many will replicate a finger print- This aspect works for you and against you!! Needless to say all molds whatever youre making need to be absolutely perfect otherwise even the tiniest mark or imprint comes out in every casting!

Hope this is of some interest- Not intending to put you off at all but thought I'd explain what I've found as it might not be as quick and cheap as you were thinking. But I'm sure it'll all work out if you choose your rubbers and resins carefully and are prepared to experiment with it!
Good luck if you do and let us know how it goes :thumbsup:

Bye 4 Now :wave:
 

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Discussion Starter #9
I appreciate the input, and you're right of course. I usually use Alumilite for resin projects and it does get expensive and the 6 month shelf life is a bit annoying. There would be almost no way of making money on the tiny wheels, I was thinking of doing them more as an archive. To be honest, I have no doubt that I would lose money on this, but I thought maybe if others are interested it might help to defray the cost a little. The biggest problem so far is finding the rare donors to begin with--I guess that's because they're rare:rolleyes:

I've done a little bit of casting in aluminum but I doubt that I could make molds for injection molding, which is a shame because it looks so cool. I even made up plans once for a home made injection unit, but I never followed through because of the problem of machining the molds.

BTW, if I can pick your brain for a second, do you know if you can injection mold Delrin? I have a could of projects that need a strong plastic, I tried Smooth On C-1509 high impact but it was too flexible. Delrin or a polycarbonate seems like it might be a better choice, but of course they would have to be heat formed. I just don't know if you can mold these safely, I'd have to look it up but I think the flash point of the two are close to the melting point so it might be risky?
 

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Just to throw in my 2 cents here. I have to disagree with metalwizard, although he does bring up some valid points though. To give you an idea where I'm coming from, I work as a prototyper and moldmaker and use RTV silicones and polyurethane resins almost exclusively. Yes, there are initial costs, but it doesnt have to be expensive. You can get small kits for as little as 30-50 bucks and have everything you need to make small molds and castings. It all depends on how much you want to get involved. I have never been concerned with smell and vapors, any silicone or polyurethane resin I've used have next to no smell. I still would never stick my nose in it, however, mixing either at chest level its odourless. Now, polystyrene resins are a different story and stink like hell, proper ventilation should be used, but leave that stuff to auto and boat repairs. Some of the urethane rubbers have a slight pungent odour, but nothing that I would consider bad. Yes there are a ton of different choices out there, and it might seem a bit daunting at first, but for the most part, they all do the same job. It also means that there is a perfect solution for any application. And if you, or anyone else, has any questions, send me a message and can help you out. I can steer you in the right direction. About the only warning that I would have about silicone mold making is that it can be a little steep on the learning curve, which can make things expensive if you make bad molds. If you do decide to delve into it, do some research, there are tons of resources online and lots of videos on youtube showing you exactly each step. Try to get familiar with the process beforehand and you will be much better off.
 

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Discussion Starter #11
I haven't had any real problems with the basic Alumilite kit, I really enjoy it actually.The thing I wish I could find is a pourable plastic that had the strength and rigidity of Lexan.
 

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I'm glad some of it was of interest :)

Mr Juice- It was indeed a urethane that sent me on my short trip to the moon. Luckily I was still holding the cans so the repeated exposure sent me back again. The RTV101 silicon rubber is all I use now for white metal, and that's fine- it has a very mild, sort of sweet smell which stays in the rubber and actually makes the workshop smell sweet when it gets hot during casting.

:eek: Guys- I didn't intend to come across as being against all this- perhaps I was a bit heavier than intended!!

If MrJuice is doing this day in and day out at work, then he might not see the costs from quite the same angle as us guys in the hobby. Whichever way we look at it, I think most of us would agree the costs of the raw materials are high. Yes, there are hobby packs available making smaller kits and quantities available at a lower cost, but there's still experimentation involved with all of it, and this was my point. Like MrJuice said- research, reading, watching videos etc is all gonna help and allthough it'll help shorten the road to success, I dont think the experimentaion is ever going to be eliminated on a subject as varied and as complex as molding and casting.

:) In short, my point was- It is brilliant stuff but it's not cheap, can be messy and you need to be prepared to experiment :)

Sidewinder-
As for injecting Delrin or Polycarb I have to admit I've not tried it. Long story short- I make a lot of machined parts in ABS, acetals and nylons etc but it was their high cost for use as hobby materials which pushed me closer toward injection molding. I was lucky in that I have a big plastics supplier only a few miles away, but they gradually reduced the amount of stock they held to the point where everything I needed had to be ordered in next day with added carriage on top. This made simple stuff like 3 metres of 10mm black acetal bar work out about 20 times the price of equivalent aluminium stock!!
I had planned building an injection molder for some time, so this just added to my previous reasons using resins etc and was the final push I needed. So, the whole point for me was to be able to use waste thermoplastics for model parts instead of having to turn and mill them from the expensive engineering plastics, or messy molding/casting with equally expensive resins.

Within about 10 months I managed to build a simple rotary caster for white metal alloys, and the plastic injection press, so I'm finally sorted for making all my own parts in house.
My biggest interest has always been Live steam- My current Loco allthough a 'small' 0-4-0 is now a bit of an animal at 40 kilos (about 88 pounds!) of rolling chassis, so it's a big contrast to working on the tiny stuff for the 1/64 cars!! The rotary caster and plastic injector isn't much use on this project, but I'm glad I made them when I had the time as they'll always be there for when I need them.

You mentioned Delrin and Polycarb having to be heat formed- As I said I've only ever machined them, but I know that Polycarbs do heat/vacuum form very well, allthough they are often considered harder to do so than other plastics more commonly used. Not certain about Delrin for heat or vacuum forming at all though. There's a lot of variations between all the specifications and brands, and I think Polycarb forming temperatures are a bit higher than most at around 350- 450 degrees Fahrenheit.
To be honest I've always regarded plastics like Delrin, Nylon and PTFEs etc as more for machined working parts like bearings, spacers and gears etc but I'm sure they are other ways of working them and lots of other uses where their characteristics would suit.
As to what process suits what you're making I would think it'd depend on the type and shape of part you are producing- thin shells like RC car bodies being a common one for forming from thin sheet, whereas chunkier plastic parts like wheels, engine details and interiors etc being injection molded. Also, I'm not sure if Delrin is available as thin sheet- I've only seen it in bar and heavy strip and plate form, but it's possible it is. I only keep a bit of black acetal and nylon bar in stock for turning and everything else that gets chucked in the molder is waste from the recycling bin! :D

Since most of my stuff involves metal (yummy), my wallet has a tough enough job keeping up with the cost of metal stock, so doing the plastics for nowt is tops for a skinflint like me!!
My Missus just informed me I've used up all my 3 months forum time doing these posts- Not to mention the half ton of welsh steam coal keeping the PC fired at full pressure, so it's back to the metal-filled cave 4 now! Hope it's of interest again :wave:
 

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Discussion Starter #14
Actually i have no idea, I need to find the donors first. As Metalwizard pointed out it wouldn't make sense to only make a set or two at a time. So if I can find proper donors, I think I would eventually be doing 30 or 40 at a time...then they could be broken up into smaller groups. So just a really really rough guess would put it at around six to ten bucks for maybe five sets (of four). That would cover the plastic cost...I think.

I may still have a problem even if I find the wheels. building channels to get the resin to all of the wheels in the mold without having it at a really visible point would make demolding and clean up much easier...and maybe critical. With the wheels being so small might make a good mold impossible.

I'll keep everyone updated if/when I make progress.
 

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I would suggest a simple 1 part mold.

exposed face of wheel \/

______
____________________|_____|_____________

the backs of the wheels would be flat, but you wouldnt see them anyway and there would be no exposed mold lines to finish. You wouldnt need any channels, just pour directly into the cavities when the mold is complete. When pouring, add a little resin to each cavity and use a throw away brush to brush all the crevices and eliminate bubbles to finished surfaces. I wouldnt do more than 8-10 at a time unless you have a resin with a long pot life.

I started out in mold making as a hobby. I used to scratchbuild scale dioramas, buildings, landcape etc. for tabletop wargaming. I got tired of making the same things over and over again from scratch, and thats what got me started. So yes, despite it being a job for me now, I know what sort of costs are involved.
 

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Discussion Starter #16 (Edited)
That's a great idea, I was thinking I'd probably lose a bunch to poor flow and I'd end up having to clean them up so much that I'd lose a lot of the details on the back anyway.

BTW, I assume you mean you do resin cars, sorry if misunderstood; Where can I see your products? I used to do a lot of modeling and no that I'm getting back into it I've been wanting to do something different.
 

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Actually, diecast cars are a new thing for me. This past year I decided to start collecting hotwheels for my boys. I started out making mostly scenery and various things for tabletop wargaming. I had an online store doing that stuff for a couple years. Time, family and work kinda put a hamper on the store so I closed it. You can see what kind of stuff i did here: http://tabletopgames.spaces.live.com There are a bunch of galleries to see.

At some point I do want to start casting some cars. I have a few already in the mold making process. Im planning on doing a custom series for both of them.

Its kinda funny, but I have had the itch to get another store going, and I was thinking about sculpting some wheels and doing what you were thinking, among a few other things. So, there already has been some thought on what you are planning on doing. If you have any questions feel free to ask and I can help you out.
 

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Discussion Starter #18
Very cool stuff:thumbsup:. Loved the chariots and the ore refining equipment.

Actually, I'm more interested in doing some 1/24 scale resin models, I was juzt kind of thinking out loud when I thought of the wheels. I kind of figured I'd get an answer like 'yeah ______ has 'em, here's the link.' :rolleyes:

Right now I'm trying to make a curbside kit for a 54 Kurtis Kraft roadster. I'm working on it in foam right now but I'll eventually cast it and hopefully sell a couple...at least enough to break even. I've done blanks for vac-u-form before, but nothing this detailed. So, I'm guessing it will only take 4 or 5 years.:confused: Life would be so much easier with a 3D printer.
 
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