Author Topic: Mold making, Some tips,tricks and links.  (Read 1145 times)

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Offline Rezal

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Mold making, Some tips,tricks and links.
« on: April 06, 2016, 02:27:38 PM »
Making a mold for a part or miniature, can be easy, or a total nightmare and waste of money. I have experimented with making molds with a lot of different items. If you wanna try copy a part, or make a mold of something you made,I can give some tips, because I have made a lot failures.

Molding material

Instant Mold or Oyumaru (hobbyist's best friend)
This stuff is amazing, I have a very small amount of it, and every time I use it I am just own back with the ease and the great detail of the casts.

Pros: Easy to use
         Reusable
         Captures most detail amazingly
         Works with both green stuff and resin
         Molds can be made in under an hour
Cons: Pricey ( not so bad if bought in bulk)
          Some detail will be hard for I to capture because its a putty, you have to "force" the detail into it( hmm onto it?)
          After 10 to 20 casts the detail starts to ware off (its reusable so once you start to notice the diminish in quality you can just   
          reheat and re use)
         
Molding Silicone (The Pro stuff)
This stuff works well, is some what cheap, you can get starter kits with resin, was a little hard for me to track down a supplier. You really
need to know what you doing when working with this stuff, with Oyumaru all you really need is a cup of boiling water, silicone you need a scale, mixing containers, a vibrating platform, mold release and a vacuum box.( you only really need a vacuum box and/or a vibrating platform if your having problems with bubbles in your mold)

Pros:  Captures detail amazingly well
         The tin based ones can be very cost effective, and its what a hobbyist will use.
         Molds can last if looked after correctly
Cons: Mistakes are permanent, only thing you can do with a bad mold is cut it into blocks and use it for filler on big molds to save some 
          silicone
          Difficult to get bubble free molds, with the right tools and experience this wont be much of a problem
         Takes up to a day to dry
         Wont be able to cast with green stuff, only resin ( the mold is soft )


Molding latex.
Yeah I could never get this stuff to work for me

Some house hold products.

Hot glue sticks
Pop it in a pot of boiling water, push it down on your part and hope for the best. Now you may be thinking why spend 10 times more buying some Oyumaru, well because stuff can go horribly wrong with glue sticks and it starts to get very hard. The pro is that's its cheap, but its glue and being sticky is not a quality you want in a mold.
Pros: Cheap
         Works with green stuff.
Cons: A mistake will cost you your part.
         Feels like working with inferior Oyumaru

Silicone caulk( the kind that smells like vinegar )
Buy the clear silicone, wash it with some soapy water, push it down on your part. The stuff works well, takes some time to dry. Never really got a great mold out of it.
Pros: Cheap
        Works alright
Cons: Might corrod metal parts, happened to me with my tomb spider
         Wont work with green stuff ( the mold is soft)

That is all the stuff I have used, I would say if you want to try and make some molds for one or 2 off parts Oyumaru  is great, anything more or bigger go with silicone.

Some links to tutorials I found very helpful.

https://www.youtube.com/watch?v=SoMLvLuUlHc

http://dedard.blogspot.co.za/2012/04/resin-casting-1-part-molds.html

Will be adding some tips and info? I guess and some info on casting resins, ummm lost track in the next few days I think

Hope that was legible and helpful

Offline Dirty Harry

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Re: Mold making, Some tips,tricks and links.
« Reply #1 on: April 09, 2016, 04:26:43 PM »
Damn dude, I'm impressed you've done this much leg work with casting. Any good stuff to report on resins?
Don't try making a unit unkillable. its a waste of time and the dice gods laugh at you for wasting your time. Dedicate a unit to a job and make sure it does it til it's either dead or running.

Offline Rezal

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Re: Mold making, Some tips,tricks and links.
« Reply #2 on: April 10, 2016, 01:01:34 PM »
Resin, where to start.

Polyurethane Liquid Plastic Casting Resin( I love this stuff)
The best resin to use, is an easy flow resin made for casting, they not even that expensive. You might have to shop around to get it.
Pros:  Easy to use
         Great detail in casts
         Easy to clean parts
         Non toxic
         Clear while wet, white when set.
         Works with hard and soft molds
Cons:  Not as strong as plastic
          Curing too fast can be problem

Green Stuff ( you sculpt with this stuff)
Easy to get easy to use, sets nice and strong, I honestly dislike using this stuff in molds, I have never been able to capture the maximum amount of detail with it.
Pros: Easy to get
         Sets nice and strong
         Works very well in 1 part molds, where you can really force it in
Cons: Detail looks rounded and soft, I have had very little luck with pushing green stuff in a mold
         Mold has to be "hard" a soft mold like silicone wont work with it.

Some home stuff

GP resin ( aka fiberglass resin)
Easy to get, little shrinkage but awfully brittle. It captures detail almost as good as the easy flow resin.
Pros: Cheap easy to get.
         Captures detail.
         Little to no air bubbles.
Cons: Very brittle

2 part epoxy ( the glue stuff)
Over here a tube of epoxy resin is half the price of "easy flow" but you get a great deal less, parts are strong, cleans up alright, never painted on it, so I cant tell how it paints. No matter how hard I try there is always a large number of air bubbles, it could just be the epoxy I used
Pros: Works alright
        Good strength in parts
Cons: Pricey
         Large amount of air bubbles.

Hot glue ( don't use this with oyumaru)
I have never use hot glue in a mold. but if I did I will only use it in a one part mold, where I can force it into the detail once its cooled off a little

I dunno what else to cover if you have any questions just ask. Also like anything you try, don't expect it to be prefect on the 1st try. Keep at it, it might be expensive at the beginning but once you get the hang, well you will be casting parts for next to nothing

Offline Rezal

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Re: Mold making, Some tips,tricks and links.
« Reply #3 on: April 19, 2016, 12:46:24 PM »
The Dirty casting method.( easy and messy)

This is the method I use. I have tried making molds more like the pros but was always riddled with bubbles.
It is a rather simple method that works with basic 2 part molds, no fancy airways and runs needed in the mold. All you have to do is poor resin in each side,work the air bubbles out with a hook tool ( I would use a tool that isn't sharp or very pointy, don't wanna damage the mold). Wait till the resin starts to get thick ( if the resin gets too thick you will have nasty flash, to "thin" you will land up making parts hollow, lose detail and make it weak, practice is the key your 1st few casts may come out terrible but you will get the hang of it) and then quickly slap them together, add some weight( too much weight will deform the part) on top of it, and wait for the resin to set hard.
Let me just say I am not a professional nor have I been able to figure out the best place to add ways, if you try this and land up wasting time and money, please don't blame me.
Pros: Molds are easier to make
         Can get close to flawless casting
Cons: It can use more resin then the "right way"
         Heavy flash and a loss of detail
         Parts are slightly deformed ( the resin gets in-between the two parts of the mold making parts slightly thicker)

I am rather terrible at explaining stuff, if I have not provided enough information, just ask and I will try to do a full guide with pics.