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Looking for advise as I prepare to make custom pieces in resin.
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TOPIC: Looking for advise as I prepare to make custom pieces in resin.
#13068
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 6 Months ago  
There are a few unique, custom pieces I really want to make to compliment my DF stuff. That being said, I intend to make them in resin. I am planning to build the two "bleacher" pieces I mentioned in the "Gladiator Arena" thread and then an ice/crystal cave.

As I am inexperienced in terrain building (and especially with the use of resin). I am hoping for any insight, suggestions or recommendations that I can get before I start.

The specific areas I am in most need of suggestions are:

Recommended techniques and materials for creating the master model (to be used to make the mould).
Recommended material (or product) for creating the mould.
Recommended resin products, (both clear and opaque if possible).
Coloured resin products (or colouring processes of clear resin -if that is even possible).

As you can tell by my questions I am new to this, so any and all advise will be greatly appreciated.

Thanks again.

Steve
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#13069
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 6 Months ago  
The master pattern needs to be perfect. By that I mean it must not be porous, and if hollow it must be well sealed - there's nothing worse than moulding rubber seeping inside a master for causing damage. It can have undercuts, but the bigger they are the shorter the life of the mould. Rough textures also reduce the life of the mould. Simple shapes are easier to mould and easier to cast. If you're making something complicated, consider making it in several parts for assembly after casting.

It's best to think about how you want to cast the object before you make the master. You need plenty of room for pouring the resin into the mould, so design a suitable place for a vent into the object (easy with DF-type pieces - pour from the bottom - under where the felt will be). With that in mind think carefully about where air bubbles may get trapped, and either design those areas out or arrange a vent in the mould when you make the mould.

Phil
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Medieval Buildings Set, Caverns x2, Cavernous Passages, Room and Passage, Deluxe Room, Octagonal Room, Narrow Passages, Advanced Builder, Wicked Additions I, Wicked Additions II, Traps I, Traps II, lots of individual pieces. I want Cavernous Rivers, and Cavernous Lakes, and Cavernous Ledges. Can you tell that I like caverns?
 
#13070
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 6 Months ago  
Steve -

Smo0th-On makes OOOMOO, which is their version of two-part silicone rubber mold material. It claims a pot life of @10 minutes, but I've ALWAYS made sure my mold masters were ready to pour before I even opened the jars to start mixing rubber! It's @$30 for a set of 1 pint bottles.
Micro-Mark has a complete starter set, which includes 2-part rubber, 2-part resin, mold release agents, Kleen Klay to help make mold boxes, mix cups, stirsticks, and (IIRC) mold-release agent brushes. They also include a one-sheet quickie text on how to make molds and castings. Their rubber and resin bottles are also @1 pint, but the set costs a LOT more than $30 - but you get more stuff.
Kalmbach publishes a couple of different books that hit on casting resin in rubber molds - check out their Web page for which books, and if your FLGS or FLHS has or can get them, go for it. I always recommend going through local stores if they can get what you want at a decent price; it helps the industry and the hobbies. If DF still worked through FLGS, that's where I'd buy it; they don't so I don't.
It's POSSIBLE to use colorant tints in the white or amber resins, but they really DON'T work that well. Micro-Mark carries clear resin as well as white, and although I haven't used it, it's supposed to be good for colored castings as well as clear. If you want a clear, colored casting, better plan on a VERY SMALL AMOUNT of colorant! Also, when coloring the white Micro-Mark resin, I noticed that the more colorant I put in, the more flexibility I got in the finished product - in fact, a couple of my floor pieces are almost rubbery! Remember, you can always PAINT the solids; it's the clears you can't do that with, unless you use clear colors such as Model Masters, or inks such as Citadel puts out.
As Phil said above, remember undercuts and vents; take a serious look at multi-part molds to avoid severe undercut troubles. And don't be afraid to make a single-piece mold (where the bottom of the piece is open-air, as Phil says) with a marked pour plug - you can always saw and sand off the plug after curing.

Good luck, remember to post lots of pics when you finish!

See ya! (In Indy?)

Jim
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#13071
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 6 Months ago  
Lego bricks are good for making mould boxes.

No, I'm not kidding!

Phil
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Medieval Buildings Set, Caverns x2, Cavernous Passages, Room and Passage, Deluxe Room, Octagonal Room, Narrow Passages, Advanced Builder, Wicked Additions I, Wicked Additions II, Traps I, Traps II, lots of individual pieces. I want Cavernous Rivers, and Cavernous Lakes, and Cavernous Ledges. Can you tell that I like caverns?
 
#13072
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 6 Months ago  
I have been using the Alumilite (through a .com on and you have the website) for the molds and the resin, just becuase my FLGS stocks that brand. and has the same type of starter kits as jkratzer mentions. You can make molds with deeper undercuts if the RTV is softer and stretches easier, i have tried two of the Alumilite rtvs, and depending on what i want it for the difference in hardness can be a really big difference in how well it handels undercuts and how many molds you can get out of it.

Also plan very carefuly how you want to make your molds from the masters, both jkratzer and philhendry talk about this and this can be one of the tricky parts, and something i am still working on so you can get the most out if your molds.
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#13073
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 5 Months ago  
There is some decent information on the HirstArts website about molding and casting.
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#13074
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 5 Months ago  
Thanks for all of the excellent advise!


As I prepare to begin making the first master, I have need of some further advise/clarification on the possible materials I may be able to use:

I was hoping to use balsa wood (or something similar) to design the base of the piece around.

If possible, is there a coating (spray or otherwise) that I would be able to cover/coat the balsa-wood piece with so I may use it to create a mould from?

If balsa is not usable, are there any suggestions of a substitute. (There are a lot of straight /linear features to these pieces, so I m hoping to avoid "sculpting" the structure, if at all possible.

Again any help is appreciated.


BTW

Jim, I'll make a point of getting pics posted of these when completed.
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#13075
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 5 Months ago  
I do my own resin castings for things not out there also.

I use the alumilite series of resins and mold rubber which can be purchased from various suppliers.

Soft wood is a horrible medium for a base as the mold rubber may permeate into it, but you could always try a small test piece and see what happens. If you are going to seal it anyway- thus creating a smooth surface then I would suggest using good, old sheet styrene built up to the base depth you want. The top layer can even be textured as many hobby sheet styrene can be found in varied textures (brick, stone, wood, etc).

ALso, unless you purchased a vacuum and pressure pot you will get air bubbles. To minimize those I do the following note the following is for a single piece mold):

- On the master I attach a small (1/4") sprue to corners or high points that act as air traps. After pouring the resin I then use a toothpick to "scrub" my detail- you would be ammazed how many bubble pop to the surface.

- On the mold itself I will use a new, sharp exacto to cut up through undercuts and/or into deep detail. AFter pouring the resin I will spread these open to make sure resin flows into those details and scrub them with a toothpick. You will get some thin flash but better some flash to scrape off then having your piece 7/8 formed. Do not worry about deforming the master- mold rubber has an institutional memory which will return to its set form. NOTE: this applies to alumilite mold rubber for sure- I cannot vouch for other types.

- WAIT until the resin is fully set- fine, thin details take longer to set then a big block. As excited as your are to pull it I now give everything about 5 minutes after pouring. I have ruined a number of pieces by pulling them too early and having the fine detail stretch like taffy and either break or set in a deformed manner.

Colored resin- I made a handful of color resin and clear. Be very clear on this- if you do not have a vacuum and pressure pot set-up you WILL see bubbles in these castings. There is no way around it. SO if you plan on casting a clear bubble free piece without the right equipment it will not happen.

For colorant use ONLY colorant made specifically for resin and even then a drop or two goes a long, long way. Food coloring will not work and can cause the resin to go berserk. As stated colored resin tends to come in clear and amber. Obviously use clear if you plan on tinting it with resin colorant.

One more word on resin color- resin can be purchased in white, tan, red and black for sure. I tend to cast in tan but when I needed to make some ruins I cast in black, washed them and then did the old dry brush of grey on them followed by a few seals of gloss and then matte spray paint. It saved me a ton of time and black undercoat to do that.
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#13076
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 5 Months ago  
One thing I didn't see here is advice on what kind of material to actually create the master piece from--the original sculpt. I may have overlooked this but if it wasn't posted, here, you might want to consider purcahsing a large tube (or two!) of "the green stuff" (two part expoxy putty) for creating your "original sculpt." You twist the two parts together (the blue and the lime-green) to make your workable putty. Sculpt and shape as necessary watching for areas that will create undercuts as someone mentioned above. This stuff can get very sticky while working with it so experiment a bit with it before you go gung-ho and start on your dream works.

Green stuff is great because it has a decent working time before it starts to harden up and cure. You can stick it in the freezer to slow down the curing process and work on it almost indefinitely by repeating the freezing process. When you're finally satisfied with your sculpt, simply let it air dry in a (relatively) dust-free area for at least 24 hours--longer if the piece is quite large. The epoxy hardens up nicely and can be coated with a powder mold-release agent, or brushed with soapy water as a mold release agent. I've never used "professional" mold release agents on the greenstuff that I've worked with so you might want to check compatibility if you do.

You can make this mold release agent by taking a teaspoon of generic dish detergent and adding it to a cup to 2 cups of water. You coat your master sculpt with it so that the resin doesn't stick to the master when you start painting your rubber over it to create your mold. Let the agent dry before you start coating your piece with rubber though!

Once you've created your perfect model of what you want the finished piece to be, start thinking of the materials you're going to use to create your mold. If you plan on making a lot of these pieces--say to trade or sell, consider investing in a GOOD RTV rubber that has a high tear rating or that can be vulcanized (heated up in an oven to really make the master mold tough).

The best results are achieved from knowing what materials work best with each other. Some RTV rubbers don't work well with certain types of resins. The rubber can't hold up to the high cure temperatures of some polyester resins for example. Likewise, silicone based rubbers don't have a very high tear rating so it's easier to destroy them in the casting process.

You'll want to make a thick mold for extra durability so as has been mentioned above, think about what kind of "mold box" you need to support the walls of the mold. I have used Legos as philhendry mentioned above. They're cheap, they're extremely well suited for making hollow "boxes" to place your master sculpt into and pour your resin over.

The first few layers of your mold are critical ones so you really want to take your time in applying the rubber evenly and with as few bubbles as possible. Use a soft brush to paint the RTV (or silicone) rubber over the master and give ample time for it to dry before you start painting on the next coat. And so on, and so on... when you get to about a half-inch of thickness (it can be a very time consuming process but the results are much better than simply pouring over your work and waiting for a week for it to dry), you can start to slather the rubber on a little thicker. Keep in mind that the RTV (or silicone) has to try adequately before you can work with the mold so don't slather it on too thickly. I don't know how the "real professionals" do it but this process works like a charm for me. When you've built up a substantial thickness (3/4" at least I'd recommend), place your piece in your mold box and pour the rubber over top to create a "block" around the mold. Vulcanizing is another thing that you may need to look up additional info on--there are safe ways to do this in a conventional oven but I don't want to encourage that and wind up with some sort of liability issue. ;-}~

When you get to the point where you're ready to pour your resin, one thing to consider when letting your resin cure is to (don't laugh--this isn't some weird sex thing...) use a virbrator or a vibrating device to "sonically lift" the bubbles out of the resin as it cures. Some have put their pourings on top of a running washing machine or dryer--I've done this--and it achieves the same type of results: less air bubbles trapped in the curing resin.

Check out TAP Plastics and Eager Plastics online for a ton of helpful information on resin products and RTV or silicone rubber mold-making products. Hirstarts does have some good advice but their stuff (if memory serves me well) fccuses a lot on the use of silicone rubber and dental plaster casts.

Hope this helps!

-Dante
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#13077
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 5 Months ago  
Wow!

Those detailed instruction are GREAT!

As for the project status: I'm off to the stores tomorrow to grab the materials for making my first sculpture/piece. After that has been completed, -perhaps a week or so (if all goes well) I'll head out for the RTV material.

This may sound a bit cliche' but (one way or another) I intend on using every bit of the advise provided here.

Once I have pics of the results I'll toss 'em up in the COOL PHOTOS section.

Thanks again.
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#13078
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 5 Months ago  
Wereweasel -

One thing I DIDN'T see here about master materials; Stefan uses beeswax, or something similar, for his masters. I don't know how well it works for him, or if he does anythign special to it, but look at what we're buying from DF!
Of course, Stefan IS a pro-trained, pro-level sculptor and painter, so he probably know a LOT of stuff WE don't.
So, ASK him.

Good luck, guy - and I'm NOT kidding; I hope all goes very well with your project.

See ya in Indy!

Jim
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#13079
Looking for advise as I prepare to make custom pieces in resin. 8 Years, 5 Months ago  
Good point Dante

Green stuff is sticky and hard to work with especially for beginners- as well as being expensive.

Basically you want to make the master out of any NON-POROUS material. I have used green stuff, lead, copper, steel, styrene, plastic bits, etc etc

For a beginner I would go to any decent art supply store and buy a brick of Super Sculpey (not plain Sculpey but Super). Sculpey is a polymer clay that can be used "As is" or can be baked to harden it up. It is very friendly for beginners and yet even experts can make extremely delicate masters from it. WHen I used to do lost wax castings I made almost 100% of my masters from sculpey.

I get my casting supplies from:
www.hobbyengineering.com/SectionBM.html#CatBMSUPPLY

They also have various "dusts" that can be brushed into a mold master then when you pour the resin it comes out looking metallic.

I would also reccomend going with simple one piece box molds for now. Two-part and more piece molds can be very aggravating.

For more info do a google for "RTV mold making" , "Resin casting" and so on. Get a good handle on what you are doing, understand how undercuts and voids can screw up a master and so on.

And just to give you a brief idea on masters here is the process for when I needed some wreck counters for Warmachine:

3 masters using metal, plastic, some green stuff for hacked detail, and sculpey (to fill the voids and give some ground texture):


A master and its first resin pull:


The painted casting:
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