Mold and Cast Help!!!

ok so i want to make some plastic weapons then put electronics in and i want to do it the mold and cast way where you get a mold and poor plastice into it and you get a cast but i have no idea how to make a weapon mold. do you get 2 pieces of plastic and make the weapon shape or something cause i don't know. i want it to be like this vid here


any help will be hugely appreciated thanks

Mr Boombas Out.

Welcome Boombas...

So... when it comes to weapons, most use a 2 part "box mold". Which be advised, it is Silicone Rubber you use for the mold. You make copies using 2part catalytic Plastic.

So I recommend reading these, and watching these videos first. DO IT.... it will help. There isn't really a walk you through it as you go video, but honestly molding and casting is a Trial by Error process when learning. You will have mess ups, you will have fails, and you will have instances where 100dollars worth of silicone goes spilling all across the floor from a failed mold box. SO have fun!


http://www.smooth-on.com/howto.php

http://sculptingtutorials.blogspot.com/p/moulding-and-casting.html

(this video here is a good friend of mine's... watch and be amazed)


And you can ALWAYS learn from Volpin...

http://www.tested.com/art/makers/455027-volpin-project-part-7-introduction-moldmaking/

You need to make a master model to mold first out of some other material either Eva foam mdf wood or some other material before you can make a silicone mold of it

When you make a master for molding you want to put in any detail you want seen in your molded one. I have found the best built master's to be sliced constructed because they have the places for electronics already built in. You can use the search bar to find sliced weapons builds and may even find a sliced file or two in the archives.

I recommend taking Gilmore of OK advice and watch the vids. Also Smooth-On has a book or 2 on the basics of making molds.

There have also been some highly detailed scratch weapons builds that may be worth looking at also.

Doing the research and a lot of reading will help keep mistakes low and also help build your skills more.

Mistakes will happen though just don't get disappointed.

Good Luck and have fun!!

Squirrelly-ORC (Orsinium Recon Corp)

I agree with Squirrelly-ORC; follow Gilmore of OK's advice and watch those video tutorials first. There's no quick and easy way to learn how to do it, it takes some time doing research into the process and reading/watching whatever you can find online. Those of us with experience in molding making and casting can help with any questions you may have

From personal experience, any and all of the mold masters I've scratch-built were made from various forms of plastic (layered sheet styrene, Sintra (PVC) board, etc.), which when complete I then primered before putting into a mold box. I typically use cut up cardboard for the walls of the mold box, which I hot glue onto a flat, level surface. I make sure to thoroughly glue all the seams (bottom of the walls, inside and outside of corners) to avoid any silicone leaking out.

One that's done, I apply a little bit of glue to the mold master to firmly secure it inside the mold box, then after applying a mold release agent to the inside of the mold box walls and doing a little bit of basic math to figure out the volume of silicone needed to make the mold (mixed at a 1:10 ratio -- 1 part catalyst to 10 parts silicone) I pour the mixed silicone into the mold box and let it cure for 18-24 hours. I usually leave it for a full 24 hours just to be on the safe side.

I myself have always done one-piece, open-backed molds for the props I've kitted out, meaning the entire back end of the prop is the pour spout as all of the detail has only ever been on one side of the piece. In your case, the process will differ slightly as you'll be making a two-part mold with specified pour spouts to make sure you get all the detail on both sides of the prop weapon you will be molding and casting.

The specific process for what you'll be trying to achieve can be learned from the tutorials linked to in this thread and found elsewhere on the 405th.

Precisely. I live next door to MorganThirteen on the RPF, and he is probably the greatest mold maker on the planet. He gave me a GREAT piece of advice, "Spend the same amount of time on your mold as you did the actual item" His molds are surgical works of art, because he puts the same amount of effort into the mold prep that he does the piece build.

Gilmore of OK said:

Precisely. I live next door to MorganThirteen on the RPF, and he is probably the greatest mold maker on the planet. He gave me a GREAT piece of advice, "Spend the same amount of time on your mold as you did the actual item" His molds are surgical works of art, because he puts the same amount of effort into the mold prep that he does the piece build.

Click to expand...

I wholeheartedly agree. Every one of the mold masters I've made in the past took weeks, if not months, to finish before molding. Just because the molding of the actual piece is the final stage doesn't mean you should use any short-cuts to get to that end result. Hastening the mold making process is what ends you up with a ruined mold that's run all over the table or the floor. Take your time with both building the mold master and molding/casting the original prop.

ok guys thanks heaps, i will take your advice and research up on this stuff and try to make a master prop first, probualy out of wood as that would be a more comfortable material, then when i get it 100% done i will take the advice Spartan II gave. my only question is what does sliced weapon files do? i ask this because i don't completely understand it.

sliced weapon files are just 3d models that are literally "sliced" into sections so you can use them on say, a 3axis CnC router. Or others refer to that where you literally start with the base shape, and build the layers up or "each slice" to get the final product.

A sliced weapons file breaks the weapon into slices. You then cut each slice out of your chosen material then glue them together in the prescribed manner, make sure every thing fits properly, sand and prep for painting (atleast a couple primer coats ) and then get ready for casting it if you are satisfied with the finished product.
If you are going to use a scroll saw or band saw I recommend using 1/4 inch plywood ( I use a marine grade plywood) Also use a sanding sealer before you decide to primer it ( this will help with getting even primer coverage with no grain show thru).
You can also use a couple light coats of spray exterior spar varathane (water borne) as a sealer instead of a true sanding sealer. It will also help keep your master (original) from soaking moisture even thru the paint and keep it fairly waterproof if you decide to carry your master at cons and stuff till you can get it molded.
For adding details I use a thin hobby plywood (Finnish Birch).
I also use urethane exterior glue (Gorilla Glue) when glueing the layers together.
I use small pieces of hard wood also for sight's, clip release buttons and other small stuff.
Also carving chisel's, needle files, and a dremel are handy for etching in detail's.
Feel free to ask if you have questions.

Good Luck and Have Fun
Squirrelly-ORC (Orsinium Recon Corp)