Need some help with how to mold my rifle please

[4505marcel]

Hey guys, I recently built a biker scout sniper rifle. I need some help with how to mold the thing as Ive never done anything like this before and want to produce some resin copies.
Now Ive watched some tutorials on you tube, so know roughly what im up against. With making a box, and half submerging it. Then making half the mold, flipping over, remove filler and pour the other half of the mold.
What Im stuck on is what exactly do I use to make the mold, bearing in mind Im UK based so that may help on where to buy. And also how to block the holes so the mold doesnt grab ect.
Hardest part is going to be the barrel I guess. I need something to use to block the main part, so I thought if I get a piece of unused box I can fill will resin and then push out to give me the internal form if you like. Making sure I leave it about 30mm longer each end to my barrel-

I then have an issue as I added a piece of tube ali to the top of my box to give it a better look, I was thinking I could cut anouther off cut and slip it inside my barrel in here-

Would it just be a case of getting some cley to seal the edges of my slots then?

The other issue is on my main reciever of the blaster, there is a recess where my barrel slips in, if the reciver is half filled and allowed to flow into the slot, when i do the other side and fill will it then be flexible enough to slip out of the slot once cured? The slot is about 60-70mm deep

Other parts are the muzzel break and scope but recon they are fairly easy to do, scope Im going to mold the scope mount clips attached

 

[Chaank]

I've been making mould all week. What a mission. I sure there are plenty of peeps on here better than me at it but as for silicon I use these guys.

Polyester - Standard, Silicone items in MB-Fibreglass store on eBay!

There's enough info on each product to cross reference it with what you've watched or read. Are you going to do a WIP? I'd be keen to see how you get on. Very interesting mission.

 

[crypto]

Have a read through this, it helped me get my head around on how to do it.

Making a Hard-Shell Mold ? DIY How-to from Make: Projects

 

[4505marcel]

Il take a look thanks so far guys

 

[bookface]

The barrel will be tricky. If it were me, I'd get a piece of wood that would be a good fit for the inside, and round the corners off so it's as close a fit as possible. Once it's inserted, I'd fill the holes neatly with some clay, ensuring the silicone doesn't just flow into the barrel and make it impossible to demould. Then the link that crypto posted would be a decent basis for making your barrel mould.

When you do the receiver, pulling the silicone out of the recess for the barrel will be tough, probably. However, if you fold both of the halves outwards from the butt, then forwards, you should be able to wiggle it loose so that the plug the silicone will have formed comes out. Someone else may have a better method, because to be honest I don't really love that idea, but it's all I can think of right now.

 

[robstyle]

**MUCH DEPENDS ON THE MATERIALS BEING USED**


for a first time mold, start with the flash hider. Everything else is going to be a cross between advanced and know how / feel for it rather than what a video or tutorial can show you. Once you get the smallest and most basic part molded proper, youll have a feel for the materials.

That flash hider, pop the screw out and get a cold drink paper cup as the "mold box". Its as simple as it seems, mount the part to a flat surface tip up, cut the bottom of the cup out and hot glue the cup around the now secured flash hider. If your silicone is thin enough with a long enough cure time you will be able to roll the entire thing around covering the part in silicone.
I should add, what I would do is clay up that flash hider tip or at least thicken it up inside. Unless your going to use a high impact plastic thats fully cured before pulling the part warping and breakage will happen if the part is not thickened or clayed in before molding.

Once the silicone sets you may be able to pull the master part out if you can get your fingers on it (strong fingers at that), a decent amount of compressed air will help. Not an air can or little compressor but actual PSI output compressor. Then you will be able to make a perfect slice down the mold on one end. This will allow cast parts to be removed. Dont hack it, youll need a long and sharp xacto blade to do this.

Mold that most basic part, then think heavily on the other parts. I already know how to do those other parts but without you having the most basic of molding and casting experience under your belt dont try them.

Also keep in mind cheap resin is brittle and breakage prone. You will need some sort of internal armature when casting up the barrel and receiver both for strength and assembly. It will also help keep the parts from warping if done right.

 

[4505marcel]

Do you think my idea of pouring resin down an un use part of the square box section, to make an exact copy of my internal barrel would work?

Then use that in my mold jacket once done

I noticed that in the link they used cley and foam sheet to block one side, Ive also seen it done where they raise the part to be molded up and then pour like a silicone instead of cley, which is best??

 

[4505marcel]

Out of interest is there anyone UK based that makes molds, that could do this for me If I really hash this up?

 

[robstyle]

Dont even attempt to mold the inside of the barrel. Like I said, start small, get the feel of the materials and how to use then, then rethink molding the rest. A one piece open face mold, such as my suggestion with the flash hider, is where to start. You are trying to jump to advanced methods and techniques without first getting your toes wet.

 

[4505marcel]

I just need to figure out the route I need to take with this, as to what I need to buy.

 

[robstyle]

for the flash hider a basic started kit should do it, as seen near halfway down the page:
Mold Making Silicone, moldmaking silicone molds resins hobby moldmaking
You should be able to locate a supplier in the UK though as shipping alone would kill any possible discount. Dont try and tackle the entire thing before you know how to use the materials in the most basic form. Trust me on this, it will save you time and money.

 

[bookface]

I get all my stuff at MB Fibreglass supplies online UK & Ireland - mbfg.co.uk, they have a pretty good selection of just about everything you could want.