2 piece mold question

[styxandstonz]

Hey guys i've decided to try my hand at casting for some personal use items. I bought the set that Hobby Lobby carries to start with(resin sets up really to fast for my skill level) Alumalite. Anyway i want to try to cast ultimate roadblocks .50 caliber with the spade grip on as part of the cast. As i try to visualize how the silicone will form over the part i realize that the space between the handles will become locked into my mold, and as i remove the clay and mold the other side, it will do likewise locking my 2 pieces together. If anyone has any tips on this or suggestions as to where im going wrong it would be greatly appreciated.

 

[daremo]

Alumalite, ewww, lol. I started out using the stuff but once I switched over to Smooth-On I'll never go back. The Alumalite molds cured hard and their resin cured too fast. I don't think you can cast it in one piece in a 2 part mold unless you break it down into its individual pieces.

It would be easier to do the whole piece in an envolope mold. One pour for the mold and no worries about venting. The key is when the mold cures that you make the right cuts while removing your part. Problem is that you can't do that with the Alumalite set you bought.

I'm no expert though. Maybe try contacting DarkWynter, Starwarsgeek, Vortious, A.V.A.C., or Tofujesse. Those guys do professional molding and casting.

 

[Pickelhaube]

Yep you want a slow set resin to use the fast set is way too brittle and sometimes sets as you pour. Smooth on makes a 30 min resin that gives you plenty of time to pour . That 1 min is just a waste of time and money .

You need to cut off the handle ( m-2 ) and make a pin nub in it so will align onto the receiver.

I also see that you have aligned a few parts to make them in one pour. That probably will not work for you.

You need to separate them to make them their individual pours.

The mould you have may work ( except the spade grip for the M-2 ) if you use the 30 min resin . But you may need to paint the parts with your resin with one of those throw away brushes.

I do this quite often in my larger pieces so as to try and combat pin holes .

 

[pluv]

I totally agree with what has been said. The Alumilite kits are great for learning how to cast. But you want to keep things as simple as possible. One solid weapon or one head per mold. Now you can do several molds, like for all the parts for the M2. The way you have it now you'll get too many bubbles and not enough flow down for what you have. Even Smooth-on resin would be tough for the injection molding that is required for what you want and even then you would need a pressure pot to cure in.

 

[Tofujesse]

Pretty much what everyone else said.

 

[styxandstonz]

Thanks for all the feedback, the learning curve for this is kind of intimidating. but maybe with all the tips i get here it wont be quite as frustrating or expensive. I've looked up a lot of it on youtube to get started and found starwarsgeek's videos to be the most helpful. Im gonna drop the alumalite resin which seems to be a headache to everyone and try the Smooth-Cast® 321(pot life 7 min demold 30)?. One further question i have is about wether the 2 piece mold is the way to go? One of my first attempts was with that shotgun alone in a 1 piece mold. I injected the resin with a syringe from the buttstock end but the plastic never makes it all the way down the barrel, I guess it air pockets and has nowhere to go, hence my elaborate 2 piece mold with the extra parts as vents. I am going to redo my set up and do each part seperate, from what you have told me. Which is the better option? 1 or 2 piece mold? daremo mentioned an envolope mold but my google search for that didnt turn up any useful results, Any pointers on how that works?

 

[Jrsmi6]

Try smooth on 326 with a pot life of 30 minutes and a cure time of 1 hour you will be glad to have a little more time to pour .

 

[Tofujesse]

Try dusting the mold with some talcum powder. That will reduce the surface tension and help the resin flow better.

 

[Vortious]

Yep, like the other have said the Alulilite stuff is just a waste of your time, and money. Smooth-on is the way to go, and you'll definitely want to build a pressure pot to get the resin in there really good.

 

[styxandstonz]

Any recommendations on specific resins? JRSMI6 recommended 326 for 30 min pot life but the spec sheet at that site says 10 min. Smooth-Cast® 325
2.5
Minutes
10 Minutes
Smooth-Cast® 326
7-9
Minutes
60 Minutes
Smooth-Cast® 327
10-20 Min.
2 - 4 Hours
So the end plastic for these are equal in properties just the pot and demold time varies?

 

[Jrsmi6]

I meant 327 sorry for the confusion. I did have 326 ,but the cure time was a bit faster than I wanted so I switched to the 327 to allow for a little more work time to get it in the mold and then the pressure pot.