help needed casting

[lenny100]

I got a idea for a project and i need 24 jet engine fans.
Now i have found the ideal part from a revel me 262, the engine front ends are separate pieces.
now rather than buy 12 kits i like to try and cast them to save costs, but i have never cast anything before,
an those with experience help me with were the best place to get the materails from etc?

[Captain Canada]

Engine covers 

Somebody here was just talking about casting, Seadude maybe ? Or Sandiego ?

[Rolead]

Try here
http://www.sylmasta.com/acatalog/Sylmasta-Casting-Kit-01---FREE-25ml-Clear-Epoxy-906.html#SID=6

or

http://www.modeldesignconstruction.co.uk/mall/productpage.cfm/ModelDesignConstruction/_CS001/427837/MDC%20Resin%20Casting%20Kit

I get mine from MDC both comes with instructions as well.
Robert

[sandiego89]

Somebody here was just talking about casting..... Sandiego ?

I confess.  I have done a few casts, including a 1/72 podded Pegasus engine, but am by no means an expert.  In this link below you can see a casting a did for the podded Pegasus.  A few pictures down shows a drak gray center section of a Harrier- that is what I used as the master.  I then cast 4 additional engines and you can see a few of them in the light tan color. Good detail- I was happy with them, but have not made my secret project yet  


http://www.whatifmodelers.com/index.php/topic,38400.msg628401.html#msg628401


I can post more pictures later if needed.  Very happy with the "super casting kit" from Alumilite http://www.alumilite.com/

$70 US.  Click on products, then support products to see the the "Super Casting Kit".  If you click on dealers, they seem to have good coverage around the world.    

Avoid brush on molds- those are OK only for simple jewelry or trinkets.

The Alumilite kit comes with everthing you need to make the mold, mixing and resin.  You may need to buy extra resin (extra bottles each in an a and b bottle), and more mold release agent if you are making 24 engines.  I liked the idea of buying an entire kit as I was not sure what to buy individually.  A great way to start.  

Good videos on the Alumilite site as well (or just search resin casting). Watch them. I ran out off the RTV mold material from this starter kit and bought another brand I was not as happy with.  I will stick with Alumilite, but there are other brands.  I really liked the flexibility of the Alumilite RTV- it is like rubber and easy to pull off from the part  

If you are just doing a fan face, you might be able to get away with a single piece mold, but if doing an entire nacelle you will likely have to do a two piece mold. Make your master, make a small box just larger than the master (lego's work!) put the master halfway into the supplied clay, pour over the top half, let stand a day.  Flip it over, remove clay and pour in the other side of the mold.  Hard part is done.  You now have a 2 part mold. Heat the mold in the microwave, mix resin (you only have @30 seconds) pour into mold. In a few minutes you have created a new replicate part ready to pop out. You can reuse the mold many times, so making 24 sets will not be a problem (but Resin is a bit expensive)

It sounds very intimidating, I was afraid, but jumped in.  It was easier than I thought it would be once I got over the unknown, if I can figure it out- anyone can.  You will mess up a few (mainly by not mixing well enough, or waiting too long to pour) I am still learning.      

[kitnut617]

I too use the Aluminite, I've got good results and like sandiego89, I don't profess to being an expert on the subjects.  Not done a two-part mould yet but have done a few open end ones.  Wheels, engine nacelles, air intakes and exhaust nozzles so far.  You have to be very precise with measuring the two parts to each though, the mould silicone rubber and the resin.  The rubber is done 10:1 and the resin 1:1, by weight --- so get a good weigh scale that can measure in 1 gram increments, I picked one up at the hardware store which can do that. I was using the wife's cookery scale but it wasn't very precise at small weights which is all I've done so far. The rubber usually has about 30-40 minutes to play with at room temperature (and then left for a minimum of 24 hours somewhere warm), the resin has 30 seconds.  30 seconds doesn't sound like a lot of time because that still includes the mixing time which has to be very thorough, but if the mould isn't too technical, it's plenty of time, especially with what you want to do.  The part can be got out of the mould in 3 minutes, but I usually leave it for five just to make sure.

Here's some parts I've done ---









Do simple ones first like your fan fronts, which can be done with a one part open mould, then as you get experience, try something a little more complex.

[kitnut617]

One other thing, don't buy a big package, this stuff has a shelf life, about 3-4 years so I found out.  I had bought the kit like sandiego89 but hadn't the courage to try it so it sat in the cupboard for ages -- when I did go to use it, nothing would set --- 

[sandiego89]

A few more shots

The Alumalite kit box.  Not all of it shown here.



The process.  The master piece that I want to replicate is a 1/72 podded Pegasus engine.  I need a 2 part mold as this is a complicated shape. The master piece is the dark gray engine.  You cna see 4 engines I made a copy of, they are in tan at the top of the picture. I made the wall for my mold out of pieces of plastic styrene.  That is the white box in the upper right. You make it just a bit bigger than the piece you want.  Too big and you waste mold material.  Too close and your mold is to thin and could break apart.  I used a hot glue gun to tack it together. More hot glue to mount it to the base (an old shelf) any non porous surface will work. You just want enough to hold it in place.  Legos work as well.    



You then cover the bottom of the mold box with clay.  Put your master piece half way into the clay.  The RTV mold is then poured over this, covering the top half of the master.  Let dry overnight. Flip it over, remove the clay, leaving the master in place.  Coat the mold with mold release agent so the two halves will not stick together (RTV will not stick to anything, excpet more RTV)   pour part two of the mold.  As Kitnut says a one part mold is much easier if your part is simple enough.  His look great. You get great detail.  

The mold out of the box.  The mold is white.  Remove the master.  




The two part mold on its side.  A hole cut to pour in the resin.  Mix the resin, part a and part b in a a cup. Quick you only have 30 seconds.  Pour in.  Let sit a few minutes and pop you your new resin piece. Here my two piece mold is shown together, it is tough to see the seam line in the two halves.



A new engine in tan between the two halves of the mold.



Hope this helps.  More simple than it sounds- go for it.