Update from beginner: 30 days later

[keycapsule]

So it's been a month since I first posted my questions about wanting to delve into the world of resin casting. Firstly, I wanted to thank the resinaddict community for being so supportive and helpful during the learning process.

Anyways, here's the update. I've gone ahead and purchase a vacuum pump, chamber, compressor and pressure pot:

* Robinair 15500 5CFM/2-Stage Pump
* Bel-Art Polycarbonate Dessicator
* California Air Tools 6.3 Gal Oil-less Compressor
* California Air Tools 5 Gal Pressure Pot

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A few things to note. Modifications for the pressure pot were a colossal pain in the ass. Stock parts were difficult to remove and weren't the best quality. I should have invested in a vice . I found that the chamber was losing pressure at a rate of 5 PSI and hour. After using the soapy water technique, I was able to troubleshoot the problem to an opening that was a stock part.

As for the vacuum, I've found that I can reach ~29 HG after 2-3 minutes. Is this normal? I suspect there may be a leak as well but am at a loss about how to find it. I'm not using the best components as it's hard to find in my area.

After the initial couple days of set up and troubleshooting, I was finally ready to start molding/casting. Here is a breakdown of each run thus far:

* First half of initial mold went without a hitch.
* Sprayed mold release and poured silicone for second half
* After cure time, opened mold to find that inside was completely gooey and only partially cured.
* As a test, I left it in my warm car. After 16 hours from initial pour, mold was still gooey.
* I suspect I might have sprayed too much mold release or did not allow release to properly cure. That may have inhibited silicon curing.

* Second run went relatively smooth. Sprayed mold release and allowed time to cure.
* Had an incredibly difficult time separating two molds after pour. I ended up cutting silicone with Xacto blade and losing the keys I made in the first mold.
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* Aside from minor flash and very small imperfections, I was happy with the results.

* Third run was a disaster. I decided to get creative with color. I wanted to create a pearlescent black by adding So-Strong black and Cast Magic pearlescent powder.
* After 8 hour cure time for resin, I noticed that resin on the top of the mold was still soft.
* Allowed another 8 hours to be safe. Opened to find it completely gooey in the center. All 4 molds not viable now because of excess resin.
* Back to square one.

Sorry for the long winded write up. Scroll here for the TL:DR questions:

* Currently using Smooth-On Mold Star 30 as it was recommended for it's rigidity and ability to last. http://www.smooth-on.com/Silicone-Rubbe ... index.html
I'm finding that the cure time leaves much to be desired as I'm waiting 24-48 hours for results (2 piece mold). What alternatives are there that are comparable and will have minimal shrinkage and retain the same amount of detail and strength?
* What am I doing wrong with the mold release agent? I'm using Mann 200. I'm finding that it's hard to gauge with the aerosol as my molds are so small. What is the correct amount/application? Do I apply it only to the first mold when I do my second silicone pour? Do I apply it before I pour resin in? What do?
* The master I am using is this: . As the walls are thin, I find that I need to add material to the walls to make it thicker. The thought of having to do this for every mold I make seems daunting and time consuming. Could I create a cast to use a template? Does that seem wasteful and time consuming? Is there a better alternative? I do not have access to a 3D printer.
* Is it possible that adding metal powder may inhibit the resin's ability to cure properly? I am using a digital scale. I'm not sure if its the additive or my ratios were off during the initial mixing.
* I'm currently using Smooth Cast 327 as I'd like a little more pot life so I can pour/pressurize at my leisure. I'm thinking of choosing a resin with a shorter cure time. Do I lose anything (besides time) by doing so?
* How do I troubleshoot leakage in my vacuum setup? I'm able to hit 29.9 most of the time but it seems like its taking a long time to get to that point.
* I'm finding that I hate Sculptey for sculpting the master. I've used Monster Clay and Apoxie Sculpt. I love the consistency of Apoxie Sculpt at the 1.5-2 hour mark. Monster clay doesn't seem as rigid as I need it to be when I've been working with it for a while. Is there a medium that I should look into?

Thanks so much for the guidance and support. Sorry for the drawn out explanations. I look forward to the feedback and advice. Thanks!

[mangozac]

[Fleafa]

I rarely use mould release. When I do, it is wax-based. Not sure what Mann 200 is - wax or silicone.
I have heard great things about Beesputty for sculpting.
Zac answers everything the way I would!
Nice setup

[mangozac]

I've used Mann Ease Release 200 before but much prefer Stoner Rocket Release E302 for resin to silicone release. It's a lecithin based product so is pretty safe to use (I think it's even food safe). It's advertised as being paintable but I wouldn't take any chances and still advise customers to wash before painting and assembly.

I'm pretty certain the Ease Release 200 is wax based and certainly shouldn't inhibit curing.

[RageofAchilles]

Your uncured silicon sounds quite familiar to me, I used to get it a lot in the early days of 2 part mould making. Once I changed my brand of plasticene to a non sulphur type the problem cleared up.
Initially I thought I had put too much mould release on and that was inhibiting the silicon cure.

I also had problems with my first trials with spray mould release and used to get moulds stuck together sometimes as well. I think the porosity of the rubber has an effect , I always shake the can really well before hand and when I spray I am looking to see if it looks wet, only then am I certain the wax has coverage. Sometimes a spray release sprays more propellant then wax, especially if it has been sitting around.

The silicon cure time you have is terrible, honestly for what you are doing , just pick up a cheap silicon from ebay or something, with a fast cure catalyst. I generally turn around a 2 part mould in 8 hours. So long as it doesn't exceed shore A 25 hardness most silicones will perform the same in terms of longevity.

As for your resin pigment issues , I have them all the time with Smooth-on products, they seem to hate pigments, especially black! I have some parts I used black pigment on from last summer and they still aren't fully cured.