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Setting Up a Harbor Freight Pressure Pot For Casting

– Posted in: Casting 101

Show Notes:

Just bought a second pressure pot for casting blanks, and I thought I’d do a little walk through on how I set it up.  In this video I show what I remove and the plumbing fittings needed to get it ready for casting resin.  I usually cast Alumilite products, but it can be used for polyester resin and epoxy as well.

Here’s the plumbing parts list (I got mine at Lowes):
-1/4″ elbow
-1/4″ ball valve
-1/4″ male air hose connector
-1/4″ cap
-Reducer to 1/4″ (I have to double check the threads on that one)

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Liz December 21, 2016, 2:30 PM

Thanks for making these great vidoes! After using the alumilite white with dye to make colored pen blanks, after the 45 minutes of pressure pot, how long do you have to wait until you drill, glue and turn them?

From your experience what are the pros and cons of melamine, vs pvc tubes vs the stuff cutting boards are made of ?

thanks

Zac Higgins December 21, 2016, 11:43 PM

Hey Liz, glad you’re enjoying the videos 🙂 Alumilite White has a 72 hour full cure schedule. You can technically machine them the same day as you cast them, but it won’t polish as well since it hasn’t reached full hardness. For best results, give them 2-3 days before you start working with them. Alumilite Clear has a 5-7 day full cure schedule, and I’d recommend waiting at least 4-5 days before working with blanks made with it.

I’m using smooth HDPE for my square molds, which is basically what cutting boards are made of. My problem with most cutting boards is they are usually textured, which makes them more difficult to demold the casting and they don’t seal too well. In my experience they were somewhat softer material than the smooth HDPE sheets I buy from Grainger. I definitely like HDPE better than melamine, but melamine works fine as well if you caulk the edges and spray with mold release each time.

I also use PVC pipes for some things too. They’re easy to ‘make’ a mold with, they work great, and you save resin since they are round. I don’t really like pouring color swirl style blanks in PVC pipes myself, I prefer the look of the swirls I get when pouring in rectangular molds, so I only use pipes for solid color blanks. You have to use a mold release when casting Alumilite in PVC pipes too, I spray them with Stoner Urethane Mold Release spray before casting.

Overall, the material you use generally comes down to what you plan to do. If PVC pipes will work, I’d probably go with those since they are cheap and easy to make. If square molds work better for what you plan to make, then I’d probably suggest going with smooth HDPE.

ANDREW murphy February 13, 2017, 8:18 AM

you could look online for sheets of HDPE they not costing that much and i have bought for molds on other projects it does fine

Wayne October 13, 2017, 4:31 AM

HTPE textured cutting boards. I have run them through the planer before, to get more cutting life out of them. That worked fine. It may also work find to cleanup one side for molds.

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