Clear castings without a pressure pot?

Hecubus114

Sr Member
RPF PREMIUM MEMBER
Is this possible? I need to make multiple casts of a crystal, so they need to be clear and bubble free. I don't have access to a pressure pot - am I outta luck?
 

SUPERprops

Well-Known Member
I think you might be out of luck man. It's very hard to cast bubble free let alone free of all the millions of tiny bubbles. depending on how big it is you might be able to get a cheap pressure paint tank which can be used to cast it in.
 

Hecubus114

Sr Member
RPF PREMIUM MEMBER
The crystal I need is maybe 4 inches tall and 2 inches wide... I know nothing about pressure pots - how small can you get them?
 

XtcofPain

Sr Member
I made my own pressure tanks with a spaghetti container, perspex lid, rubber seal, clamps, a tire valve and a bicycle pump. Works great for me. Cost bout 25 euro in all to make. I can also connect it to a compressor. Ive had it at 50 psi before and works fine.
 
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exoray

Master Member
The crystal I need is maybe 4 inches tall and 2 inches wide... I know nothing about pressure pots - how small can you get them?

2 1/2 Gallon is a common paint pot size and cheap easy to find and re-purpose solution...

As for necessity, I would say you are wasting your time and money even attempting to find a way around pressure casting...
 

exoray

Master Member

If you follow their sales (yeah it's on a small sale now) you can get it for 40-60% off sometimes...

For me I just kept my eye out on Craigslist and Ebay for someone local selling a used 2 1/2 gallon paint pot... I got my first one for $10 local, a built like tank vintage Montgomery Wards rebrand, and then I found another of the same style a few years later, brand new in the box for $20 that some was selling on Ebay from an estate sale...

Now I have my grand daddy pot I picked up last year, a 10 gallon pressure paint pop rated up to 110 PSI, the beast weighs in at just under 100lbs but 5 gallon buckets drop right in with room to spare! I paid I believe around $100 delivered for it as no one wanted to pay the outrageous shipping so I was the only on that bid on it...

So keep your eyes out if you want a deal they are out there...
 

DrewSmith007

Sr Member
RPF PREMIUM MEMBER
Never used it, but this stuff might be thin enough to case without pressure.

EasyFlo Clear

there's a company, brickintheyard, on youtube that have a ton of casting videos and they recommend this stuff often. You should check out their stuff.
 

exoray

Master Member
And your mold has to created in a pressure cast environmrnt also.

Doesn't necessarily have to be but from my experience yeah make the mold under the same PSI as you will be casting... If the mold is not made under pressure any entrapped air pockets in the silicone will compress when casting and can deform the mold, or...

Even worse I have experienced what I will call a 'prickly' (think afternoon beard stubble) surface when pressure casting in molds that where not made under pressure, this causes a bunch of little scratches in the silicone when removing the part as well as requiring the entire surface of the part to be smoothed out... All those microscopic air bubbles in the silicone that never caused any issue on regular casting can jump out like a beast when casting under pressure...

Never used it, but this stuff might be thin enough to case without pressure.

EasyFlo Clear

No where near enough open time to even get the bigger bubbles out let alone the microscopic sized ones...

Trust me you will spend more time, effort and frustration trying to find a way around the pressure pot then you will simply getting the pressure pot and getting superior results right away...
 

Finhead

Sr Member
No where near enough open time to even get the bigger bubbles out let alone the microscopic sized ones...

Trust me you will spend more time, effort and frustration trying to find a way around the pressure pot then you will simply getting the pressure pot and getting superior results right away...

QFT.
Besides that listed resin is amber not clear. ;)
 

DrewSmith007

Sr Member
RPF PREMIUM MEMBER
Besides that listed resin is amber not clear. ;)

Hrm, didn't catch that... I saw some stuff somewhere that poured like water and was just as clear. It was intended for making awards with the text suspended inside. I thought it was that stuff, but can't seem to find what I'm thinking of.
 

zorg

Master Member
RPF PREMIUM MEMBER
if you get one of those pressure pots you can put a clear lid on it and use it as a vac chamber as i do. 2 birds with one pot.

don't waste time trying to get round it just bite the bullet and thats it done.

-z
 

exoray

Master Member
if you get one of those pressure pots you can put a clear lid on it and use it as a vac chamber as i do. 2 birds with one pot.

You can use it as is for vacuum as well, you just can't see what it happening ;) With a a little trial and error you don't really need to see what is happening all the time when vacuuming you can develop a pattern that works if you do it often enough with the same products, but there are certainly times I would like a clear lid... Nothing like missing your pattern and having a boil over, that instantly makes you wish you had the clear lid...

I have a universal vacuum and pressure gauge on the tank and an air hose quick connect on the tank, with opposite quick connects on the air compressor and vacuum pump, easy swapping between both pressure and vacuum...
 

BGHUNTER

Well-Known Member
We made a preusre pot at work to day , easy, (though we do have a strong pump)
Though Ive used clear pollyurathains and been able to achieve it just be carfull when mixing no to whip air in to it,
though pollyesters Ive found it almost imposible
 

Mxlplx

Sr Member
I've watched my buddy pour flawless clear castings without a pressure pot. I'm not saying it is the correct way to do it, but it worked for him.
He always said to "Pour slow"! If its an open mold, pour slow from one corner of the mold and let it fill slowly. If it's a closedmold with just a pour spru and a vent, again, "Pour Slowly" hitting the wall of the pour spru and let it flow slowly.

This is just a helpful hint, might not be the right way, but it worked for him!
 
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