Clear prop casting help

mrt88

mrt88

New Member
Hi Guys,

I hope im posting this in the correct section.

So im about to start reproducing some simple glass vials for some props (pensive vial kind of look) . I unfortutly cant have them made by a glass blower, Simply becasue its a home prop project i want to try my hand at and they have quoted me over £50 each and i need 24 of them.

So ive come up with two realistic options. 1) casting. 2) Lathe turning. I would love some help deciding how best to to this and any other methods you guys can think off.

1) Resin casting

So this looks like a realistic option for me. I have a master vial i can cast a mould off. The only downside from my initial reserch is degasing and presure forming clear resin seams like a must to get a glass like finish.

I dont have either of these bits of eqipment.

From what i can see the simple encaptulation epoxys might be my best bet so far. I would love to try this as my first port of call.


2) Lathe turning.
Again i would need a small desktop late or i can make one with a drill as the power source, My main conserns are repetablilty, acuracy and clarity from the chosen plastic.


Im a woodworker by trade so im very handy and i have tools coming out of my ears. I think with some practice i'll have the skills to eventuatly do either option.

Im just not sure whats the best method for my project. Any Ideas or input would be amazing.

Thank you all. :)
 
Sounds like a fun project. I too asked this question when I first began casting and I later discovered that it would have been better to just spend the cash and get a degassing chamber. Best investment ever.

Goodluck,
Mike

Sent from my KYOCERA-E6560 using Tapatalk
 
PropReplicator2 said:
Sounds like a fun project. I too asked this question when I first began casting and I later discovered that it would have been better to just spend the cash and get a degassing chamber. Best investment ever.

Goodluck,
Mike

Sent from my KYOCERA-E6560 using Tapatalk
Click to expand...

What did you end up buying for your degassing setup? I'm trying to locate a reasonable set-up.


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If you don't have a degassing chamber or pressure pot, use the epoxy resin (there is now a UV stable version) and pour your parts in layers. Use a heat gun, or can of compressed air to pop the bubbles as they raise. Cover with cling wrap to keep dust and bugs out during curing, then pour the next layer once the previous has turn to a gel state. You don't need to fully cure each layer and in fact, better bonding occurs at gel state anyway. Just that you need to let each layer set so you are not mixing in more air than can escape.

A lot of people don't like Epoxy because of the amount of heat it produces during the exotherm kick. In shallow layers, this is not a problem. Epoxy is way thinner than other clear resins like the polyurethanes. I used a very expensive PU clear once (never again until I get a pressure pot) and it requires the use of a pressure pot after degassing for stable curing. For the parts I did, I let them cure on the bench as I would for any other PU resin and when I cam back to demold, most of my castings had bubbles that formed during the cure stage. I'd never seen that before. I have since seen it when catching up with a local (to me) member who also had the same nasty bubble occur.

One of those small $200 pump/chamber kits will be totally worth the investment if you are doing many parts or will continue to mold and cast. Consider long pot life silicones can also be degassed and in fact give better results when they are.
 
PropReplicator2 said:
https://youtu.be/XQj0Fw9AaE0
Click to expand...

Tips to extend the life of your pump -

1. Always check the oil level BEFORE you ever turn it on.
2. Alway remove the exhaust cap prior to turning on the pump (it tends to launch).
3. Always have your valves slightly open BEFORE you start the pump.
4. Close the valves once the pump is running.
5. Once you have degassed, open the valve BEFORE turning off the pump. I let mine drop from 30"Hg to about 25"Hg before I flick the switch to off.

Failure to re-pressurize the chamber prior to shutting down the pump can result in the oil being sucked out of the pump and right into your product. Neither is good for the pump or your product.
 
cavx said:
Tips to extend the life of your pump -

1. Always check the oil level BEFORE you ever turn it on.
2. Alway remove the exhaust cap prior to turning on the pump (it tends to launch).
3. Always have your valves slightly open BEFORE you start the pump.
4. Close the valves once the pump is running.
5. Once you have degassed, open the valve BEFORE turning off the pump. I let mine drop from 30"Hg to about 25"Hg before I flick the switch to off.

Failure to re-pressurize the chamber prior to shutting down the pump can result in the oil being sucked out of the pump and right into your product. Neither is good for the pump or your product.
Click to expand...
Just for additional info. That's not my setup in the video. That's the video I based my build off of.

Sent from my KYOCERA-E6560 using Tapatalk
 
Step 1. Make sure your master parts are as good as possible.
Step 2. Make your molds so you can get a heap of pulls from them.
Step 3. By degassing, it is possible to pour your casts bubble free.

I certainly have no regrets with the set up I have given the results I get.

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Do you think home made degassing chambers are worth it ? Or am I better off buying a small starter kit type set ?
I think it'll be a fun little project, but not much point if the results won't be up to scratch
 
mrt88 said:
Do you think home made degassing chambers are worth it ? Or am I better off buying a small starter kit type set ?
I think it'll be a fun little project, but not much point if the results won't be up to scratch
Click to expand...

Mine is pretty much DIY, but maybe I got lucky. If you were to buy my chamber (30 litres) and 9CMF pump, you'd be looking at a few grand. All up, my set up cost me less than $800 where $350 of that was spent on En-Zed the hose doctor to ensure I did not have leaks. My chamber itself was made my a local plastics fabricator for less than $200. The first pump was only 3CFM and I paid $103 for that and later sold it for $100 after servicing it for the guy. My 9CFM pump is listed at $1100 locally. I found them on ebay for the same price, added to watch list and found that as the seller sold pumps, he reduced the price. He started with 20 at $1100 and by the time I bought mine, it was 2 left for $219 each. I should have bought both.

That little 1 Gallon kit with a pump is a perfect starter. You will be surprised what you can do in that.

What some people fail to understand is that, even with all the good toys, bubble free parts are all dependent on how you pour. That is something you only learn from practice and during that learning curve, you will find yourself making less than perfect parts until you work out what your gear does and what your product does.
 
If you main goal for this project is to cast parts as clear as possible, a pressure pot will be much more useful then a vacuum setup. You can get a cheap compressor on craigslist and the 2.5 gallon paint pot from harbor freight for around $100. Vacuuming resin removes all bubbles from the actual material. But its still susceptible to trapping bubbles in detail of your mold as you pour. Casting under pressure (I use 45PSI) eliminates all bubbles. Also, it allows you to use resins with shorter pot lives.

Side note: I hate harbor freight, but these pots are the only thing I will buy from them. I just replace the bolts with much stronger ones from home depot. I also normally pour a urethane rubber seal.
 
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