I am new to the group and hopefully i have found the right one. I am trying to make firgueres of ho (164) scale people and i am trying to find the best method...
I am looking at doing some castings in the near future, however the (untried) method I am planning on using doesn't seem to be in much use. When making my...
You might find it easier and cheaper to use pressure casting. You need a source of compressed air @ about 40-60psi and a pressure vessel that your mold will...
The two most common mistakes I've seen in vacuum casting with bell jars are these. First, make sure you release the vacuum from the jar before you turn the...
I tried to do this and I did manage to suck oil through. Learned not to do that again. However, no success otherwise. When I tried to vacuum the resin in the...
I've considered this as well, as it seems to be a more commonly used set up. My source is more about 90-120 PSI, do you think that might be too high for some...
Hmmm... That is one thing I thought about, but wouldn't have expected to happen. Not like I know a darn thing about it. Did you try this same mold in another...
I assumed it was air still trapped in the mix. I degassed the component parts, then mixed them. Due to the pot life, I poured into the mould and place into the...
The problem with urethanes is that the Polyol component is affected by vacuum. In a vacuum it boils out, much like water does in vacuum, since the parts of the...
On my pressure pot, I just removed the wing nuts and replaced them with standard hex nuts. These are easily spun down rapidly with a screw-gun modified to...
Have you tried mixing the resin components, THEN degassing, pouring into the mold, cover the mold, place in pressure vessel, seal the vessel, and pressurize? ...
Not enough time for all of that.....best way is to pour urethane into the mold, put the mold into a pressure pot and use between 50-60 psi. ... From: Charles...
It works, there are special considerations to go with it though. The big one is that the air in the mold doesn't leave, it just rises to the top of the mold....
... That would seem to be what I observed, it did look like it was boiling. ... Will have to try harder to get this to work. Will try to find something to use...
With the small resin castings (HO scale freight cars) that I've produced, I've kept the pressure around 25psi. Imperfections are very rare. Also, the resin you...
Yeah, with the boil then that would make sense. As far as the lack of flat bottom in the tank giving you hassels with inserting the molds, could you place some...
... That's what I did. Actually a couple shelves that lift out. I also drilled holes in the shelves (made of thin plywood with threaded rod for legs). ... I...
As I have read and tried to educate myself about casting, pretty much All I hear about are resins ans white metals. Does anyone use plastic? Would it be...
The problem with "normal" plastics, known as thermoplastics, is that you can NOT melt and pour them easily. Requires high, tightly controlled temps and ...
I have tried what you're suggesting with polyethylene. The plastics you're talking about are melted and injected into metal molds under pressure. I'm sure...
I have acquired a pressure pot which includes a valve in the air line. My question is how fast to pressurize, and depressurize. So, I mix my urethane...
There is Polymorph (http://www.mutr.co.uk/product_info.php?products_id=550&osCsid=8956bae37203aa52dfcb6bcd35293ba5) available at all Maplin Electronics shops. ...
Back in my youth.... Took a shop class and at the same time a friends dad had plastics injection machine. This machine used metal molds and that somewhat...
Surely someone on this list will know a lot more about plastics than me, however.... High temps are necessary to liquefy plastics. The temp can be critical as...
I am not a plastics expert either, but this is surely confusing some here. The polyurethane resins that 99.9999% of us use here ARE "plastics" as well. By...
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