A Series of Questions

[amphoterik]

Thank you for the answer paulson. Can you go into any greater detail regarding your 2-sided mold for bases?

Thank you

[blind pig]

[mangozac]

Yeah I've always had my pressure pot half filled with sand, although not in a plastic bag (which is a good idea). I've had a couple of times where I've removed the vacuum too quickly causing the sand to all jump about and got some in my silicone

[amphoterik]

I bought a second hand 2-gallon pressure pot and a new compressor. Got it all setup and tested it out only to find that the pressure point wasn't even close to air tight. The owner told me it was a new gasket (and it looks new) but it doesn't seal a thing. *sigh*

[mangozac]

That sounds strange. Does it seem fixable? Maybe take it to a specialist air equipment shop and see if they have any comment?

[blind pig]

[amphoterik]

if I put this pot in soapy water, it would look like a jacuzzi. The whole gasket is leaking. I have pulled it out and am using a hair dryer the remold it to the lip of the pot. Once the shape has been fixed and the pot has been cleaned I will re-seat it with rubber cement. Otherwise, there is always the mold a gasket stuff from the auto shop.

[paulson games]

How are you tightening down the lid?

I've found that you need to partially tighten opposing sides at the same time, then switch to the other screws tightening each set a little at a time, kinda like when you put a tire on a car. If you tighten one screw down completely before doing any of the other ones it'll cause the lid to seat unevenly.

Also when the gaskets wear out they will leak no matter what you do, but on a new tank it shouldn't be leaking.

[amphoterik]

I am tightening it down like you recommended. It is not a new pot, just new to me. I read somewhere that you can make a gasket with mold max 30 silicone. Has anyone tried this?

Also, is there a difference between the micromark 300 resin and the smooth cast 300 resin (besides the squeeze bottle, which is a great idea)?

EDIT: also, my gasket is free (as in, not glued down). Should I glue it into the lid with rubber cement or something? Could that be the reason it leaks?

[mangozac]

Theoretically the mould making silicone should work for a new gasket. You would have to make sure the lid is perfectly level before pouring it into the channel though.

All gaskets are generally "loose" but just held in place by friction. Gluing it down would probably only help if you fixed it with some silicone sealant or the like.

[paulson games]

When buying in volumes larger than the start up kits the smooth-on resins are considerably cheaper than micromark which is why I do the bulk of my casting with smooth-on. I tend to buy the 1-gallon bulk set as I go through tons of material and at that volume it's about 30% cheaper.

As far as working properties both have pretty much the same curing time. The Micro Mark is a bit thinner so I use it on parts that I have difficulty casting. The micro mark stuff also seems to be slightly denser and slightly tougher once cured.

The wolf saddles I make sometimes have issues with bubbles and I find I get a lot fewer miscasts when I'm using the micromark resin on those due to the thinner viscosity. However with the rest of my parts like the wolf bodies and the boneswords the smooth-on resin works fine and I don't notice any measurable differance in the castings between brands.

I keep a reserve of micromark resin specifically for the saddles and everything else gets cast with smooth-on to help keep costs down.

It's important not to use micromark silicon with smooth-on resin as the chemical formula doesn't quite mix right and the smooth-on resin sticks to the micromark silicon pretty tightly and wears the molds fast.

However, the smooth-on OMOO silicon works fine for both brands of resin.

Also I keep the left over micro mark bottles to use for my smooth-on resin as the pour spouts are really nice, I just make sure to clean out the bottles and let them completely dry for a few days as any left over water will contaminate the new resin. I also make sure to mark them with what brand is inside that way I don't accidentally mix them up.

[amphoterik]

Thank you paulson.

Can anyone tell me is Crayola Modeling Clay is the same thing as Kleen Klay? The crayola clay is oil based, but it is also very soft and sticky. I believe Kleen Klay is supposed to also be oil based but not stick to your hands. Can anyone tell me if this is the same stuff?

[paulson games]

Kleen clay does have a very slight stickiness to it but it's quite firm at room tempature, it softens up if you work it for a bit and it absorbs tempature from your hands. Most items will come out without much clay clinging to it. You'll need to give it a quick scrubbing with a toothbrush to get all the fine details cleaned up but it only takes a few seconds.

The crayola stuff I have no on. Kleen clay you should be able to pick up at hobby lobby, micheals crafts or just about any craft store that carries clay products.

[blind pig]

The Crayola is softer and much more expensive.

We can buy Kleen Klay here in Australia for about $7 a kilo.

Kleen klay also comes in three hardnesses: Extra Hard, Hard, Meduim and Soft. I usually go the hard Klay as it seems to resist my sometimes rough handling of part-finished moulds (I am a clumsy bugger) and gives a cleaner line to two part moulds IMO.

I warm Kleen Klay up in the microwave, about 30 seconds for each 500 grams does the trick without it getting too hot, prior to using it.

I have also used a clay product (below) that is designed to be melted and poured into moulds for stop-motion production. I have found it to be pretty good to make two part moulds with pretty clean and level parting lines, by simply pouring the melted clay into a formwork up to the desired level of the parting line.

http://www.barnes.com.au/catalog/produc ... cts_id=775

Care must be taken not to get it too hot, as it can bubble a little when poured into the formwork and then the surface needs to be cleaned-up to make a smooth surface.

[amphoterik]

Thank you everyone. My system is running now and I can begin making casts en masse.