I have now had the opportunity to use a new silicone for molds. OOMOO 25. Its technically the same as OOMOO 30. By that I mean it has all the exact same properties as OOMOO 30...
EXCEPT.....
OOMOO 30 has a pot life of 30 minutes. OOMOO 25 has a pot life of about 3-4 minutes. OOMOO 30 has a 1:1 volume ratio and cures in 6 hours. OOMOO 25 has a 100:130 mixing ratio by weight or 1:1 ratio by volume and cures in 75 minutes.
I like to leave my molds in the pressure pot for the entire cure time. The OOMOO 25 offers me the ability to make molds in a much shorter time. That doesnt mean I can make more molds in a day. Because the OOMOO 25 has such a short pot life, I can only make 1 maybe 2 mold halves at a time and they have to be small molds.
When you pour your silicone, you want to do it from a respectable height and in a controlled small stream. This breaks up most of the air bubbles caused by mixing. This takes some time. And if you are using the OOMOO 25 the silicone is starting to set by the time you have poured the one mold.
With the OOMOO 30 you have the luxury of a 30 minute pot life. So you can make more molds at once and depending on the size of your pressure pot and depending on how you utilize the space in that pressure pot, you can actually make more molds in a day with the OOMOO 30 even with a 6 hour cure time.
The more relaxed you are the less likely you are to make a mistake or have a mishap. With the OOMOO 25 you feel rushed and you have to pour your silicone into the mold as fast as possible. Mixing air bubbles and all. You dont have the time frame to afford an error.
Each product is made for a specific purpose. And if you use them for the proper purpose they will both work fine. My recommendation is if you are only going to make one mold or a couple of relatively small molds...then use the OOMOO 25. It will be faster and the shortened pot life shouldnt affect you if you are organized.
But if you have a few molds you want to make at once or are making larger molds, then I highly recommend using the OOMOO 30. You can follow all the procedures without being rushed and the extended pot life means you can also make more molds without having them start to cure at an accelerated pace before you get them into the pressure pot.
*** When I say a small mold, I am referring to a mold that would make a 3 3/4" figure part or an accessory for a 3 3/4" figure. When I say larger mold, I am referring to a mold that would or could cast say a Magno Leg or anything larger or even a 3 3/4" figure if it were all in one piece. ***
Hi. I realize this is an old post, but do you need the pressure pot? I thought this stuff did not require it.
ReplyDeleteNO...you don't. A pressure pot just ensures you get really good results. If you do NOT have a pressure pot then you will need to mix WELL and pour it quickly to ensure the silicone gets into he nooks an crannies before the silicone starts to set. A Pressure Pot does this.
ReplyDeleteI will not cast without a pressure pot. There is a lot of waste and wasted time and effort.
Is there a difference in the amount of heat that either mixture can tolerate? We want to use it to make molds for sugar bottles, and the sugar mixture will be heated to about 300 degrees. The instructions we're working from recommended Oomoo 25, but Amazon sent us Oomoo 30. We'd like to use what we have, but don't want to have the experiment go south.
ReplyDeleteIf the recommendations called for 25, then I would not deviate. These products have specific purposes. Heat concerns being one of them.
Delete