Well I finally had the motivation and need to make silicone molds to make parts for a client. Not pen related by any means. I have a vacumme chamber I use for the casting process so I had bought some Mold Max 40. thinking at one point I might want to make my own molds for blanks or what ever. I cheerfully got 3 plastic 5 qt buckets to mix in and rags for spills and set up a scale to measure with. With Mold max 40 you need an accurate gram scale.
I watched the videos again. I read what ever I could find. I used their weight calculator.
I opened the bucket of MM40 "A" which had never been opened and tipped it over to put some in the mixing bucket on the scale.............. :biggrin:
Nothing came out..............
I look in the upturned bucket and its sloooooowwwwwly oozing towards the edge. I dont remember slowly oozing in the videos. So I take my mixing stick and cut a slop or two into the mixing bucket on the scale. The weight calculator on their site said around 2.5 lbs so I added another slop and it went to 2.8lbs/. Close enough for my first attempt. Added my part "B" catalyst of .280 to it and started to stirring. Heck its a good thing my stirring stick was 3/4 x3/4 oak. What a work out!:biggrin: I finally get the goo stirred into a mint green, no white streak glob and put it in the vacumme chamber and hit the switch. Now they tell you it will expand about 2 1/2 to three times its volume under vacumme.
IN A PIGS EYE! It came up the side of the bucket and kept right on going. Spilling out of the bucket running down the sides of the plastic dome. Until about half of the original goo was left in the bucket. Crap!
I take one of my extra buckets and set it next to the vacumme bell and when I shut off the vacumme pump I pick up the whole thing and kinda lift one side of the bell and let the goo slide into it.... And all over the counter.... and some on the floor. I scrape all of it I can into one of the two buckets that now have mint green taffy in them and take them over to my uhmw molds with the masters in them and pour both bucket into them. Its short of goo.
Fortunatly you have 45 minutes or so of work time so I grabbed the 3rd bucket and scrapped another 1lb of goo into it added catalyst and this time as it started to boil towards the top under vacumme, I opened the release valve and then shut the release valve letting it fall until it finally peaked one last time and fell on its oiwn. I then left it under vacume for 2 minutes before using it to fill the rest of the mold. At this point its almost Midnight I have 2 more molds to pour but Im going to wait until the next day to see how the first one turned out. I started to clean up all the mint green goo on my vacume table....... and the cabinet top....... and the floor. I learned that a spray bottle of Goo* Gone is just the thing to dissolve mint green goo. That and a few hundred paper towels cleans it right up. I checked the mold the next day and it had set up just fine, cut the mold apart and removed the master and no voids or mini bubbles all over the surface. I seem to remember this stuff has a shelf life and temperature plays a big part in it. UHhhh I may have had it longer than I thought and in my garage at 85+ most of the time probably didnt help. Any way I used what I had and filled up one of the other molds and the large part of the 2nd one the next day. I need a little bit to make the last part of the last mold so I ordered more Yesterday. I think I may find a little difference in the consistency of the next batch. I checked the second mold today and it came out just fine also. Im waiting for the new Mold Max 40 to show up to finish the third mold. I had a lot of fun making these and will probably be looking for something else to make just for the heck of it. Maybe next time I wont make such a mess. :biggrin:
