Silmar 41 first try...

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woodgraver

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Nov 8, 2010
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Location
Federal Way, WA
I finally have just about everything I need to try my hand at casting some PR blanks. I've purchased Silmar 41 and some translucent and opaque dies. I've read quite a few posts and watched the videos I could find on you tube, but I'm still a bit iffy on a couple of steps.

I plan on pouring the resin into a few small cups and placing them in a warm bath inside an ultrasonic heater from HF. Then I will mix in the different dies. When I'm ready to pour them into the mold I'll add the hardener. From what I gather, to get color separation and the swirl effect I need to wait until the first color starts to set up before I add the hardner to the next color and then start to mix it in.

Am I on the right track here?

Thanks,

Jim
 
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Yes, I think your are ready to play and learn from experience. Be careful with the heat - it speeds things up. On my first try with the heated ultrasonics, it went from starting to gel to jello in the amount of time it took me to pick up the cup and start to pour. It literaly solidified mid pour. What I do now is remove from the heat right after I stir in the catalyst, and be more carefull with how much I add (try 4 drops per ounce). The little bit of cooling from removing from heat at this time seems to slow it down just enough.

ALso, everyone has there own method, but I find waiting until one gells to add hardener to the other is way too late. I just wait until I've stirred one then add to the other. This offsets them a little
 
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That isn't my method, but everyone does it a bit different.

You can try that as a starting point and develop a method that works for you. After a few casts, you will get a feel how the resin is going to react for you.
The important thing is... have fun and be safe.
 
First ... Im no expert at this. I would not mix them both at the same time but I dont think I would wait until the first starts to set up. By the time you finish stiring, it might be too late on the first cup. I use Silmar almost every other day and Ive found that if you tilt the cup and slowly pour out of the container so that the resin hits just inside the cup on the side wall, you wont get many bubbles at all. Kind of like using a beer tapper so you dont get a lot of foam in your drink. lol Good luck.
 
I use a different method to get color separation. I'm also using Silmar 41. I pour my resin into the cups, then add colors (1 color per cup) mix well. add catalyst (3-4 drops per oz of resin). if i've timed everything right both will start to gel at the same time. I do not heat my resin, only because I want more time to plan out my pours and set everything up. Once they are starting to gel (think honey or thick syrup) I'll pour into my mold and swirl using a dental pick or something with a curved end. Then set it aside on a level surface to cure. Be sure to have good ventilation and be safe. Wear gloves bc it will get sticky and nasty no matter how careful you are. Don't forget to post your work! Most cool blanks are the one's we think are hideous and ugly at first so don't be discouraged by whats on the outside!
 
Thanks for all your advice. I'm now waiting on my back ordered HF Pressure Pot...I'd say one month from now I'll be able to upload pictures of my first castings. This really is an awesome place to share knowledge, I really appreciate each of you taking the time to provide some steerage :)

Jim
 
woodgraver said:
Thanks for all your advice. I'm now waiting on my back ordered HF Pressure Pot...I'd say one month from now I'll be able to upload pictures of my first castings. This really is an awesome place to share knowledge, I really appreciate each of you taking the time to provide some steerage :)

Jim
Click to expand...

Why wait for the pressure pot? I'm a relative newbie compared to some of these more experienced artisans, but I've never used a pressure pot and have always had good results.
 
I've just read a few posts today where lots of people are saying they don't use pressure at all for PR castings...I just figured that was something you graduated to, but maybe I'll give it a try and see how it turns out. Thanks for the nudge, I needed that ;)
 
oh no, go ahead and get started! You won't need a pressure pot for color casting. When you want to start adding objects or clear casting stuff then you'll start needing the pressure pot. Right now it's fair game so now lets see some blanks!:biggrin:
 
I have casted with clear as well as normal resin and have never used a pressure pot.. I wont argue and say I am right or anyone else is wrong.. but it works for me... I just do everything very carefully!!!!!
 
I too have stopped using pressure as long as there is no objects. The only time I use pressure now is if there is something that can trap or leak air such as something like shredded money, worthless wood, feathers, cactus you get the idea. Cast that have objects that air can leak out of pressure is necessary.

My method of mixing and casting say a label or color (no objects). I would pore the resin in a cup that can handle it (not all can some melt beware the cheap frosted cups they don't work) than I put the cup in a pot of hot tap water to heat the resin about 100 deg. At the same time I preheat the mold if I am doing labels it has the tubes already in the mold ready to cast. I preheat to about 125 deg. I have an ultrasonic used it a short time and I found I do not need it and think it causes me more problems. Now with the resin heated it is time to add die and or pigments but remember the more you add the more it effects cure times if you add a lot of color you will probably need to add more MEKP to get it to set. Now with the color added I now take the resin out of the hot water add the MEKP slowly mixing it in. With the PR hot bubbles should not be a problem it will be thin and easy to mix. If you get some bubbles they should rise when you pore. Then as was said when poring your resin start in a corner and slowly pore and let the mold fill. The less MEKP you can use the better I use 3-4 drops per once unless I add dies & pigments then I my go up to 10-15 drops. Now ambient temperature is important also especially in winter. Ideally you want between 75-80 deg. If it gets below 65 it will not set up (or take a LONG time) if it gets above 90 it will set too fast. You may need to heat the area I sometimes hang a 60 watt light over the mold for the night. Now after it has set I give it 12 hours the surface will be tacky this is normal it is not a problem just an annoyance. Stick your cast with a stick if you can't push it in it is set the tacky surface will just turn off. To get the surface to set I put the cast outside in the warm sun but now it's winter just leave it in a warm well vented area a few hours and it should set up. You can post cure in a oven but don't go too hot too long not over 150 say 30 minutes then let cool or you will make the resin more brittle.

Well I gave you all my experiences and that is just me everyone has a little different way. It takes time and the more different things we do the more unknown it is we are all in uncharted waters.

Have fun
Bruce
 
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