Resin Preferences

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Jmhoff10500

Jmhoff10500

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So i have been using CC PR for my whole casting resin career and an starting to get tired of clipping coupons and buying 32 ounces at a time of the stuff when i need it so i am thinking about converting over to Silmar 41. What are your guys thoughts on resin, and other preferences? Thanks!

Oh, and silmar 41 use the same catylist as CCPR?
 
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I have gone through about 25 gallons (5-5 gal. pales) of Silmar 41 over about a little more then 2 years. Lately the 5 gal. pale is lasting longer with the resin saver molds. What I do now is I saved one of my metal 1 gal cans from before and I pore from the 5 gal into the 1 gal. That way I am not constantly opening the 5 gal. I do notice a difference when I get down to the end of the 1 gal and then pore a fresh gal from the 5 gal pail. So by opening the can all the time changes the resin slightly. What I notice is the viscosity of the fresh is slightly thiner and the color is more blue like it should be also the fresher from the 5 gal cures a little faster.

So my conclusion the more you open the top the shorter your shelf life is expediently.
Take your cap off and get it back on fast. Think of your resin as a sponge soaking up the moisture and what ever else is in the air.

Silmar 41 is working great for me. I had no complaints the key is, at least I think it is, the least amount of MEKP you can get away with I do 3-4 drops per once let it cure over night at least 12 hrs. NO POST CURE I think that will add to the brittleness to the resin. I take my cast still in the mold outside to finish off in the warm air hardens the tacky surface in about 3-4 hrs.

good luck
 
I too use Silmar 41 from US Composites. I also have used and like the clear PR from Douglas and Sturgess aka http://www.artstuf.com Don't know whose resin artstuf sells but it has always worked fine for me.
Do a good turn daily!
Don

Jmhoff10500 said:
So i have been using CC PR for my whole casting resin career and an starting to get tired of clipping coupons and buying 32 ounces at a time of the stuff when i need it so i am thinking about converting over to Silmar 41. What are your guys thoughts on resin, and other preferences? Thanks!

Oh, and silmar 41 use the same catylist as CCPR?
Click to expand...
 
I also use the Silmar and was getting it from USComposites . My only complaint about them is is always takes a minimum of 10 working days to get it . I found a new place that's a little closer to me https://www.carbon-fiber.us I ordered from them on wednesday night and had it on monday morning , I got it before I had gotten the email that it had been shipped . The same Silmar 41 and just about the same price (like $.50 more) .
 
kinggabby said:
Don which PR is it that you get from http://www.artstuf.com
?
Click to expand...

I would bet it is this one Douglas & Sturgess clear casting resin.
http://www.douglasandsturgess.com/m...ct_Code=PR-1008&Category_Code=POLYESTERRESINS

Here in Florida Michaels has it labeled under a different name. Casting Craft "clear polyester resin"
http://www.eti-usa.com/indust/castrind.htm

I kind of think they both start at the same place and are just labeled differently.

Not sure though Don will correct me if I am wrong.

thanks
 
I too started with the CC resin. It's ok. Great in emergencies since you can just run over and get it.

I was buying the Douglas & Sturgess and it seemed more consistent than the CC stuff. I broke down for my last gallon and tried Silmar 41 from US Composites. Wow. MUCH nicer to work with. I just ordered another gallon a couple days ago and it shipped today. UPS Ground means next Wed or Thurs before I get it here in CO.

The point about the air in the can bears repeating. Keep it sealed and it will last longer. I punched 2 screwdriver holes in the can on opposite corners. Small pieces of duct tape keeps the air out (enough, anyway. I use it pretty quick.)

Here's another tip: Are you finding bubbles already in the resin when you pour it into the cup? Try pouring it onto the side of the cup, like pouring a beer to keep the head down. Makes a HUGE difference.
 
bruce119 said:
Silmar 41 is working great for me. I had no complaints the key is, at least I think it is, the least amount of MEKP you can get away with I do 3-4 drops per once let it cure over night at least 12 hrs. NO POST CURE I think that will add to the brittleness to the resin. I take my cast still in the mold outside to finish off in the warm air hardens the tacky surface in about 3-4 hrs.

good luck
Click to expand...

The instructions that I got with the Silmar said to use 15 drops per oz. I'm pretty new at this and find that it still takes 24 hours to cure completely. should I be using 3-4 drops?
 
I preheat my resin (Silmar41) and only add 3 drops per ounce then post cure and can turn the blanks in 3 or 4 hours . The secret to heat with PR is not to overheat it . I commonly hear of people post curing resin at 180 to 200 degrees , that will make it just as brittle as adding 20 drops of MEKP . I preheat and post cure at 125 degrees and my blanks are very easy turning with no real brittleness to them .
 
Minotbob said:
bruce119 said:
Silmar 41 is working great for me. I had no complaints the key is, at least I think it is, the least amount of MEKP you can get away with I do 3-4 drops per once let it cure over night at least 12 hrs. NO POST CURE I think that will add to the brittleness to the resin. I take my cast still in the mold outside to finish off in the warm air hardens the tacky surface in about 3-4 hrs.

good luck
Click to expand...

The instructions that I got with the Silmar said to use 15 drops per oz. I'm pretty new at this and find that it still takes 24 hours to cure completely. should I be using 3-4 drops?
Click to expand...


Bob,

I assume it is fairly cold in ND this time of year. Are you casting in a cold garage or shop? If this is the case, preheating your mold and resin is almost a must. Like Butch said, resin takes heat to cure and if it is cold and you only put in 3-4 dp/oz, you will never get the resin to kick over and cure.

Get yourself a toaster oven from Wal-Mart or the like and do as Butch said. I think your results will improve greatly!!
 
This is the poly resin I purchase from douglas and sturgess aka artstuf:
http://www.douglasandsturgess.com/m...ct_Code=PR-1009&Category_Code=POLYESTERRESINS

I do not know if it is the same as that sold as Castin Craft. I have never used the castin craft p;olyresin. I don't think it is the same as silmar 41. Maybe if glassscratcher sees this thread he can get it all straight for us.

I now use silmar 41 from US Composites.

Do a good turn daily!
Don
 
The blanks I poured yesterday seem to be a little brittle and I suspect that is because I used 15 drops/oz. It's off to Wally World tonight. I have a heated shop so temperature outside is not a factor.
 
I also heat the resin in an ultrasonic cleaner. But, before I was heating I used only 3 or 4 drops of MEKP per ounce and never had a problem. But I must say that I only clear cast and adding dyes and pigments will change the curing time and some colors are quite pesky.
Do a good turn daily!
Don

Minotbob said:
The blanks I poured yesterday seem to be a little brittle and I suspect that is because I used 15 drops/oz. It's off to Wally World tonight. I have a heated shop so temperature outside is not a factor.
Click to expand...
 
After reading Bruce's post, I can only say the only difference between us is instead of a toaster oven, I pour my cups of silmar 41 and place a clip on light about ten to twelve inches over the cups with a 100 watt bulb and let it warm the resin for about 20 to 30 minutes before I stir in the 3 drops per ounce. It thins out nicely and allows the air bubbles time to rise to the top. Everything else that he said I also do and it works perfect for me and I go through a 5 gal bucket about every month. When I use my pressure tank, I place it in the spare room in the house near the heat duct over night. That warm air keeps the tank air warm enough that my post cure time in the sun outside is cut way back.
 
I to heat the resin I take the resin in my cup and put that in a container of HOT water from the tap about 110. I also preheat the mold about 125 with blanks in to be cast. Then I use 3-4 drops of MEKP be sure the outside ambient temp. is at least 70 deg. There are a lot more factors such as mass more mass such a a deep large solid pore adds a LOT more heat. Pigments added to the resin can effect things a lot. I give it at least 12 hrs cure time the tops are still sticky I just put the mold and all out in the warm sun to post cure for about 3 hrs. If it is cold outside you can probably post cure in an oven at no more then 125 for an hour then leave set to cool in a warm place. It will be still be a little tacky till it cures and the longer it sets the more it cures. If you rush things you are asking for the brittle problems.
 
When I use a pressure pot and it is cold that isn't often I will clip on 3 60 watt lights to the pot to keep it warm wile it cures.
 
I've use ArtStuf resin, US Composites Silmar41, and even something I got locally. For the most part I haven't noticed any significant difference.

If you browse my Resin Color Library you'll find data on how long it took the resin gel in many recipes. Not quite the same as hardening to tack-free, but it's a good data point.

For post curing, I usually set them outside under a clear cover (old apple juice jug). But then, in AZ it gets pretty warm.
 
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