PR & hardener shelf life

[laspringer]

My PR is taking 48 hrs to set up.
I am using 3 drops per oz of hardener.
This amount of hardener worked ok last fall.
I've had the PR and hardener for about 8 months.

Alan

 

[Gary Max]

Lots of things affect the process----temp--humidity---brand of product---what type of Catalist. Not really one good answer.

 

[its_virgil]

How many ounces of PR are you casting? How does that compare to the "last fall" cast? How thick is your cast? What is the ambient temperature where you are casting and how does it compare to the ambient temp of the "last fall" cast? According to one manufacturer of PR I contacted, PR has a shelf life of 6 months from the date of manufacture. BUT, I've never had any that I thought had gone bad, or expired, even when I had had it for several months. Were you adding colors? What kind? how much? Was the "last fall" cast exactly the same as this one? I use three drops per ounce, cast 16 ounces in a mold that is almost 1" thick and have had no problems. Think about this cast and the "last fall" cast and compare the two.
Do a good turn daily!
Don

Originally posted by laspringer
<br />My PR is taking 48 hrs to set up.
I am using 3 drops per oz of hardener.
This amount of hardener worked ok last fall.
I've had the PR and hardener for about 8 months.

Alan

 

[laspringer]

I am casting snakeskins.
I am trying to cast the skins in delrin to make them round, it takes
about 1/2 oz of PR per tube. Last fall I used the square mold system,
and that is about the only difference. The temp is about the same in the shop 50 deg, same PR and hardener as last fall.The delrin is not working as planned and will go back to the square mold.

Thanks for the help Alan

 

[its_virgil]

It is taking longer to cure because of the quantity of resing in each mold... i.e. each delrin tube. The heat buildup is cumulative. More resin per mold means more heat and less catalyst can be used. Less catalyst for me has been better final resin blanks to turn. You could increase the catalyst if you a bound and determined to use the "tube" molds. I've tried them all and casting in a block has worked best for me...it is quicker to pour, cure and cut into individual parts than to pour into individual tubes and then remove them from the tubes. I've used every suggestion that has been made in the last three years and I'm still casting my snake skins in one block...5 pens per cast. Watch out, too much catalyst will be too much heat and your skins will vanish...vaporize...burn up...only leaving the brass tube. Oh, BTW, if you find a really unique and time saving way...please share it with the rest of us. Thanks and cast on.
Do a good turn daily!
Don

PS: Okay all of you non PR casters....now is your chance...mix equal parts...always works...never fails...You guys are slipping [][][}][}][}][][][]

Originally posted by laspringer
<br />I am casting snakeskins.
I am trying to cast the skins in delrin to make them round, it takes
about 1/2 oz of PR per tube. Last fall I used the square mold system,
and that is about the only difference. The temp is about the same in the shop 50 deg, same PR and hardener as last fall.The delrin is not working as planned and will go back to the square mold.

Thanks for the help Alan

 

[MesquiteMan]

PS: Okay all of you non PR casters....now is your chance...mix equal parts...always works...never fails...You guys are slipping [][][}][}][}][][][]

Don,

I am just trying to tone it down a little! Beleive me, I sure thought of it when you guys were talking about needing the right ambient temperature, mass, humidity, thickness, etc, etc.. You do know that with Alumilite it is a 1:1 ratio and none of that matters don't you? [][][}][}] Oh yeah, it only takes 15 minutes to set too![^][]

 

[Jeff-in-Indiana]

Where was the resin purchased ?? The ClearCastin you get from Michaels is different than that which you purchase from Mr.Fiberglass ..
The ClearCastin uses around 3-5 drops of catalyst per ounce, the Silmar41 &lt;?&gt; uses a larger volume of a different formulation of catalyst, more in the range of 1%-2.5% per ounce ... (a little less than 1cc per ounce)

Good Luck ...

 

[Mudder]

Originally posted by MesquiteMan
<br /> You do know that with Alumilite it is a 1:1 ratio and none of that matters don't you? [][][}][}] Oh yeah, it only takes 15 minutes to set too![^][]

Hey,

You also forgot to mention it's about 3x the price of PR [}][}][]

 

[MesquiteMan]

Originally posted by Mudder
Hey,

You also forgot to mention it's about 3x the price of PR [}][}][]

Not quite! Alumilite Clear is $80 per gallon plus shipping. That puts it about twice the cost of PR but with 1/10th the hassle, smell, and time needed to cast![][]

 

[its_virgil]

Most all polyester resin is Silmar 41. I've purchased from several suppliers who have their own labels on the can and when I asked how it compares to Silmar 41 I was told it is Silmar 41 purchased in drums and repackaged into smaller cans. The catalyst forpolyester resin (and vinyl ester resin) is Methyl ethyl ketone peroxide or MEKP. Recommended rate is 1/2 ounce per quart, but for me and in my shop I use 3 drops per ounce when casting snake skin blanks.....no matter whose polyester resin I am using.
Do a good turn daily!
Don

Originally posted by dishripjlt
<br />Where was the resin purchased ?? The ClearCastin you get from Michaels is different than that which you purchase from Mr.Fiberglass ..
The ClearCastin uses around 3-5 drops of catalyst per ounce, the Silmar41 &lt;?&gt; uses a larger volume of a different formulation of catalyst, more in the range of 1%-2.5% per ounce ... (a little less than 1cc per ounce)

Good Luck ...