Some problems with 1st PR casting

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Dale Allen

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Joined
Oct 27, 2012
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Massillon, OH
Hello all and thanks in advance for letting me throw out some info and get some input from the group.
I bought a basic kit about a week ago and got the chance to try my hand this past Wednesday. I'm using the basic PR with some blue dye and white and gold powder.
One mold is made from an old poly cutting board. I made 4 sides and a bottom and used CA thick to glue it up. I also used the same thick CA to run a bead on the inside seems. This was also sprayed with activator.
Two other molds are made from 3/4" PVC pipe with the side cut off and the ends plugged.
Admittedly I may have been doing too many things at once for a beginner.
One of the PVC tube molds has a tube with labels that I wanted to do a clear cast with. That one set up fine in about 8 hours and was real hard after 24 hours. The other PVC mold had blue dye with white pearlisent powder. It also set up fine.
Now, the one in the square mold was the consistency of thick pancake mix after 24 hours. In that one I put...don't laugh...some shavings from a black stabilized blank, blue dye and some brass shavings. I wanted to just see what that would look like turned. Anyway, it did not set up.

Room temp was about 65F, low humidity. I did not preheat anything.
On the 2 that set up I used some paper dixie cups that held up fine.
The one that did not set was mixed in a plastic tumbler that held up while poring but later melted the bottom. That was also the one I used to measure with water to find out how much stuff I needed.
Could some leftover water on the bottom rim of the tumbler have caused the problem? I wiped them out but may not have got into the corners of the bottom rim. Could the shavings or brass have caused it to not set?
I used about 8 drops of dye and the cup had about 1.5 oz of PR in it with about 5 or 6 drops of hardener.
I checked the date on the PR but I really cannot blame that because the others set up. Same with the hardener.
I have one of those oil filled heaters in the shop right now and it is sitting on a piece of wood on top of the heater. That's should keep it well into the 80s. It's been there for about 2 hours now and I'll keep checking to see if it begins to harden.
Any ideas as to why that one may not have set?
Again, thanks all for your time and input. This casting process has more of a learning curve than I anticipated but it does show some promise!
 
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One other observation to add.
This evening I took the ones out of the PVC molds.
The one with the dye and powders is still too soft to turn. It was tacky on the surface but that as I recall is normal. I can actually bend it slightly.
The one that was cast clear is as hard as you would expect.
So, maybe it is the PR! The date on the can says 9-28-11. I assume that is the date it was made so it is 15 months old when I got it, which was about a week ago. That cannot be good!
 
Since the clear one (the control) cured, I'd suspect the additives in the others as the culprit. What did you use for dyeing?

If you have a toaster oven, put them in it for a couple hours at 150*F. Even PR "fresh out of the can" will cure if heated; it already has a very small amount of hardener added before you buy it--it just takes a really long time. Adding hardener to it just speeds it up.

The age on the can doesn't bode well, though.
 
Thanks Brad;
The additives were ordered with the resin and selected from the list of items that are sold for that purpose. Polyester resin dyes and Pearl-Ex Powders.
 
The amount of dye used is the biggest part that caught my eye. For that little amount of PR you'll want to add very little pigment. Too much will cause it to cure VERY slowly, which is what I think is happening here. Also, you said you bought it at the same place as the PR. Is there a brand name or company name you can give us? Some dyes are stronger than others so it could help us narrow down how much to use per oz.

If it's still pancake mix right now you might want to try and flip it over bc the shavings have probably settled all the way to the bottom and won't be in the actual turned product (if it ever sets up). Having near the heat source is about all you can do now except throw it out and try again. It might take several days to harden.

The possible water contamination is another thing. You're better off getting another cup if you need to measure out with water, that and be sure the mold has dried completely! I use the paper cups for all my casts, but if you use plastic be sure the recycle code is 1 or 5. Anything else will melt.
 
Jonathon, thank you for your advise and suggestions. I can't turn the mold as it would spill out. That one I give up on.

I'm trying again and my concern now is that if this stuff is supposed to heat up during the reaction, it isn't doing it.
 
Apparently I am not supposed to be doing this.
I've had 7 oz of resin, 20 drops of dye and 42 drops of MEKP in a provided cup being stirred every 5 minutes.
It has been 45 minutes and there is no sign of heat being generated and it is no thicker than when I poured it in the cup.
There seems to be something wrong with the resin or the catalyst.
 
Here's a "quick and dirty" PR resin test. In a temperature of 65 degrees or better, pour 1/2 ounce of CLEAR AND UNCOLORED RESIN and add 5 DROPS of MEKP, stir and mold in a 3/4 x 3/4 x5 1/4 inch horizontal pen blank mold. This should yeild approximately a 1/4 to 3/8 thick blank.

According to PR manufactures, water clear non-structural poly resin (silmar41, Castin craft, etc) poured at 1/4 inch thickness and catalysed at 10 drops per ounce, should be "tacky" on top, but solid it 1-2 hours.

IF IT IS NOT HARD IN THIS TIME, Repeat exact as the first time EXCEPT use a new, UNOPENED bottle of MEKP.

This process will allow you to more quickly eliminate the possible causes.

FWIW, below 65 degrees causes havoc with my pours. If you just bring your shop temp to 65 degrees, that DOESN'T mean your resin is 65 degrees. It's sorta like putting a beverage at room temperature in a 40 degree refrigerator. It may take HOURS to get the room temp beverage to 40 degrees.

Respectfully submitted.
 
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Another thought is the moisture content of the shavings. PR HATES WATER, so if the moisture content of the shavings is high it could cause problems.

The problem solving exercise above will help you find the exact cause.
 
Andy; that is a great test. I may try that just to test the MEKP.
Thank you for that and your insights.
On my second attempt I got some additional education. It took a long time to begin the thickening process, then it seemed to thicken quickly. I had the cups sitting on top of a heater and apparently once the temp of the mix began to warm, it reacted effectively.
I had a small amount in 2 cups, each with a different pearlex added.
Well, those began to gel to the point where they could not be mixed anymore.
So, I poured the blue base in the tray mold and began a rather laughable process of trying to incorporate the gelled stuff and some additional pearlex.
If I get anything usable out of this it will be a surprise.

Alumilite is sounding like an alternative!:rotfl:
 
Wow. I wonder why you're having such troubles when my first pour ended perfectly. Have you read the tutorials through repeatedly to ensure you understand them and have you watched any of the videos on YouTube?
 
Brad, where did you buy your resin?
I read many tutorials and researched the library, u-tube, other write-ups and other websites and forums.
I did not go into this blindly!
 
Brooks803 said:
The amount of dye used is the biggest part that caught my eye. For that little amount of PR you'll want to add very little pigment. Too much will cause it to cure VERY slowly, which is what I think is happening here. Also, you said you bought it at the same place as the PR. Is there a brand name or company name you can give us? Some dyes are stronger than others so it could help us narrow down how much to use per oz.

If it's still pancake mix right now you might want to try and flip it over bc the shavings have probably settled all the way to the bottom and won't be in the actual turned product (if it ever sets up). Having near the heat source is about all you can do now except throw it out and try again. It might take several days to harden.

The possible water contamination is another thing. You're better off getting another cup if you need to measure out with water, that and be sure the mold has dried completely! I use the paper cups for all my casts, but if you use plastic be sure the recycle code is 1 or 5. Anything else will melt.
Click to expand...

I agree 100% with all of this, but I think the dye is probably the most difficult problem for new casters to zero in on as a problem. I say that only because it happened to somebody I know. Not me, I promise:biggrin:.
 
I had a failure today...because I waited *this* long to pour--I had my cups in hot water to thin it, and at 13 minutes, noticed it was gelling. Pulled them from the water, wiped the cups off, and tried to pour. No dice. It was goop. Dumped the two colors into a mold and will keep adding "waste" resin to it until it's full.

Remixed and did everything the same, but instead poured at 7 minutes. It went perfectly.
 
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