Boiling PR

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glycerine

glycerine

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Does PR boil?...
I had some PR that I mixed last night with lots of coloring. It was very thin when I poured it and I was afraid that it wouldn't cure because I put so much coloring in it (the liquid transparent coloring). So, I checked it this morning and it was still liquid. I don't have an extra toaster, so I grabbed a halogen worklamp and put it right above my mold.
Went and did some other things for 20-30 minutes and when I went back out to check it, it looked like a bubbling mud pool, like something you'd see in Yellowstone. Was it just that the heat caused it to cure so fast and that was the chemical reaction or was it boiling? I'm sure this has happened to others. I know I had the worklight too close, but it seems to have worked. Looks like it also created a nice swirl pattern on it's own instead of me having to make sure I stir it right before the gel time.
We'll see when I turn it if it's weaker than "normal" PR...
 
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I had a similar situation, but it was my error since I left the PR in the garage to cure and forgot that the garage was pretty cold. It did not set. I brought the mold inside the house the next day and it took about a week to cure. I suspect the halogen brought temp well above the curing temp to give you the cause and effect you experienced.
 
Druid said:
I had a similar situation, but it was my error since I left the PR in the garage to cure and forgot that the garage was pretty cold. It did not set. I brought the mold inside the house the next day and it took about a week to cure. I suspect the halogen brought temp well above the curing temp to give you the cause and effect you experienced.
Click to expand...

Yeah, it was cooler last night as well, so that might have had something to do with it.
I cut the blank just a few minutes ago and it cut like normal, but the swirling is awesome! I think I've found the secret to getting good "figure" in PR blanks. Adding heat on purpose seems to do the trick.
 
Here are some pics. I cut the blanks and polished the inside so you could really see what they looked like.
I was preparing for the Christmas themed PITH. The green PR cured on it's own for the most part. The red was the one that I kick started with the "heat lamp"...
The first pic is the bottom, which pretty much looks the same on both blanks. The second pic is the top, where you can really tell the red one was in motion when it cured. And the last pic is the "inside", cut and polished.
 

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Was it the heat, or the light i wonder?

I am gonna havta mix some solid color blanks and put em in the oven to see what happens. This could be a really cool way to get some mixture in the PVC tube multi color blanks!
 
RAdams said:
Was it the heat, or the light i wonder?

I am gonna havta mix some solid color blanks and put em in the oven to see what happens. This could be a really cool way to get some mixture in the PVC tube multi color blanks!
Click to expand...

I'm assuming it was the heat. I was thinking if they made the heat resistant silicone molds in small rectangular shapes, I'd be good to go!
Just curious, do you know how much heat PVC can handle?
 
The heat causes movement in the resin as it cures. This is a natural convection.
With a solid color, you don't really see it. But with pearl in it, you can watch it
doing a gentle roll as it heats up.
 
NewLondon88 said:
The heat causes movement in the resin as it cures. This is a natural convection.
With a solid color, you don't really see it. But with pearl in it, you can watch it
doing a gentle roll as it heats up.
Click to expand...

I have this problem all the time with clear resin on my feather blanks. It makes for lots of extra work as I cut the wavy surface off, and sand and buff to make it transparent. I cure in the oven on low heat so I can get them cut up and move on to the next batch.
 
Sounds like someone should be using a ResinSaver mold. (Shameless Plug® ) :tongue:

I wonder if there's something in the resin that is reacting with something
in the blank? I'm not sure why you would see the movement in a clear resin.
Even if it is moving (which it is) .. clear is clear.. :confused:
 
When you try to create movement in the resin, it will turn to mud. The colors mix together instead of staying seperated. It's just like stirring it.

Give it a try, maybe you might come up with something.

I wouldn't place it close to a halogen lamp or place it in an oven though.
It might just be me, but when they state the flashpoint is at 88*, I don't feel safe testing the claim.
 
I'm pretty sure that the flash point of 88 is for just the styrene component, not
the mixed resin. But I've been wrong before.

OK, no I haven't..
 
The MSDS claims 88* for the resin. Since the styrene is already mixed in, that wouldn't make a difference. It would still make it flash at 88*.
Kind of like mixing gasoline with diesel, it will flash at the gasoline flashpoint.

I still don't want to be the tester for the claim.:tongue:

You guys let us know how it all works out for you.:wink:


It also states not to use near excessive heat sources or open flame.
 
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Well, we have had it higher than 88, but I don't recommend halogen lighting as a heating element.

(NOT a LOT higher, but we also don't push our luck!!)
 
It will sustain higher temps, without an ignition source. I'm sure different resins have a different flashpoint and it probably isn't exactly 88*, but other factors would have to be taken into consideration also. With any type of heat element or pilot, that is the ignition source. It's not the resin that causes the problem, but the vapors, just like gasoline. The vapors are heavier than air, so they fall to the ground where pilot lights reside.

I just don't want to read on here that someone got injured from something preventable. Not to mention your insurance company declining your claim.
 
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DozerMite said:
The MSDS claims 88* for the resin. Since the styrene is already mixed in, that wouldn't make a difference. It would still make it flash at 88*.
Kind of like mixing gasoline with diesel, it will flash at the gasoline flashpoint.
Click to expand...

Are you sure you're not confusing the flash point with the autoignition temp?
 
No sir, it says flashpoint. If the autoignition was that low, it would ignite in the can in summer weather. The autoignition is always much higher than the flashpoint and I didn't see the autoignition temp.

An example...

Gasoline

Flashpoint...-45*
Autoignition temp. ...475*


Diesel

Flashpoint...143*
Autoignition temp. ...410*
 
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