Resin won't harden

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RSidetrack

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Hi all - I am attempting to cast my first mold and it has been about 10 hours and the resin is still very liquid with only a slight gel consistency. I did what the instructions and articles I found online said and put in 7 drops of catalyst per ounce. The instructions were making me believe it would be hard within 8 hours - if this is correct then something is definitely wrong with my mold. Any ideas? Thanks!
 
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7 drops per ounce...should've hardened. How about humidity? As mentioned by G1Pens, coloring will add to the curing time, but 10 hours seems excessive to me.
 
Give it time - some liquid pigments slow down the cure considerably. If you can heat it gently that will help. I sometimes put the mold under a light or in a warm (less than 150 degree F) oven
 
alumilite dye will work with PR. The question is...how much did you use? More than a drop and you risk it not curing properly. I've had a mold with slightly gelled resin for about a month now waiting to see if it would harden. No luck, so I finally got everything out and now trying to clean it all up. Overloading the resin is your most likely issue.
 
The problem is likely not the PR but the MEKP. The PR will last a long time if stored in the right conditions. The MEKP is an oxidizer and if it is exposed to oxygen, it will go bad.

I have heard you can buy it at the big box hardware stores but I haven't found it because I haven't looked for it.
 
PTownSubbie said:
The problem is likely not the PR but the MEKP. The PR will last a long time if stored in the right conditions. The MEKP is an oxidizer and if it is exposed to oxygen, it will go bad.

I have heard you can buy it at the big box hardware stores but I haven't found it because I haven't looked for it.
Click to expand...


You can get the MEKP at Hobby Lobby. In fact you have to purchase it separate from the resin.
 
I am going to go stick it in the sun - it can't hurt.

I did just put a drop in - unfortunately the bottles are horrible so the drop was considerably large.

As far as the catalyst - it was a brand new bottle that I just opened that I bought from Michaels with the resin. Hopefully the sun trick will work - I will let everyone know.
 
PTownSubbie said:
The problem is likely not the PR but the MEKP. The PR will last a long time if stored in the right conditions. The MEKP is an oxidizer and if it is exposed to oxygen, it will go bad.

I have heard you can buy it at the big box hardware stores but I haven't found it because I haven't looked for it.
Click to expand...

You'll find it with the glues and the Bondo. It comes in what looks like a
small toothpaste tube (only clear-ish) for a couple of dollars.
 
The best way to tell if it is the resin or too much dye is to do a small clear cast with nothing in it. Just take a small amount of resin and catalyze it. If it works with clear, the resin is good and you added too much dye.
 
My bet is going to be simply not enough heat. I don't know about PA, but it's only 75 here and dropping into the 60's at night. Adding more catalyst is probably a waste of time. You can set that stuff off with less than what you already used, and less you use the better. I'm betting once that sits in the sun for a hr it will heat right up and cure. I do like Fred's experimental theory though. If it won't harden up in an hr of sunlight, I'd definitely mix up a bit of clear and set that outside in the sun and compare.
 
Well it sat out in the sun all day and it has become a gel now - so progress :rolleyes: I will set it in the sun again tomorrow if it is another nice day and see what happens.
 
Wow...it should be hard by now. It must be too much of the Alumilite dye like Charlie said. Learn something new every day! I didn't even know you could use that dye, let alone use too much. I never heard of catalyst going bad either, but maybe it does..I have some in the shop a few years old that still works every time I dig it out. Pretty interesting. Most of the time I use alumilite and the only time it doesn't harden is if it's not mixed thoroughly enough and if that happens it's into the trash because it will never fix itself.
 
Well - checked it this morning - it is more of a solid object than a gel, but tacky to the touch. Placing in the sun again today - I expect it should be fully hardened by the end of the the day. Now watch I will go to turn it and the whole thing will blow up :rolleyes:
 
Okay - update...

I removed the blank from the mold - it hardened enough to do so - but some of the color is definitely not dry yet - just ask my hands and the mold. I am going to clean up the mold and let the blank sit another night and see if it dries up a little bit more - it may never - apparently I added way too much dye even though I thought it was a very small amount - the blank is darn near black - and it was blue dye. Hey gotta start somewhere :)

As for the culprit, definitely appears to have been the dye - I ran another blank without color and it is setting much more quickly - though it is going to be a very big dud of a blank :mad: I have air bubbles everywhere - and even with my band saw / grinder running as vibrator it couldn't lift the bubbles up - I see them within the mold. However.... the mold I already determine was probably going to be a bust anyway, I was experimenting. I am going to leave the surprise on what I was experimenting with once I see how it turns out - most on here will probably already know it wouldn't have worked :rolleyes: But that's me - an experimenter. Also - remind me not to cast in my basement anymore, whew - talk about a headache - and my office is down here :redface:

I do have a question, how do you guys dispose of your cups when you are done. I figured the trash, and of course the cups melt - but my first mold (the blue disaster) it had melted through the cup and of course the trash bag which I didn't think about. So any insight on this would be greatly appreciated.

Also - I created two more home made molds out of silicone - they are larger molds and for individual blanks, but I made one for the 5/8" by 6" divided by 2 lol - I split it into two halves so I can make individual castings. Then I also made another mold with 3 - 1" x 1" x 7" slots for larger castings. The molds are not completely set up yet, only been 24 hours, but so far looking good. All I can say is it is a good thing I love experimenting lol.

Okay - so I also had ordered the cast-a-kit from Penn State - figured it would be cool to try products from two different places, though I am not sure what kind of resin the stuff from Penn State is. Anyway - my question on the kit - it came with this container of what looks like black bb's - any idea on what these are for? I haven't a clue.
 
Using polyurethane dyes for PR is tricky. Take a toothpick, pick up a small
amount and wipe it off on a piece of paper. What's left on the toothpick is
probably the right amount. :tongue:

The black BB's might be filler. We do castings for pens, but most casters
don't. They'll use fillers like glass beads, plastic beads etc. to take up the
bulk so they can use less resin. Saves money.

As for cups, there's certain types that won't melt. I have my resin in
bottles with a #1 recycle code on them and no melting. IF you search
there are lots of posts about which cups to use.

Casting in the basement .. the fumes can be killer. (maybe literally!) If
you can mix and pour outside, do it. Put your mold in a large Tupperware
container with a lid. Once it is closed, then you can bring it inside. Bring
it back outside before you open it. If you're in a cold area, this will allow
you to cast in the winter.
 
NewLondon88 said:
Using polyurethane dyes for PR is tricky. Take a toothpick, pick up a small
amount and wipe it off on a piece of paper. What's left on the toothpick is
probably the right amount. :tongue:

The black BB's might be filler. We do castings for pens, but most casters
don't. They'll use fillers like glass beads, plastic beads etc. to take up the
bulk so they can use less resin. Saves money.

As for cups, there's certain types that won't melt. I have my resin in
bottles with a #1 recycle code on them and no melting. IF you search
there are lots of posts about which cups to use.

Casting in the basement .. the fumes can be killer. (maybe literally!) If
you can mix and pour outside, do it. Put your mold in a large Tupperware
container with a lid. Once it is closed, then you can bring it inside. Bring
it back outside before you open it. If you're in a cold area, this will allow
you to cast in the winter.
Click to expand...
I do have ventilation luckily so the fumes don't stay around too long. I do wear a respirator when I do the molds so that helps. I just haven't sat in my office right afterwards to experience the lingering joys :biggrin: I will start casting outside - but I fear bugs getting in the molds - I HATE BUGS! (They got in the clear coat of a car I painted - they are trapped, forever - or until the next paint job)

Interesting - filler - wouldn't have thought Penn State would have sent it along, but hey - gives me something to throw around when I get mad :rolleyes:

I guess I will pick up cups, I was looking for something very cheap without having to clean. Though I might be able to find #1s that are disposable.
 
I use the 'hard' clear plastic cups to mix. I might get a little drag on the bottom
(getting soft?) if I leave resin in there too long, but I usually only measure and mix
in the cups, then pour. So it isn't an issue for me. But warehouse stores or something
like Big Lots usually has stacks of 25 for a buck or so.

ps.. bugs won't get in your tupperware..
 
NewLondon88 said:
I use the 'hard' clear plastic cups to mix. I might get a little drag on the bottom
(getting soft?) if I leave resin in there too long, but I usually only measure and mix
in the cups, then pour. So it isn't an issue for me. But warehouse stores or something
like Big Lots usually has stacks of 25 for a buck or so.

ps.. bugs won't get in your tupperware..
Click to expand...
I hear ya on bugs not getting in the tupperware, but when I am mixing and pouring :)
 
NewLondon88 said:
I use the 'hard' clear plastic cups to mix. I might get a little drag on the bottom
(getting soft?) if I leave resin in there too long, but I usually only measure and mix
in the cups, then pour. So it isn't an issue for me. But warehouse stores or something
like Big Lots usually has stacks of 25 for a buck or so.

ps.. bugs won't get in your tupperware..
Click to expand...
I got 200 dixie cups from wally world for around $3.00
 
Alright - so my first mold solidified completely and well - it is just plain too dark. I am making it my first contribution to my end-of-day pile.

My "experiment" failed horribly - but the resin hardened just like it was supposed to. The experiment was casting red/white/blue rubber band fragments. I figured it would have blow outs like none other - and I was right. Impossible to turn, even with CA. The mold looked great - but it just cannot be turned, but eh, whatever, it was an interesting experiment, though an expensive one all things considered.

Anyway, I went and cast another mold today with using way less dye - I still think it is too dark - it is amazing how little it takes. All I did this time was stick my stir stick in the bottle, wiped off the excess and stuck it in the resin and man did it fill in quickly. I am hoping it turned out okay - once it got gel like I took a toothpick with color and hopefully made swirl patterns.

Anyway, will keep everyone posted.
 
The BBs used to weigh down pen tubes when casting. -- You should have also received rubber stoppers which would be used to seal off the ends of the tubes and hold the BBs in. -- Once cast, you cut off the end of the stoppers and put the BBs back in the container for the next use.
 
louie said:
The BBs used to weigh down pen tubes when casting. -- You should have also received rubber stoppers which would be used to seal off the ends of the tubes and hold the BBs in. -- Once cast, you cut off the end of the stoppers and put the BBs back in the container for the next use.
Click to expand...
Oh nice! I am about to cast my first one over a pen tube so that is good to know.
 
You can also put the mold in the oven for an hour at the oven's lowest setting (150-175) and get it to cure.

EDIT: Whoops, didn't see the other two pages of replies. :eek:
 
DurocShark said:
You can also put the mold in the oven for an hour at the oven's lowest setting (150-175) and get it to cure.

EDIT: Whoops, didn't see the other two pages of replies. :eek:
Click to expand...
I would put it in the oven except I only have the one I cook food in lol - I would prefer not to bake it in there. The sun seems to do a good job - especially today - working on another one with the dyes (less dye, still too much I think) - but 95 degrees and it is setting on asphalt, so should help a good bit :)
 
Get a toaster oven. They're $20 new at WallyWorld and similar places, or $5-10 at yard sales or thrift stores.

Best investment in my penmaking I've made to date. Not only lets me post cure resin, but bake enamel as well. I suppose if I get into powder coating I could use it for that too!
 
DurocShark said:
Get a toaster oven. They're $20 new at WallyWorld and similar places, or $5-10 at yard sales or thrift stores.

Best investment in my penmaking I've made to date. Not only lets me post cure resin, but bake enamel as well. I suppose if I get into powder coating I could use it for that too!
Click to expand...
Good advice. Also works good for polymer clay
 
I think I might go and get a toaster oven - sounds like a worthy investment.

Also - attached are the pictures of my Rubber Band mold - it looked so good as a mold, but just can't turn - I was in the 4th of July spirit.
 

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Maybe you can still take that idea and run with it, but as you found out the
rubber bands won't do it for you.
Try making up some small batches of resin in these colors and pouring
them onto a sheet of glass. You'll need plenty of white or powdered
pigments to make the resins opaque, but it should work. When the resin
cures, you can peel it off of the glass in a sheet (use a razor blade to lift)
and cut it into small pieces. Then cast it as you have done.
It wouldn't be as easy as using rubber bands, but should get you where
you want to go..

and the toaster oven is definitely a good idea. They can be had for a dollar
or two at yard sales. I even found an oversized convection oven for $17
(brand new and big enough to hold a pizza!) at one of those overstock places.
 
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I don't understand "rubber band" mold". What I see a picture of looks like a big block of clear resin with tons of little strips of plastic embedded in it. Are those strips inside the pour rubber bands? If those strips are plastic, It should be turnable, but rubber, well that's gonna be tough to spin as it will not cut easy and want to stretch and pull on the chisel...or so my guess would be. You kinda lost me on what this is.
 
If you can't turn it with a chisel, you might try using some 36 or 50 grit sandpaper on hand sander to work it down to shape. I dunno, it might be impossible to keep the thin ends from lifting out even if you can shape it, or it might get dirty real easy, but I kinda think that the combination of softish rubber in the hard matrix might make an interesting kinda "easy grip pen"
 
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jskeen said:
If you can't turn it with a chisel, you might try using some 36 or 50 grit sandpaper on hand sander to work it down to shape. I dunno, it might be impossible to keep the thin ends from lifting out even if you can shape it, or it might get dirty real easy, but I kinda think that the combination of softish rubber in the hard matrix might make an interesting kinda "easy grip pen"
Click to expand...

Well - I still have a blank, I might give that a try :)
 
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