# Clear acrylic casting resin



## mrmurph

While thumbing through an old "Kit Builders" magazine I found a reference to clear acrylic casting resin. The author explained that this stuff is sold to railroad model enthusiasts to create water and other liquid effects. He discussed methods of adding tint for colors, and cautioned that the curing process gives off a lot of heat (it is "exothermic," for all of us science nerds). 
My question is this: Have any of you used this resin on or in your clear Bride/ Witch/ Jekyll bottles & jugs? If so, to what effect? Any insights would be appreciated.
- The insomniac mrmurph


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## frankenstyrene

I too would like to know if there's currently an effective brand of clear curing resin, and where one can get it.


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## razorwyre1

ive never used it for those particular applications, but i have used clear resin from time to time. 
the stuff sold in most hobby and craft stores is polyester... in other words fiberglass resin. the quantities which youre talking about are so small that the exotherm isnt that much of a worry, but the resin itself is solvent in nature, and i dont think it would do the styrene parts any favors if you filled them with it. in my experience they always cure with a tacky surface, and shrink somewhat while curing. 
there are now water clear urethane resins available from companies like bjb enterprises and smooth-on, which, while they have their own technical idiosyncrasies, are preferable to the polyester resins in many ways, and arent solvent in character.


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## spe130

Fiberglas resin becomes impressively warm when it's curing.


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## veedubb67

Couldn't you just pour some Future into the bottles or flasks?


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## frankenstyrene

Could you just recast the bottle (or whatever) in clear resin, then paint a level of liquid on the outside, and finally seal the whole thing in Future? Would that make for a believable item?


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## spe130

frankenstyrene said:


> Could you just recast the bottle (or whatever) in clear resin, then paint a level of liquid on the outside, and finally seal the whole thing in Future? Would that make for a believable item?


Or make some tinted but transparent resin, fill the mold partway, let it get partially set up, then add clear resin to finish filling the mold.


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## razorwyre1

frankenstyrene said:


> Could you just recast the bottle (or whatever) in clear resin, then paint a level of liquid on the outside, and finally seal the whole thing in Future? Would that make for a believable item?





spe130 said:


> Or make some tinted but transparent resin, fill the mold partway, let it get partially set up, then add clear resin to finish filling the mold.


again, in both cases, youre back to finding a clear resin that wont melt the styrene part or wont set with a tacky surface, so once again youre back to using the urethane.
frankenstyrenes idea has one problem, most resins shrink as they cure, and would pull away from the inside of the flask.
heres an idea: pour a tiny bit of tamaiya clear color paint into the bottom of the piece, and allow to dry, repeat the process until youve built up the desired quantity of "potion" in the model part.


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## spe130

razorwyre1 said:


> again, in both cases, youre back to finding a clear resin that wont melt the styrene part or wont set with a tacky surface, so once again youre back to using the urethane.
> frankenstyrenes idea has one problem, most resins shrink as they cure, and would pull away from the inside of the flask.
> heres an idea: pour a tiny bit of tamaiya clear color paint into the bottom of the piece, and allow to dry, repeat the process until youve built up the desired quantity of "potion" in the model part.


I was thinking of making a mold of the styrene part, then filling the mold with the resin, disposing of the original part entirely. If someone wanted to get REALLY clever, they could mold a tinted "core" then put it in a larger mold and fill that one with clear - forming a clear "bottle" around the tinted core.


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## frankenstyrene

spe130 said:


> I was thinking of making a mold of the styrene part, then filling the mold with the resin, disposing of the original part entirely.


That's my thought, too. Seems it'd be the easiest workaround, and the most effective IF a resin is really clear as glass.


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## razorwyre1

ok, then you'd really want to go with one of the urethanes from bjb or smooth-on. 
the stuff sold in most art/craft/hobby stores always sets with a tacky surface. always.

edit 5 pm est: on a trip to micheals crafts today i found a new item (for both them and me): an epoxy clear casting resin kit. 8 oz for about 10 bucks. 2 parts, 1:1 by volume mix ratio. (the box says its for a max casting volume of 6 oz.. this is probably due to the exothermic reation. ive seen clear resins get so hot they crack themselves.) tomorrow im going to give it a try on some small skull molds i have laying around... i'll report when i get a casting.


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## razorwyre1

well i tried the epoxy casting resin from micheals. it sucks.

i cast a 4 ounce skull. while it doesnt set with a tacky surface, it does come out a light amber, instead of water clear like the urethanes. also it degasses as it sets up, which means the chemical reaction that occurs while it sets causes micro bubbles in the resin, giving the whole thing a cloudy appearance. (if i had put it in a pressure pot while it was setting, that wouldnt have been an issue, but most hobbyists dont have a pressure pot at home. (the cure time is 24 to 48 hours depending on the thickness of the casting.)

the upshot is that it has all of the disadvantages of the urethane clear resins without any of the advantages. the ONLY thing it has going for it is the non-tacky surface (as opposed to the polyester clear resins also available at craft stores). all in all youre better off contacting someone that distributes bjb or smooth-on products and go with one of their clears.


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## frankenstyrene

Was it in a rectangular metal can? If so it sounds like the same stuff at HL.

Also - does Alumilite cure with the tacky feel you mentioned? Haven't played with mine yet, was waiting for the upcoming break from school.


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## razorwyre1

frankenstyrene said:


> Was it in a rectangular metal can? If so it sounds like the same stuff at HL.
> 
> Also - does Alumilite cure with the tacky feel you mentioned? Haven't played with mine yet, was waiting for the upcoming break from school.


no, the stuff in the can is the polyester. tacky, stinky, lousy.
alumilite is polyurethane resin. unless they have a clear variety that i dont know about, its opaque, and pretty much like all the other casting resins out there. no tacky surface.


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## frankenstyrene

Thanks for all your postings on this - it's very helpful. Now I'm afraid I'll have to return my Alumilite sets to HL for a refund, since they may well be past their shelf life (read that on another site) and the resins won't work very well.


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## razorwyre1

some people swear by alumilite, others swear at it. im one of the latter. you'll notice how few garage kits are amber? thats cause nobody that uses resin regularly uses alumilite (we've all tried it though). 
check with some of the special effects suppliers (motion picture fx, stage door studios, butrman foam, davis dental supply) and see if they carry small quantities of either smoothcast 300 by smooth on, or bjb's equivalant. 
oh wait: mail order art supplier dickblick.com carries pour-a-cast. good stuff, resin wise. 
as to clear: again, youre gonna have to contact smooth-on or bjb enterprises, and ask for a small quantity.


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## frankenstyrene

Will do. I'm planning to experiment with the Alumilite over break; I'm hoping it's not past its shelf date on either the silicone or the resin mix. Only one way to find out, I guess...


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## wanted2buyit

Actually,

I recomend casting craft clear resin for the "filling" of bottles. Make sure its the 50-50 mix not the 9 parts clear resin to 1 part cataylist. (The 9 to 1 not only stinks but doesn't really want to set right in an enclosed bottle.)

First mix the resin you require. (You'll have @ least four hours of work time. ) add the coloring agent (they make tints in both transparent and opaque.) And then fill one side (half) the bottle. 

When you close the bottle, wrap it in scotch tape (tightly) and let it sit..... the next day (just to be sure ) you bottle will not only be "glued" but you will have the bottle half full (or empty depending on what floats yer boat. ) 

Wanna fill it up fuller??? With this method... you either are quick with closing the halfs, or like to smoke the crackpipe.


Kurt.

Yeah I know I'm a newbie, don't go to wonderfest, because I'm already @ a con that weekend. But I really dug aurora, and polar lights. However @ recentlly I'm addicted to paper card models right now.


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## razorwyre1

wanted2buyit said:


> I recomend casting craft clear resin for the "filling" of bottles. Make sure its the 50-50 mix not the 9 parts clear resin to 1 part cataylist. (The 9 to 1 not only stinks but doesn't really want to set right in an enclosed bottle.)


the 9 to 1 is the polyester that sets tacky, the 1 to one is the epoxy that sets yellowish and bubbly. 
avoid casting craft brand clear resin products altogether.
pour-a-cast (formerly by synair) has a new clear resin too. its pricy because it comes in a 2 quart kit. its available from dickblick.com. i'm going to give it a try and let you all know.


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## wanted2buyit

Razor??

Ummm which version of the one to one ratio are you useing? I don't mean to mence words but yellowish and bubbles? I remember not mixing it with a 50/50 ratio and got some yellowing, but I started to make sure my measurements were correct and that stopped. As for bubbles, the only time I got bubbles was useing smooth on (3 min and 7 min cure) and ironiclly pour a cast as well, even alumnite. (The smooth on 20 min cure was eventually stopped bubbling by de-gassing it. With anything 3 min and 7 min cure, I could never de-gas it.) 
But see that was the whole non bubble thing with castin craft transparant, it cures over 4 hours (full cure 24 hours.). So any gas has a chance to escape. Plus with a lower tempature cure, I just don't see how bubbles could have been an issue... 

Did you get moisture in the resin? Moisture in the mold? Was it really really really humid? I mean sure iver poured it in 90% humidity and still didn't get bubbles. 

Get back to me, I am curious. 

Kurt


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## razorwyre1

wanted2buyit said:


> Razor??
> 
> Ummm which version of the one to one ratio are you useing? I don't mean to mence words but yellowish and bubbles? I remember not mixing it with a 50/50 ratio and got some yellowing, but I started to make sure my measurements were correct and that stopped. As for bubbles, the only time I got bubbles was useing smooth on (3 min and 7 min cure) and ironiclly pour a cast as well, even alumnite. (The smooth on 20 min cure was eventually stopped bubbling by de-gassing it. With anything 3 min and 7 min cure, I could never de-gas it.)
> But see that was the whole non bubble thing with castin craft transparant, it cures over 4 hours (full cure 24 hours.). So any gas has a chance to escape. Plus with a lower tempature cure, I just don't see how bubbles could have been an issue...
> 
> Did you get moisture in the resin? Moisture in the mold? Was it really really really humid? I mean sure iver poured it in 90% humidity and still didn't get bubbles.
> 
> Get back to me, I am curious.
> 
> Kurt


ok the stuff in question is casting crafts clear epoxy resin. we were very careful about the ratio, and we were dealing with low wintertime humidity. 

the bubbles i am referring to are not air trapped in the mixture, but are caused by the resin producing gas as it cures. acccording to the folks at bjb, this is going to happen with the clear polyurethanes (and apparently epoxies) if you dont cast it in a pressure pot. all of your conditions can be ideal and your mix 100% accurate, but because the mixture releases gas, you will get bubbles. 

when you write about the smooth on, pour a cast, and alumilite products, are you talking about clear or opaque resin? the opaque resin will foam up if theres moisture in them, but again its a very different sort of phenomenon that the bubbles that the clear materiels produce.

as to degassing short cure resins, you have to work FAST. i place the empty mold in the pressure pot, then pour the resin in, slap the lid on and open the air valve. you could do it pouring the resin then placing the mold in the pot, but that would be too fast for me.


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## Bobman

razorwyre1 said:


> , most resins shrink as they cure,


Um.. No they don't.

Bob


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## razorwyre1

Bobman said:


> Um.. No they don't.
> 
> Bob


um yes they do. 
slight correction: most resins of they types we have been discussing that i have had experience with shrink somewhat. (these include pour a cast, pour a cast 2, alumilite, smoothcast 300, bjb tc-800. thats the opaque stuff. ive used a few clear resins as well)
check the specs on em... or, do a multi batch pour (where youve allowed the first batch to set completely before pouring the next one. you'll see the new batch creep around the edges of the previous one) 
the shrinkage is very very slight, but it happens. the shrinkage on the bjb tc 800, according to their material specs, is .007% for a piece thats 12 inches by 1/2 inch by 1/2 inch (1 1/2 cu. inches) . im sure the other brands i've mentioned are similar. the shrinkage on the clear urethane stuff is about the same. the casting craft polyester i worked with shrank much more.

now you may ask: that shrinkage is so slight, so what? well in the applications we are discussing (filling little clear plastic bottles) its enough to show.


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## wanted2buyit

Ok actually, 

Sorry bob.... raz is dead correct, you always experience shrink in resin cast.

But I think I see the issue with bubbles...

Raz how big of a mold were you pouring?

The only reason why I'm asking is, for what the guy needs and that's pouring bottles, he should be filling a cavity which is 1 cc total. (Maybe 2cc but I think I actually filled the bottles with .05 cc of product. 

And on stuff that small. Hell I would even say up to something that was poured with 30cc.... casting craft clear did not suffer "cure bubbles" because of the low heat produced from the cure. 

Now the smooth on cold cast 300. Isn't that the 3 min cure.... but its opaque I'm talking about the clear resins. 

I used to work in a place that all we did was prototyping bits for people. the fun part is, me and four others only had one or two projects a week so we got to experiment.... a lot. The downfall was, ofcourse, the company went out of business after 2 years.

But as for the "experimenting" you name it we pretty much did it. The typical stuff like submerging things in resin to make paperweights. Mixing parts a and b from two diffrent resins. Hell even experimenting with food coloring to see what would accept it what would. (You and I both know only water based resin.) But haven't ya ever gotten the urge to to mix a batch of rtv silicone, then as its setting, about an hour later pour in a resin compound to see what the effects would be? Would you get chunks of plastic suspended in silicone? Would the resin mix great with the rtvs and increase the shore? Did it stink worse then it already did? Did it cause bubbles? Did nothing cure @ all like rtvs does when it touches a high sulfure clay? Is it actually possible to take a dead mouse and cast it in clear resin to make a paperweight that would not only be a conversation piece but would insure your wife never ever steps foot in your "no mam" lounge. Well, we did. And no my wife doesn't step into my hang room. 

Sorry if I came off as brash. But I assure you for what he wants to do. There's no need to spend the extra cash. A cheap little 8 dollar set of the resin and a 4 dollar set of castin crafts 4 basic colors will suit him just fine. No bubbles, no yellowing. (The styrene bottle would yellow before the resin does.)

Kurt


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## Bobman

razorwyre1 said:


> um yes they do.
> slight correction: most resins of they types we have been discussing that i have had experience with shrink somewhat. (these include pour a cast, pour a cast 2, alumilite, smoothcast 300, bjb tc-800. thats the opaque stuff. ive used a few clear resins as well)
> check the specs on em... or, do a multi batch pour (where youve allowed the first batch to set completely before pouring the next one. you'll see the new batch creep around the edges of the previous one)
> the shrinkage is very very slight, but it happens. the shrinkage on the bjb tc 800, according to their material specs, is .007% for a piece thats 12 inches by 1/2 inch by 1/2 inch (1 1/2 cu. inches) . im sure the other brands i've mentioned are similar. the shrinkage on the clear urethane stuff is about the same. the casting craft polyester i worked with shrank much more.
> 
> now you may ask: that shrinkage is so slight, so what? well in the applications we are discussing (filling little clear plastic bottles) its enough to show.


I really think you're splitting hairs. At this scale tho, it is alot. 

I have used most of the ones you listed and they are recommended for hobbiests. Which means they don't care how they work. All of them are crap except Smooth-on. Stick with Smooth-on products. You can't go wrong.

As for filling little clear plastic bottles, you can use clear expoxy glue. Put a few drops of you color of choice in it, mix and pour. If you don't want tiny bubbles in the mix, then pressure cast it. Most mad lab beckers have bubbles. You can add alittle cotton to the expoxy as it's in the final setting stage. "Pull" it away and it will leave little "wisps of steam". Also the expoxy will get hot. Put it in the frig. It will slow down the cure time alittle, but it will still set-up.

Bob


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## razorwyre1

well bob, it would be splitting hairs if when filling clear items the resin didnt pull away from the sides of the item. it does and it shows. besides that amount of shrinkage is tangible... as i said, do a multi batch pour and you'll find out just how real it is. 

the epoxy glue is an ok idea but it will yellow over time. make sure to use the extra working time version to cut down on the heat. i still think that if filling a ready-made clear bottle is the goal, then successive layers of tamaiya clear paints is the easiest way to go (it'll just take a while to accomplish).

kurt, this thread is getting really confused with opaque vs. clear resins. that happened many posts ago when alumilite was mentioned. my casting was 4 ounces, and yes tiny quantities have less of a problem with the bubbles, but i do not think the exothermic reaction is the cause of the gas release, but instead is a simultaneous but separate side-effect of the curing. (im trying to find one of the same skulls i cast up bjb's water clear urethane without pressuring it to show you the comparison between the clear epoxy and the clear urethane (as well as one of the clear ones that was pressurized)

bob brought up something i was going to mention here, and he's absolutely right about it. be it resin, or latex or whatever, with rare exception, the molding and casting materials sold in craft and hobby stores are substandard materials, all of which are available in a professional grade version elsewhere. this goes for "casting craft", "body p-arts", "rigid wrap", "insta-mold", "alumilite", "mountains in minutes"... the list goes on and on. they are pretty much junk, across the board. that being said, smooth-on is only one of a number of companies that do produce professional grade molding and casting compounds. there's also bjb enterprises, synair, silpak and a number of others that produce materiels every bit as good as smooth-on, and in some cases better, depending on the application.


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## wanted2buyit

OK	I can agree with bob, most resins sold in generic craft hobby stores (hobby lobby,michaels,yadda-yadda-yadda) are really worth that much. But given what he was talking about (2cc or less) he should be absolutly fine. Its not like he's gonna recast the warp engine plates of the enterprise in blue. Lol

4oz? You know, I think I poured just about 4oz of clear to cast a ziggy handlink from quantum leap useing the casting craft back in the day. . But I was casting a base plate with walls.... and I don't think I had any thing real thick. Ill check in for the picks of the skulls. If you can try and put something in for a size refrence, that would be grand. 

As for the mix up with alumlite and clear and opaque... that was my bad...I should been specific. They or may not make it anymore, but alumlite used to make a clear resin. And they even sold the powder like smooth on that can even produce the blacklight reactive effects. But alas, I don't know if they do make clear resin anymore or not. 


Kurt


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## Bobman

Hey guys no harm no foul. I think we're all on the same side here: just trying to get the best results.

Bob


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## wanted2buyit

Lol yeah bob, for a moment there I thought someone was going to step in and proclain "lucille". (Yeah, see I read the polarpedia.)

My side of the matter is..... I'm cheap. I go to a discount store and find kits on sale for a buck, I buy 10 of them and sit for soemthing to have fun with. And even more so for bits of this and that. Back when I work for j and m plastics, we never used casting craft brand. The only reason why I know about it is because when my wife forces me to go with her to hobby lobby I usally check out the clearance bins and I got a few sets (once again like a buck.) So I just used it like a lot of the "cheaper" things I find.... where it might fit. And I myself filled bottles on the bride kit with the intention of... "its cheap and should work." 

The frugal fat guy in ohio,

Kurt


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