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This is a question for the resident molding and casting experts here. I'm looking for a material that is translucent and fast curing. I definitely don't want to use polyester resin.

Working on a project and need a fast curing clear resin. The part I'm making has a fairly simple shape and about the size of a thumb. The mold is RTV silicone. Currently I'm using 'Castin Craft - Clear Casting Epoxy' which looks fine but cure time is too slow.

The finished parts are required to be translucent and definitely NOT water clear transparent. I need a material with a fast curing time; ideally under 30 minutes.

Do any of you know of materials with these properties? Do they exist?

Any specific recommendations for products and manufacturers you might offer would be greatly appreciated.

Regards,
MattL
 

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You can use clear two part 5 min epoxy.mix slowly to minimize air and use a probe to work out bubbles.pour work fast,then let set for at least an hour.
 

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Discussion Starter #3
You can use clear two part 5 min epoxy.mix slowly to minimize air and use a probe to work out bubbles.pour work fast,then let set for at least an hour.
Thanks but the project requires a quantity of at least 100 pieces so an hour each would take quite a long time to make. The solution I'm seeking would cure fast so I can pump out a large qty of parts in a few days. I see a lot of after market casters use a white(ish) material that they tell me cures in 10-15 minutes. What I need is a clear equivalent.
 

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There are NO fast curing clear resins. It's why they can be clear.

What I do (and most other casters) who need lots of clear parts, is create gang-molds, and cast that way. So instead of making one part at a time, you can make as many as you have molds for. The more molds, the faster you can make a larger qty.
 

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Spockr,

You say these are small fairly simple shapes. Would it be possible to vacuum-form them using clear plastic sheets? That would take care of all your resin casting problems and be way faster to boot. If your items must be solid, you could still fill the clear shells with translucent resin, which would save you the effort and expense of making a lot of RTV molds.

I don't suppose you'd care to be more specific about just sort of parts you're planning to manufacture - ?
 

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Discussion Starter #6
There are NO fast curing clear resins. It's why they can be clear.

What I do (and most other casters) who need lots of clear parts, is create gang-molds, and cast that way. So instead of making one part at a time, you can make as many as you have molds for. The more molds, the faster you can make a larger qty.

Thanks for your input. Not sure I understand the relationship between speed of curing and whether or not its clear or not but I'll take your word for it because I haven't found anyone out there who makes one with those properties. At least so far.

BTW I am planning a multi-cavity mold. Still would like to keep its size small. Maybe about 8 cavities.
 

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Spockr,

You say these are small fairly simple shapes. Would it be possible to vacuum-form them using clear plastic sheets? That would take care of all your resin casting problems and be way faster to boot. If your items must be solid, you could still fill the clear shells with translucent resin, which would save you the effort and expense of making a lot of RTV molds.

I don't suppose you'd care to be more specific about just sort of parts you're planning to manufacture - ?
Mr Bride, I can't be specific (yet) about the part I'm making. Needless to say they are beautiful and everybody with WANT one or five (at least that's what I hope)

I did consider vaccum-form parts but there are a number of reasons I had to reject that path. Mainly due to local unavailability of a contract vacuum former and also the need to have a matte finished part. I didn't think vacuum formed parts could be produced with a matte finish. Unless you might know otherwise?

The epoxy resin I'm using give the appearance I need it'll just takes too long to crank out the numbers I need.

I do have interest in vacuum-forming in general, I'm in Western PA do you know anyone over here or eastern Ohio that does contract work?

Thanks and Regards,
MattL
 

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...I didn't think vacuum formed parts could be produced with a matte finish...
Sure they can, and made translucent in the bargain...just spray 'em with Testors Dullcote. There are resources all over the Internet that describe way of making your own vacuformer. If your items aren't too detailed, you might even be able to stretch form the parts over your master sculpt by hand.

 

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Thanks for your input. Not sure I understand the relationship between speed of curing and whether or not its clear or not but I'll take your word for it because I haven't found anyone out there who makes one with those properties. At least so far.

BTW I am planning a multi-cavity mold. Still would like to keep its size small. Maybe about 8 cavities.
Resin uses a chemical reaction to generate heat, that heat then "sets" the resin. Clear resin is clear because it uses different chemicals. And to keep it clear, it has to do more chemical reaction than heat, less heat, longer cuing times. Too fast a chemical reaction will cause the clear to fog, and is therefore no longer clear.

Your mold need not be huge, but you can have several molds. The current project with clear I have on the casting bench right now has 5 molds (2cmx13cmx5cm) and has 3 sets of parts in each mold. It's the on ly fast way of getting more clear parts; Have more molds. :) I guess it depends on the size/number of pressure pots you have too.
 

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Just curious but the chemical reaction does generate the heat but is not that heat a byproduct of the reaction and not the actual process responsible for the resin "curing?" I mean even if the resin did not heat up would it not still cure? The reaction of the resin and catalyst produces the heat and it is not required for the curing process I think. I believe even plaster of paris produces some heat because of the reaction going on with the components.
 

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Just curious but the chemical reaction does generate the heat but it not that heat a byproduct of the reaction and not the actual process responsible for the resin "curing?"
Most resin will cure without heat. But most people don't have a few weeks for that to happen. The smaller and thinner your parts, the longer they will take to fully set. Reason being is that the amount of heat generated by the chemical reaction is related to the cross sectional area. The bulkier the part, the faster the set time, faster you can demold.

In slow setting resins, you have more pot life (and longer set time) as the chemical reaction is retarded to generate less heat. Less heat, longer working/set times.

Cast on a hot day, resin kicks faster. Cast on a cold day, resin kicks slows. In the winter, I need to double my pot time (uh, the time the parts say in the pressure pot that is :)). I keep the house at 18º. This gives me more working time, but as a result of the cooler temp, longer set time.
 

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Or to put it another way, the chemical reaction is what solidifies the resin but the heat generated accelerates the reaction, as heat tends to accelerate most reactions, such as oxidation.

My first recommendation would have been 5 minute epoxy for a small batch of castings but 100 or more castings would make it worthwhile to obtain actual casting resin. I have never done clear parts but have looked into it. I'll take that back. I did use epoxy to simulate a jar of liquid once and while it is thicker than PU resin, I'd say that it should work well for parts which don't have really intricate detail. Mold life would probably suffer with epoxy, especially if the piece has a matte or frosted surface. Depending on the bulk of the part, 5 min epoxy may actually set too fast for you. Of course there are slower epoxys.

It seems that clear resins are more noxious than regular PU resin, and that is saying something. Be careful with your lungs. Usually pressure casting is recommended for perfect castings but it sounds like you don't need crystal clear pieces so that may work to your advantage.

This was all several years ago and new products seem to be coming along regularly so hopefully you'll find something that fits the bill perfectly.
 

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As stated,there are no Clear resins that have a curing time less than 24 hours, even when they are in heated molds.I've tried many products over the years,I did a whole side of a 1/32 scale Zero,and have used military grade optically clear resin,all which take 24-48 hours to cure.Various parts for different projects curing.
 

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http://www.smooth-on.com/Urethane-Plastic-a/c5_1120_1156/index.html

In the chart notice a resin with a 90 minute demold time--depending on part thickness. Although labeled optically clear, there are ways around that. The first that comes to mind is using a release agent such as "Eject-It"--I don't remember where I bought it from, but it was relatively inexpensive and gave parts a nice fine pebble-grain-type texture. Not like sand paper, but not glass smooth either.

Of course, if your masters aren't polished smooth, you'll have molds and parts that will have some texture anyway.

You might also tint the resin. There may be a white tint available.

Hope that helps!
 

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try specialtyresins.com (might be singular). Can find them on evilbay too. They have everything from resins to RTV.
Bruce
 

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If you are looking for a resin that is "translucent" and doesn't need to be "clear".... get thee to Smooth-On and check out SC-320 series.

Standard resin...no post curing required....cures "slightly" amber.

I use the stuff with RTV molds and have very few issues.

You'll love it !
 

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This is a question for the resident molding and casting experts here. I'm looking for a material that is translucent and fast curing. I definitely don't want to use polyester resin.

Working on a project and need a fast curing clear resin. The part I'm making has a fairly simple shape and about the size of a thumb. The mold is RTV silicone. Currently I'm using 'Castin Craft - Clear Casting Epoxy' which looks fine but cure time is too slow.

The finished parts are required to be translucent and definitely NOT water clear transparent. I need a material with a fast curing time; ideally under 30 minutes.

Do any of you know of materials with these properties? Do they exist?

Any specific recommendations for products and manufacturers you might offer would be greatly appreciated.

Regards,
MattL
Its been awhile for you but in case others need to know, Silmar41 is fast clear curing resin. It can get hot, not sure if this is a problem for you. Not super hot unless you over mix the catalyst. Illstreet composites yet they have changed their name, you can probably find them under the silmar41 name
 

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Its been awhile for you but in case others need to know, Silmar41 is fast clear curing resin. It can get hot, not sure if this is a problem for you. Not super hot unless you over mix the catalyst. Illstreet composites yet they have changed their name, you can probably find them under the silmar41 name
This is a question for the resident molding and casting experts here. I'm looking for a material that is translucent and fast curing. I definitely don't want to use polyester resin.

Working on a project and need a fast curing clear resin. The part I'm making has a fairly simple shape and about the size of a thumb. The mold is RTV silicone. Currently I'm using 'Castin Craft - Clear Casting Epoxy' which looks fine but cure time is too slow.

The finished parts are required to be translucent and definitely NOT water clear transparent. I need a material with a fast curing time; ideally under 30 minutes.

Do any of you know of materials with these properties? Do they exist?

Any specific recommendations for products and manufacturers you might offer would be greatly appreciated.

Regards,
MattL
Also i forget if its epoxy etc... I know its fast, its clear and stays clear a long time, so far at least 4 years if done right. (aka not mixing stuff that would bleed colors into the resin). Bests to all who need this, its good stuff, low cost also.
 
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