# Question about mold release agent.



## hal9001 (May 28, 2008)

I've got a small project to do and have never used silicon molding material and (clear) resin products. What I wanted to know if there is a simple trick to prevent the resin sticking. I know there are specific products for this but I really didn't want to spend a lot of $ for this simple piece.

Any advice would be very helpful.

Thanks,
Carl-


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## Trek Ace (Jul 8, 2001)

I'm one of the believers in "the right tool for the right job". So, if it were me, and I had just invested in casting resin and silicone rubber molds, I would want to use the correct mold release intended for that purpose. It is easy to come by (you can almost always find it locally), only costs $10-15 for a spray can, and can be used for more than one casting. And, best of all, it helps with the longevity of your molds.

I've heard that some people have tried Vaseline, PAM and even WD-40 as a mold release - with varying results. But these may actually do harm to the molds and even give unacceptable finishes to the surface of the castings. This can actually waste a lot of time, use more casting material (because of multiple attempts at a clean pull), and even ruin the molds, if you are not careful.


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## Mark McGovern (Apr 25, 1999)

hal,

What brand(s) of molding material and resin are you using? The safest choice would be to use whatever release agent the mold material's manufacturer recommends.


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## hal9001 (May 28, 2008)

*Trek Ace*, yes that's sound advice but was hoping to use some common item to avoid the expense but may not have a choice. Like I stated this is a simple project and bought a very small quantity two part molding putty. And will go by my LHS tomorrow to get the resin.

*Mark*, not sure what brand resin yet, I've not bought it. Suppose I'll have to get, hopefully, a small can of the same brand release.

I was just hoping there may have been some nifty trick using some house hold or other common item.

Thanks for the input,
Carl-


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## djnick66 (May 2, 2008)

Why cheap out on 1/3 of the items you need? Honestly... I use Alumalite resin and their mold release (purchase it at Hobby Lobby). A bottle is only something like $5-$7 and you can use their 40% off coupon.

Casting in clear resin is hard enough as it is without handicapping yourself by cutting corners.


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## hal9001 (May 28, 2008)

Ok, ok, I won't "_cheap out_"! I'll spend $15.00 on a one time small piece. :drunk:

I have too much money anyway and need to get rid of some.....

Carl-


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## Spockr (Sep 14, 2009)

I cast some of my 'clear' flames in that type of mold. The methods I describe below will produce parts that have a matte finish and are not water clear. 

What is needed for mold release depends a lot on how many copies you plan to pull from the mold. Amazing mold putty has an oily coating when it is freshly made and that is usually enough for the first casting. After a few 'pulls' that coating is gone and you can use mineral oil or just a dusting of baby powder will do the trick. If I plan to use the mold for a long time I use both. 

If using mineral oil you only need a thin skim coating so the surface feels slick not wet. Brush some on with a Q-tip or brush. You don't want puddles on the bottom of the mold or you will have voids in the cast piece. If you put too much on simply wipe it out with a tissue. 


If using baby powder. pour in a small amount into the cavity. Cover the cavity with you hand and shake to coat the sides of the mold. Take away you can and shake the excess powder out the mold, You may also want to blow out the excess powder.

If using both. Mineral oil first followed by baby powder.

Tips.

1. Do not use polyester casting resin. Its massively toxic and its vapors will clear out the room. For small jobs I use Easycast casting epoxy which is about $20. Exactly follow their instructions for mixing and pouring .

2. If using the casting epoxy I suggested wait 24 hours before pulling the parts out of the mold.

3. Wipe with a lint free cloth and rubbing alcohol to remove the mineral oil.

Does this help?

Regards,
Matt


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## djnick66 (May 2, 2008)

hal9001 said:


> Ok, ok, I won't "_cheap out_"! I'll spend $15.00 on a one time small piece. :drunk:
> 
> I have too much money anyway and need to get rid of some.....
> 
> Carl-


I know what your saying but to do just a one time thing right can still cost some $$. Small parts arent necessarily easy and clear resin is very fussy to get a clear smooth (and bubble free) finish.


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## hal9001 (May 28, 2008)

djnick66, it's all for naught this weekend anyway because the sales person at *Hobby Town *doesn't know the difference between casting resin and epoxy glue!!! Had to drive a long way too.

They did have a small bottle of rubber to rubber mold release, would this work for a silicon mold and clear resin?

Carl-


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## djnick66 (May 2, 2008)

FYI I have never seen casting resin at Hobby Town. Since its expensive I buy mine at Hobby Lobby.

Isn't that the kind of mold prepper you use to keep a mold from sticking to itself?


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## Mark McGovern (Apr 25, 1999)

hal9001 said:


> They did have a small bottle of rubber to rubber mold release, would this work for a silicon mold and clear resin?


That sounds like Alumilite's release agent for keeping its RTV mold rubber from sticking to itself. As the name "rubber-to rubber" suggests, it prevents a new batch of material from sticking to an old one - when you're making a two part mold, for instance. Alumilite's resins don't usually require much in the way of mold release agents.

As Spockr pointed out, a dusting of talcum powder does make it easier to pull the resin from the mold. But mainly the talcum powder helps prevent air bubbles, a/k/a "pinholes" from forming in the surface of the casting. I don't know what effect the powder would have on the appearance of clear resin pieces.

Don't be shy; can you tell us what you're planning to do, and with what material you want to do it?


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## hal9001 (May 28, 2008)

Mark McGovern said:


> Don't be shy; can you tell us what you're planning to do, and with what material you want to do it?
> [/SIZE][/FONT]


It's no big secret Mark (just don't tell anyone...), I've sculpted some flames that I would like to cast in clear resin for lighting purpose. Plus I might like to also cast the flames on the Moebius Dracula kit to light like I've seen others do.

Not having a lot of knowledge in mold making and resin casting I bought a small quantity of two part putty for making molds not realizing it was for "smash molding" but in the end I was able to use it to make a perfect mold. Live and learn.

Carl-


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## Mark McGovern (Apr 25, 1999)

hal,

There are much easier ways to do flames: let Starlighting Projects do them for you! Check out their "Terror Torches". I'm planning to make them one of my first stops when I get to the WonderFest vendors rooms.


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## J_Indy (Jan 28, 2013)

I've tried Ice Resin (it is jeweler-grade resin) and it cures nice and clear - but depending on your mold you may get a matte finish where the mold contacts the resin.

I have heard (not tried) that Nail Acrylic brushed over the matte finish will restore the crystal-clear look of the Ice Resin. I don't have any available, so I tried wiping some Realistic Water that I have lying around on it and it pretty much did the same thing.

I think some of those mold releases are just aerosol Vaseline to get a thin even coat on.


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## -Hemi- (May 5, 2014)

I've een molding for years and I must say the best yet, I have found is in fact Alumalite. there mold making materials are superior to anyone else, AND their release agent as well is just the highest quality. DO NOT cheap out on any these products, the end result could be a ruined mold, SURE, that's OK? How about that master copy? IT too can be ruined as the release agent has to not re-act to the silicone, IF it does, all that gooey silicon uncured is now all over your master copy!

Just something to think about and ponder....


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## robn1 (Nov 17, 2012)

You say you've already made your mold, I assume it's silicone mold putty? If so you can cast just about anything without a release and be fine, as long as you're only making one or two pieces. Any more than that and you should use a release. The chemicals in resin will deplete the oil in the silicone making it hard, and reducing it's release properties (stuff will stick to it). Mold release will prevent the chemical absorption.

I've used Mann Ease Release 200 and it works well. Stoner is another popular brand.

Baby powder was mentioned, but I don't know what good it will do as a release. Powder is used to prevent bubbles or voids in the casting, it reduces the surface tension of the resin allowing it to flow into all the recesses of the mold. The powder will give clear parts a dull frosted appearance, but it can be polished clear.


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