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release agents for latex molds???

January 7, 2006

Hi everyone, have been away from the forum for a while but plan on coming back with a vengence. I have just purchased my first latex mold, greenman face, and quite intricate. I have never poured one before and am quite nervous. Which would be the best release agent? I got instructions with it but they called out just using motor oil??? I just dont know. Also they said to use just 1 part portland and 1 part sand and enough water to pour does this sound right. I am just scared that I won't get enough mold release in it and ruin my mold. Help anyone. thanks susan

Comments (25)

  • Grancru

    Try this site. They have a number of different items that may work well for you.
    Where did you get your mold? I have been looking for a Greenman myself.


  • Running_Dog

    Hi Willow,

    If you're nervous, why not mix up a tiny quantity of sand/cement/water (just a couple of tablespoonfuls), rub some motor oil into the mould, and plonk your small mix onto a flat part of the mould. Allow it to set for a day or so, then check to see how easily it releases from the mould.

  • willow2003

    hi Grancru thanks for posting. I just purchased it on EBAY. Didn't realize how intricate it was though. . Are you familiar with latex molds?.

  • paws4pets

    I am not a expert but when I talked to a "Concrete Guy", been in the business quite a few years he said never use motor oil in a latex mold it will degrade the latex. I use Universal Mold Release from Smooth On. Works good for my plastic molds as well. When you pour your mold make sure you vibrate/tap/settle the crete to help remove the air bubbles. I use a back massager to settle the crete into the crevises. Good Luck. We like to see pics!

  • Dena6355

    When I have made latex molds, I have used either nothing or a little bit of a product called Synlube 531 release agent (this is a spray on release agent and can be purchased at cement supply stores, pottery supply, internet). Very important that if you use a release agent that it go on smooth and not create bubbles, there is even a product that will eliminate the bubbles, Imagine. No matter what you use or do not use it is very important to clean your mold after use to get rid of little gritty spots.
    Without using any release agent I have been successful at being able to peel off the latex when done. Now about the mix, 1:1 mixes are considered a neat mix and are not very durable. If your green man has a lot of detail you may want to try release agent, then a thin "neat mix" to get all the detail, making the mix thin enough to be able to make a thin shell, then while the neat mix is still damp, add a more durable mix with a little bonding agent to make the structure a little more sound. Other mixes to consider might be a tufa mix (lighter for hanging), a 1:3 mix or a pre-mix with aggregate (more durable).
    Happy casting,

  • Running_Dog

    paws4pets - a back-massager is a great idea! I used to have a large vibrating table but didn't want to get another one because of the noise, and the amount of space it took up. I never thought of something as simple as a back-massager.

  • davidmcdn

    Pad sander works pretty good as well for vibrating.

  • paws4pets

    My girlfriend doesn't think so since it used to be hers but she was nice to let me use it. Works good for getting in some of the small spaces on the rubber molds. It has the 2 balls on the front that can fit into the small spaces.
    The back I use for my flat molds like stepping stones.

  • faerygardener

    Susan - I also picked up an ebay mold - but mine is from these folks:


    and they offer good instructions. Note the bottom of the page hint to have less stress on your mold by sandwiching between plywood (even tho you can use it alone). Their notes say Pam and sprays are often not thick enough, although vegie oil should work. I'd go with their instructions or Dena's - I haven't made my mold yet myself.

  • faerygardener

    Realized mine is heavy plastic, not a latex mold. Nice part about this site for the newbie is they also tell you how much dry mix to start with to fill one mold.

  • davidmcdn

    Heavy mineral oil mixed half and half with a vegetable oil is an excelent release mold for most stuff. It also smells nice and is great for your skin.:)

  • rickharmer

    I only use Crete-lease.Check for a supplier near you.It comes in spray or drum.Not cheap,either,but worth it.You can spray it on,come back to it days later and it will still be good.I've used it on plastic,metal,latex,wood,you name it and no problems.No mess,either.And cleans up with water.
    I've tried the Pam route;this stuff that I use is WAY better.
    cheers from here

  • lazydaisy

    Thanks Rick, I'm going to check that one out.

    Do not use mineral oil on latex...it breaks it down.

  • rickharmer

    The company is Cresset.There are several types,I'm sure that you'll find the one for you.
    Cheers from here and,in the spirit of the moment,GO SEAHAWKS!!!!!!!!!!!!!!!!!!!!!!!!!

  • tango88

    I would suggest that you contact someone like Reynolds Advanced Materials (Mold Making supplies & accessories, see link).

    There are a lot of great "homebrew" releases, but using the wrong one on the wrong material can destroy a mold. Ask the experts. They are great about giving free advice and have never steered me wrong. But first, you have to confirm what kind of mold material you have.

    Here is a link that might be useful: Mold Release Info

  • davidmcdn

    Quality latex molds require a properly formulated release agent or they don't last long.
    My niece is a hobby monster costume creator.
    But for most stuff concrete as it applies to most work here I find that good ole vegi oil works great.
    Adding mineral oil seems to improve the finish, less bug holes.
    There is a spray lube (not oil)designed for dog clippers that my niece uses on latex. She says it is great and really inexpensive and comes in a big bug spray type can.

  • scooterbug

    The company I got my latex molds from told me I do not need a release, Just clean the mold once in awhile with warm soapy water and air dry inside out .

    They were right, never had a problem at all ;))

  • lazydaisy

    Quality latex, cheap latex, latex gloves and other things "latex" will break down chemically using mineral oil (because it's a petroleum product). In the "birds and the bees" area, you can make your life and someone else's very miserable not knowing that. :) And it would be a waste to spend so much time and money making even a homemade mold to have it fail early. Yep, I think professional outside advice would be the route to go here.

  • davidmcdn

    And wind and rain breaks down mountains.
    It's all relative.

  • lazydaisy

    Yeah, but I'll leave a higher being than any of us to take care of that. Not quite the same relativity.

  • chuckr30

    What about cooking spray? It should be vegetable based and be ok for latex molds.

  • justadncr

    Has anyone tried to use WD40 for a release. It has about 200 uses.
    I want to use a glass platter to make a birdbath but dont have any mold release. What would you all use.

  • gerald_lobo

    We have developed a termoplastic elastomer(TPE) mould where any kind of designs can me made. These moulds are highly durable and does not require cleaning..only while changing colours. WE have at present developed more than 120 designs in wall tiles, external flooring and pavers.
    The tiles of these moulds can also be easily demoulded. please be free to mail me for futher details

  • concreteartist

    I have been in the concrete business for quite a few years and I have made latex molds and pour concrete ornaments using latex molds. Latex does not like petroleum based products and sunlight. Your best bet is either castor oil mixed with methyl hydrate 1 part castor oil and 8 parts methyl hydrate. For such a small mold, just rinsing with water will work for a while but I wouldn't do it all the time.

  • Nelda Walsh

    I bought a couple of latex gnome molds from ebay without back up. The back up isnt the problem..its taking the plaster of paris gnome out of the latex mold once it sets up. I've broke the foot off a couple because its a little hard to pull down the mold . I've used castor oil & alcohol...its not working very well. Any ideas please?

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