Removing Bubbles: How to Remove Air Bubbles in Plaster Castings

www.plastermaster.com
Dan Kijak tells how to prevent air bubbles when pouring plaster castings. The Plaster Master shows his secret methods to remove air bubbles.

Commenti

  • Dante Rodriguez
    Dante Rodriguez

    When making plaster mold castings for pottery by means of filling the area with clay slip... Should I reverse the image or letters on my negative silicone master to create a positive plaster master mold for pouring pieces in production...Thanks.

    6 giorni fa
  • annelissemarie
    annelissemarie

    Thank you for posting this! I use hydrocal, a silicone mold and Ease Release spray. Tomorrow I'll swap that spray for 50/50 Windex, fingers crossed. About sealers-what do you recommend to keep close to the bare hydrocal look? Would a local hardware store wax work? These sculptures will be for sale so the sealant should be protective and permanent.

    12 giorni fa
  • annelissemarie
    annelissemarie

    @ThePlasterMaster hi again! I tried wax, krylon, shellac, all with different doable results, but strong smelling. Do you think coating the hydrocal with coconut oil til it sinks in and dries and polishing with a Shea butter and pigment mix would discolor the sculpture or go rancid somehow in the long term? Cause it looks nice now and is so much gentler on me. Also the Windex didn't work out with the molestar 15 platinum silicone. Smooth on suggested talc instead.

    8 giorni fa
  • annelissemarie
    annelissemarie

    @ThePlasterMaster thanks for replying! I had to get an early start bc one needs to be ready by this afternoon. So I actually just bought clear shellac, denatured alcohol, and a wool cloth b4 seeing your reply. Well if it doesn't work I'll try the wax and spray sealer. And the Windex for the next round this afternoon.

    12 giorni fa
  • ThePlasterMaster
    ThePlasterMaster

    Local Hardware Store wax might work for you. Krylon Spray Sealer might also be an option. You could test concrete bonding agent on a small piece.

    12 giorni fa
  • Litegenius
    Litegenius

    What kind of release agent would you recommend to mold a plaster object in a plaster mold? Your video was so helpful . . thanks!

    28 giorni fa
  • Ulises Ortega
    Ulises Ortega

    =O Master!!

    Mese fa
  • mike woodruff
    mike woodruff

    Thank you for the insider tips! Does the surfactant act as a mold release as well?

    3 mesi fa
  • Sheep Slayer
    Sheep Slayer

    Plaster powder is very bad to breathe, I would recommend a mask. Great tips though, thanks!

    4 mesi fa
  • El Pretender
    El Pretender

    Thanks to the Plaster Master I got an A+ in my project, congratulations

    4 mesi fa
  • Andrei Malychenkov
    Andrei Malychenkov

    Great work, I’d like to learn more about the plaster👍👍👍

    6 mesi fa
  • sir assalot
    sir assalot

    straight to the point, 10 min video felt like 1 minute. instant subscriber, also liked your video. this is my first comment in years had to give you probs. thank you.

    8 mesi fa
  • Melvin Mcisaac
    Melvin Mcisaac

    Fill the mold then dump it out refill slowly tap well

    9 mesi fa
  • David Kapral
    David Kapral

    very good, especially for this novice!

    9 mesi fa
  • Federico Heller
    Federico Heller

    Thanks so so much!!! you solved my problem

    Anno fa
  • Michael Thorsby
    Michael Thorsby

    @theplastermaster Great video! I am currently experimenting with casting in balloons and no matter how much I try to get rid of bubbles before closing the balloon as the plaster set there is a cavity forming at the top inside the ballon that ruins the round beautiful shapes. Is air or any type of gas part of the chemical reaction or is there any way I can avoid this?

    Anno fa
  • sazure2
    sazure2

    Here is a link where balloons are used - no cavity at the top but there is the shape of where the balloon is tied off (so fill or file down). Good luck. artfulparent.com/plaster-balloon-sculptures-with-kids/

    7 mesi fa
  • sazure2
    sazure2

    The bubbles are oxygen (or some form of a gas) (I tried to research what might be given off during curing but it's complex). That said one can add plaster to plaster (from an old book that I have) but the first plaster set has to be wetted down. So perhaps when it is strong enough to be removed from the balloon you wet it down (let it absorb the water over time) then add a thicker plaster (more like a putty or paste consistency) to the tip and after it hardens a bit use a very soft brush to shape it. If you can create some scratch marks it will help the newer plaster set to the old (now wetted down). I add a plaster slurry to my cast molds to fill in the bubble (holes). On this site to learn how to eliminate them, to begin with.

    7 mesi fa
  • metals
    metals

    Wonderful video. Thank you for sharing. I am new to using epoxy resin and was wondering if these surfactants you mentioned could be used with epoxy resin. I see you answered a question with 'polyurethane resin', but I am not sure if that is the same. Thank you

    Anno fa
  • sazure2
    sazure2

    There are many types of Epoxy resins but usually, a silicone mold will allow it to pop out. Moisture can damage the product. juxtamorph.com/the-resin-faq-casting-resins-into-molds/ Epoxy resins are highly toxic. Make sure you use an OSHA mask and highly ventilate. No pets (fish included) around. One needs to know the exact product and call the company (or see on their information page). www.ehow.com/how_5594524_prevent-gas-bubbles-epoxy-resin.html Examine for bubbles. If you see tiny bubbles while the resin is still wet, you might be able to get them out with CO2 or a heat source. Use a low-intensity flame like a cigarette lighter or alcohol burner and pass the flame lightly above the area with the bubble. Do not attempt to heat the epoxy--it can catch fire. The CO2 in the flame should draw out smaller bubbles. Make sure that your brand of resin is not flammable and that the manufacturer suggests the flame treatment for bubbles before proceeding. Some manufacturers suggest not using a heat source because it can leave waves in the surface. Instead, try breathing or blowing gently on the areas that have bubbles. Pop larger bubbles. If you have a large air bubble, use a pin or needle to get the air out. Do this well before the resin starts to set or it can mar the finish. Push the pin or needle into the bubble, then wobble the pin back and forth to allow the bubble to reach the surface--it should vent out and the bubble will disappear as it fills with resin. Use a drill to remove bubbles after the epoxy has hardened. Apply a second coat of resin to get a glassy, seamless finish. A very thin final coat is less likely to have bubbles. If bubbles remain in the final finish, they are easier to remove using the CO2 method. Tips & Warnings Thinner coats and thinner epoxies are less likely to get trapped bubbles. You can thin epoxy resins with a variety of solvents--check with the manufacturer for suggested thinners. Make sure the working time (time before the epoxy hardens) is sufficient to allow you to work on any bubbles that might form after you apply the resin. Don't apply epoxy finishes in direct sunlight--this will almost guarantee out-gassing and bubbling. Uncured epoxy resin and catalyst are toxic. Handle with appropriate protective clothing and safety equipment. Epoxy generates heat as it cures. Never allow a large container of epoxy to cure solid--it can catch fire or explode. Check with the manufacturer for the maximum volume of epoxy that can be cured safely. Make absolutely sure the manufacturer suggests using the flame method for getting rid of bubbles. Uncured epoxies can be flammable. If you use a thinner that is flammable--do not use the flame method. Always use epoxy resins and thinners in well ventilated areas.

    7 mesi fa
  • Fly Oz
    Fly Oz

    Now THAT is a great idea Thanks

    Anno fa
  • Сникерсон
    Сникерсон

    Tell me please, how long does it take to wait between the spray and the casting of the gypsum?

    Anno fa
  • Сникерсон
    Сникерсон

    I get a foam from the soap. What am I doing wrong?

    Anno fa
  • jackjersey11
    jackjersey11

    VERY HELPFULL. WHAT ABOUT PUTTING A BIT OF SOAP WITH PLASTER MIX?

    Anno fa
  • ThePlasterMaster
    ThePlasterMaster

    Soap will deteriorate your plaster if you mix it in with the mix. It will make the plaster soft, and not harden up well. Only mix soap with water to spray on your mold.

    Anno fa
  • inot90745
    inot90745

    I just tried this, you ARE the "THE PLASTER MASTER"...NO MORE BUBBLES!! THANK YOU, THANK YOU, THANK YOU!!!!!!!

    Anno fa
  • ruxion prajapati
    ruxion prajapati

    What can we use for not sticking each other plaster mold while we make it

    2 anni fa
  • John Morrow
    John Morrow

    Vaseline

    Anno fa
  • Mohamed Motala
    Mohamed Motala

    hello there,I am in the process of trying to make 3d wall panels but I don't know what plaster would be best for this project can you please help,thanks

    2 anni fa
  • Christie Jones
    Christie Jones

    Thank you for sharing 🙏

    2 anni fa
  • חותם הגוף LifeCasting.co.il
    חותם הגוף LifeCasting.co.il

    Thank you for this great video! Does the Windex trick works also with alginate molds?

    2 anni fa
  • Anne C. Undmitzett
    Anne C. Undmitzett

    Hi, Thank you very much for the tutorial. I want to make a face cast for halloween protheses and read a lot about bubbles that make a lot of work afterwards to even the surface. Now I wonder if the trick with the windex still works when the plaster form is prepared with vaseline (petrolatum) so you can eaysily get rid of it?

    2 anni fa
  • allyzza piawan
    allyzza piawan

    thanks a lot, sir this video is very useful to me because of my sculpture subject it helps me a lot a tip to mix and remove air bubbles in plaster casting

    2 anni fa
  • allyzza piawan
    allyzza piawan

    hi, sir DAN KIJAK I'm Allyzza Piawan a fine arts student. I just want to know if it's okay if my base or molder is made of clay it is okay to use dishwashing as a surfactant on clay base?

    2 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    A light spray would probably work.

    2 anni fa
  • Aaron Walderslade
    Aaron Walderslade

    40 years and you still react like a boy when pulling the moulds off. This hobby's gonna keep me young!!

    2 anni fa
  • SCOT CAMPBELL FINE ART
    SCOT CAMPBELL FINE ART

    Great video, thanks.

    2 anni fa
  • holohulolo
    holohulolo

    I've used plaster of paris before, but recently I bought this product, supposedly plaster. Used it the same way, but somehow the mixture just won't cure, although it somewhat hardens and forms, the entire thing is still soft and moist. I remember plasters starts to get warm in 10-15 mins or so. The plaster I used recently also did that, although not as warm as the ones I've previously used. Since you mentioned there are different types of plaster, I wonder if the one I bought was different and if it needed some binder or hardener added to the mix? The Ibeen cold lately it's been raining and I left it to dry outside, and I thought that was the problem, but still, I left it for days and it's still moist and doesn't cure. Or does it have anything to do with shelve life, if there is any? I don't understand where I did wrong.

    2 anni fa
  • Melvin Mcisaac
    Melvin Mcisaac

    Plaster of Paris will give you a no set when it's old gets damp ..But you should have lumps in the bag at that time.6 month shelf way longer in dry warm storage.Some plasters are mixed with lime.Let the person know what your doing with the mixture.Use cold clean drinkable water

    9 mesi fa
  • ThePlasterMaster
    ThePlasterMaster

    If plaster is stored in a damp place, the hardening effect can be diminished. Plaster of Paris is a generic term for the softer grade of plaster that is betahemihydrate. Harder grades of plaster are called alphahemihydrate. They are hydrocal and hydrostone and ultracal. You can check out my website about mixing plaster. plastermaster.com/islands%20style.html

    2 anni fa
  • holohulolo
    holohulolo

    I tried it again, and this time it's not as moist and soft, but it still doesn't seem to dry and hardens completely. Could you elaborate what you mean by "bad plaster"? Have you had similar experience? I was wondering if plasters can expire or "go bad" depending on the storing. Do you have any reference where I can read more about the difference between these plasters? Also is plaster of paris another different type of plaster to these?

    2 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    It sounds like you got some bad plaster. I don't know what type of plaster you purchased. The usual types to use are: casting plaster, pottery plaster, hydrocal.

    2 anni fa
  • Kashif Riley
    Kashif Riley

    This is a awesome video on how to mix plaster of Paris properly. A lot of artists who are making metal castings from Lost PLA rush the mixing process, resulting in pitted casts. I wish plaster could be degassed

    2 anni fa
  • Pat Glenn
    Pat Glenn

    I'm lost on one item.... At 9:31 you apply detergent to the OUTSIDE of the mold in order to make it slip off the item. Can you please explain the logic of this?

    2 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    The detergent is used to help the mold slide over itself. You do this when you are pulling the latex rubber off of the casting.

    2 anni fa
  • Marie Morrison
    Marie Morrison

    Any tips for getting rid of air bubbles in baby casting when using an alginate mould? I keep loosing fingers!!!!

    2 anni fa
  • michael pearson
    michael pearson

    pat glens video its clear that he is saying using diluted window spirit helps prevent air being trapped when he spray's the inside of the mould first. to cast plaster. and soap on the outside of some moulds will act as a release agent when removing the mould from the casting. in the case of casting hands and feet in an alginate rubber mould the spray will help you remove air bubbles so yes it can be used. to help you stop loosing fingers use the shaft of an artists paint brush to poke in the wet plaster to make sure the plaster reaches the parts that form air pockets and there will be no more lost fingers or toes.

    8 mesi fa
  • ThePlasterMaster
    ThePlasterMaster

    Shaking the mold, tapping the mold or using a vibrating table can help to remove air bubbles

    2 anni fa
  • Marie Morrison
    Marie Morrison

    ThePlasterMaster I use crystacal R- I'm in the U.K. And haven't been able to find hydrocal.... would you think a vibrating table would help?

    2 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    Be sure to use a very hard, strong type of plaster, such as Merlin's Magic, Dental Plaster or Hydrocal. Roll the mold around with the plaster in it. Tap it gently to remove bubbles. Bang it gently on the tabletop to release bubbles.

    2 anni fa
  • David Curtis
    David Curtis

    In my rock molds for the HO layout I just pour a thin layer of plaster and use one of the "acid brushes" you can find in hardware stores. They are about 1/2 inch wide and have round metal handles. I stipple the bottom of the mold and this breaks up any bubbles that might be there. Then just fill the mold to whet ever thickness you need because if there are bubbles in the second pour, it does not matter.

    2 anni fa
  • David Curtis
    David Curtis

    I use nothing but "wet water" as a mold release. I've never had any problems with unmolding the plaster.

    2 anni fa
  • Seamus mc ardle
    Seamus mc ardle

    thank you for sharing you knowledge,wonderful help.

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    Your welcome.

    3 anni fa
  • Galactic Empire
    Galactic Empire

    Would those bubble prevention techniques work in alginate molds?

    3 anni fa
  • Galactic Empire
    Galactic Empire

    ahh yeah, I see what you mean. Alright, cheers! Keep up the good work, my friend :)

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    My guess is that it would probably not be much help, but you can give it a try. The alginate already has so much water to start with.

    3 anni fa
  • holohulolo
    holohulolo

    I wonder if mixing the plaster with the mixture of water and some dish soap or the windex instead of just water would help reduce the forming of bubbles as it is poured or mixed? Not that it's necessary since the surface is bubble-free, but just wondering if it would still cure if the solvent is not 100% water? BTW thank you so much for sharing, this is very insightful. I especially appreciate you explaining about the water tension.

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    Do not mix soap with your plaster. It will soften the plaster.

    3 anni fa
  • wilmon abiera
    wilmon abiera

    beautiful! whooo!

    3 anni fa
  • orcagna164
    orcagna164

    PlasterMaster... air bubbles in my hydrocal casts have been driving me crazy. I am working with large rubber (Smooth On) relief molds. Because there is a great amount of variation in the surface of the molds and a tremendous amount of detail, I would probably be tempted to overspray its surface with the Windex/water solution for fear of missing spots. So my question is - after the initial surface spray, would you ever consider lightly brushing that spray coating around - with a soft-bristled brush - so as to ensure it has reached every spot in the rubber mold? Thank you so much for your great generosity in sharing your knowledge with the public.

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    Yes, brushing the spray around with a brush to make sure it's in every crevice is a good idea.

    3 anni fa
  • SevSaint
    SevSaint

    Its hard to find learned wisdom like this. Thanks for sharing what took you years of trial and error with us. I just started a business and this information shaved 100's of man hours and tons of waste off our casting process. Have you used Excaliburs or Merlins Magic for mold making. Its ranked up there with dental plaster.

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    +SevSaint Thank you. I appreciate you're taking the time to write. I have only used Merlin's Magic for casting or making plaques. I have not used it for mold making.

    3 anni fa
  • Pat Glenn
    Pat Glenn

    Can you please explain the logic of how coating the OUTSIDE of the mold with soap makes it come off the casting easier? 9:30 I'm not questioning that it works, but I'm baffled as to why. One would naturally think coating the inside (where the mold actually touches the casting) would make it come off an item easier.

    3 anni fa
  • Pat Glenn
    Pat Glenn

    OK I think I get it now - Thanks

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    +Pat Glenn I coat the outside of a latex mold with soapy water so that it slips over itself more easily. It's like taking a rubber glove off your hand. If you coat the outside of the glove with soapy water, it slips over itself more easily.

    3 anni fa
  • Wrongway346
    Wrongway346

    Thanks

    3 anni fa
  • Wrongway346
    Wrongway346

    Thanks

    3 anni fa
  • Wrongway346
    Wrongway346

    Hi.. I am a model builder, and I'm casting a wooden model in silicone rubber. I was thinking of trying plastic, being cheaper then resin, and clean up easier. resin I have to order by mail, but plaster, I can pick up a Rona, home depot. Question. what would say I should look for in type. I like to get something that strong, but also able sand off edges, on the molded parts, before assembly. What Glue would be the best to use. i have to be able to glue the parts together.. Mike

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    +Wrongway346 I would recommend White Hydrocal. I use Devcon 5-minute Epoxy to glue parts together, after the plaster is dry.

    3 anni fa
  • Rhia Legaspi
    Rhia Legaspi

    May I ask where did you get the hooks you used for the plaster? Or at least what they are called?

    4 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    +Rhia Legaspi I was getting my hooks from Yaley Enterprises. They own Deep Flex Molds. It looks like they changed their hooks though. You can just make them out of wire.

    4 anni fa
  • Sonia Taylor
    Sonia Taylor

    Thank you so much for this video!! you have helped no end!!! awsome. Thank you :)

    4 anni fa
  • Manuel Luis
    Manuel Luis

    +Manuel Luis to:@jackie klan

    3 anni fa
  • Manuel Luis
    Manuel Luis

    ... do not apply to the mix . no . Blush it or spray it to the inner walls of the metal mould . ( do not smoke or fire ).

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    +Sonia Taylor Glad to help.

    4 anni fa
  • Lord Nelson
    Lord Nelson

    Great video by the way and i've subbed. I have just bought some abs moulds similar to the horse one in the video and i am getting 8 bags of fine casting plaster (cheapest grade) delivered soon, i was wanting to know if i could mix it with any other plaster to make it set harder,like herculite 2 or crystacal? Also when you you stated using the detergent in the bottle this is used as a release agent right? You never put anything else on either did you?

    4 anni fa
  • Steves Projects
    Steves Projects

    I use silicone moulds which as you say are quick to bead up the water making air bubbles troublesome The best method Ive found is to mix in a degassing liquid, including pushing the plaster detail of the mould with your fingers no vibration or tapping the mould is needed this method yields near a perfect result everytime I prefer to not spray detergent on to the surface as I feel if degrades it slightly Mixing I just use a drill paint stirrer and whip it all together regardless of putting air into the mix however the consistency of the plaster needs to be like a running cream as always the contents should sit for a while before pouring slowly into the mould Anyway will give your method of spraying the moulds with detergent a go all the same I welcome any method of making life easier cheers

    5 anni fa
  • sazure2
    sazure2

    @Steves Projects Hmmm??? Some sort of equipment to drive the gasses out. Can't find your liquid - boo hoo.

    7 mesi fa
  • ThePlasterMaster
    ThePlasterMaster

    @tthomasan Good advise. I agree.

    4 anni fa
  • tthomasan
    tthomasan

    @edward coggins Use a brush to push the plaster into the details. You are not trying to paint it with plaster, you are tapping the brush hard, forcing the bristles into the corners and details where bubbles are most likely to form. Then put in more to complete the gel coat. If its a small bust where you can't get your hands in, pour in a small amount of liquid plaster and rotate the mold all around. Do this to coat the entire mold, and pour out the remainder. This insures you are coating all the mold. This first coat is extremely important to get right, before adding the rest of the plaster. If you eliminate the bubbles in that coat, they won't be a problem. It also helps to tap or vibrate the mold. If, its a very small solid cast bust, cap the opening with wood and rotate until there is a good coating of plaster all around before adding the rest. Also, he uses Windex, which I have not used. I use liquid Ivory Soap. What matters is not the specific product, but make sure its liquid soap, not detergent. Also I use a much smaller percentage then he does- not 50-50, just a squirt of soap into a spray bottle of water. The water should not be 'soapy' it should just feel slippery. That won't degrade the surface of the plaster. As for mixing, you don't need to use a drill except for castings of 3 gallons of plaster or more. Smaller then that, hand mixing works fine, as long as you let the unmixed plaster sit for a couple minutes before mixing to let the water soak thru all the plaster. I prefer hand mixing small amounts as it lets less air into the mix, and there is more working time with the plaster. Drill mixed plaster has more air and sets faster. I've never found it necessary to let the plaster sit after its mixed.

    4 anni fa
  • paul coggins
    paul coggins

    Not so easy if you are casting a bust where you cannot get fingers into small details though

    4 anni fa
  • Steves Projects
    Steves Projects

    SOLID CAST 630 DEAERATOR from australia

    5 anni fa
  • jevgenij cvetkov
    jevgenij cvetkov

    how i have to mix alginate without bubbles?

    5 anni fa
  • jevgenij cvetkov
    jevgenij cvetkov

    thank you

    5 anni fa
  • Parallel Dimension
    Parallel Dimension

    Alginate is much different than plaster. I am not familiar with removing bubbles from Alginate.

    5 anni fa
  • yzyrider
    yzyrider

    Thank You so much! this is THE best way to take plaster molds of plastic too! i was in a hole before watching the vid! :)

    5 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    Glad to help.

    5 anni fa
  • Dave Amico
    Dave Amico

    Where's the LOVE button? Thank you I heard every word clear as a bell and took notes. Great alternative to mold release.

    5 anni fa
  • Terry Smith
    Terry Smith

    Thanks brilliant. but when are you guys gonna catch up with the rest of the world and use the metric system! just sayin. thanks again.

    5 anni fa
  • Rich William
    Rich William

    Why should they?

    Anno fa
  • daniel moos
    daniel moos

    Thanks for the great tips Dan! All I heard before is just shaking the table or mold... this seems much better!

    5 anni fa
  • joe vella
    joe vella

    Plastermaster would plaster of Paris work for plaster casting and or mold making???

    5 anni fa
  • joe vella
    joe vella

    very good thanks

    5 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    Yes, Plaster of Paris will work for making a casting. It is a soft grade of plaster. If you mix it thick enough, it should make a strong cast.

    5 anni fa
  • Dre H
    Dre H

    Does the windex trick work with silicone molds? Also, I have some thin undercuts, any recommendations for pulling the mold of without chipping?

    5 anni fa
  • michael pearson
    michael pearson

    use a spray release agent before filling the silicone mould with resin.plaster or cement. this will help you peel the mould of without getting stuck to the casting when it sets.

    8 mesi fa
  • Dre H
    Dre H

    @ThePlasterMaster Thank you! Can you tell me why I have some streaks in the plaster when I pull it out of the mold? Did I not mix it enough or is it separating when I vibrate the mold when the plaster is poured in? I am vibrating more than in your tutorial because I have a lot of undercuts (I am casting a folded piece of vinyl) and when I do this some water seeps up to the surface and separates, creating a micro pool of water on top, is this ok? I am using hydrocal 95

    5 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    Silicone is a more oily mold material, and water tends to bead up on it more so than other mold making materials. If the 50/50 Windex/water mix doesn't work, try a teaspoon of dish detergent in a quart of water and put it a spray bottle. The only recommendation for pulling the mold of your thin undercuts is to use a really strong plaster, such as Hydrocal, Ultracal. or HydroStone.

    5 anni fa
  • jackie klan
    jackie klan

    Very good article on surface voids, much appreciated. Maybe I can now start producing better castings thanks you your help.

    5 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    My experience with concrete is limited. Most of my life has been spent pouring plaster statues. The issues with concrete are different from that of plaster. Smooth-On has a number of helpful articles on pouring concrete. If you type into Google, "Smooth-On Eliminating Surface Voids in Concrete", the link will take you to a good article on this subject.

    6 anni fa
  • jackie klan
    jackie klan

    Hey Dan, question. I make concrete statues, using aluminum molds what would you suggest I use in the mix to make them come out better? Thanks much

    6 anni fa
  • Manuel Luis
    Manuel Luis

    ...1_ liquid soft-soap . or :... 2 _ i personnally use W.D.40 . i descovered it was my best shot in life. but of course l don't know how it will work for other artists .

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    No. The cleaner cannot be used with polyurethane resin - only plaster casting. I do not have anything to recommend.

    6 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    Try it and let me know how it works out.

    3 anni fa
  • Manuel Luis
    Manuel Luis

    ... why not W.D. 40 ??? ( as a demouldant )

    3 anni fa
  • ThePlasterMaster
    ThePlasterMaster

    I add a couple of drops of dish detergent in a spray bottle of water. I spray my molds with this liquid. I do not add it to the plaster. Soap weakens plaster.

    6 anni fa
  • David Pilling
    David Pilling

    hi, i cast plaster ornaments for dipping latex, but have noticed some of my moulds have grown mould on them over some time, is there a reason for this, and is there a way to avoid it or remove the mold? thanks

    6 anni fa