Ghetto casting

Discussion in 'Replica Props' started by juno, Jul 31, 2006.

  1. juno

    juno Sr Member RPF PREMIUM MEMBER

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    I'm all out of silicone and I want to do a casting of a non-hardening (non-sulphur) clay piece that I'm hot to finish. I want to cast it in resin. Any ideas?

    Unless someone knows a shop in Cincinnati that consistently sells silicone. (The Hobbytown here sometimes has it, and sometimes doesn't.)
     
  2. Jimbo890

    Jimbo890 Well-Known Member

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    On another board I read somewhere, there is a recipe for silicone mold material made from hardware store silicone caulk. IIRC, water is added in a certain ratio to react the curing catalist, and the result is a silicone mold on the cheap. You might want to PM Starkids1990 for more details.
     
  3. rigormortis

    rigormortis Well-Known Member

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    I've used it for small & quick projects. It's not as durable as the real thing, but works in a pinch. Here's the recipe...

    10oz tube GE Silicone I or II Caulk
    50 drops Glycerine per tube (catalyst)
    1-5 drops acrylic paint (to aid checking mixing)

    Sets up quick, but remains workable for about 10-15 minutes. Smooth with icecube while setting (water will not effect the curing).

    Hope that helps.
     
  4. juno

    juno Sr Member RPF PREMIUM MEMBER

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    Have you ever had it fail? I'm so tempted to try it, but I don't want to ruin my piece.
     
  5. Kylash

    Kylash Master Member RPF PREMIUM MEMBER

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    is Glycerine something you can get separate at a hardware store? Im not familiar with what it is
     
  6. rigormortis

    rigormortis Well-Known Member

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    Never had it fail, but have had it stick to the piece like a mushy gummi bear if the mixture was not mixed properly. A little soap and water cleans it right up.

    You can get glycerine from any drug store (doubt you'll find it in a hardware store). Women use it for a base for hand-made lotions.

    Please only use this knowledge for your own work, not to rip others off. People work too hard for months to have someone whip up a little silicone for a few bucks and rip them off.
     
  7. hydin

    hydin Sr Member RPF PREMIUM MEMBER

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    also, baby enemas.

    ive used the quick/dirty way to mold before. the only thing i can say is dear sweet god it reeks, but it does pick up a lot of detail. make sure you are wearing gloves, and make triple sure you check the seals and make sure there are no air pockets.

    chris
     
  8. rigormortis

    rigormortis Well-Known Member

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    Agreed. Use it only in a very well ventilated area - or your garage or workshop will reek for weeks. It's probably poisinous as well.
     
  9. hydin

    hydin Sr Member RPF PREMIUM MEMBER

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    nah, its just vinegar/acetic acid from what i can tell. that or a close relative of it.

    it just reeks horribly. use a fan, use .... febreeze, use something. this stuff reeks worse than castincraft resin does when its curing.

    chris
     
  10. dkwd

    dkwd Well-Known Member

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    Is the Glycerine needed?
    I thought Thorston James said that one could use silicon silicone as a mold in a pinch. I'd have to check again, but I don't recall him mentioning have to mix it with anything.

    That said, I haven't tried it yet.

    David
     
  11. rigormortis

    rigormortis Well-Known Member

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    It acts as a catalyst to cure it faster, otherwise you'd have to wait several days for a thick layer to fully dry. Plus it makes it tougher than plain caulk, which you could rip with your hands. This ensures it's a little tougher.
     
  12. SurferGeek

    SurferGeek Sr Member RPF PREMIUM MEMBER

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    Juno... if it's truely something you don't want to ruin, wouldn't it better to wait than to have to resculpt the piece? Unless it only took you a short time to sculpt it in the first place. ;)
     
  13. juno

    juno Sr Member RPF PREMIUM MEMBER

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    Gosh SurferGeek, kill me with logic ;)

    Well, I asked, and Buddha provided. But I'm definitely going to try the silicone caulk method on SOMETHING.
     
  14. SurferGeek

    SurferGeek Sr Member RPF PREMIUM MEMBER

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    <div class='quotetop'>(juno @ Jul 31 2006, 03:25 PM) [snapback]1291458[/snapback]</div>

    I try... :lol
     
  15. Matsuo

    Matsuo Sr Member RPF PREMIUM MEMBER

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    <div class='quotetop'>(juno @ Jul 31 2006, 05:25 PM) [snapback]1291458[/snapback]</div>
    Hey I know I've probably gained a few, but Buddha?...Come on. :cry

    I have indeed provided and am prepared to do the same if called upon again for any of my brothers and sisters.
    I enjoy making things for people and raking in the piles of delicious money from the fruits of my labor... :rolleyes ...but my truest joy is being able to empower my people to find their own way.

    M
     
  16. motman241

    motman241 Well-Known Member

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    I have done the caulk method - buy 100% clear, silicone caulk.... coat the item in petrolium jelly, squirt caulk all over it. Done. But, yes, it does take a long time to cure. I'll have to try the glycerine thing.
     
  17. clownluv15

    clownluv15 Well-Known Member

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    do you HAVE to coat it in petroleum jelly or will a clear coat be enough?
     
  18. motman241

    motman241 Well-Known Member

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    Silicone sticks to EVERYTHING (almost). The petrolium jelly on the project will release it when the silicone mold has cured.
     
  19. Boba Frett

    Boba Frett Sr Member

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    Use clear acrylic spraypaint, and Babylax is the brand name for the Glycerine.

    I use to do the water method, but the Glycerine and latex works alot better.

    I live in Covington, and if you want to see how it works I can show you how I just done one :)
     
  20. clownluv15

    clownluv15 Well-Known Member

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    so should i just mix a little bit and test it on a small piece of my work and see if it sticks?show how it works.
     
  21. Rebo

    Rebo Well-Known Member

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    Hey guys...

    I'm just experimenting with the chaulk and glycerine method to see if I can get it to work for me, can you give me a rough idea how long it takes to set?.
    I've only mixed up enough to cover one of the nippers matchboxs cars and smoothed it over with an ice cube.

    One last thing is it glycerine or glycerin, or are they the same thing?.

    <div class='quotetop'>QUOTE(rigormortis @ Jul 31 2006, 04:40 PM) [snapback]1291242[/snapback]</div>
    Okay I should learn to re-read stuff. :rolleyes
     
  22. frosty

    frosty Sr Member

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    Recaster. how will a little company like matchbox survive with you casting there products for profit..., :p

    Never tried this myself i will have to give it a whirl
     
  23. Rebo

    Rebo Well-Known Member

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    <div class='quotetop'>QUOTE(frosty @ Dec 17 2006, 04:01 PM) [snapback]1379772[/snapback]</div>
    Oh's no, busted. :cry

    I will destroy molding and mold upon completion of experiment :p
     
  24. kdawg1

    kdawg1 Sr Member

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    I think Michales Crafts has silicone for molding.
     
  25. Rebo

    Rebo Well-Known Member

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    <div class='quotetop'>QUOTE(kdawg1 @ Dec 17 2006, 04:27 PM) [snapback]1379785[/snapback]</div>
    Ah....just one problem with that, well two actually, im in the Uk and im a miser. :lol

    Ive just had a cruise round the bay and came across a product call "gelfex" meltable rubber.
    Can this be melted down in a pan on the stove (shh... the Missus is close by) and used with a polyester resin?
     
  26. exoray

    exoray Master Member

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    I suggest doing it "right" unless it's not a big deal to replace the sculpt you made, cutting corners and going cheap has more risk then it's worth in most cases...

    Check your local Hobby Shops for Alumilite stuff

    http://www.alumilite.com/index.php?page=dealers_OH
     
  27. Rebo

    Rebo Well-Known Member

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    Hmmm.. 2hrs on....

    Mold has skinned over, but with gentle taps I can feel its still gooey underneath.

    Maybe I haven't added enough glycerin. At a rough guess I mixed 50ml to 5ml.

    I'll keep checking it every so often.
     
  28. patsmear

    patsmear Sr Member

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    You could also use mold latex. I get it at Michael's. It is usually next to the resin. you paint it on about 3-4 coats thick. Drying inbetween coats.

    Kinda like this stuff:

    http://www.modeltrain.com/rubbermold/rubbermold.html

    Although I use a plaster jacket. If you do the plaster route, you need to make sure there are no straight edges or undercuts or else it will lock in the mold. I know this from experience.:)



    Pat
     
  29. Boba Frett

    Boba Frett Sr Member

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    Are you using 100% silicone rubber?
     
  30. Rebo

    Rebo Well-Known Member

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    :confused Probably not, it's bathroom sealant.

    Still aint set...
     
  31. Admiral Vaughn

    Admiral Vaughn Well-Known Member

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    <div class='quotetop'>QUOTE(Rebo @ Dec 17 2006, 02:57 PM) [snapback]1379898[/snapback]</div>

    Here Is The Correct Way To Do It.

    ((4 Drops BabyLax and 4 Drops acrylic paint Per Tube of %100 Silicone Rubber is Perfecto.))

    2 Tubes get 8 Drops of each etc..

    (smaller amounts?)..1/4 Tube gets one Drop of each..1/2 Tube gets 2 Drops of each etc..

    and don't forget to MIX IT REALLY WELL :)

    Never layer more than 1/4" thick, or you Will have problems.

    I Know it stinks :eek:

    Have Fun.

    ~Russ
     
  32. jedi5150

    jedi5150 Well-Known Member

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    So what's the viscosity of this mixture? Is it pourable, or brushable, or do you just "moosh" it all over your piece??
     
  33. Admiral Vaughn

    Admiral Vaughn Well-Known Member

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    It's Brushable..and mooshable too :)

    Repeating some good advice already in the thread:
    Brush in the 1st detail layer avoiding air bubbles and thick spots. every layer after that can be troweled on so you don't waste brushes..build it up how you want it, and make a plaster(or whatever)backing support, if needed.

    If mixed and applied well, it should cure quickly...I've never timed it.

    If you use it on regular clay, or a clay with a sulphur base, spray a coat or two of (Acrylic) clear coat on your sculpt...I clear coat everything made from clay.. just in case.

    ((Don't use clear coat with petroleum products on clay))

    Plastics like items(toy cars etc..) should not need a clear coat.


    ~Russ
     
  34. motman241

    motman241 Well-Known Member

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    Or the even cheaper, easier way (as posted before):

    Coat the item in petrolium jelly, squirt on the clear 100% silicone caulk. After about an hour, you can smooth out the outer part of it with your finger. No mixing. No muss. No fuss.

    depending on the item size, and thickness you applied, it could take several days for the silicone to cure.
     
  35. EchoLeader

    EchoLeader Well-Known Member

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    For small applications you can find Silicone gasket making materials at auto supply stores. Below is a sample of what can be used.

    Gasket Material

    Slow drying, non-hardening sealant designed for sealing cut gaskets and stamped parts. Allows for easy disassembly if required. -65 to 400 degrees Fahrenheit temperature range. Resists common shop fluids and fuels. Use where sealing is more important than adhesion for valve cover and oil pan gaskets. Use on gaskets, flanges, pipe joints and threaded connections.
    Product Details
    Price From: $2.70
    Manufacturer: Permatex
    Model Number: 80016
    UPC Number: 686226800169
     
  36. Rebo

    Rebo Well-Known Member

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    Ah sod it, it didnt set so I binned it..... Probably would have, had I left it a few days. It was only a little experiment anyway.

    Thanks to a UK Rpf member who gave me info on a uk supplier for all my casting needs. :thumbsup

    The supplier has suggested that I use a medium hard rtv with a polyurethane fast cast (1/1 mix) resin and filled with blr 2 filler powder.

    Now, I didn't want to look too dim while talking to him, as I understand how to use the first two (maybe), but how do you introduce the filler?.

    Is there a straight forward ratio I can follow for mixing it in and when you add it does it change the viscosity much?.

    One more thing, will I have to move fast with this stuff as he quote this "Expect set within around 5-10 mins and demould tack free within 30".
    Now i'm thinking, mixing resin and then adding filler takes time, any method you lot care to share, just so I don't end up with cups of un-pourable resin?.

    Oh one last thing (I know, I should have opened a new thread), do I need to order a release agent?.
     
  37. Rebo

    Rebo Well-Known Member

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    Bumpty...

    Guys, I'd like to get an order in, so any info/suggestions on the above questions would be great.

    Just discovered a chaps thread, he has used the same ingredients as im thinking of ordering, but he says it too brittle for his needs.

    Where as he is making a large wearable prop, I am planning on making smaller parts, airfix size. Will I suffer the same problems with smaller casting?.
     
  38. Boba Frett

    Boba Frett Sr Member

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    <div class='quotetop'>QUOTE(Admiral Vaughn @ Dec 17 2006, 11:53 PM) [snapback]1380147[/snapback]</div>

    Here Is The Correct Way To Do It.

    ((4 Drops BabyLax and 4 Drops acrylic paint Per Tube of %100 Silicone Rubber is Perfecto.))

    2 Tubes get 8 Drops of each etc..

    (smaller amounts?)..1/4 Tube gets one Drop of each..1/2 Tube gets 2 Drops of each etc..

    and don't forget to MIX IT REALLY WELL :)

    Never layer more than 1/4" thick, or you Will have problems.

    I Know it stinks :eek:

    Have Fun.

    ~Russ
    [/b][/quote]


    Nice work Russ
     
  39. Admiral Vaughn

    Admiral Vaughn Well-Known Member

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    Thanks, Bud. :)

    I Learned From A Master ;)

    ~Russ
     
  40. BlindSquirrel

    BlindSquirrel Sr Member RPF PREMIUM MEMBER

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    What's the concensus? 4 drops of Glycerine or 50 drops per tube?
     
  41. Boba Frett

    Boba Frett Sr Member

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    <div class='quotetop'>QUOTE(BlindSquirrel @ Mar 6 2007, 06:03 PM) [snapback]1433217[/snapback]</div>

    4 drops of Glycerine and 4 drops of latex per tube.
     
  42. BlindSquirrel

    BlindSquirrel Sr Member RPF PREMIUM MEMBER

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    I just read that someone used Naptha to thin the silicone mixture (1:1) to a honey-like viscosity for brushing. A regular coat is applied after it dries.

    Has anyone tried this?
     
  43. jason1976

    jason1976 Sr Member

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    Dumb question, but what constatutes a "drop"?

    I've tried this a few times now, and I love the molds I've been getting, but they're taking forever to set up, and I think it's because I'm not putting enough babylax in, so when everyone say's "1 drop of babylax, and one drop of paint per 1/4 tube of silicone" what is a "drop". (Oh, and yes I am making sure not to make it any thinker then 1/4" think per layer, so that's not my problem . :) )
     
  44. BlindSquirrel

    BlindSquirrel Sr Member RPF PREMIUM MEMBER

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    I just tried that formula and after a week it's still sticky and barely solid. If the Glycerine is a catalyst, then I'm leaning toward the 50 drops ratio.
     
  45. SgtFang

    SgtFang Sr Member

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    I don't know how many places still do this, but you could try calling around to various silicone suppliers and see if anyone would be willing to send you a free sample of actual molding silicone. I know Silicones Inc. here in the States used to do that, but too much word got out, and they finally started charging for them. :$

    -Sarge
     
  46. Boba Frett

    Boba Frett Sr Member

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    I ran across this myself awhile back, it has to be 100% silicone, some tubes will have Bioseal added to it, and it will never dry.

    This is one I made with tube silicone, 4 drops baby lax, 4 drops latex paint per tube.

    [​IMG]
     
  47. Sporak

    Sporak Sr Member Gone but not forgotten.

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    That's right...any silicone with additives will take forever if ever to cure.
    Get the cheap stuff...100% silicone and Babylax now called "Pedia-Lax" by the way...Liquid glycerin suppositories.These are really eyedroppers and make for easy drop measurement.I add about 5 drops to mine just to be safe.

    I have a project in the works right now and it's working great!

    This technique works nicely for a one off piece that you're going to re work before making your final mold in the good stuff.
     
  48. Sculptzor

    Sculptzor New Member

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    I used this a couple of times for small resin pieces. I thinned the caulking with naptha for a detail coat then used acrylic paint with the caulking to back it up. I don't know what brand you guys use that needs glycerine as a catalyst but a dash of acrylic and the caulking would set in 5 minutes top. Maybe my "drops" were too liberal? Either way make sure to use some form of mold release because it does not come off as easy as the real stuff. I wouldn't recommend it for anything important but it makes a cheap waste mold.
     
  49. Boba Frett

    Boba Frett Sr Member

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    I haven't used any mold release at all, and haven't had any trouble, the glycerine helps it to not stick. ;)
     
  50. jason1976

    jason1976 Sr Member

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    Well I've tried this twice now, and I finally have an ok mold, but I still think the description "drops" is a bit vague. I used 4 "drops" of acrylic paint, and 4 "drops" of baby-lax, per tube of 10o% GE silicon. And, it took over 2 WEEKS to set up. So the next time, I used a little more then a dropper (maybe it was two droppers I forget) of the baby-lax, and a little more liberal "drops" of paint, with the same silicon, and wall it set up a little faster, is still took at least a week to be able to demold with out it being uncured inside.

    Oh, and I've been careful not to put it on too thick.

    So why is mine taking so long to set up? What constitutes a "drop"?
     

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