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Re: [casting] Sealing Lego brick mold boxes

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  • Bruce .
    I ve never done this and have only the vaguest notion what you re doing. Nonetheless, what comes to mind is to line the entire Lego structure with a plastic
    Message 1 of 12 , Dec 15, 2012
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      I've never done this and have only the vaguest notion what you're doing.

      Nonetheless, what comes to mind is to line the entire Lego structure
      with a plastic bag. Common LDPE (low-density polyethylene) is
      impervious to most chemicals (being chemically rather similar to
      petroleum jelly).

      You can melt paraffin WAX* (not liquid paraffin, please) and add
      petroleum jelly to it to get a substance with properties intermediate
      to the two. Try small quantities first as not all proportions work.
      When I do this sort of thing, I like to weigh in the quantities and
      keep track of them. For example, start with 5g of wax and 5g of
      jelly, melt together and let cool. If that's too hard, weigh in, say,
      another 3 g of jelly, melt and cool. If that works, what you have (in
      this example) is 5g wax to 8 g jelly, and you can scale up the batch
      using those proportions.

      You can extend this mixing if a harder substance is needed. You can
      dissolve small pieces of LDPE in melted paraffin wax and get a
      stiffened wax. I suggest limiting the mix to two ingredients as not
      all proportions will necessarily be stable.

      * NEVER melt wax over an open flame or red-hot electric element.
      Rather, use a double-boiler arrangement, as by putting a metal can
      into a cooking pot containing water, and melting the wax in the can.
      If possible, do this outside, away from structures. Never leave the
      melting wax unattended -- cut off the heat source before leaving.
      Keep pets and children away from the hot melt as it can cause
      gregarious burns. Always remember that wax, etc., are pure fuels, and
      ignite fairly easily when hot. You can burn yourself or burn down
      your house doing this in your kitchen. Always think this sort of
      thing through thoroughly. Taking a little extra trouble can save you
      from terrible consequences.

      On Sat, Dec 15, 2012 at 7:33 AM, andrea m <minicurios@...> wrote:
      > Hi everyone
      >
      > I am looking for some ideas on how to seal mold boxes built with Lego bricks.....
      >
      > Currently, if I don't seal the Lego brick joints on the inside face of the mold box with some sort of filler, the silicone seeps into the joints and fills the cavities of the bricks with silicone. As the silicone level decreases over a few hours of seepage, a top up of more silicone is required. Or worse, the silicone leaks completely out of the box (via the walls- not around the mold base).
      >
      > I have tried smearing vaseline on the inside mold box walls which works ok, however in the hot summer here in Australia, the vaseline turns to oil. This in turn becomes very slippery and messy!
      >
      > My current method is to scrape/fill along the Lego brick joints with a sulphur free plasticene clay. This works well as a joint filler but it is so time consuming I spend more time sealing the mold box than claying up the model and cleaning up the bricks when done.
      >
      > I am wondering if anyone else has this problem and whether they have overcome this issue. I know I could use other types of mold boxes but I love the Lego's as they are easy to build the boxes, accurate and store well. I can also build the mold box while watching TV <g>
      >
      > Any ideas would be much appreciated.
      >
      > Cheers
      > Andrea
      >
      >
      >
      > ------------------------------------
      >
      > Yahoo! Groups Links
      >
      >
      >



      --
      Bruce
      NJ
    • Jimi G.
      Simple. I use packing tape from my tape gun. Works like a charm, you can cut to fit, and it peeled off easy.
      Message 2 of 12 , Dec 15, 2012
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        Simple. I use packing tape from my tape gun. Works like a charm, you can cut to fit, and it peeled off easy.


        ------------------------------
        On Sat, Dec 15, 2012 9:35 AM EST Bruce . wrote:

        >I've never done this and have only the vaguest notion what you're doing.
        >
        >Nonetheless, what comes to mind is to line the entire Lego structure
        >with a plastic bag. Common LDPE (low-density polyethylene) is
        >impervious to most chemicals (being chemically rather similar to
        >petroleum jelly).
        >
        >You can melt paraffin WAX* (not liquid paraffin, please) and add
        >petroleum jelly to it to get a substance with properties intermediate
        >to the two. Try small quantities first as not all proportions work.
        >When I do this sort of thing, I like to weigh in the quantities and
        >keep track of them. For example, start with 5g of wax and 5g of
        >jelly, melt together and let cool. If that's too hard, weigh in, say,
        >another 3 g of jelly, melt and cool. If that works, what you have (in
        >this example) is 5g wax to 8 g jelly, and you can scale up the batch
        >using those proportions.
        >
        >You can extend this mixing if a harder substance is needed. You can
        >dissolve small pieces of LDPE in melted paraffin wax and get a
        >stiffened wax. I suggest limiting the mix to two ingredients as not
        >all proportions will necessarily be stable.
        >
        >* NEVER melt wax over an open flame or red-hot electric element.
        >Rather, use a double-boiler arrangement, as by putting a metal can
        >into a cooking pot containing water, and melting the wax in the can.
        >If possible, do this outside, away from structures. Never leave the
        >melting wax unattended -- cut off the heat source before leaving.
        >Keep pets and children away from the hot melt as it can cause
        >gregarious burns. Always remember that wax, etc., are pure fuels, and
        >ignite fairly easily when hot. You can burn yourself or burn down
        >your house doing this in your kitchen. Always think this sort of
        >thing through thoroughly. Taking a little extra trouble can save you
        >from terrible consequences.
        >
        >On Sat, Dec 15, 2012 at 7:33 AM, andrea m <minicurios@...> wrote:
        >> Hi everyone
        >>
        >> I am looking for some ideas on how to seal mold boxes built with Lego bricks.....
        >>
        >> Currently, if I don't seal the Lego brick joints on the inside face of the mold box with some sort of filler, the silicone seeps into the joints and fills the cavities of the bricks with silicone. As the silicone level decreases over a few hours of seepage, a top up of more silicone is required. Or worse, the silicone leaks completely out of the box (via the walls- not around the mold base).
        >>
        >> I have tried smearing vaseline on the inside mold box walls which works ok, however in the hot summer here in Australia, the vaseline turns to oil. This in turn becomes very slippery and messy!
        >>
        >> My current method is to scrape/fill along the Lego brick joints with a sulphur free plasticene clay. This works well as a joint filler but it is so time consuming I spend more time sealing the mold box than claying up the model and cleaning up the bricks when done.
        >>
        >> I am wondering if anyone else has this problem and whether they have overcome this issue. I know I could use other types of mold boxes but I love the Lego's as they are easy to build the boxes, accurate and store well. I can also build the mold box while watching TV <g>
        >>
        >> Any ideas would be much appreciated.
        >>
        >> Cheers
        >> Andrea
        >>
        >>
        >>
        >> ------------------------------------
        >>
        >> Yahoo! Groups Links
        >>
        >>
        >>
        >
        >
        >
        >--
        >Bruce
        >NJ
      • Edward Traxler
        I wonder if something as simple as white glue would work? Just paint it on. Should seal the bricks nicely .. and you could peel it off afterwards. Ed Traxler
        Message 3 of 12 , Dec 15, 2012
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          I wonder if something as simple as white glue would work? Just paint it on. Should seal the bricks nicely .. and you could peel it off afterwards.

          Ed Traxler
        • Daniel
          Hi, I used that trick a few times in the past, as a convenient way to build small and easy boxes. But I never had your seeping issue! I was using real Lego
          Message 4 of 12 , Dec 15, 2012
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            Hi,

            I used that trick a few times in the past, as a
            convenient way to build small and easy boxes. But
            I never had your seeping issue!
            I was using real "Lego" brand, the small version
            like 1/2" x 1" for the typical brick, not the
            large ones intended for very small children.
            I also liked the fact that they provided by
            themselves nice register plugs on all the surface.
            I'm thinking... are you using them upside down?

            I guess you could always put some large
            transparent tape inside, but IMO if you use a
            generic brand you should try again with the "real" stuff :-D


            At 07:33 AM 15/12/2012, andrea m wrote:
            >
            >
            >Hi everyone
            >
            >I am looking for some ideas on how to seal mold
            >boxes built with Lego bricks.....
            >
            >Currently, if I don't seal the Lego brick joints
            >on the inside face of the mold box with some
            >sort of filler, the silicone seeps into the
            >joints and fills the cavities of the bricks with
            >silicone. As the silicone level decreases over a
            >few hours of seepage, a top up of more silicone
            >is required. Or worse, the silicone leaks
            >completely out of the box (via the walls- not around the mold base).
            >
            >I have tried smearing vaseline on the inside
            >mold box walls which works ok, however in the
            >hot summer here in Australia, the vaseline turns
            >to oil. This in turn becomes very slippery and messy!
            >
            >My current method is to scrape/fill along the
            >Lego brick joints with a sulphur free plasticene
            >clay. This works well as a joint filler but it
            >is so time consuming I spend more time sealing
            >the mold box than claying up the model and cleaning up the bricks when done.
            >
            >I am wondering if anyone else has this problem
            >and whether they have overcome this issue. I
            >know I could use other types of mold boxes but I
            >love the Lego's as they are easy to build the
            >boxes, accurate and store well. I can also build
            >the mold box while watching TV <g>
            >
            >Any ideas would be much appreciated.
            >
            >Cheers
            >Andrea
            >
            >


            Daniel
            daniel@...
            http://www.nutsnbits.com


            [Non-text portions of this message have been removed]
          • Harold
            I don t use Legos, I just buy large sheets of foam board from the dollar store.  I cut it out with an X-acto knife and glue it with a glue gun. After
            Message 5 of 12 , Dec 15, 2012
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              I don't use Legos, I just buy large sheets of "foam board" from the dollar store.  I cut it out with an X-acto knife and glue it with a glue gun. After curing, I tear it off the mold and toss it.




              Hi,

              I used that trick a few times in the past, as a
              convenient way to build small and easy boxes. But
              I never had your seeping issue!
              I was using real "Lego" brand, the small version
              like 1/2" x 1" for the typical brick, not the
              large ones intended for very small children.
              I also liked the fact that they provided by
              themselves nice register plugs on all the surface.
              I'm thinking... are you using them upside down?

              I guess you could always put some large
              transparent tape inside, but IMO if you use a
              generic brand you should try again with the "real" stuff :-D


              At 07:33 AM 15/12/2012, andrea m wrote:
              >
              >
              >Hi everyone
              >
              >I am looking for some ideas on how to seal mold
              >boxes built with Lego bricks.....
              >
              >Currently, if I don't seal the Lego brick joints
              >on the inside face of the mold box with some
              >sort of filler, the silicone seeps into the
              >joints and fills the cavities of the bricks with
              >silicone. As the silicone level decreases over a
              >few hours of seepage, a top up of more silicone
              >is required. Or worse, the silicone leaks
              >completely out of the box (via the walls- not around the mold base).
              >
              >I have tried smearing vaseline on the inside
              >mold box walls which works ok, however in the
              >hot summer here in Australia, the vaseline turns
              >to oil. This in turn becomes very slippery and messy!
              >
              >My current method is to scrape/fill along the
              >Lego brick joints with a sulphur free plasticene
              >clay. This works well as a joint filler but it
              >is so time consuming I spend more time sealing
              >the mold box than claying up the model and cleaning up the bricks when done.
              >
              >I am wondering if anyone else has this problem
              >and whether they have overcome this issue. I
              >know I could use other types of mold boxes but I
              >love the Lego's as they are easy to build the
              >boxes, accurate and store well. I can also build
              >the mold box while watching TV <g>
              >
              >Any ideas would be much appreciated.
              >
              >Cheers
              >Andrea
              >
              >


              Daniel
              daniel@...
              http://www.nutsnbits.com


              [Non-text portions of this message have been removed]



              ------------------------------------

              Yahoo! Groups Links



              [Non-text portions of this message have been removed]
            • Ken Burney
              I use a thin coat of petroleum jelly. it is a pain to clean up afterword I normally put them in the silverware basket in the dishwasher after I use them. Ken
              Message 6 of 12 , Dec 15, 2012
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                I use a thin coat of petroleum jelly. it is a pain to clean up afterword I
                normally put them in the silverware basket in the dishwasher after I use
                them.

                Ken the guy from AR

                On Sat, Dec 15, 2012 at 6:33 AM, andrea m <minicurios@...>wrote:

                > **
                >
                >
                > Hi everyone
                >
                > I am looking for some ideas on how to seal mold boxes built with Lego
                > bricks.....
                >
                > Currently, if I don't seal the Lego brick joints on the inside face of the
                > mold box with some sort of filler, the silicone seeps into the joints and
                > fills the cavities of the bricks with silicone. As the silicone level
                > decreases over a few hours of seepage, a top up of more silicone is
                > required. Or worse, the silicone leaks completely out of the box (via the
                > walls- not around the mold base).
                >
                > I have tried smearing vaseline on the inside mold box walls which works
                > ok, however in the hot summer here in Australia, the vaseline turns to oil.
                > This in turn becomes very slippery and messy!
                >
                > My current method is to scrape/fill along the Lego brick joints with a
                > sulphur free plasticene clay. This works well as a joint filler but it is
                > so time consuming I spend more time sealing the mold box than claying up
                > the model and cleaning up the bricks when done.
                >
                > I am wondering if anyone else has this problem and whether they have
                > overcome this issue. I know I could use other types of mold boxes but I
                > love the Lego's as they are easy to build the boxes, accurate and store
                > well. I can also build the mold box while watching TV <g>
                >
                > Any ideas would be much appreciated.
                >
                > Cheers
                > Andrea
                >
                >
                >


                [Non-text portions of this message have been removed]
              • IAN HANRATTY
                Hi Gang I use brown parcel tape around the inside of the mould box, and attached the walls to the base with more brown tape on the outside. This stops the
                Message 7 of 12 , Dec 15, 2012
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                  Hi Gang


                  I use brown parcel tape around the inside of the mould box, and attached the walls to the base with more brown tape on the outside. This stops the liquid rubber from flowing between the bricks.


                  I hope this helps.

                  Cheers

                  Ian

                   
                  Ian Hanratty
                  Friendship Models
                  12 Delta Drive
                  Musselburgh
                  East Lothian
                  Scotland
                  EH21 8HR
                  United Kingdom
                  0131 665 0866
                  07877 166 225
                  www.friendshipmodels.org.uk.
                  http://stores.shop.ebay.co.uk/Friendship-Models
                  www.facebook.com/FriendshipModels



                  ________________________________
                  From: Ken Burney <wkburney@...>
                  To: casting@yahoogroups.com
                  Sent: Saturday, 15 December 2012, 18:54
                  Subject: Re: [casting] Sealing Lego brick mold boxes

                  I use a thin coat of petroleum jelly.  it is a pain to clean up afterword I
                  normally put them in the silverware basket in the dishwasher after I use
                  them.

                  Ken the guy from AR

                  On Sat, Dec 15, 2012 at 6:33 AM, andrea m <minicurios@...>wrote:

                  > **
                  >
                  >
                  > Hi everyone
                  >
                  > I am looking for some ideas on how to seal mold boxes built with Lego
                  > bricks.....
                  >
                  > Currently, if I don't seal the Lego brick joints on the inside face of the
                  > mold box with some sort of filler, the silicone seeps into the joints and
                  > fills the cavities of the bricks with silicone. As the silicone level
                  > decreases over a few hours of seepage, a top up of more silicone is
                  > required. Or worse, the silicone leaks completely out of the box (via the
                  > walls- not around the mold base).
                  >
                  > I have tried smearing vaseline on the inside mold box walls which works
                  > ok, however in the hot summer here in Australia, the vaseline turns to oil.
                  > This in turn becomes very slippery and messy!
                  >
                  > My current method is to scrape/fill along the Lego brick joints with a
                  > sulphur free plasticene clay. This works well as a joint filler but it is
                  > so time consuming I spend more time sealing the mold box than claying up
                  > the model and cleaning up the bricks when done.
                  >
                  > I am wondering if anyone else has this problem and whether they have
                  > overcome this issue. I know I could use other types of mold boxes but I
                  > love the Lego's as they are easy to build the boxes, accurate and store
                  > well. I can also build the mold box while watching TV <g>
                  >
                  > Any ideas would be much appreciated.
                  >
                  > Cheers
                  > Andrea
                  >

                  >


                  [Non-text portions of this message have been removed]



                  ------------------------------------

                  Yahoo! Groups Links



                  [Non-text portions of this message have been removed]
                • Kenny Anderson
                  Using Lego blocks is definitely the way to go. You can make the mold box to fit the master thus saving money on silicone. And we all know how darn expensive
                  Message 8 of 12 , Dec 15, 2012
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                    Using Lego blocks is definitely the way to go. You can make the mold box to fit the master thus saving money on silicone. And we all know how darn expensive silicone is. Most resin casters are using Legos now or atleast any of the one's that I know of are.  I do too but sometimes in the winter when the heat is on in my worshop I've lined the inside of the Legos with Silver Duct tape. I usually don't need it in the summer as I'm running the air conditioner and the cooler temps keep the silicone a little thicker in consistency. It's sticky enough to hold up against the silicone but easy to remove the Lego blocks from  after the silicone cures. Another trick with tape is to use the thicker metal(aluminum) tape on the inside of your master to cover open areas like windows in model train engines or model car masters and then only use a 1/4" of clean clay inside that to keep the silicone from seaping into the cavity of your master. It's therefore much
                    easier to clean out the cavity instead of digging and scraping clay from your master risking breaking or destroying your master.  A quarter inch of clay inside the aluminum tape will hold back the silicone very well.  Both of those tapes are strong and will hold back silicone either on your Legos or your master but are easy to remove once the silicone is dry and cured.. They are readily available at Home Depot, Menards, Lowes, Ace hardware, etc. for very little money and a full roll will last you a very long time.
                    Kenny/Blue Oval Resinworks


                     
                     
                     
                     

                     

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                    [Non-text portions of this message have been removed]
                  • Silvester
                    I have used Lego extensively for mold boxes and have not had problems to the extent that yuou describe... I tend to use NEW blocks straight from a Lego store
                    Message 9 of 12 , Dec 15, 2012
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                      I have used Lego extensively for mold boxes and have not had problems to the extent that yuou describe... I tend to use NEW blocks straight from a Lego store where I buy them unpackaged and get all the same ugly color I would never use for anything else.

                      As some others have suggested, a coating of white glue or plastic tape might be a good solution for you.

                      Silvester

                      --- In casting@yahoogroups.com, "andrea m" <minicurios@...> wrote:
                      >
                      > Hi everyone
                      >
                      > I am looking for some ideas on how to seal mold boxes built with Lego bricks.....
                      >
                      > snippage <
                      >
                      > Any ideas would be much appreciated.
                      >
                      > Cheers
                      > Andrea
                      >
                    • Brian Slack
                      I ve been using Lego for my mold boxes for years.  I make my box and then line the inside with pieces of packing tape.  Work a treat! Brian Xmarx.com
                      Message 10 of 12 , Dec 16, 2012
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                        I've been using Lego for my mold boxes for years.  I make my box and then line the inside with pieces of packing tape.  Work a treat!

                        Brian
                        Xmarx.com

                        [Non-text portions of this message have been removed]
                      • andrea m
                        Hello again Thanks to everyone for your input and creative ideas about solving my Lego mold box issues. I will try out a few and see what works best for me.
                        Message 11 of 12 , Dec 16, 2012
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                          Hello again

                          Thanks to everyone for your input and creative ideas about solving my Lego mold box issues. I will try out a few and see what works best for me.

                          For those of you who are wondering - yes I do use genuine Lego bricks in the standard size (not the larger Duplo blocks) and all of my bricks were purchased brand new for mold making purposes only.

                          I have tried the foam core box method previously but much prefer the rigidity and the ability to build my mold box to conform to the shape of the model that the Lego's provide.

                          It is nice to know that other list members also have had the same problem with seepage in the brick joints as I have not noted it as being an issue amongst other casters previously. Maybe the ideas mentioned will help you too.

                          I will let you know the solution that works best for me after I have completed my experiments.

                          Kind regards

                          Andrea
                          Australia

                          > > Hi everyone
                          > >
                          > > I am looking for some ideas on how to seal mold boxes built with Lego bricks.....
                          > >
                          > > snippage <
                          > >
                          > > Any ideas would be much appreciated.
                          > >
                          > > Cheers
                          > > Andrea
                          > >
                          >
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