I just bought a Woodland Tunnel portal made from Hydrocal. I want to make some more portals using a mold but I forgot who makes them. As I use Hydrocal for scenery I figured it would be a good idea.
A name please. Thanks
Harold
Your local Hobby Lobby or Michaels Crafts has Latex for casting, and things like mold release. Build a ‘box’ a little deeper, and at least an inch wider than the tunnel portal. I used either .040 or .060 styrene for mine.
Lay the portal down for the front detail ‘up’. Paint it with mold release and mix/pour your latex over it - you want about 3/4" to 1" over the face of the portal. Pour slow and use a tooth pick to assist releasing any air pocket/bubbles. Now walk away and let it dry.
The next day, work the portal out of the mold. To use the mold, clean it up and paint the interior with more mold release - Then pour your Hydrocal. You should be able to work out your new casting within two hours. I have build dozens of stone/rock walls off of Chooch or Pee Wee castings over the years. The biggest problem I have found is that many Chooch castings are ‘wrapped’ - Either they pulled then from the mold whole still warm or that shrink wrap deformed them. To ‘fix’ them, Boil some water in a kitchen pot(or at least get it hot). Place your warped casting in the water(back side down) and let it ‘relax’ to the point it can be ‘formed’ flat again.
Jim
Thanks Jim
Just cliped my 40% coupon from Michaels.
Harold
I’ve also made molds using liquid latex. I used the Woodland Scenics stuff, but I’d imagine they’re about the same.
I made mine by painting several thin layers to build up thickness. I used a junk brush to build up the mold, about one layer every 24 hours. Following the advice of others, I put in a layer of mesh after several latex layers and then continued with a couple of more layers. The mesh stiffens the mold and keeps it flat. I used garden ground mesh. Others have used cheesecloth.
I made this low stone bridge using a mold made from the WS tunnel portal. My castings needed to be much thinner than the original portal, and the mold let me do that. The latex, as you can see, does a pretty good job of preserving the detail of the original casting.
This was my first home-made mold, and I didn’t know enough to apply a mesh to keep the base flat. You can see the indentation to the left side of the casting where the mold lifted up a bit and gave me an uneven surface.
One of the problems w/ building up the latex and using the “new” mold is that the latex is quite flexible and will need proper support to pour, especially for flat castings. Irregular shaped rock etc, will only need to edges supported w/ stripwood, wadded paper towel etc. For laying up to pour portals, retaining walls etc, your mold will need to be placed to hold the edges upright (square, straight) and many times the flat base will need sopme shimming as well. Even those production “latex” ones will require support. I will construct a shallow box to fit the mold’s shape, and generally just shim w/ whatever is on han
I am new to all of this and learning as I go and you guys do a great job. I hope it is easy to do as I have plans for a big layout and want many rock faces and ledge.
My local Michael’s only carries the rubber that you brush on. I think Dick Blick carries the 2-part rubber that you can pour onto a master.
Steve S.
www.micromark.com carries all kinds of mold making and casting supplies. You want the One-To-One RTV Moulding compound.