Holding Wood Down

[montmill]

I'm casting stabilized wood pieces in a box mold with alumilite clear slow. The mold is silicone. Do I need to worry about the wood floating and if so how do you recommend holding it down? Also is it necessary or advisble to spray the mold with mold release spray? Thanks so much for your help. First time trying this.

 

[KMCloonan]

Yes, wood will float. If you can wedge it in the mold so that it is held by friction that should be ok, but you have to be careful not to distort the sides of the mold too much.

Another option is to use some plastic mesh (something like 1/4" squares, or mesh bags from oranges or other produce) and cut a piece the size of the mold. you can fill the mold, then use large rubber bands to hold the mesh in place along the top of the mold. The mesh will be cut off and disposed of when you demold. You can also pour your resin through the mesh into the mold if that's easier. The mesh can also hold your wood down if it's stiff enough.

I'm not 100% sure about using mold release. Silicone molds demold pretty easily, but I think I have heard that some Stoner Urethane mold release can extend the life of silicone molds.

 

[duncsuss]

Tim McKenzie once commented that he uses Museum Wax to hold pieces down when he makes hybrid blanks. LINK TO POST HERE.

 

[1080Wayne]

Duct tape over the wood and around the mold will also work . Just leave free space to allow easy pour of the resin into the mold . Have never used mold release , but it might extend mold lifetime .

 

[JohnU]

The above posts are good, also… I often put a small block of wood on top of the pieces being cast, and then place a skewer or popsicle stick across that and tape or clamp it in place. After being cast, I cut the scrap piece off.

 

[Kenny Durrant]

I use all the above methods depending on what I'm casting. The only difference is I use blue painters tape instead of duct tape. Not that duct tape doesn't work, I used it as well, but the blue tape is easier to work with. I use museum gel with small pieces of wood and window screen for beer hops. I do use HDPE molds so I'm not sure how the gel will work with silicone molds. I'd also use a good mold release for every cast with any mold. Although the blank may demold easily with a silicone mold the resin will dry it out so it won't last as long. As far as the mold release I use it's a spray silicone. I've never had any trouble with it and it makes for a clearer blank rather than a wax based release I used to use.