MAGNETS AND MOLDS or LOBSTROS ANTENNAE.

Remember I discussed using magnets in molds...well here is a perfect example. 

Here, Im choosing a vertical orientation.  If we can avoid splitting the mold across detail all the better.  The best orientation to avoid having to sand and restore detail for this project...

Are you ready...Lobstros Antennae. 

So I made a Lobstros Antennae out of some very nice 4340.  I only need one.  I'll make 2 molds of it.
And as stated the best orientation IMO is vertical.  Now...if I push the 5mm peg end into the clay, even just a little bit, this will give me a mold split tattle tale where I don't want/need one.  On the 5 mm peg. 

If we don't, there is nothing holding the 'master' in place and the silicone will knock it over when we pour it in.

So I added an earth magnet.   I pushed it flush into the clay.

 

This will now hold the 'master in place when I pour the silicone.

Here in this next photo Im holding it in the air to show how strong and capable the magnet is at holding the 'master' in place.

 

This will allow me to essentially make a flawless cast with no cast lines save the top edge or according to the picture, the bottom edge of the master or on the edge of what will be the 5 mm peg.  Shrinkage allowance has been calculated and added to the 'master' so when complete the 5mm peg portion of the antennae will indeed be 5mm and not a loose fit.

I am just making this now while other things are drying.  I'll need to repeat this process to make 2 molds.  I'll be using a urethane rubber as opposed to a silicone rubber so I can still use silicone molds.  Also it will help differentiate my work from the original.

I put a lot of work and effort into my casts.  I want people to know which items I made.  :-)

I'll be working on this in my spare time this weekend.  Hopefully I will have some working Lobstros Antennae by Mondayish???

Magnets and Molds

Im trying an experiment.  If it fails, no harm done.  I can still use the mold.

In industry, you never have a pin and a hole made of the same material.  If they jam, they will basically weld themselves together.  One is usually a milder or softer material meant to be replaced with wear.

In particular is the Diaclone Pilots.  They have metal pins for the which the arms/legs to hitch onto.  It lessens the wear.  I was considering only making half the mold and then putting in the pin by hand and then pouring the second half and thought that left too much room for error.  Plus I want the resin to 100% cure around the pins I make for this.

So Im trying to see if I can use magnets to hold the pins in place when I pour the resin.  I simply laid the magnets on top of the bed.  This way except for one face, the entire magnet field is held in the silicone.

If it doesn't work, I can simply remove the magnets and fill in the space with more silicone.

Now to wash it up and pour the silicone and see if it works.  On a personal note...I always make one alignment peg different than the others.  Its easy to get confused when pouring and get your orientation of the mold halves mixed up.