You need a Bitcoin Cash wallet.  You can copy your wallet.dat file from Bitcoin Core over and it will "work", but it is dangerous to actually use.

I would suggest this procedure.

On Bitcoin Core, create a new address and get ready to send 0.001BTC to that address.

On Bitcoin Cash, create a different address and get ready to send 0.002BTC to that address.

Make sure you pay slightly different fees on both sides.

Press send on both clients at the same time and then wait.

This creates two transactions and sends one to each chain.  However, they are both valid on both chains.  

This means that one of them might end up on both chains.

Since they send different amounts and have different fees, if each chain ends up with a different transaction, you will see a different one listed on each client.

If that happens, then success.  Wait until both chains have confirmed by 10 blocks.

If you end up with the same transaction on both chains, then try again.

Once you have a different transaction on both chains, you can then send all your money back to yourself on one of the chains.  This is safe since you are moving the money to your own address, but it means that all your current outputs are now spent on that chain.

This means that they can only be spent on the other chain.  The new output (with all your money) is also only spendable on the first chain.


Basically, A is your coin on the current chain.  When the fork happens, there is a split.

You want to move that coin to different outputs on both chains.

B is the output of one of the transactions and C is an output from the other transaction.

If you can get each chain to accept a different output (and you wait 10-20 confirms), then you have an coin available to spend with all your other coins.

If it happens that the transaction ends up on both chains, then you haven't improved things.

Having said that, it is probably best to wait until someone has a safe/user friendly way to do it.  You should keep you money stationary from July 31 for a few days at least.