Fykus said:
Just thought it might help me get a bit more in there to buy silver with, and i was thinking about putting in just enough so that im knocked back down into the lower tax bracket.

ok, but it's worth is still inaccessible to you until retirement age. Unlike if you use your own post tax funds to buy silver for your private use.
One of your goals is to reduce the tax payable on your income and salary sacrificing is a tool used to achieve this purpose. However by salary sacrificing your extra super contributions, you are only benefiting one way ie saving tax. Have you considered other forms of salary sacrificing that will achieve the desired effect of paying less tax BUT also other benefits? For example depending upon your employer you can salary sacrifice a host of items that you have to pay for ordinarily out of your post tax salary and you will get a double benefit - save tax and still get the benefit now. Eg:
Loan repayments
Rental payments
Salary Solutions Card (expense payments / bills)
Laptop computer and Mobile Devices (PDAs, Mobile Phones)
Motor Vehicle
Regular Payments.
You can have your regular expenses paid on your payday.
Mortgage payments
Rent payments
Loan repayments
School fees
Salary Solutions Card.
Offers a flexible and convenient option to allow you to pay your everyday expense payments and bills including:
Utility Bills (gas, electricity, council etc)
Supermarkets
Retail stores
Petrol
Entertainment
School fees
Insurance premiums
Many of these items above may be things you have to pay for, salary sacrificing them may make better financial sense than super.
Now you're only a kid still, so you won't hopefully have school fees etc, but get your SMSF organised, and while you are waiting you will need to talk to a financial adviser about salary packaging - your employer may have a list of preferred advisers.
Edited to get rid of the spiel from the website I nicked this from