Great idea, if it works for you. I have a checking account that is in a different bank than where the family primary account is. It is MY hobby fund with PayPal attached. All my clad gets cashed in at the end of the season minus the halves and dollars and is deposited. I use this money for upgrades, repairs and other MD related necessities. In 2014 I dug over $500 in face value, last season it was about $360, and I will be close to that again this year. The only money that goes through the coin star now are the pennies, the rest gets cleaned, rolled and deposited.
I have yet to sell any of my finds even though my brother-in-law made me a great offer for my Key Date IHC. Someday I might sell it and and cash in my gold rings.
I keep my eyes peeled on the local classified ads and craigslist. Over the past few years I have bought detectors on the cheap and sold them for a minimal profit, leaving some meat on the bone for the buyer to make a profit if they choose to. Those funds also go into the hobby account. There are great deals to be had if you just look for them. I bought two $1200 detectors for $400 each, a $700 detector for a little over 10% of retail. My water detector was bought at about 30% retail cost. Call me cheap, but it works for me. Heck I even traded my boat for a metal detector (XP DEUS). The boat had set idle for 5 years.
If the wife didn't do so much around the house, I'd be tempted to trade her for a CTX 3030.
One of the ways I save money is that many of the items I need for this hobby go on my Christmas list. Santa has been very good to me the past 2 years. In 2015, my birthday present was a NEL 15" x 12" butterfly coil.
What Santa is bringing this season (2016)
http://www.treasurenet.com/forums/general-discussion/523251-what-s-your-christmas-list.html
What Santa brought me last year (2015)
http://www.treasurenet.com/forums/g...y-christmas-all-what-did-santa-bring-you.html
Good luck on funding the Excal, I am certain it will happen since I can sense you are as obsessed with this hobby as I am.
P.S. One way to lose money is to become emotionally attached to your gear. I see some people who have every detector they ever bought. If I don't use a detector anymore, I sell it before it depreciates.