how can I insure a shipment for more than $10,000

I took it to Fedex. I don't know what the limit is , but they did go $19K. It looks like the 3rd party sites that offer discounted shipping have their own limits. The ones I am used to using cap it at $10K. 

all good... thanks

Registered mail through the US post office is your best bet.  You can insure any shipment for up to $50,000.

It’s cheaper than buying insurance from FedEx or UPS.  And it’s very safe—your box will be locked up during the shipment process.

However it can be very slow.  It could take anywhere from 7 to 18 days to be delivered from my experience.

You also have to seal every edge with brown shipping tape.  You can find the tape on Amazon.  It’s the type you have to wet down with water to stick.

I’ve shipped almost 100 packages using registered mail and every one was delivered.

I have found using the Mail to insure, has been $$$$.  If you can put the equipment on a palette, most trucking companies have very low insurance costs.  I suppose the reason is they rarely have to pay a claim?  A pair of amps I shipped recently, insured for $40,000, cost me $65 for the insurance.  Cheers.

A few additional things you should do if you ship high dollar value items (above the  maximum insurance levels) with FedEx or UPS.  The company I worked for prior to my retirement used to ship high value metals all the time and FedEx/UPS provided guidelines for us.  (Some shipments were approaching $1M USD. )

• Use descrete packages,  i.e. blank boxes.  Don't do anything to advertise what the contents are.
• As @gregrolka mentioned, you need to seal every edge, corner, etc.  And use "tamper proof" printed tape.  It makes it a bit more difficult to slit the box open and then retape it.  You can get it on Amazon.
• If handing the package directly to the driver, make sure he/she is aware of the value.  Their protocols should have them segregate the package in the truck so it can be locked up when it is unloaded at the depot.
• Otherwise, take the package to the actual FedEx or UPS desk at their respective shipping centers, not at the UPS Store or Walgreens, etc.  One, you will get a better rate, and more importantly, if you let them know the high value, the supervisor will lock them in the "cage" until ready to be placed on the truck/plane.
• Ship overnight or 2 day delivery instead of ground if possible.  Fewer transfer points and hands on the package.  Less likely to get misplaced or "lost" in transit.