I intend to sell my silver rather than hoard it but I do like to read about hoards of Roman or Saxon coins being found in the UK. They tend to get buried in clay pots or lead containers. They usually end up spread across a field by a farmer's plough at some stage. Or they crack open and the contents oxidise. I have also heard of more modern day hoards being put aside in glass jars, and these tend to fill up with water when the seals break or they crack open and water gets in. In the book "How to bury your goods" https://www.amazon.com/How-Bury-You...coding=UTF8&psc=1&refRID=F9Q67ZE2F8HA9SFMD7Y7 they mention vertical rather than horizontal burial so that it presents less of a target for metal detectors, but to me that would put the hoard at more danger of damage from ground movement. Burying my hoard where there is no frost would certainly save a lot of issues from having the whole lot heaved up to the surface within a couple of years. And with Queensland being such an iron rich land there is probably no need to spread nails all over the place to mineralise the soil to deter detectorists. I like glass jars because of their inertness, they wouldn't weather, or get attacked by any chemicals in the ground, it doesn't deteriorate like plastic or metals do and can stand being constantly wet. Also rodents can't chew threw the stuff they way they can get through other materials. But the seals are the weak point, any rubber seals are likely to breakdown, wax or leather are subject to being gnawed at anyway even if they don't rot or get worn away. I have seen some of the more modern products for hoarding https://www.amazon.com/MTM-SAC-Surv...coding=UTF8&psc=1&refRID=46S8DD9JJQT5C9HSHKYN But I am not sure I like metal screws underground, and they would be an entry point for water to get into the cache. Plus there doesn't look to be any way for that tube to be kept underground, if it is mostly air inside and the ground is damp, it is going to want to float up to the top. A big rock on top might help to keep it down and mark the spot as well as protecting it from any lazy metal detectorists. I am guessing PVC pipe is made to contain water and remain underground, as long as it remains underground it should be safe from UV light which would deteriorate it. There are plenty of fixings like threaded end caps, seals and the like. It is a little bit flexible so it won't crack at the first bit of earth movement. Maybe glass jars sealed up inside PVC pipes would be a good combination for internal protection from air and moisture and external flexibility and impact resistance. I just have a lot of Moccona Jars and I am running out of things to do with them...
The trouble with all those ideas is that Moconna jars are not as airtight as they appear. Can't even keep the weevils out of the flour. I am guessing I can come up with a better way of sealing them but even so, those larger jars are about a year's supply of marmalade for me.
No, it is the softener that is added to PVC to make it flexible. That's the stuff that breaks down to form chlorine gas which causes the damage. Hard PVC is a different beast entirely, it is unstable in Ultra violet light but pretty good if you keep it painted or out of the sunlight.
No kids, no one to pass it on to, still don't want it to stay buried though, fully intend to sell the stuff before I die, of course getting hit by a bus might throw a spanner in the works. Accidental digging up is pretty much how most of these are found, that or detectorists actively looking for them, that's why I bought t comprehensive manual on how to bury them, full of tips etc. but the main concern I have is environmental damage. I have the bulk of my metals stored with Goldstackers, it is unallocated and free and as it is Self Managed Super Fund's Metal I am more concerned with the Gov stealing it than I am with the dealer running off with it. I would generally avoid putting my metals with someone else because there is third party risk but all the SMSF regs mean that it is easier for someone else to hold it than it is for me to hold it. I can also do GSR swaps easily with my metals at the dealer's establishment. But all the little coins etc. are starting to get under my feet. Silver is too bulky and low value to keep it all in a safe, but too expensive to just leave it lying around. Home break ins are not something to encourage by keeping the stuff onsite and visible. Even a small box of silver coins gets heavy quickly, and a glass jar of metal on a high shelf is asking for trouble. Plastic boxes warp and if you stack them on top of each other the bottom ones start to collapse. Plus if you buy the rigid boxes with a decent seal it start to cost a bit of money. I don't need to look at the coins, they are not part of an ongoing series or collection that needs constant managing and adding to. I don't need to get to them in a hurry if spot changes or anything like that. So somewhere out of sight but close by would be good, but they would need to be preserved.
Sadly the prize is a load of empty jars. My wife won't let me bring any more home, the shed is full of them, my sister won't take anymore, my niece's school don't need any for crafts, they are too heavy and fragile to post and Gumtree is usually full of them. I might try freecycling them. I am now filling up my education centre with the damn things as I put in plenty of storage.