Valve repair for vintage speed bag

[ChuckM]

Hello again,
A nice old speed bag arrived here today; it's old enough that the valve is at the top of the bag! The bladder will hold air, but there is nothing on the bladder to keep the air inside.
In the picture you can see a pair of hemostats pinching the opening to the bladder shut. In the last picture there is a .32 caliber slug wedged into the opening; that might be good enough for display purposes, plus it looks pretty tough.
Does anybody know a good way to plug up the bladder in a case like this? This bag will probably be a display bag, so it doesn't need to be a very strong seal; let me know if you have had any experience with this type of issue.
Thanks a lot, Chuck M

[Dutchman]

Whoa , nice one! Before the invention of the pinch valve, sporting goods with bladders were set up like what you see here. The inflation tube was sealed off with a plug, usually made of rubber then stuck back down under the laces. This was done not only with striking bags but with basketballs ,footballs,etc. So you could use a suitable plug from a laboratory or industrial supply house ( McMaster Carr comes to mind).

[ChuckM]

Thank you Dutchman!
Never heard of McMaster Carr before, but you were right, they do sell plugs that will fit just fine for a nice low price.
Appreciate it, Chuck