In the old days folks put buttermilk into an inner tube or air mattress to fill a small slow leak from the inside out. Worked suprisingly well. Anyone have any ideas on what we might use today in place of buttermilk to accomplish the same result??
There is injectable leak repair that goes in through the valve stem. However it makes a terrible mess inside the wheel and I strongly recommend against it. Many shops won’t work on a wheel that’s had this stuff injected in.
Instead I suggest filling the tire to the maximum pressure per the sidewall, dropping the wheel and tire into a kiddie pool full of water, marking the spot where the bubbles come up from, and getting the leak repaired. You may have to sit back with Sam Adams until some bubbles come up. Just remember to drop the tire pressure back to where it should be before putting the wheel back on.
I would think that a bicycle tire repair kit would work for the inner tube and probably the air mattress. This patch is done from the outside. I did try some tire sealant (repair in a can) on a basketball that wouldn’t hold air. It did stop the leak, but the basketball dribbled like a bowling ball and was also way out of balance. If you are using the inner tube for swimming, this might work for you. It should work for the air mattress, unless you are really sensitive to bumps in the bed like the Princess in “The Princess and the Pea”.