Just can't get a good seal on my boiler lid! 8g pot still

[Asos21]

So I found this old pot in a garage sale. It had apparently been used as the boiler for a cheap Chinese still.

I constructed the lid from 2 36cm stainless steel mixing bowls. Drilled at the top with a 28mm tank connector fitted into the top.

The pot has the original gasket and the clamps still attached to the side of the pot.

Even when all clamps are connected the mixing bowl lid just doesn't make good contact with the gasket. About 3 inches from each clamp I can literally slide a piece of paper in between the lid and gasket.

Anyone got any ideas on how I can fix this? I've even tried a PTFE gasket in between and the lid still makes poor contact between each clamp.

Could I possibly use flour paste or maybe some extra little clamps in between?

Or possibly I could stop using the boiler clamps and just use a big set of the hand clamps all the way around the lid?

It's driving me absolutely mad now!

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