With no weak point A1 fitting secures tons (8)
I believe the answer is:
airtight
'with no' is the definition.
Both the definition and answer are adjectives. Maybe you can see a link between them that I can't see?
'weak point a1 fitting secures tons' is the wordplay.
I cannot really see how this works, but
'a1' could be 'a' and 'a' is present in the answer.
'tons' could be 't' and 't' is located in the answer.
'point' could be 'right' (right is a kind of point) and 'right' is found in the remaining letters.
A single letter 'i' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for airtight that I've seen before include "Not allowing gas to enter or escape" , "not letting out a breath?" , "With no opening" , "(Of a defence) having no weaknesses" , "Sure" .)