The phrase "are not solid enough" is correct and usable in written English.
It can be used to describe something that lacks sufficient strength, stability, or reliability in various contexts, such as arguments, plans, or physical objects.
Example: "The foundations of the building are not solid enough to withstand an earthquake."
Alternatives: "are insufficiently strong" or "lack adequate stability."
Simon Vozick-Levinson from Entertainment Weekly gave the live album a D, opining that "the stripped-down treatment of MTV Unplugged does Perry's yowling voice no favors", and that "[the] songs just aren't solid enough to stand on their own without loads of glossy production".
"But it's the nature of the sport and you want to build athletes who are resilient, who are solid – and we're not solid enough".
Ms. Krosby added that last week's gains were not accompanied by strong volumes, which suggested that the rally was not solid enough to extend the gains.
In these arias and in the final duet, "O namenlose Freude!," sung by Ms. Brewer and Mr. Cole, the orchestra's playing was not solid enough.
Sometimes, the investigators are trying to force the hand of reluctant prosecutors who may believe the case is not solid enough to support an indictment.
Brazilian businessman Germán Efromovich tried to buy ailing national airline TAP for €36m last week, but his offer, which reportedly included a further €315m in capital for the airline, was turned down after the government said his financing was not solid enough.
As the crowd around No. 18 gave Woods a standing ovation, he took off his cap and acknowledged the cheers, knowing deep down that his game today was not solid enough to beat Mickelson.
Ms. Caproni also said that even though the F.B.I. manual says agents can open assessments "proactively," they still must always have a valid reason — like a tip that is not solid enough to justify a more intensive level of investigation but should still be checked out.
Secretary Rumsfeld said the United States, which had the compounds under direct surveillance from the air and the ground in the days beforehand, had decided on the raid because the information gathered was not solid enough to justify an airstrike against what was suspected to be a Taliban or Al Qaeda base.
