I have a hairline crack in the bottom frame.  The underside where the arms slip over the frame.  It is half inch long with the direction running Paralell to the drone.  There is still alot of material holding around it.  Also by flexing the L and R arms I cannot feel any difference in deflection applying moderate force.  Applying a high amount of force say 10 lbs applied to the middle of the arm causes noticible deflection and you can visually see the crack open up.  Yes I have a broken arm also.
So I have it tore down and parts ordered.  Has anyone ever fixed a crack in a frame?  I plan on bonding the crack together to prevent spread.  It is in one of the few locations this could work.  Anyone have a better suggestion?  What to use for Bonding?  Stupid Idea?  My after care is over and crash caused by pilot error so no warranty to worry about.

I am aware repairing my own drone is not sanctioned by DJI and will void what warranty I have.  I do not care.....

Thanks everyone!!!

Anyone chime in.

Hi, thank you for reaching out. We're sorry for the unpleasant experience. In this kind of situation, I'm afraid that you may consider sending the unit in for a proper diagnosis. You can contact our support team to start up a ticket at https://www.dji.com/support. Thank you for your understanding and support!

I have crashed before with broken front arm and cracked middle frame socket connecting the arm. I think my case might be similar to yours. My post here.

I currently replaced the arm and left the cracked middle frame in use. I only applied epoxy in the single crack of the middle frame. I put about 20 flights with aggressive manual maneuvers and so far the crack has not grown further. My thought was even the crack around the socked grows further, the center bolt (M2.5) pulling the arm into the frame will still hold the arm, probably with more flexibility. So I think with my cracked middle frame, in the worst case, the arm will show some progressive sign before it completely detaches from the frame.

But I have to stress that this is for my specific case that I made this decision weighing in the obvious increased risk, my recent flight scenarios (short distance, over vacant land, low altitude, ect.), and expectation that I might very well crash again. And I have a replacement middle frame in my possession already to be installed anytime.

Hope this helps.

Thanks I plan on the same thing.  what did you use to bond the frame?  Torn between getting out the plastic welder "Ideal" and just slobbering some JB weld over it and filing it down. "easiest".  Anyone else chime in on a good chemical bonding agent?