I just installed a set of Hed Black Dog aero bars with Hed 31.8 clip-ons. I can move the clip-ons no matter how tight I make them.
I have tried carbon paste.
Are there other fixes?
Should I be sanding/roughing the clip-on brackets that mount on the basebar?
Any other foolproof fixes?
Do not sand anything! If you can find some try a wrap or two of mylar tapearound the base bar. Clear packing tape would also do. You need to take up any slop between the base bar and the clamp of the clip on. Assembly paste can only do so much. Overtightening is very bad also. I have very successfully used this fix for many years with no problem. It is completely removeable is the need arises.
Update- another forumite gave me the tip to contact Jasonogk- he sets up Hed stuff for a lot of pros.
He gave me the tip to use not only carbon paste, but a sparay adhesive like Effetto Mariposa ar 3M spray adhesive. So I put a layer of the spray adhesive on the basebar and a layer or tacx carbon paste on the extension brackets before mounting. Gave it a bit of set-up time- grips like iron.