Clamp starts to slip string

Could you link the bases and clamps?
A video of it slipping would be great. You should be able to clamp it without it slipping, however it might snap the string.
Have you tried to do as kwun in this video?

 

Unfortunately, the Pro's Pro clamps do not do so well on thin or slippery strings. Either it slips or you tighten it too much the string gets crushed as you clamp.

It may be time to get some badminton diamond dusted clamps as an upgrade if you still want to string using those strings.

 

Tbh, buy other clamps if you like it easy. Maybe your starting routine is not that great. Marks are visible with eagle eyes, but shouldn't be an issue. If your string snaps, you should clean them with a "Drahtbürste". Then try to adjust them. Pull first 10kg and see if it slips and than increase the tension. If you want to string BG66UM beyond 12kg, you need new clamps, no other way out. The magic between the adjustment is to adjust the clamps to the point were the strings don't slip without crimping and marking toomuch. This is a real "Eiertanz" and needs patience. Just 2mm too much tighten the wheel and it can snap or 2mm too less and it slips. I recommend to mark the wheel if you string various strings. I adjusted my clamps and set a marker for 0.65mm strings and one for 0.70mm strings. The rest is adjusted between by feel. I adjust usually up to 15kg, to be safe.

If this doesn't work and you don't want to invest into expensive clamps, you can just switch to flying clamps, but this also means, that the quality and tension of your jobs drop, but you won't snap strings anymore. 2 decent YY flying ones are 40€.

 

Does it mean, that you weave and tension the mains on one side up to the tie-off and then the other side? If you do so...oh dear!

 

Just to get it out of the way: You should be doing left and right evenly or in a alternating pattern after the first few to keep the pressure as balanced as possible on the frame.

As a previous Pro's Pro owner and user, there are no cheap or easy methods to improve the PP clamps. They're cheap enough that you can play lucky dip, buy some more and hope you get a decent one, or purchase a known "good" one second hand. I had one decent PP clamp that would hold BGAS without crushing or slipping up to 29lbs. The other would still slip with BGAS at 25lbs even when it was crushing the string.

My solution (prior to getting a whole new machine) was to use good (i.e. Yonex) flying clamps on slippery strings and/or at higher tensions. The string bed won't be as tight as good fixed clamps BUT still better than using crappy PP clamps. Although you will loose some tension with the flying clamps relative to good fixed ones, the string won't be slipping! The better solution, although costing more would be to buy some decent, non-PP clamps. The cheaper solution would be as above, to get some decent flying clamps.

 

My PP clamps can hold around 30lbs with 66UM, which is ok for me, however I have a pair of the Superstringer Gamma-style clamps on the way from Tennisman. Hopefully those will be able to hold 34lbs

 

I find even with diamond dusted Gamma clamps, I need to clean them after a few string jobs to remove built up plastic or else I risk slippage, you also need to ensure that they are tightened correctly, I find they start to move apart after some usage.

 

Toyozouki or Yonex clamps don't have that issue.......Get a set of those. PM me if you need a set. I have a set for sale