Gymnasts perform a variation on the pullup called the "kip" in which the exerciser uses a kicking motion to create momentum that powers their body well above the bar. Due to the whipping of the lower body in the movement, the wall mounted pull-up bar standard in many home gyms won't suffice since there isn't enough room between the bar and the wall. This leads to the need for a do-it-yourself free-standing pullup bar that can handle the kipping motion.
Set the buckets in an area either outside or inside, but realize if you're setting up indoors that the ceilings need to be considerably higher. It is advised for safety's sake that indoor ceilings be at least 10 feet in height to give your head sufficient clearance for the movement. Space the buckets about 5 feet apart and pour empty each bag of dry mix quick drying cement into each bucket.
Lay the longer 7 foot metal pipes out flat on the floor or ground, parallel to one another, and lay the shorter 5 foot length horizontally across their top ends. Thread a metal elbow connector onto each pipe end then attach the shorter pipe to the longer pipes via the connectors. You now should have what resembles the lower half of the letter H. Set aside.
Mix the quick drying cement powder in the buckets according to the package directions, using the appropriate water to dry mix ratio. Stand the metal pipes up vertically and place each of their free ends down into each bucket – you may need some additional assistance handling this part of the job. Set each end so it is firmly snug at the bottom of each bucket and hold the bars erect for about 20 minutes in order for the cement to partially cure. Let go of the bars – they should stand on their own, but still the cement won't be cured all the way, so allow several hours for the cement to dry and harden throughout the buckets.
Check the drying progress periodically: if the bars have a little give, they aren't ready. If they don't budge, they're ready for the next step if desired. For additional stability in the bars – and this only works if you're placing your kip bar outside – coil chains around the ends of the horizontal bar and pull each free end of the chain to the ground and hammer them in place using tent stakes.