Ditch Witch FT5 - Manual (Page 19)

FT5 - SETUP 19
SELECT DRILLING FLUID
Bentonite
IMPORTANT: Before adding bentonite to drilling fluid, be sure
boring unit is equipped to use a bentonite mixture.
Bentonite is a dry powder. When properly mixed with water, it
cakes on bore walls, lubricating the bore, keeping it open, and
holding fluid in the bore.
Some things to remember when mixing bentonite:
• Use clean water free of salt, calcium, or excessive chlorine.
• Use water with a pH level between 7.5 and 10.
• Do not use bentonite containing sand.
• Mix bentonite thoroughly or it will settle in tank.
• Do not mix bentonite to a funnel viscosity of over 50.
For information on measuring funnel viscosity, read “Measuring
Funnel Viscosity” in OPERATION.
Polymer
This drilling fluid additive provides excellent lubrication and
increases viscosity. In swelling clay, polymer can reduce swelling
that traps pipe in the bore.
There are two types of polymer:
• long-chain such as Baroid E-Z Mud.
• medium-chain such as Baroid Quik Trol.