810 Agricultural Mechanics and Technology Systems
Copyright Goodheart-Willcox Co., Inc.
2. Using a scrap piece of steel, set up the machine parameters according to
manufacturer’s specifi cations and run a test bead. Make any adjustments
to fi ne-tune the settings.
3. Strike the arc. Remember to call out the word cover before striking the
arc to alert anyone nearby to avoid looking at the arc without adequate
protection.
4. Tack weld the two coupons lengthwise and parallel to each other leaving
a gap no wider than 3/32″, Figure 29-59. It may be necessary to realign the
plates after placing the fi rst tack due to contraction of the cooling tack weld.
5. Welding a 10″ long 3/4″ or 1/2″ pipe handle to the
tacked coupons will make the part safer to handle
and provide an excellent location for attaching the
ground clamp.
6. Position the coupons on the welding table so that the
joint is facing up and the back side of the joint does
not contact the top of the table. The coupons may
have to be bridged across pieces of scrap to achieve
this position. Contact with the table on the back side
of the joint invites the introduction of contaminants
into the back of the weld.
7. Use a 3/32″ or 1/8″ E6011 electrode to weld a single-
pass bead along the joint of the coupons. This is the
root bead.
8. Leave the welding machine running. The duty cycle requires a cool-
down time to protect the internal components of the power source.
9. Thoroughly clean the root bead using a chipping hammer and a wire
brush. Although it may be tempting to cool the coupon at this point, this
is a bad habit. Rapid cooling deteriorates bead quality.
10. Evaluate the root bead quality by answering these questions:
• Is the surface uniformly textured?
• Is the top of the root bead slightly concave, and do the edges blend
smoothly and evenly to each side of the joint?
• Is the penetration complete?
• Are there discontinuities? How many? How severe?
11. Weld a second bead on top of and penetrating into the root bead. This
cover bead should blend smoothly to both edges of the joint.
12. Clean the welds thoroughly. If desired, continue fi lling the joint until it
is full. Doing so affords you more practice and helps you improve your
technique.
13. Clean your work area and return all equipment to its proper place.
Goodheart-Willcox Publisher
Figure 29-59. Tack weld for groove weld practice.