Lesson Four: Joining and Assembly Techniques

What is the difference between fusion welding and brazing or soldering?

In fusion welding, the base material melts, while it does not in brazing\soldering.

What is the difference between soldering and brazing?

Soldering filler melts below 840F and brazing melts above that.

What are the five basic weld joints?

Butt joint, T joint, corner joint, lap joint, and edge joint.

What is a butt joint?

Two pieces in the same plane, end to end.

What is a T joint?

One piece meets the middle of another at a 90 degree angle.

What is a corner joint?

Two pieces join at their ends to form an L

What is a lap joint?

Two pieces overlap, one on top of the other.

What is an edge joint?

Two pieces side by side with edges even.

How do you weld a butt joint?

A groove weld.

How do you weld a T joint?

Fillet weld on one or both sides.

How do you weld a corner joint?

Fillet outside or groove/fill outside

How do you weld a lap joint?

Fillet along the overlap edge.

How do you weld an edge joint?

Edge weld across the tips.

What is a fillet weld?

A triangle shaped weld laid into a corner.

What is a groove weld?

Weld metal fills a gap or groove between two edges.

What are the five types of groove preparations?

Square, V, bevel, J, and U.

What is a square groove?

Edges are left square, tight or slightly gapped.

What is a V groove?

Both edges are chamfered to form a V.

What is a bevel groove?

One edge is chamfered while the other is square.

What is a J groove?

One edge is given a curved (concave) edge while the other is square.

What is a U groove?

Both edges are curved.

What is a tack weld?

Short welds at isolated points that temporarily hold parts in place.

What is a stitch weld?

Short welds with gaps in between, rather than a long seam.

What is a plug weld?

Weld metal fills a round hole in the top piece to fuse it to the piece underneath.

What is a slot weld?

Like a plug weld but through an elongated hole/slot.

What is a spot weld?

A small, localized weld through overlapping sheet

How do you check square?

Measure both diagonals, if they are the same length, the item is square.

Why does metal distort?

It expands under heat and shrinks when it cools.

What is backstepping?

Laying short welds whose direction runs opposite to your overall progress.

What is the skip stitch method?

Welding short segments spaced along the seam, then coming back to fill in.

What is a butted joining?

The square cut end of one tube sits against the side of the other.

What is a mitered joining?

Both tubes are cut at a 45 degree angle to make a clean corner.

What is a coped joining?

The end of a round tube is cut in a saddle shape so it hugs the tube it meets.