Which AWS D1.1 Welder Certification Test Kit Do I Need? (Limited vs Unlimited Explained)

If you’re trying to get your welder certification under AWS D1.1, the first question isn’t “Which kit should I buy?”

It’s this:

Do you need Limited thickness or Unlimited thickness qualification?

Choosing the wrong one can cost you time, money, and a retest — so let’s break it down clearly.

Step 1: Limited Thickness (3/8") vs Unlimited Thickness (1")

3/8" Limited Thickness Qualification

A 3/8" plate test qualifies you for a limited base-metal thickness range under AWS D1.1.

This is commonly used when:

• An employer specifically requires limited thickness qualification

• A school program is qualifying students under a controlled curriculum

• The work being performed does not require unlimited thickness qualification

It’s a valid and code-compliant qualification — but it does not cover the same thickness range as an unlimited test.

1" Unlimited Thickness Qualification

A 1" test plate qualifies you for a broader thickness range under AWS D1.1.

Most welders choose unlimited thickness when:

• They want the widest acceptance

• They’re qualifying for structural field work

• An employer wants the most flexible qualification range

If you are unsure, ask whoever is requesting the qualification:

“Do you require unlimited thickness qualification under AWS D1.1?”

If the answer is yes — choose the 1" plate.

Step 2: What Process Are You Testing With?

Your qualification is specific to the welding process used.

Common options:

• SMAW (Stick)

• FCAW (Flux Core)

• FCAW-G (Dual Shield / Gas-Shielded Flux Core)

You must test with the process you intend to be qualified in. Passing SMAW does not qualify you for FCAW, and vice versa.

Step 3: What Positions Do You Need?

Positions matter just as much as thickness.

• 1G – Flat

• 2G – Horizontal

• 3G – Vertical

• 4G – Overhead

Many structural jobs require vertical and overhead (3G + 4G).
If that’s what the employer expects, make sure your test matches.

What Employers Actually Care About

When someone says “We need your certification,” what they typically want is:

• AWS D1.1 qualification

• The correct thickness classification

• The correct process

• The correct positions

• Proper documentation (WQR)

If your documentation matches their requirement, you’re good.

Quick Decision Guide

Choose 3/8" Limited if:

• The requirement specifically calls for limited thickness

• You’re qualifying within a school or structured program

Choose 1" Unlimited if:

• You want the broadest qualification range

• You’re qualifying for structural or field work

• The employer requires unlimited thickness

Still unsure? Match your kit to the exact requirement being requested — not what “sounds better.”

Recommended Next Step

If you want maximum flexibility going forward, most welders choose:

• Unlimited thickness

• In the process they actually run

• In the positions required for their job

Match the qualification to the real-world requirement — and you won’t have to retest later.