How Welding is Estimated
Estimating a welding job involves two main parts: calculating the amount of filler metal needed and estimating the time it will take. The amount of filler metal is determined by the volume of the weld joint, which depends on its shape (e.g., fillet or groove) and dimensions.
The welding time is calculated based on the total weight of the filler metal and two key factors: the **Deposition Rate** (how quickly the welding process deposits metal, in pounds per hour) and the **Operating Factor** (the percentage of time the welder is actually welding, also known as the arc-on time).
Typical Factors
| Parameter | Common Range / Value |
|---|---|
| Deposition Rate (SMAW) | 3 - 8 lb/hr |
| Deposition Rate (GMAW/MIG) | 5 - 15 lb/hr |
| Deposition Rate (FCAW) | 8 - 25 lb/hr |
| Operating Factor | 15% (Field work) to 40% (Shop/Robotic) |
How to Use the Calculator
- Select the type of weld joint you are creating.
- Enter the dimensions of the weld joint (e.g., leg size for a fillet, thickness and angle for a groove).
- Enter the total length of all the welds for your project.
- Input the deposition rate for your welding process and the operating factor (arc-on time percentage).
- Click "Calculate" to get the estimated filler metal weight and total time.
Frequently Asked Questions
What is the "Operating Factor"?
The operating factor, or arc-on time, is the percentage of a welder's workday that is spent actually laying a bead. The rest of the time is spent on setup, cleaning, changing electrodes, positioning, and breaks. It is a critical factor for realistic time estimation.
Does the required weight account for waste?
No. The calculated weight is the weight of the finished weld. You must add an allowance for waste, such as stub loss for stick electrodes (up to 20%), spatter, and grinding. A general rule is to purchase 15-25% extra filler material.