Vocabulary Terms
In many welding jobs, you will need to make a quick sketch. Sometimes your supervisor cannot understand a problem unless you draw it. Other times, you may need a sketch with measurements to show an apprentice how to finish a task. When you know how to sketch, you can communicate more clearly, work more effectively, and become a more valuable worker.
Out in the field, you often work from sketches made on whatever is available—napkins, cardboard, pieces of wood, or any flat surface. You will definitely work with professional blueprints and drawings, but sometimes you must rely on simple sketches made on the spot.
You do not need to be an artist to make technical sketches. Sketching is not difficult if you follow a few basic rules. At first you may be slow, but with practice you will be able to make clear, useful sketches without much effort.
No one expects you to draw like a professional drafter or architect. However, you must be able to show—using simple lines—what needs to be built, repaired, or modified. This skill takes practice, and it is an important part of being a successful tradesperson.
Sketching Techniques
All you need to start is a pencil and some paper. A soft pencil works best for most people, so try a #2 or an F. Keep the pencil sharp, but not too sharp: hold it with a grip firm enough for control, but not so tight that your arm isn’t relaxed. Don’t draw heavily at first. That way it is easier to erase without smudging. Darken the sketch when it begins to shape up the way you want it.
It’s generally best to begin sketching with plain paper, although some people like to use grid paper. On the job, you may find yourself sketching on the back of a work order or piece of packing crate. In any case, it’s learning to sketch quickly and effectively that’s important.
Practice lines
Here are some limbering up exercises wot get you started. To keep your pencil sharper longer, and for more even lines widths, try turning your pencil slowly while completing the lines in the exercises below.
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Next, try sketching the objects on this page. Make your sketches as much like the examples as possible.
Remember; sketching means freehand drawing. No Straightedges, compass, coins, etc!
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Lettering
Now that you are warmed up, we will take the straight and curved lines from the sketching exercise and use them to form letters. The entire alphabet can be formed from the straight and curved lines you have practiced.
Look at the lettering on the worksheet below. If your printing is similar, and is easily readable, you can skip this exercise and go on to oblique sketching. If not, do some practicing. Some of the work ahead (and tests) require good lettering.
Practice Lettering
Remember, the most important requirement of good lettering is legibility. There is no use making a drawing if the person looking at drawing cannot read your writing.
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Oblique Sketching
Oblique sketches are a type of pictorial having one plane parallel to the drawing surface, and the visible side sketched at an angle. Usually, that angle works best at 30◦ to 45◦, or somewhat in between. Beginners often have trouble keeping the 30◦ or 45◦ lines as the same angle. If that happens, your sketch will look distorted.
Here’s how to sketch an oblique cube in three steps:
Possibly you might want to show the left side of the cube, or perhaps draw the hidden lines, as at the right;
Practice oblique sketches
Sketch the objects in oblique, as shown:
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In this more difficult exercise, you are to make oblique sketches of the objects shown.
The third problem is drawn in isometric. You are to sketch it in oblique.
Convert problem four from orthographic to an oblique sketch.
Isometric Sketching
Isometric sketches, unlike oblique, must maintain an angle very close to 30°.
Therefore, to get the “feel” of an isometric, try sketching 30° angles in this exercise:
Sketching in isometric can be done in different ways. Generally, it’s recommended that you start and the bottom of the object and “box it in”, thereby enclosing it within a rectangular framework. For example, if we were to take a simple object like this,
The steps needed to sketch it in isometric would be;
The unnecessary lines are then removed, leaving the object. Once you gain some practice at this, it will be possible for you to make an ISO drawing without the “guide” lines. It is important to use them early on the help train your brain.
To the beginner, building a “frame” before sketching the object often seems unnecessary. That may be true with simple objects. However, when things become more complex, a frame gives you a means of developing the various parts in an organized way. Without such guidelines you can easily “lose” your sketch.
Practice with isometric sketching
Sketch the examples given, using guidelines as shown in the first exercise. Draw the guidelines lightly. Notice that 3 and 5 require the use of non-isometric lines. Since those lines are not at 30◦, it is best to connect the end points of those lines after the sketch nears completion.
Circles and arcs, when sketched in isometric, become elliptical in shape. If a circle is used, it will appear distorted, as in this example:
Practice with isometric circles and arcs
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Now, let’s try putting all the details together.
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Orthographic Sketching
Of all the methods of making drawings, orthographic projection is the most commonly used by draftsperson. Although the other methods serve their purposes, they cannot always show the parts of an object as well as orthographic representation.
Orthographic projection is a system of projecting from view to view to graphically describe the object. As a way of reviewing, study the views of the small garage in this drawing. Notice the location and relationship of each view to the other views.
The important thing to remember in orthographic sketching is the alignment of views. The top view is projected directly above the front view. The front and side view also line up with each other. The height, width, and length of the object must remain the same from view to view. There should be enough distance between the views to prevent crowding; and to leave room for dimensions.
Online Practice
Review information available for free online about orthographic sketching.
Orthographic Sketching by WiscTechOpen.org (2026)
Practice orthographic sketching
Follow the directions for each worksheet.
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Now let’s try sketching three orthographic views.
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Try these objects with advanced features.
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“On-THE-SPOT” Sketching
Now that you have learned the three different methods of sketching, it is time to make sketches you can place in front of you and touch, rather that sketching from drawings on paper.
Sketching “ON-THE-SPOT” is a standard industry practice. A piece of machinery needs to be changed, a support needs to be added, or pictorial information in some way requires a sketch.
Instructor will give you an object to sketch.
You will need to produce an isometric of the object and also an orthographic drawing with as many views as required to show details of object to be built.
Questions
