Most sewer cameras ship with one or two skids or guides and most owners never fit them. That is a mistake: a guide lifts the lens off the pipe floor so the picture is centred and clear, keeps the lens out of grease and grit, carries the head over joints and offsets, and in large pipe is the difference between seeing the wall and seeing the floor. This guide is about using them: which one for which pipe, how to attach them so they stay on, what they cost in bend radius, and what to do when one is left behind in the pipe.
Quick answer: run bare or with a small guide spring in 2 and 3 in pipe where a skid would not fit; fit the small skid in 3 and 4 in pipe to lift the lens off the floor; fit the large skid or a centring guide in 4 to 6 in pipe to centre the head; in 8 in and above a push camera needs a large centring guide or the picture is of the floor. Attach guides exactly as the manual shows, check the fastener before each push, and remove them for tight bends and traps. A guide that comes off in the pipe is retrieved with the camera itself, a retrieval tool or a jetter, and is why guides should be fastened and not just slipped on.
What each guide is
A skid is a plastic or rubber sleeve or cage that slips over the head and spring, with fins or a ring that holds the head off the pipe wall; small and large sizes come with many reels. A centring guide is a larger ring or wheel arrangement that holds the head in the middle of a bigger pipe. A guide spring is a helical spring or a ball that fits behind the head to lift it slightly and smooth it over joints in small pipe. Guides and skids explained covers the types; this guide covers using them.
Why the lens position matters
A bare head lies on the pipe floor, so the lens looks slightly upward at the far wall from a low angle, the floor fills the bottom of the picture and the LEDs light the near floor brightest. Lifting the head an inch puts the lens near the pipe’s axis, the picture shows the whole circumference evenly and the lens stays out of the grease and grit on the floor. Keeping the lens clear in grease depends on this, and scratch prevention does too.
Matching the guide to the pipe
Measure or know the pipe. In 2 in pipe nothing but the head fits; a guide spring may help over joints. In 3 in pipe the small skid may fit and lift the lens a little. In 4 in pipe the small skid is right for most heads and the large one for a 23 mm head in clean pipe. In 6 in pipe the large skid or a centring guide. Above that, a centring guide sized for the pipe or the picture is unusable. Skid sizing and the head sizes guide give the figures, and when you need a guide the decision.
Fitting a skid so it stays on
Skids clip, screw or slide onto the head or the spring behind it, and the manual shows which. Slide-on skids rely on a tight fit and come off in the pipe; check the fit and, if the design allows, secure with the supplied clip or a cable tie through the skid’s anchor point. Screw-on skids are tightened by hand and checked before every push. Never tape a skid on; tape peels in the pipe and leaves adhesive on the head. A skid left in a lateral is a blockage the customer did not have before.
What a guide costs in bends
Every guide makes the head longer and stiffer and raises the minimum bend radius. A large skid will not pass a tight 90 degree fitting or a trap that the bare head would. For a run with known tight bends, use the small skid or none and accept a lower picture; for a run of straight 4 in pipe, use the large one. Bend radius and elbows covers the geometry.
Guides and steering
A centred head has less bias and is harder to steer at a wye; a bare head follows the rod’s curve and can be pointed. On a job with junctions to negotiate, fit the guide after the junction is passed or steer before fitting it. Rotating to steer covers the technique.
Guides and the sonde
Plastic skids do not affect the sonde. Metal centring guides or wheel assemblies near the sonde can reduce its signal; keep metal guides behind the sonde if the head design allows.
Guides and retrieval
A guide that passed a lip going in catches on it coming out, because its leading edge is now trailing. Retrieve slowly, rotate at any catch and push forward an inch before pulling again. Retrieving a stuck camera covers the worst case.
Getting a lost guide back
If a skid comes off, it usually lies where the head was. Push the camera back to it and the head will often push it forward to the next junction or the main, where it is gone and harmless; or it can be hooked with a retrieval tool on the rod, or flushed by a jetter. Note the position in the report if it cannot be recovered. Prevention is the fastener.
Running bare
Traps, tight branches, 2 in pipe and any run where the head must be as small as possible are run bare. Expect a low picture and a lens that needs wiping. Heads for 2 in pipe and why size alone does not determine fit cover small pipe.
Carrying guides
Both sizes and their fasteners in the spares box, and a spare of each, because they are lost. Spares to carry lists them.
Common questions
Do I need to use the skid that came with my sewer camera?
In 4 in and larger pipe, yes. It centres the picture, protects the lens and carries the head over joints. In 2 and 3 in pipe it often will not fit.
How do I stop the skid coming off in the pipe?
Fit it as the manual shows and secure it with the supplied clip or a cable tie through its anchor. Check before every push. Do not rely on a slide fit.
Which skid size for a 4 inch sewer line?
The small skid for most heads and for lines with bends; the large skid for a 23 mm head in straight, clean 4 in pipe.
Related guides
See when to replace a camera head, water inside the head, and a fixed-head reel reviewed here.