Stone Guard

This design is from my good mate Al and can protect gas bottles and jerry can as well.

The first steps are to provide the structure to hold the shade cloth fabric stone guard. Remember the cardinal rule: ‘measure three times and cut once.’

Pop rivet a length of aluminium track to each side of the van, in front of the existing track for annexe wall. Leave space above and below this track to allow for an eyelet in the stone guard to tension the fabric with ‘stayput’ single fasteners. We chose to span our stone guard from the bottom of the van to top of the grey line decoration so a 400mm length of track was appropriate.

It is possible to use the annexe track for your stone guard, but this requires removal of stone guard whenever you want to put up your annexe.

Measure the space available on your draw bar and buy a suitable rectangle of 3mm aluminium checker plate. This is to support the front of the stone guard with a ‘pipe in a pipe’ welded to the plate, which is then pop riveted to the draw bar. A very helpful local welder, Aldo, was an excellent source here. Not only did he find a bit of off cut of checker plate around the work shop, but also did the welding and provided valuable design ideas.

Aldo also found two off cuts of pipe around his workshop: the bottom, outer one, was aluminium to weld to the checker plate. This was to avoid any problems of electrolysis arising from welding different metals together. The inner pipe was stainless.

Cut out a cardboard template showing the draw bar where the plate will go. An opened-out beer carton is a good size. The template should include cross members of draw bar and positions and size of things like jockey wheel mount and gas bottle mounts that you will have to cut around for the checker plate to be riveted flat to the draw bar. If you intend modifying your gas bottle mounts to include an extra fuel mount, do that before you make your stone guard for a neater job.

Use the template to mark all cutting lines on checker plate with a felt tip pen. Drill suitable holes where the cuts for the jockey wheel mounts end for a nice curve to the end of the slots you cut for them. Cut to shape with an angle grinder with a very thin disk.

Drill a suitable hole in the top of the outer pipe to self-tap a small locking bolt to hold the loose inner pipe. Cut this pipe at an angle that will slope your stone guard forward and up to deflect stones downward rather than back at the tow vehicle. A bit of guess work comes in handy here. Cut the bottom of stainless inner pipe at the same angle to that of the welded outer pipe and to a length of about 500mm.

Mark position on the checker plate to weld outer pipe, centred from side to side. It should be positioned far enough forward so the stone guard clears the gas bottles and, if you have it, the jerry can mounts. Have it welded to the checker plate. Cap the inner pipe with a small plastic cap. Pop rivet the checker plate to the draw bar.

Now to the fabric of the stone guard: Use about 4 metres of shade cloth available from Bunnings. We chose grey to match our Cruiseliner’s colour scheme. Lay the shade cloth out as a rectangle of double thickness. Using masking tape as markers & staples to hold the fold for cutting helps here.

Allow 100mm extra for sewing to the folded width and to each end. The finished height of our stone guard was 530mm and 3400mm long so we cut from folded shade cloth a rectangle 630 x 3600mm. This allows 100mm extra for each side for sewing the hems of the stone guard. You will need to adjust your measurements for the height of stone guard you want, the position of your front support post and for the position of the aluminium track at each side of your van. It is better for stone deflection that the bottom of the fabric is loose around the front post, rather than being tailored tight.

Begin by sewing the sides and then turn inside out. Use nylon or 100% polyester or nylon thread for durability. Remove all staples and masking tape. Cut four separate lengths of nylon rope to reinforce the sides, top and bottom of the stone guard. It must be able to slide in the track but be big enough to hold the stone guard in the track. Sew 25mm hems to hold the rope. Then resew the hems to hold the rope as near the edge as possible. Use separate lengths of rope to ensure the sides of the stone guard will be able to enter the side tracks. Test that the fabric and rope will slide into the track. A squirt of silicon spray will help here.

Because the boot of our van is fibreglass, we chose to protect the sides with cut-down foam mats. (Six for $18 from K-Mart.) I cut two mats to slope from 370mm on one side to 440mm on the other. Work out your own measurements and don’t forget to reverse the slopes for the opposite side.

Before sewing the top of the stone guard a sort of pocket to hold the mats in position was made for each side by sewing up from the bottom to about 200mm from the top edge of the shade cloth. These pockets are about 650mm wide from the sides of the stone guard. Place the cut pieces of foam mat into these pockets.

After this fold down the top edges of the shade cloth and sew a separate length of rope into a hem across the top as outlined above. However, when sewing along the top, leave about 300mm unsown in the middle to insert a pocket to slip over the ‘pipe-in-a-pipe’ to hold the front of the stone guard.

Position the stone guard on your van and mark with masking tape on it the position of the ‘pipe-in-a-pipe’ the pocket will fit over. Back at the sewing table, sew three 120mm squares of off-cut shade cloth to make the pocket. Insert one side of the square in the section of left unsown earlier then complete sewing the rope into the top edge hem. Complete by sewing the sides of the pocket down inside the stone guard.

All that now remains is to insert eyelets in the four corners of the stone guard and two more at the bottom of the stone guard, 650mm from each side, to hold it in place. Very simple tools are available to achieve this. The one I use has one punch to make a hole and another that, with a dolly, fixes two parts of the eyelet to each other through this hole. A few lightish taps of the hammer is all it takes.

To fix the stone guard to the van position it once more in its side tracks with the pocket over its post. Stretch a bottom corner downwards so the reinforcing rope is just below the bottom of the van and backwards a little. Remember that the bottom of the stone guard is better slack at the post than taught. Mark the position of the bottom corner eyelet with a felt pen. Position a ‘stayput’ on this spot and pop rivet it to the van. Repeat on the other side of the van.

Tension the eyelet above the side track on both sides upward and backward to hold the stone guard flat to the side of the van. The front-to-back tension of the top of the stone guard is only for appearances and need only be tight enough to hold the whole stone guard together. Finally pop rivet the ‘stayputs’ for the eyelets 650mm from each side so the bottom reinforcing rope is just below the bottom of the van and the job is done.

Lindsay Reed (2230)