This is a propane tank cover I made out of fine wire mesh and "thin-set mortar" used for setting tiles. Unlike cement, the thin-set doesn't shrink, so cracks are rare. It is also easy to seal any cracks by cleaning and brushing on more thin-set. The thickness is only about 1/8 or 1/4 inch, so the material used is minimal.
This grew out of my nylon-cement technology (rebar, fishnet and cement) I used to make my home, only with material substitutions to go for thinner walls. I plan to use it in the future for lots of things. It's pretty low-cost, quick and easy.
Step 1: Attaching the Mesh to the Wall
This is simple add-on construction. First I cut some wire mesh squares, bent them in half and stuck half of the square to the wall with some thin-set mortar. When that was hard, I used small paper fasteners (with the head and two legs you push through and bend over) to attach the mesh form to the wall attachment points. If you have a problem with the fastener legs pulling back out, take needle nose pliers and bend the tips to go back through the mesh and fold over again. That way, they can't pull back out.
Remember that curvature in your design helps give strength.
Before getting into the plastering, I covered all the exposed stove line hoses, and tie-down chain with plastic bags to protect them.
Step 2: Plastering With Thin-set Mortar
I love thin-set mortar as a sculpture material, and sculptural decorations can easily be added to thin-set surfaces.
Spread out a tarp to keep the floor clean. I used a large palette knife to do most of the plastering with, but you can use other small trowel-like tools. Use rubber gloves to protect your hands and you can wipe on material with your hand sometimes to save time.
The yellow color coat is just thin-set with powdered pigment in it. The pigments can be found in hardware stores for coloring cement. I brushed it on with a small house painting brush.
I put a piece of pipe, as a curtain rod above the tanks (can't see it in the pictures) to later hang a curtain from to hide the tanks. Holes drilled into the walls at either end allow stainless steel pins to enter the pipe from either end and hold it in place. The pins can be pulled out to remove the pipe. If you have to plaster around the pins (I did at one end), cover the pin with Vaseline first to keep the thin-set from sticking to it.
Try this thin wall technique and I think you will like it. It could work for outdoor storage structures, for example.