Howto build a Launch Cage with Guide-rail – Part 3

This is the final part of the launch cage construction posts, it  covers the addition of the mesh, the access for the air hose as well as final adjustments. We learnt a lot about applying mesh and have included tips below which should speed up the time to do this task for others.

Attaching the Mesh
The mesh that we used is a zinc coated welded steel mesh made by Whites Wires here in Australia. Its has a 6.5mm (1/4″) square aperture and a 0.6mm wire diameter. This mesh  is usually used for  snake and mouse protection on aviaries.  The welded mesh provides more rigidity to the mesh than twisted wire mesh such as chicken wire.

Closeup of Mesh

TIP 1 : SAFETY SAFETY SAFETY – Anytime you are working with mesh or wire its very very important to wear wraparound  eye protection and gloves  while handling the wire and mesh.  Wire strands can easily get into your eye and you dont get a second chance with your vision. Also the mesh is very sharp when cut so gloves are needed !!!!!!

The initial plan was to use wire to wrap the mesh to the frame. So first a section of the wire was cut to size for one side. This took quite a while with wire cutters, cutting each wire individually.

TIP 2:  USE A ANGLE GRINDER TO CUT THE MESH – Use an angle grinder to cut the mesh. It cuts through it like butter and also trims off the sharp edges all in one go.

Once the wire was cut to size it was placed against the frame. Initially the mesh was cut right up to the edge of the frame. As the frame is 35mm wide, it doesnt need to go all the way to the frames edge as it will expose the edges. Its safer to cut the mesh about 10mm away from the edge.

TIP 3: CUT THE MESH 10mm SHORT OF THE FRAME EDGE to prevent cutting your leg as you walk past it once its on.

The mesh was trimmed then using wire it was strapped to the frame by wrapping the wire around the frame and through the mesh. Basically sewing it to the frame. While this did work and the mesh was tight against the frame, it took about an hour to do one side and left a lot of the sharp ends of the strapped wire exposed .

There had to be a better way….  We did  some research on how  mesh was added to the frames of aviaries. The answer it turned out was universal and quite simple ….  tek-screws !

Tek Screw with Hex Nut

A tek screw has a self drilling point and the ones we used had a hex bolt head that held the mesh tight against the frame. We also used a magnetic hex Tek bit for the power drill which made installing these very fast.

TIP 4: USE TEK SCREWS TO ATTACH THE MESH TO THE FRAME

Once the wire wrapping was removed, the same side section was attached with Tek screws in about 5 minutes. Here is a closeup of the tek screws holding down a mesh section.

Closeup of tek screws holding down sections of mesh

In all we used about 125 tek screws to attach all of the mesh to the frame. Where the mesh needed to be trimmed it was done with the wire cutters but in most cases it was cut to size with the angle grinder before being put onto the frame.

Securing the Access Door
The access door is covered with mesh from the inside, it uses the two wooden stoppers to stop the door falling into the cage and the  sliding bolt to hold the door in place.

Sliding latch on access door

Air Hose Connection
The air hose connection to the launcher is fed through a small hole cut in the mesh. Access  to connect the airhose to the launcher is via the access door. Here is the airhose in place and the accessdoor open.

Airhose connected to launcher with access door open

Final Adjustments
Finally, here is the water rocket car in place on the rail and attached to the launcher. Some small adjustments on the lugs were made to get the exact height correct. Several manually powered launchers were made to check all was working satisfactorily. Some grease will be applied to the rail before a powered test is made. Here are some pics of the final cage.

Finished Cage - Side View

Finished Cage - Rear View

Water Rocket Car attached to the launcher and guiderail

One tip we found after we had already applied the mesh was to paint the mesh itself black. This virtually makes it dissapear to the eye and is usually performed to make viewing birds easier. With the white frame we have, we probably wont bother trying to paint the mesh black :)

Only thing left to do now is some powered tests of the rail and the cage. Hopefully we will get this done shortly, then head to the launch site to try to set some records :)

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This entry was posted on Tuesday, January 25th, 2011 at 11:04 pm and is filed under Development. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

 
 

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