I glue the rubber to the mount before gluing the flat fold areas. Notice the angle of the shock cord. This makes a flatter mount, important for easier ejections in smaller diameter tubes.
On the left is how much glue is applied. This is a cardstock mount, paper doesn't need much glue to adhere well.
On the right is how much glue is left after smoothing and removing the excess.
Before the two glued sections dry,
Shape the mount by pressing it into the inside curvature of the body tube. No glue on the back yet.
The mount is to be glued 3 1/2" below the top lip of the body tube.
Mark the rubber cord with pencil using a ruler at the 3 1/2" length. Use the pencil mark as a depth gauge. Drop the glued mount into the tube until the pencil line is at the tube edge.
When I use the Mount. I do it as you shown us on your site. Happy New Years
ReplyDeleteGood points on the shock cord mount.
ReplyDeleteGluing the rubber shock cord onto the shock cord mount before folding helps to keep the rubber from shifting around when you fold over the sections.
As you stated, setting the rubber cord at an angle keeps the assembly flatter (i.e. though the rubber may be flat, it's much thicker than paper, and that adds up). It also means the folded-over section could bond better (since we're not accumulating the thickness of the rubber).
Keeping the glue to just what's required -- using too much glue means it takes longer to set and dry - increasing the chance the folds could unravel due to the rubber wanting to straighten itself out (i.e. unlike paper it doesn't crease and doesn't want to stay folded).
Not immediately gluing the mount into the tube -- as with the excess glue when assembling the mount, it'll take longer to set and dry. Again, this increases the parts could shift around and not make proper contact before the glue dries.
All of the above isn't always stated in the instructions, but we eventually find out after a while (e.g. the shock cord mount on first model rocket I built came loose after a while).