Shrink molding canopies etc
03-18-2004, 12:11 AM
#1
Junior Member
Thread Starter
Join Date: May 2003
Location: Blenheim, NEW ZEALAND
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
Shrink molding canopies etc
I have been told of heat shrinking clear plastic drink bottles over a mold to make a canopy. I had made a mold for the canopy so I cut the ends off a large Soft-drink bottle and put the mold inside and wedged some wood under it to pull the plastic firmly over it. I used a hot air blower (heat gun paint stripper) on low heat and was amazed to see the plastic pull firmly to the shape of the mold.
It is amazing and so simple.
The technique as it was explained to me is to make a smooth mold of the canopy (custom wood, plaster of paris etc), cut open a large clear plastic soft-drink bottle. Pull the plastic around the mold and secure the edges with staples all around. Heat the plastic with a heat gun as you would for heat-shrink covering film. It is amazing to watch as wrinkles disappear and the plastic takes the shape of the mold.
I was worried about the stability of such a canopy in high temperatures so I left a canopy on my car dashboard on a sunny autumn day, there was no distortion so it should be OK in reasonable conditions.
For canopies too large for one bottle put a strip of cardboard over the mold at the joint location (frame) to form a step in one piece, so the forward piece will overlap the rear.
This technique would also be ideal for plastic wingtips and wheel spats.
It is amazing and so simple.
The technique as it was explained to me is to make a smooth mold of the canopy (custom wood, plaster of paris etc), cut open a large clear plastic soft-drink bottle. Pull the plastic around the mold and secure the edges with staples all around. Heat the plastic with a heat gun as you would for heat-shrink covering film. It is amazing to watch as wrinkles disappear and the plastic takes the shape of the mold.
I was worried about the stability of such a canopy in high temperatures so I left a canopy on my car dashboard on a sunny autumn day, there was no distortion so it should be OK in reasonable conditions.
For canopies too large for one bottle put a strip of cardboard over the mold at the joint location (frame) to form a step in one piece, so the forward piece will overlap the rear.
This technique would also be ideal for plastic wingtips and wheel spats.
03-18-2004, 12:22 AM
#2
Senior Member
Join Date: Dec 2003
Location:
Posts: 171
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrink molding canopies etc
Kahu, Great Info !!! Thanks a lot for the article. Do you happen to know which glue is good for strong joints on plastic bottle material ? I have an idea for a project but have not found a glue that can strongly join this plastic to itself.
Anticipated Thanks. JT
Anticipated Thanks. JT
03-18-2004, 12:50 AM
#3
Junior Member
Thread Starter
Join Date: May 2003
Location: Blenheim, NEW ZEALAND
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrink molding canopies etc
I use J&Z R/C-56 Canopy glue for canopies, but must admit I have tested it on this canopy yet. It claims to work on a variety of plastics and I don't know what type of plastic is used for these bottles.
I'll do a test piece tonight and let you know if it works.
I'll do a test piece tonight and let you know if it works.
03-18-2004, 10:09 PM
#5
Junior Member
Thread Starter
Join Date: May 2003
Location: Blenheim, NEW ZEALAND
Posts: 17
Likes: 0
Received 0 Likes
on
0 Posts
RE: Shrink molding canopies etc
The glue I mentioned above produces a strong joint if the plastic is overlapped about 1/8 inch. It can be peeled apart but takes some force. It would not be exposed to peel force much on an aircraft. Shear strength is good.
