Deepdraw Depron
On the internet are many subjects about deepdraw with Depron. But there
are no specifications, or they don't want to give them away.
Until a movie appeared on www.rcmovie.de from
crasspilotrw. He shows in the movie how it's done with normal tools and
equipment. Thank you very much crasspilotrw.
RCMOVIE Yak tiefziehen
The specifications in his experiment are:
- two grills from each 1000W;
- distance between the Depron and the grills is 300mm;
- one normal vacuumcleaner.
When the grills are turned on the Depron starts to heat-up. After a
moment the Depron deforms. This is the time to turn on the vacuum
cleaner. He made the form out of concrete, which was a leftover. In this
he drilled holes from 2mm.
Making the form
After this I got inspired and want to make it for myself. So I started to
build a positive form from a yak 54. This plane has round edges and is
for this reason more sutable in mine opinion. After putting the form
together I added a couply of layers of varnish.
I used plaster from Knauff a trademark in the Netherlands. I made a box
so it will be a sort of tile when it's done. The box made it also easier to aply the plaster. Before the plaster is
put into the box I first creased the form so it does not stick to the surface.
After a day I pull out the positive form and it came out very nicely. The plaster
must dry for several days so it wont break when drilling the holes for the vacuum.
First attempt
I made a vacuum box to hold the form. I connected an vacuumcleaner to the box and
tape of every opening which should not have to be open. After this I place a peace of
depron on the form and turn the heating on. In my case a electric bathroom heater.
When the depron starts to deform I turned on the vacuumcleaner and turned off the heating.
The vacuumcleaner was to strong for my form and it broke! So I have to start all over again.
This time I made the form from cement. And to be safe I even reinforce it.
When the form is dry its time to drill the holes (again), but this time the cement was much
stronger than plaster. I even have to use a stone drill.
In the picture above you see the broken form and the new cement form.
Second attempt
So back to the vacuumbox for more testing. This time I know the form won't break.
I repeated all the previous stapes above and turn on the vacuumcleaner. The depron start to take
the form from the form. Some places not all the way, but it is a start.
The key is control the heate. The bathroom heater was on to long and it becomes to hot.
The air inside the bubbles from the depron increase because of the heat. When this happens
the depron breaks into two layers. This heapend to me where the distortion is the biggest.
Because of this the fuselage unfortunatley is no good. So I must search for a way to control
the heat and deforming so it won't happen again.
Never the less I'm still pleased with the results. Where the deforming is not to much it came
out very nicely. The biggest depth of the form is at 35mm. This means I have to make a new
form which is less deeply.
To keep the scale for a yak54 with it's round fuselage means the plane becomes smaller to stay
unther the 35mm. Actual the yak54 isn't a good test model because of its round fuselage. The
form must became thinner so i'm looking for a new plane for making a different form.
This is where I am today. When I make new progress I will put it on the website.
Tips or stories from your deepdraw adventure is highly appreciated.