Hi all ,
here under a little "how-to" to build cowl ventilators , out of paper .
I needed some ventilators for my Zinnia project , I bought some but no one satisfied me , I won't put here the brands I ordered , no need to , I'll just show how I built mine ...
the glue I used therefore is a CA glue , sold by "Bison" , with a brush to applicate the glue , first time I bought CA glue in such a "little-brushed-bottle" , it's just wonderful
First , some drawings to explain what we need and how we'll do it :
1 : this is what we have to get :
Dimensions , in my case , were a opening with a diameter of 12 mm ( just less than half an inch ) , the diameter of the shaft being 5 mm ( 1/5 of an inch )
2 & 3 : Following the plans I had , the cowl had to have such a developpment :
I came to a radius of 12 mm for the outside developpement ( A ) of the cowl and 6 mm for the inside ( B ) , drawing 3 is the flattened cone ...
4 & 5 : the flat part has to been cut like the drawing here under , and rounded to get a cone without top & the tube is made also in paper , wraped around a wooden rod in my case , use whatever you want , you may either use a drill bit for this .
6 & 7 : the cowl has to be opened at his base , to be glued on the shaft
8 : a thin strip of paper is glued to join the top of the cowl with the after part of the shaft
9 : the two little side pieces are cut and glued on the sides of the cowl , to the shaft
now , let's go to the pictures ...
a cowl already shaped to a cone , with the opening for the junction with the shaft :
cowl & shaft already joined by the little thin top strip :
the two side pieces glued and blend into shape :
the six pieces made got their layer grey paint . Got some problems on three pieces here , as the first coat of Humbrol enamel troubled the first coat of acrylic that followed . I guess the enamel wasn't all dry
the main difficult part in this job was to shape the two little pieces on each side of the cowl : they come nicely around the cowl , but they have to be pushed down gently against the cowl while the glue sets ...
Once the whole is made , apply some coats of CA glue , in & outside , to straighten each ventilator & to get a even surface , and the whole can then easily be sanded to become a even finish before the paint job .
I hope you enjoyed the reading , I'm waiting for your inputs once you have tried
Regards ,
Laurent