Pattern for Dome Cover in PVC Membrane

[Srikanth Bandla]

Hi group

This is my first post here in this group although I have been reading and learning a lot from all of you for a few weeks now.

I'm doing my first 6m dia 4v dome as an event tent and have some doubts. Hoping some of you may be able to guide me in my first dome project. Since this is my first project, any/all handholding will be highly appreciated.

For the struts I'm planning to use galvanised powdercoated steel pipes 25mm dia, 2mm thick flattened and connected with m8 bolts ( is this fine?)

I'm anchoring the dome using huge concrete planters.

My main concern is the cover for the dome. For the material I've narrowed down to Serge Ferrari white PVC membrane for the major part of the dome with front three rows in Clear PVC or flexi vinyl membrane.

The vendor for the cover is asking me to provide the pattern for welding the cover together. I understand the pattern is crucial for getting a tight fit cover around the dome.

First I assumed the best fit would be to cut individual triangular pieces just as the dome structure and weld them together for the best fit but my vendor says too many welds are not advisable.

Can anyone help me with this?

Another issue is the Clear PVC membrane for the front, will supposedly yellow over a period of time. So some vendors claim yellowing in 7-8 months & some claim 1.5 to 2 years. Ferrari doesn't offer clear PVC at least in India. 

Any leads would be most helpful

Thanks in advance.

Srikanth

[Ashok Mathur]

Dear Srikant,

First, let me answer the question that you have asked.

What you are looking for are called 'gore patterns'.
They are also called 'lay-out'patterns for dome cover.

A google search will yield answers that you seek.

I would always cut a scaled down pattern in cheap cotton first to understand how it all comes together before cutting expensive materials.

Secondly, you will save about 40% of your total costs if you switch to 3v dome of the same diameter and material. Its strong enough.

Regards

Ashok

Regards

Ashok

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[Ashok Mathur]

Dear Srikant

Pl see this link
http://www.domerama.com/calculators/cover-pattern/

Regards

Ashok

Regards

Ashok

[Srikanth Bandla]

Dear Ashok

Thanks for the quick reply... I had seen the gore pattern ( didn't know the term though) but wanted to avoid the long vertical seams which will be very obvious from inside. Would prefer to cut patterns such that the seams are along the geometry of the dome to keep the seams concealed as best possible for optics.

I found another on Domerama - http://www.domerama.com/calculators/cover-templates-for-3v-59-geodesic-dome/cover-template-for-a-10-foot-3v-59-geodesic-dome/

This method seems to solve my need to conceal the seams.

Yes I agree with your suggestion....I am actually building a 4ft dome just to get the cover right. Will post pics next week when it is ready. 

Decided on 4V coz I needed 1/2 sphere and want to keep this standard for future projects if any at all. 3V was either 3/8 or 5/9 using the Kruschke method for a flat base. 

 

Again.....Greatly appreciate your inputs...

Regards
Srikanth

[Gerry in Quebec]

Srikanth & Ashok,

The Domerama page mentioned by Srikanth pertains to a 3v dome with a spherical diameter of 20 ft, not 10 ft as advertised by Domerama. The diagram and numerical information about the dome cover were pirated (plagiarized) by the original owner of the website, who died in 2013.

- Gerry in Québec