Challenge - Worlds longest screen print frame

[wouldnot]

hi all,
I'd be grateful for some advice on how to build the worlds longest screen print frame.
It needs to be 35 metres by 1.5 metres. An example of what one of these is can be found here http://www.instructables.com/id/How-...-silk-screens/

I plan to make it out of 35mm by 75mm timber with bracings every 1 metre. I'm not sure how to join all these lengths together so they are as strong as possible.
Also I don't want it to bend from side to side like a parallelogram.There will be about 16 people to lift it on and off the material which it will be used to print on.

I look forward to your thoughts.

[Toymaker Len]

First thoughts - sixteen people is eight per side spaced 4-5metres lifting a frame 1.5 wide which doesn't sound very good. Maybe you should be looking at a mechanism above the table which allows you to raise and lower the frame. Also the idea of bracing every metre kind of defeats the purpose of having an extra long screen print. Really you want to be able to run the squeegee the full length uninterupted. I'd be thinking welded steel structure with box ribs above. Interesting idea though. Whats the occasion?

[wouldnot]

Thanks Toymaker Len, its for an arts event in December. We can certainly get more people to help lift and it only needs to lift once. Agreed i need to reduce the number of bracings.

[Handyjack]

35 metres long. Is it to be used outdoors or in? Will you be assembling on site or transporting to site - by semi trailer perhaps?
Just at that length there will be joins. Many hands will make light work or you will be using a crane.
Good luck with the challenge, and show us how you do it.

[ian]

for a frame that size I'd be looking at square section aluminium tube.
guaranteed straight and a lot less "floppy" than timber-- meaning fewer braces. Available in very long lengths which means far fewer joins.

However, critical issues like
will the frame be built on the 36m long table that will hold the material being printed or transported to the printing site.
you and your team's skill set working wood and aluminium and designing structures
how flat and uniform is the 36m long printing table

affect the advice that can be provided

[Master Splinter]

Scarf joints at a 60 degree angle would be my suggestion for joining it, but I'd also think about adding a second piece of 70x35 timber at right angles to the first just to try to reduce floppyness.

I'd actually think that making a plywood box beam at 150x100 out of 12 or 16mm ply might be more rigid... although an aluminium section would be significantly better and it comes in 6 meter lengths, if you have someone who can TIG weld.

I would also think you'd need braces to stop the screen tension pulling the sides together - removable so you can pop them out of the way when squeegeeing then put them back after you move past that point (even then I'd have worries about it looking like a pretzel!).

[ian]

you should be able to get aluminium tube in 12m lengths -- and possibly up to 20m lengths by special order.
a standard semi trailer is about 12.2m long, so 12m lengths should be easy to obtain,
a simple butt joint could be assembled using flat bar stock to spline (or splint) the joint. The flat bar could be attached to the square tube using rivets or self taping screws.

There are things about this project we don't currently know.
at one level Wouldnot may be able to build a frame that is braced to the table supporting the material that is being screen printed
at another level, Wouldnot may need to build a frame for the screen that looks a lot like a truss girder

if built with aluminium tube, a strip of 35 x 25 screwed to the outside edge would provide a surface to which the pattern material could be stapled.

[wouldnot]

Thanks for all the advice everyone. I'm thinking the braces could be removable for the squeedjee.

[ian]

So wouldnot, how is your project coming along?

Can you share some pictures?

[wouldnot]

The screen has been cut and is ready to install at tomorrow's launch. https://www.facebook.com/events/1672051379732133/
10cm lap joints on the external frame parts and dados cut in the cross pieces. There will be photos and a video regardless of the outcome...

[wouldnot]

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So I built a 40 metre frame roughly. Used the router to make dados (I think that's what the grooves are called) for the cross pieces. 10cm lap joints for the big pieces. Once the print was finished we screwed the cross pieces in place and 40 people lifted the frame.
Worlds longest screen print at 35 metres.

[Thylacene]

Congratulations on a success Megalo celebrates 35 years with the world's longest screen print attempt