number of tubes & thickness of perspex for a light box

[Andrew Fleming]

Usually to get a good light spread you need a tube every 12 inch, and the tube should be about 6 inch from the front face, it doesn’t matter what thickness you use in Perspex, but for that size you should use 5mm, and if the face is to be white use opal 050 or 028 anything else will show more tube lines

[David Rogers]

I did a 10m x 1.1m box a few weeks ago.

Was 24 tubes in total. (see pic) and nice & bright.

To be honest, I wouldn’t MAKE a box no matter how cost conscious the client is…buy it ready made. Takes all of the hassle out of it.

Also – need 5mm thickness and some way to join sheets

Dave

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[Philip Gibbs]

thanks for your advice

[Ian Johnston]

General rule of thumb for even brightness,

if box is 150mm deep space between tubes twice that, 300mm as both tubes light half the space,
but top and bottom spacing should be only 150mm as it is only lit by the one tube
This is important for 028 as it shows the tubes a lot easier than 050.

if your using 050 you can increase the spacing generally by 50% and get away with it. it tube spacing of 450mm ,
painting the backing white is also a good idea as it spread the light a lot better than plain aluminum

[Philip Gibbs]

"painting the backing white is also a good idea as it spread the light a lot better than plain aluminum"

that’s interesting. Ive never seen that before.

Very clearly explained rule of thumb. Out of interest does this work with double sided light boxes as well?