how do you make the groove to join 2 acrylic boards??

[Robert Lambie]

i am guessing what you are meaning by a grove is each sheet having a small overlap. a bit like to "steps" being slid together?

if so you creating it by using a hand held router with a flat top cutting bit. set it to half the depth of the thickness of your acrylic.

make sure the bit your using is for acrylic plastic.

it helps if you also run a strip of clear down the rear of one of the panels which creates the idea of the "tongue and groove" joint used by joiners/carpenters.

[Martin Pearson]

Like Robert says a hand held router will work ok with the correct bit. I normally use a guide bar/straight edge which is longer than the panel, this helps to stop the rounding effect you can get with hand held routers at either end.
Don’t use to high a speed or try to cut to much in one pass as this can chip the edges and you may also generate to much heat which will lead to the acrylic melting.

[Chris Windebank]

and to finish off you can use click lock like these half way down the page
http://www.signmakersproducts.ltd.uk/sign-fixings.html

[Phillip Patterson]

Thanx for your replies.

I’v always assumed the step was used for opal sheets, on lightboxes to prevent the light behind from casting a silhouette of the clear perspex used to hold the boards together. I’m hoping to use this metod to eliminate any sillohuette or visible shadows on the boards once the light is on. So i take it this method should be sufficient.

🙂