laminating or gluing polycarbonate to cast acrylic

[Ian Stewart-Koster]

Hi Folks,

I've just about finished routing the 2nd big lithophane I've been working on, (4' x 2.5') and it's pretty thin in places
I'm going to back it up with 1/4" clear polycarbonate, for strength.

I can simply place them together, and then sandwich them between the two 1" square hollow galvanised steel section, or I can try and make a more positive join.

I did try some samples of polycarb glued to acrylic using straight Methylene Chloride, and using MeCl with acrylic shavings disolved in it, but all I got were solid bits of fizz- bubbles I could not get rid of.

I'm just wondering if anyone can offer me some advice on how to do it so that it does not look worse than none-at-all !

Gluing with Silicone 401? But that's a large area - 10 sq feet.

Thanks in advance for any suggestions...

[Glen Monaghan]

There is a clear UV adhesive that stays liquid until you expose it to UV light, which cures/hardens it. You can apply it, make sure the pieces to be joined are completely and properly mated, no air bubbles, etc., then expose to UV light. Once cured, it remains clear so it is often used to join glass pieces, but might be an option here.

[Doug Fisher]

>>I can simply place them together, and then sandwich them between the two 1" square hollow galvanised steel section<<

Since you have this option, I would use it and let the pieces "float" as needed. Laminating two different types of plastic that are very likely to have different heat/cooling expansion and contraction characteristics will most likely lead to warping. Add in the fact that you have routed one of them to a very thin thickness in multiple places and I think you could be setting yourself up for some fracturing in the areas that would get stressed by any warping.

[Kev Williams]

Loctite "Go2" adhesive would be good for this, it dries crystal clear, no bubbles and strong enough to glue glass award parts together. Drawbacks are, to cover 10 sq feet would get spendy as it comes in these small plastic squeeze jars (maybe there are larger sizes?) and it takes a day to set up good.
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