[Boatanchors] Fixing cracks in clear plastic?

[J. Forster]

Philip Atchley wrote:

> Hi,
>
> [snip]  The entire front panel is
> what appears to be molded of a single piece of clear plastic, over which
> the factory painted the Escutcheon, Logo, control labels, slide rule
> dial etc (dial and control labels appear to be engraved on the backside
> and "filled" with white paint).
>
> The problem is this.  The bottom section of the plastic (clear part) has
> a number of cracks radiating from the two mounting screws that reside
> behind the tuning knobs, as well as from the headphone jack. NO pieces
> are missing, or broken out.  I suspect these cracks are due to somebody
> tightening the screws/nut down too tightly. Behind  this clear section
> the sub-panel is painted black.

> The Question:  Is there a way to fill these cracks in and then "polish
> them out" so that at least they aren't so noticeable?  I've repaired
> cracks in plastic with Superglue before, but if it gets on other parts
> of the plastic I'm afraid it may turn it milky.

[snip]

It depends on what the plastic is. Likely it's Plexiglas or Lexan. They often
get stress cracks. There are clear glues for each, which are little more than
bits of the plastic dissolved in the appropriate solvent. If the correct glue is
applied to the surface of the crack (perhaps thinned a bit first) it may 'wick'
into the crack and seal it by solvent welding it. You need to apply a very small
amount, because the solvent will also dissolve the plastic. You might also try
applying the glue from the center of the hole outwards.  I would NOT try super
glue.

If it were my set, and I didn't want to risk loosing it, I'd take it to a good
local plastic fabricator or airplane repair depot and ask for their advice.

FWIW,
-John