Method for preserving Allison plastic grilles

soundweasel

Super Member
As anyone who owns a pair of Allison Acoustics speakers knows, because of their age and design, the round and oval plastic grilles are extremely fragile and subject to breakage by even the most careful handling.

While gluing cracks in the grille can be done, even the most careful application of glue on the inside of the grille looks as though it has been repaired. :sigh:

After weighing a number of options, including attaching grille cloth to the grilles, I've come up with something that seems to be working very well -- Krylon Fusion spray paint for plastic.

A week ago I took a pair of damaged oval grilles (cracks, no missing pieces) that I'd glued, and removed all the glue from the repaired area using my thumbnail as a scraper (don't use metal tools). I then fitted/aligned the cracked areas and applied a total of three coats of Fusion paint to both sides of the grille over a two-day period. The paint dries to touch in 15 minutes and for handing in one hour. Instructions on the can say to apply additional coats before 24 hours, or after seven days.

After seven days the paint forms a "fully chip-resistant" coating. Because the paint seeped into the cracked section it appears gluing is no longer necessary.

Photos attached. Photo on left is untreated black grille. Photo on right is brown grille painted black.

I just applied two coats of Fusion to a pair of undamaged -- but very fragile -- round grilles with the idea that this will preserve them by forming a hardened, chip-resistant coating on them. I will report back in seven days to share the results, and will post some pictures. Note: I just applied a third coat and it is worth noting that this paint adds some weight to the item you're painting.

The paint is available in gloss, satin and flat finishes. Gloss would be too shiny, and flat would reveal the damaged areas, so I used satin as a compromise. Satin has just enough shine when it dries to conceal the damaged areas better. I used black because the brown shades didn't look like a good match for the plastics used by Allison, and Allison used both black and brown grilles on with all their cabinet finishes.

Here's the link to the Krylon Web site: http://www.krylon.com/products/fusion_for_plastic

Stay tuned. :yes:
 

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How did you hold everything in place to apply the paint and while it set up?

The sides of the cracks in the grilles snapped into place and were held into place by the tension between the two sides. I set the grilles on a rigid surface for spraying so I didn't need to touch them. After the first coat they stayed in place.

With a crack starting on an edge I tied the open end with some black thread, sprayed it, let it dry and then removed the thread for subsequent coats.

Spray both sides of the grille so it is "wrapped" in a chip-resistant coating.
 
The thread thing is clever (hey, I'm trying to be affirming, here!).
Wonder if this approach might work for my mongo Allison One grilles (which are about as fragile as Old Kingdom mummies at this point).
 
The thread thing is clever (hey, I'm trying to be affirming, here!).
Wonder if this approach might work for my mongo Allison One grilles (which are about as fragile as Old Kingdom mummies at this point).

Depending on how long/large the cracks are, you might want to use a binding stitch the length of the crack, spray them, and leave the thread in place. The paint will be thick enough to hide it.
 
My Allison One grills were in great shape when I got them and I was reading some info here in the speaker forum to keep them that way. To reinforce them, someone suggested using a clear wood finish lacquer on the inside of the grills. Well thats what I did and they've been holding up great.



Retro
 
mine are brittle as the bejabbers (but the price was right).

For $5 a can the paint has proven to be a worthwhile investment. If I weren't confident in what it could do I wouldn't have risked spraying it on undamaged but fragile grilles.

How damaged are yours? What's the largest/longest crack in them? Smallest?

Can they be transported? If you're not willing to do this, I might be. :scratch2:
 
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