Painting Alarm Sensors – Yes Or No?
Painting Alarm Sensors – Painting alarm sensors can be fraught – you’re almost certain to void the warranty but if your customer can’t bear a beige plastic box on the wall or ceiling of the room they’ve paid 10s of thousands to beautify, you could take matters into your own hands.
The key thing is going to be masking or removing the lens – masking has to be done in such a way as to protect the lens from daubs while remaining easy to remove. You could use a range of options, including paper, plastic – anything that allows you to create a protective barrier from brush bristles.
The sorts of plastics that can be painted include things like ABS and polycarbonate – the things sensors are most often made of. You can also paint HIPS and acrylic devices but there are a number of plastic types you shouldn’t even think about painting. These include things like PVC, polypropylene, and polyethylene. The rule of thumb is that any plastic that can be glued using solvent can be painted, while plastics that must be welded at the joins can’t be painted.
The challenge is going to be making sure you don’t get talked into slapping on a coat of whatever water-based paint has gone onto the walls or ceilings by an uninformed homeowner. This may be easy, but it will likely look awful, the finish will be streaky and uneven and there’s a chance it will impact on sensor operation.
Instead, the best paint for plastics is acrylic lacquer, and when it’s being applied to acrylic or polycarbonate a half-strength thinner is generally required. Materials such as ABS and HIPS usually need a special plastic primer to be applied first but these will also need a half strength thinner.
You must clean the surfaces to remove dust and ensure paint has correct adherence. Since most plastics are sensitive to solvents like aromatic hydrocarbons, concentrated alcohol, and ketones, clean with care. Clean surfaces with a 25 per cent solution of denatured alcohol and distilled water.
For stains such as oil or grease, you can use a stronger cleaning agent like a drop of kerosene on a clean, damp cloth. Be sure the plastic surface is dry before painting. If these extremes don’t work, you could think about replacing the sensor and starting out fresh.
Another important thing is to neutralize electric or static charges that accumulate on the surface of plastic when tape is removed after painting or preparing. Since tearing tape off a device will create a static charge, all pieces should be treated. You do this is with an ionizing air gun. These guns safely and effectively neutralize electric charges and they’re commonly used when acrylic sheets are being spray painted.
Painting Alarm Sensors – Yes Or No?
For smaller jobs you can employ techniques like wiping the sheet with a damp, lint-free cloth or cleaning with a diluted alcohol-water solution. You should avoid anti-static cleaners since they may leave a residue and cause paint adhesion problems.
Before painting alarm sensors, practice on a few old test devices to ensure paint viscosity is correct. Too much paint will cause paint sag and/or crazing due to too much solvent. Too little paint will result in a matte surface caused by dusting. This is less important if you’re simply trying to hide a sensor against a dark ceiling in a venue.
If you need to remove paint from the surface of a plastic device, take it off immediately with the paint manufacturer’s recommended cleaner. Apply the remover using a cloth; wipe off paint using a different clean cloth. Because paint removers contain organic solvents, minimize the time the remover is in contact with the plastic to reduce the chance of crazing.
If you’re painting alarm sensor housings, remove the board and any connections (mask what can’t be put to one side), and be sure to remove the lens rather than masking it. More complex sensors have look down lenses you’ll need to be equally careful with. When you’re done and the paint is dry, rebuild the sensor and conduct walk tests just as if you’re recommissioning a new zone.
While it’s possible for a careful tech to paint smokie housings in much the same way, we can’t recommend this practice. Given the fact smoke sensors are designed to protect human life we think it would be a mistake for anyone but manufacturers to fiddle about with their specifications.
You should contact the manufacturer directly to assess your options when beige smoke sensors start clashing with a client’s designer decors. If you can’t avoid issues with colour clash you could think about moving the sensor but only if the coverage and performance of the system is not diminished.
Something else to think about with painting alarm sensors is that some manufacturers will do custom jobs – it may be worth asking what’s possible, especially if you have a very large client.
You can find out more about painting alarm sensors here or read more SEN news here.
“Painting Alarm Sensors – Yes Or No?”
