UV Wavelength & Substrate Selector
The most common reason a UV adhesive “won’t cure” is a wavelength that doesn’t match the adhesive, or one the substrate blocks. Answer two questions and this selector points you to the right wavelength band and system.
Questions
What UV wavelength do I need to cure through glass or polycarbonate?
A longer band. Glass and polycarbonate transmit longer UVA (395–405 nm) and visible while blocking shorter UV, so use a 395–405 nm source with an adhesive formulated for that band, or the longer end of a broad-spectrum arc. A 365 nm-only adhesive behind those materials will not cure.
Which UV system should I use if I do not know the adhesive wavelength?
A broad-spectrum arc like the SunSpot 2, it emits 275–650 nm, so whatever band the initiator needs is present and you are never blocked by a wavelength mismatch. Switch to a matched-wavelength SkyBeam once the chemistry is settled and you want LED efficiency.
How do I match UV wavelength to my adhesive?
Read the adhesive datasheet for its cure wavelength or initiator absorption, then pick a source that emits that band. Shorter (365 nm) suits surface cure and the widest initiator range; longer (395–405 nm) penetrates deeper and passes through more substrates.
