salmonetin
Well-Known Member
But also silicone conformal coatings ,due to their thickness are more prone
to delaminate from thermal cycling .
( “ Think I saw an Irish youtube spiderfarmer SF1000 review where the coating was peeling back and appeared floppy. I made the assumption that it was silicone-based off that. “)
(...)
First, determine the expected operational temperature range for the circuit board – the highs and the lows. Should this be greater than 150-160°C, for example, it is almost certainly an application for a silicone, rather than an acrylic or polyurethane conformal coating. Also, consider the temperature excursions; if thermal shock or thermal cycling is not taken into consideration, it could lead to cracking, severely compromising a coating’s protective capabilities.
Second, what degree of chemical resistance is required? Acrylic materials, while easily removable when reworking, are generally highly susceptible to attack by solvents. Polyurethane materials, on the other hand, provide more chemical resistance but are generally not amenable to rework. Assess whether immersion or splash resistance is required and whether the coating may be exposed to heated solutions of potential contaminants, which will increase their ability to act as a solvent.
Third, consider what level of corrosion protection is required. Humidity generally only becomes problematic when condensation occurs, which would require close attention to the thickness and coverage of the coating. But do remember, while a thicker coating might provide superior protection in condensing environments or where salt-spray or corrosive gases are present, anything more than the 50 micron target thickness may be prone to cracking under conditions of thermal shock or thermal cycling.(...)
Why you should select the conformal coating for PCBs with care
The components used in printed circuit boards (PCBs) are sensitive to a host of environmental conditions that can have far-reaching consequenceswww.electronicsb2b.com
EDIT:
I’ve not yet come across a specialised
LED silicone based CC in spray can
form ...
Any link(s) ?
I can relate with the “water proofing “ concept ,as those lights could be used in greenhouses or other facilities where water sprinklers are used for irrigation ,foliar feeding and spraying various phytochemicals.
Still these conditions are far different from the usual conditions inside the average
private grow tent or room .
Thus ,-regarding DIY designs -the sacrifice of total water proofing for gaining in other aspects like thin coating ,reworking and ease of application does not seem that important .
But yes ,
the acrylic CC does not fit
in applications with high temperatures involved.
But then,if such high temperatures are achieved ,that the acrylic CC will deteriorate by them -something is not right already .Efficient cooling of the LEDs will never allow an acrylic CC to deteriorate by high temperatures.
There’s also the Urethan 71 from
Kontakt Chemie .A PU cc without
UV tracer.Still it’ s a bit yellowish in appearance as it is stated at the product’s TDS.
EDIT: For my next DIY LED grow light
project I’ve ordered a PU CC
from Electrolube ( UR 5634 ) .
UR5634 Optically Clear Polyurethane LED Potting Compound - Electrolube
Optically clear polyurethane LED potting compound formulated to protect LEDs from the environment. UV and mould resistant, suitable for indoor or outdoor.electrolube.com
....ya me imaginaba que la cosa iria por estos derroteros....una pena verlo desde mi pov actual ...
...me tomo mi tiempo de infusion... y me voy adaptando a estos nuevos tiempos...
..poco a poco... y a veces mucho a mucho... mi trabajo me cuesta... partiendo de 0...
....me aplico lo del ...dejalo estar...
Saludos
jejeje
