I've got the red dewalt dw088 - great, but not visible outside if it's sunny. Detectors still work. No idea if the green one is better in that regard but the internet says it is.
AFAIK there are no construction lasers which work outdoors in full rotary line mode on a bright, sunny day, not even the megabucks models such as the Leica Rugby or the big Topcon models - for outdoor work you generally need a detector, although the ability of top end rotary models to be stopped and show a visible dot or do a narrow segment of an arc oscillation is great, it comes with a price bracket well above the £200 max mark mentioned earlier
Green is more visible than red (it's to do with the greater sensitivity of the human eye to green) meaning that a green laser will be easier to see indoors in semi-bright conditions.
If you want a cross on the ceiling for example you just turn cross on and tip it over
I'm sorry, but I can't see that achieving much of practical value. Normally if you are projecting a line at a ceiling it is to do something like mark out centres for lighting cut outs which need to be plumb and in line with something on the floor, or you might be drilling holes for something like a soil stack, dentist 's chair, etc which need to be in line. Sticking a laser on its' back doesn't do this
I acknowledge their usefulness on site, but how did people manage all those millennia with a plumb bob and water level and string line?
The answer is... Slowly! Take a look at the tools the Egyptuans created for surveying - it will be an eye opener
...the line is maybe a millimetre thick close to the level but spreads out fatter as you get further away; I tend to work to eg the top of it if it's got too fat.
Then you are guilty of a "schoolboy error". You always mark the
middle of the line (the answer is in the optics part of school science)
One of the guys that came on site to do some concreting revealed the trick - two glass tubes connected with a flexible rubber hose and filled with water creates something like a massive spirit level where the water finds the same level at each end - a technique I've used since just with a bit of clear hosepipe..
Yes - it's called a water level, and
@blup mentioned it earlier. Still useful for measuring round corners (i.e out of line of sight) and for doing things like sorting out levels on wall plates/ring beams of big buildings where the roof is being redone piecemeal, but in general a lot slower and less convenient than a laser. At one time site carpenters used to haveca pair of "Nivochoc" ends for a water line (Stanley made them until the 1990s or so - Stabila still offer them). BTW, there is evidence to suggest that a form of water level was used to build the pyramids, but then the Egyptians weren't bad at surveying
