Plastering 120 degree angles

[recognise]

ok, im very confident in plastering...... although I do have a question as to how to plaster 120 degree angles....... or at least what looks like a 120 degree angle, give or take a few.
which is if you picture it...... a normal 90 degree angle plus a bit more,........ like sloping walls in loft convertions?

the goal of this is to achieve as straight a line as possible along the ceiling line and the sloping angled wall running down from it,

in the past i have spent a long time doing it successfully by eye and hand, brushing it in etc, this time im thinking of running a skim stop bead along the ceiling line and plastering off the bead and achieving the straight line.

you do get trowels that shape but ive not seen one in any merchants or even online, but my journeyman had one ages ago, never used it tho but im sure its a 120 angle

even without wet corners it it difficult to get the straight line, anyone who has tried this will know,
i can do it, it just takes a lot of time and im just sure there is another technique to this, i recon the stop bead will do the trick although there must be some other way?

thanks for any input

 

[roughcaster]

Most of what your after will depend on how straight your boarded walls are to start with. It is very difficult as you said, but I don't know whether the stop bead would do the trick. If you put the stop bead on, perfectly straight and level, along a sloping wall/ceiling angle that might be "off" and bent/twisted, that could be some job trying to sort out. Quite often, judging it by eye is the best way. With a thin skim coat of plaster on plasterboard,you don't have much chance of straightening out, apart from small dips here and there. I always think in this type of job, if it looks good to the eye, then i'm happy.

Roughcaster.

 

[recognise]

yeah, your right, as with most things in plastering its got to look good to the eye,
although, in the past the time i have spent getting these lines right isnt available to me on this job due to the size therefore i feel a 'true' surface is required to work off in order to get this line along the ceiling.

personally i can visualise this method failing, but beads havent been around forever and there must be another method of obtaining a perfectly straight line along the join of ceiling and wall

thanks for the reply

 

[Richard C]

I recently finished plastering a stud built en-suite & matching, built-in cupboards on the opposing wall, both had around 130 degree vertical joints back onto the main block walls. I used stop beads fixed to the stud walls & butted against the block walls, the join being pre-tapped; these walls just needed re-skimming. It worked very well, giving a nice level edge to trowel up to each side; result was a nice straight vertical joint which would have been difficult & time consuming to achieve in the normal way. As Rough says, it’s important that the surface you fix the stop bead to is nice & flat (why I fixed to the stud wall) or you will end up with a curved joint line; if you find the mating wall is out, fill out first before doing the final skim.

 

[roy c]

I also use stop beads to get straight lines.but I set them up to a string line and eye it thru so it looks ok, staple your stop bead on along the line.to make sure it is straight. Also just skimmed to the string line with good results.....

 

[recognise]

thanks for the good advice guys, i will go with the stop bead then, and i will give the string line a go as well when lining up the beads.

its onto plasterboard so it will be flat, the guy made a point of saying he wants these lines perfect so i thought i would get a more reliable method than doing it by eye and hand,

cheers