darbys, feather edges, and bits of wood

[spreadandlay]

hi there ol wise ones,

When i was taught plastering, i only even needed a 6 ft or 4ft featheredge for screeding off, where do darbys come into it? i dont often see them being used, thanks for clearing this up for me.

 

[maaaaaaaaat]

ive never used one either,but then ive only been at it 25 years.

 

[trowelmonkey1]

me neither, never heard much good about them to be honest but sure they have there place, would like to know myself....anyone heard or used a trowhawk either?

 

[Micilin]

A Derby is usually used for heavy walls, ie thick coats, to get flatter before the next coat.

Some spreads use them to do the initial ruling off and filling out before final ruling off with straight edge.
They are also used instead of a spatula to flatten krend/monocouche

 

[external]

darbys for render,for the simple reason its heavy,and the fact you can put on what you rule off with like a big trowel (thats if your good enough that is !)biggest ive seen was a ten footer four handles and two man job,i use one for plaster two ,mainly cause i work one all week but you will allways need a good straight edge by you to check.

 

[wozza56]

I always use one in the way Micilin says to rule off and fill in etc before using a straight edge to finally get it all squared up .I also use it when doing large areas of sand and cement float finish and if i have already used the straight edge and just need to fill a small patch i get the derby out .I just think of it as a shorter lighter straight edge .
I never use a piece of wood !!

 

[joe-90]

I often use a darby when I want perfectly flat walls. Your trowel follows the humps and hollows but a darby won't. It makes the final skim a doddle.

 

[spreadandlay]

thanks so far, any more ? oh one more question, who uses an external corner trowel? and when / why?
thanks

 

[Micilin]

thanks so far, any more ? oh one more question, who uses an external corner trowel? and when / why?
thanks

Used where you don't have a bead.

They are not so common now, but years ago when beads were not used (or too dear!), they were used on external angles.

Walls were floated to timber battens, and they were skimmed using the external angle tool.

We used them a lot in recent years in damproofing where the spec did not allow beads

Nowadays they are mostly used for matching old work, or for externals that are not straight.

Some people called the internal the "Guzinta"
and the external the "Guzonta" (Goes on to - geddit)


Anyone else?

 

[external]

still use them daily on textures both acrylic and silicon.

 

[Micilin]

still use them daily on textures both acrylic and silicon.

What make you using ? Hard to get nice ones now

 

[roughcaster]

When we did external angles, onto brick/block,, (bb),, before beading,,, the corner was formed with the float coat, using the batten as Micilin said, but we never left the corner sharp. The following day, while the coat was still "green", we rounded it to a bullnose, or even a smaller pencil round, (depending) using a wooden float and a water brush. The bottom 5 or 6 inches of the corner were left at 90%, to allow the skirting to fit close. The wall/s were then set using siraphite, and the finished bullnosed corner, after troweling, was finished with the piece of polythene, dipped into water, and gently run down the corner from top to bottom,, without stopping. A square "sharp" plastered external corner (bb) was easily damaged, especially in houses/busy areas, and could also be dangerous. We used Keenes Cement (remember that) on external corners in the corridors of Haslar Hospital, Gosport when i worked there in the 60's, because of the extra strength needed, (trollies being pushed around etc). In the houses, we did window reveals and soffits with the external angle tool because they were less easily damaged, but put a round on door reveals, again to prevent damage to the corner. Forming a wet corner without a bead,, just using a batten,, and not even fixing the batten to the wall, just using the suction of the float coat to hold it, and then carefully slide it up and away to use it on the opposite side of the corner is a work of art. One wrong move and you pull off, what you've spent hours to put on. No big deal with quick setting gypsum plasters of today, but if you got it wrong with a cement render/float coat, late in the day, it was a set back.

 

[Micilin]

Yes RC, we did the same as well, more or less - and this bit

"rounded it to a bullnose, or even a pencil round, using a wooden float and a water brush. The bottom 5 or 6 inches of the corner were left at 90%, to allow the skirting to fit close" we called a 'bird's beak' or 'bird's mouth', same at the top of the wall if it was to be coved. Anyone else?

A lot of the hospital/school work we napped the bottom half of the wall in sand and cement , ran a dado along dado rail height with a little tool and skimmed the half of the wall above the dado. I don't think there was any name for the tool only " the dado" but I haven't seen one for years.

 

[roughcaster]

There was another topic on here yesterday about rendering a vaulted ceiling. We did some work on some maisonettes over Portsmouth,, (again years ago ). The undersides of the balconies were all scratch coated and rendered,,, (this is to do with un- necessary fiddling). At the end of this particular day, not far from knock off time, the render would have had it's final rub of the sponge, and then i remember seeing a tiny blister in the render. So i got a trowel and decided to gently poke the corner of the trowel into the blister, to let out any trapped air, and flatten the blister/bubble.
Disaster!!! before i knew it, that little blister in the render that i'd poked with the trowel corner, had caused a 3 or 4 inch circular area of render to fall away, leaving the scratch coat showing. I then had a mad panic trying to get a small amount of render to "carefully" patch back in the render that had fallen off,, (impossible,,, too late),,, and i swore that i would never fiddle with it again once i was happy with it,,, ever. There's a moral here,, once you finished rendering/plastering, don't fiddle, just leave it, it's not worth the hassle, and you'll probably make it worse anyway,,, i did, and learnt from it.

 

[roughcaster]

Yes RC, we did the same as well, more or less - and this bit

"rounded it to a bullnose, or even a pencil round, using a wooden float and a water brush. The bottom 5 or 6 inches of the corner were left at 90%, to allow the skirting to fit close" we called a 'bird's beak' or 'bird's mouth', same at the top of the wall if it was to be coved. Anyone else?

A lot of the hospital/school work we napped the bottom half of the wall in sand and cement , ran a dado along dado rail height with a little tool and skimmed the half of the wall above the dado. I don't think there was any name for the tool only " the dado" but I haven't seen one for years.

I know what you mean Micilin,,, you would have run the dado tool into the plaster float coat, using the hard top edge of the lower render as your guide. Improvisation would have been the name of that tool.