My wife is wanting me to attach a solar light to the brick wall of the
house. Because of a concrete "shelf" above the front door, which would
shield the charging cells from seeing any sunlight, the light would need to
be on an aluminium pole (supplied with the light in case it is needed) to
extend it forwards of that shelf. But I am worried about the turning force
of a weight of about 300 grammes on the end of a 40 cm pole that is screwed
into a flat plate which it turn is screwed to the wall.

I always have problems with rawlplugs not really biting into the masonry
that that are put into. I drill a hole of the correct diameter for the
rawlplug - I've even tried using a slightly small drill to allow for the
drill bit wandering a bit and leaving a hole that is larger than the drill
bit.

Even if the rawlplug is a tight fit (maybe requiring a bit of gentle tapping
to get it to go in) when I screw into it I often find with rawplugs that
they turn as the screw is tightened or else they pull out. Getting a really
solid fixing is a problem. Maybe our house just has soft crumbly bricks :-)

For this light, there's a large tuning moment (300 g on the end of a pole 40
cm long, fastened to a plate that is about 5x2 cm which has two screw holes
about 4 cm apart in a horizontal line) and I'm worried that the light will
just pull out, especially if there are gusts of wind or if starlings etc
decide to land on it.

The alternative is to mount the light directly on the wall by means of two
screws in the wall with their heads standing proud to lock into slots on the
rear edge of the light - much less turning moment but the problem then is
that the light sensor that turns it on at night has an incredible angle of
view and could be triggered by climbing plants on the wall just below where
the light is mounted.

My feeling is that it's a pretty crap design to have the charging cells on
the upper surface so you can't mount the light under a "shelf" that is
designed to shelter the front door and which has a movement sensor that can
see such a wide angle of view.

I'm very tempted to overrule SWMBO and go for a three-part light where the
sensor, charging cells and light are separate units that can be mounted in
the best place for each - I have a couple of these which I know are great
(we use them in other places) and they have configurable sensitivity and
"on" time after triggering, whereas this unit is fixed sensitivity and fixed
time (10 seconds).

On 25/10/2016 12:20, NY wrote:

I always have problems with rawlplugs not really biting into the masonry
that that are put into. I drill a hole of the correct diameter for the
rawlplug - I've even tried using a slightly small drill to allow for the
drill bit wandering a bit and leaving a hole that is larger than the
drill bit.

You are using the wrong plugs for your drill.
You should need to tap them in with a hammer.
The bracket will break before the plug comes out if you do it properly.

Fischer make nice plugs if you need to buy some.

I always use those bolts that have an expanding threaded socket, ie rawl
bolts or their variations. Plugs on outside walls tend to flex otherwise and
come out. One of course assumes the wall is of good quality in the first
place. I have also seen people use three guy pieces to help this problem on
very windy, ie sea front places used.
Brian

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This newsgroup posting comes to you directly from...
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Blind user, so no pictures please!
"NY" wrote in message
o.uk...
My wife is wanting me to attach a solar light to the brick wall of the
house. Because of a concrete "shelf" above the front door, which would
shield the charging cells from seeing any sunlight, the light would need
to be on an aluminium pole (supplied with the light in case it is needed)
to extend it forwards of that shelf. But I am worried about the turning
force of a weight of about 300 grammes on the end of a 40 cm pole that is
screwed into a flat plate which it turn is screwed to the wall.

I always have problems with rawlplugs not really biting into the masonry
that that are put into. I drill a hole of the correct diameter for the
rawlplug - I've even tried using a slightly small drill to allow for the
drill bit wandering a bit and leaving a hole that is larger than the drill
bit.

Even if the rawlplug is a tight fit (maybe requiring a bit of gentle
tapping to get it to go in) when I screw into it I often find with
rawplugs that they turn as the screw is tightened or else they pull out.
Getting a really solid fixing is a problem. Maybe our house just has soft
crumbly bricks :-)

For this light, there's a large tuning moment (300 g on the end of a pole
40 cm long, fastened to a plate that is about 5x2 cm which has two screw
holes about 4 cm apart in a horizontal line) and I'm worried that the
light will just pull out, especially if there are gusts of wind or if
starlings etc decide to land on it.

The alternative is to mount the light directly on the wall by means of two
screws in the wall with their heads standing proud to lock into slots on
the rear edge of the light - much less turning moment but the problem then
is that the light sensor that turns it on at night has an incredible angle
of view and could be triggered by climbing plants on the wall just below
where the light is mounted.

My feeling is that it's a pretty crap design to have the charging cells on
the upper surface so you can't mount the light under a "shelf" that is
designed to shelter the front door and which has a movement sensor that
can see such a wide angle of view.

I'm very tempted to overrule SWMBO and go for a three-part light where the
sensor, charging cells and light are separate units that can be mounted in
the best place for each - I have a couple of these which I know are great
(we use them in other places) and they have configurable sensitivity and
"on" time after triggering, whereas this unit is fixed sensitivity and
fixed time (10 seconds).

On 25/10/2016 12:20, NY wrote:

I always have problems with rawlplugs not really biting into the masonry
that that are put into. I drill a hole of the correct diameter for the
rawlplug - I've even tried using a slightly small drill to allow for the
drill bit wandering a bit and leaving a hole that is larger than the
drill bit.

Even if the rawlplug is a tight fit (maybe requiring a bit of gentle
tapping to get it to go in) when I screw into it I often find with
rawplugs that they turn as the screw is tightened or else they pull out.

Decent plugs don't turn. Buy better ones.

Screws need to be big enough to expand the plug. Buy decent screws.

*Always throw away the screws and plugs that come with the item.*

You should normally need to tap the plug in. If it's a loose fit, it
won't work. Having tapped the plug in, I insert the screw by hand, then
give that a good tap, too. No harm in driving the plug in below the
surface before tightening the screw.

"GB" wrote in message
...
On 25/10/2016 12:20, NY wrote:

*Always throw away the screws and plugs that come with the item.*

How very true: they usually supply plugs and screws that are too small in
diameter and length to get a good purchase on the masonry.

You should normally need to tap the plug in. If it's a loose fit, it won't
work. Having tapped the plug in, I insert the screw by hand, then give
that a good tap, too. No harm in driving the plug in below the surface
before tightening the screw.

Yes I've done that before now: use the screw as a means of driving the lip
of the rawlplug slightly below the surface of the brickwork.


Another lesson I learned: make sure the screws are made of a nice hard
metal. I bought some crosshead screws and corresponding plugs, and they
seemed to be a fairly reputable make. But as I was screwing them in, the
screws started to bind in the plugs, even though I'd squirted some WD40 into
the plug first. Not a problem: push hard on the screwdriver and turn it
little by little till the screw was firmly in. But before I'd managed to do
that, the head of the screw started to disintegrate until I was left with a
rounded-off cross that the screwdriver could no longer get any purchase on
(*). I eventually had to drill out the head so I could get the aluminium
shelf rack off the wall again and then grab the remaining shank with mole
grips to be able to unscrew it. Next time I used proper steel screws with
flat rather than crosshead top.


(*) Goodness knows what metal the screws were made of. But it certainly
wasn't up to the job of withstanding the forces of screwing them in. As I
was unscrewing one of the screws, the head sheared off the shank, even
though the crosshead remained intact. The were probably aluminium or brass,
plated to look like steel. :-)

On Tuesday, 25 October 2016 15:16:15 UTC+1, dennis@home wrote:
On 25/10/2016 12:20, NY wrote:

I always have problems with rawlplugs not really biting into the masonry
that that are put into. I drill a hole of the correct diameter for the
rawlplug - I've even tried using a slightly small drill to allow for the
drill bit wandering a bit and leaving a hole that is larger than the
drill bit.

You are using the wrong plugs for your drill.
You should need to tap them in with a hammer.
The bracket will break before the plug comes out if you do it properly.

Fischer make nice plugs if you need to buy some.

Then use screws fat enough that they go in firm not loose. If necessary take the screw out, whack matchsticks in and reinsert screw.

If the problem is masonry disintegrating making wonky holes,
a) put PVA in, fill, redrill 2 days later.
b) use resin instead.


NT

On 25/10/2016 16:57, NY wrote:

Another lesson I learned: make sure the screws are made of a nice hard
metal. I bought some crosshead screws and corresponding plugs, and they
seemed to be a fairly reputable make. But as I was screwing them in, the
screws started to bind in the plugs, even though I'd squirted some WD40
into the plug first. Not a problem: push hard on the screwdriver and
turn it little by little till the screw was firmly in. But before I'd
managed to do that, the head of the screw started to disintegrate until
I was left with a rounded-off cross that the screwdriver could no longer
get any purchase on (*). I eventually had to drill out the head so I
could get the aluminium shelf rack off the wall again and then grab the
remaining shank with mole grips to be able to unscrew it. Next time I
used proper steel screws with flat rather than crosshead top.


I've never squirted wd40 on a plug! You're not doing it right.


You need screws that are decent enough for the job. They need to be
threaded along the whole length. Posizdriv is vastly superior to
straight slot.
http://www.screwfix.com/p/turbogold-...1000-pcs/20938

These plugs will do.
http://www.screwfix.com/p/plasplugs-...m-52-pcs/8120k


Plus a pack of screwdriver bits.
http://www.screwfix.com/p/dewalt-poz...mm-15pcs/33178


Plus a drill driver to put them in.

On 25/10/2016 16:57, NY wrote:

Another lesson I learned: make sure the screws are made of a nice hard
metal. I bought some crosshead screws and corresponding plugs, and they
seemed to be a fairly reputable make.

What make? Name and shame...

Next time I
used proper steel screws with flat rather than crosshead top.

Pozi are _way_ better than flat. Flats are now only really used where
the looks matter.

Sure, you bought some duff ones - but decent ones are the best choice,
and can be obtained in big boxes for relatively small prices in many
places. Treat yourself, buy them by the box :-) (100 or 200 or similar,
bigger screws may be fewer)

On 10/25/2016 12:20 PM, NY wrote:
My wife is wanting me to attach a solar light to the brick wall of the
house. Because of a concrete "shelf" above the front door, which would
shield the charging cells from seeing any sunlight, the light would need
to be on an aluminium pole (supplied with the light in case it is
needed) to extend it forwards of that shelf. But I am worried about the
turning force of a weight of about 300 grammes on the end of a 40 cm
pole that is screwed into a flat plate which it turn is screwed to the
wall.

I always have problems with rawlplugs not really biting into the masonry
that that are put into. I drill a hole of the correct diameter for the
rawlplug - I've even tried using a slightly small drill to allow for the
drill bit wandering a bit and leaving a hole that is larger than the
drill bit.

Even if the rawlplug is a tight fit (maybe requiring a bit of gentle
tapping to get it to go in) when I screw into it I often find with
rawplugs that they turn as the screw is tightened or else they pull out.
Getting a really solid fixing is a problem. Maybe our house just has
soft crumbly bricks :-)

For this light, there's a large tuning moment (300 g on the end of a
pole 40 cm long, fastened to a plate that is about 5x2 cm which has two
screw holes about 4 cm apart in a horizontal line) and I'm worried that
the light will just pull out, especially if there are gusts of wind or
if starlings etc decide to land on it.

The alternative is to mount the light directly on the wall by means of
two screws in the wall with their heads standing proud to lock into
slots on the rear edge of the light - much less turning moment but the
problem then is that the light sensor that turns it on at night has an
incredible angle of view and could be triggered by climbing plants on
the wall just below where the light is mounted.

My feeling is that it's a pretty crap design to have the charging cells
on the upper surface so you can't mount the light under a "shelf" that
is designed to shelter the front door and which has a movement sensor
that can see such a wide angle of view.

I'm very tempted to overrule SWMBO and go for a three-part light where
the sensor, charging cells and light are separate units that can be
mounted in the best place for each - I have a couple of these which I
know are great (we use them in other places) and they have configurable
sensitivity and "on" time after triggering, whereas this unit is fixed
sensitivity and fixed time (10 seconds).


I agree with what other posters say about correct selection and fitting
of plugs and screws, but your *real* problem here is the two screws 4 cm
apart. You correctly identify that having a weight on a pole applies a
moment to the bracket. What you may not have explicitly recognised is
that this moment has to be counteracted at the bracket, which means that
there is a tension pulling the top screw out of the wall which from your
figures is of the order of 3 kg. Now, you can certainly get screws and
rawlplugs to provide this, although they almost certainly need to be
more beefy than those supplied with the unit. Exactly what you need
depends on the wall materials. But, as you note, you will also have to
consider wind gusts and this may tend to loosen your fitting over time.

The *smart* thing to do is to arrange for the fixing screws to be much
further apart, in the vertical plane, than 4 cm because this will reduce
the pull-out force proportionately. Also, I never like to rely on just
two screws (one of them will almost always be a bit loose in masonry),
you are far safer with four.

So one option is to screw a vertical wooden batten (or perhaps a piece
of plywood) on to the wall, and screw the bracket to that, preferably at
the bottom. Another might be to extend, modify, or replace the bracket
to achieve the same effect. Could you perhaps canibalise a traditional
metal shelf bracket?

Another might be to put something like a screw eye into the wall some
distance above the unit, with a piece of suitable wire on the diagonal
from there to the light. There is still some force pulling the eye out
of the wall, but the "weight" is also helping to lock it in place,
especially if it goes deep (like a vine eye, for example).

But to be honest, I think you have already identified a better option,
namely to go for separate units, especially since you have experience of
them. Point out to the wife that the complication of doing it "my way"
will take time, and lead to a less elegant fitting than she thinks she
might be getting.

On 25/10/2016 18:05, GB wrote:

You need screws that are decent enough for the job. They need to be
threaded along the whole length. Posizdriv is vastly superior to
straight slot.
http://www.screwfix.com/p/turbogold-...1000-pcs/20938

You don't want those!
They are designed to cut into the material and will not grip as well as
a normal screw that doesn't cut away half the plug as you screw it in.

Maybe you meant

http://www.screwfix.com/p/quicksilve...2800-pcs/84042

In article ,
"NY" writes:

I always have problems with rawlplugs not really biting into the masonry
that that are put into. I drill a hole of the correct diameter for the
rawlplug - I've even tried using a slightly small drill to allow for the
drill bit wandering a bit and leaving a hole that is larger than the drill
bit.

Some tips for drilling into masonary.

Hammer action leaves the remaining hole walls shattered and significantly
weaker than the solid masonary. This means the material may give after
you expand the rawlbolt (or rawlplug), and allow it to be pulled out more
easily than it should.

There are a few things to do to mitigate this...

Always try to drill without hammer action first. It's not always needed.
If you use hammer action when it's not needed, that can do serious damage
to strength of the remaining masonary. However, dont't try too hard if
it obviously isn't going in easily, as you will overheat and blunt the
masonary bit.

Don't try and drill a wide hole in one go. Start with smaller bits which
will drill in more easily, thus without damaging the remaining brickwork
so far out from the hole. As with the above point, try each larger bit
without hammer action first, and in particular, the last (largest) bit
to do the final widening should be done without hammer action if at all
possible. This will give a clean strong-sided parallel hole in which
the bolt can exert high pressure over a large area without exceeding
the breaking force of the masonary. Rough holes, besides having weaker
walls in the first place, result in excessive pressure on just the
high spots which then fail, leaving the bolt loose. (This is slightly
counter-intuitive, as you might imagine a rough hole will grip the
plug better, but it doesn't.)

For lightweight concrete (thermal) blocks, never use a masonary bit
or hammer action. Use a metal bit such as HSS. It will knacker the tip
quite quickly, but for these blocks it's really important to have a
smooth parallel hole with no damage in the hole wall, as the breaking
force is not high to start with, and any excess force on high spots
will very easily crush them and lose grip.

In all cases, blow the dust out of the hole before inserting the
rawlbolt/plug, as it can act as a lubricant and allow the plug to
slide afterwards. Avoid blowing it into you mouth, eyes, lungs, etc.

For plastic plugs, I will often use a tiny dab of grease on the
screw tip, so it can rotate more easily in the plug, without
transferring the rotation force to the plug-wall, which helps get
it started without the plug spinning in the wall. Don't use too
much, or it might end up seeping out and damaging decorations.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On 25/10/2016 21:10, dennis@home wrote:
On 25/10/2016 18:05, GB wrote:

You need screws that are decent enough for the job. They need to be
threaded along the whole length. Posizdriv is vastly superior to
straight slot.
http://www.screwfix.com/p/turbogold-...1000-pcs/20938


You don't want those!
They are designed to cut into the material and will not grip as well as
a normal screw that doesn't cut away half the plug as you screw it in.

Maybe you meant

Well, I meant the ones I linked to. I have used them for pretty much
everything for the last 20 years. You may be right, of course, so I'll
try the ones you suggested. Having two different sets of screws is a
nuisance, though.


http://www.screwfix.com/p/quicksilve...2800-pcs/84042

On 25/10/2016 12:20, NY wrote:
My wife is wanting me to attach a solar light to the brick wall of the
house. Because of a concrete "shelf" above the front door, which would
shield the charging cells from seeing any sunlight, the light would need
to be on an aluminium pole (supplied with the light in case it is
needed) to extend it forwards of that shelf. But I am worried about the
turning force of a weight of about 300 grammes on the end of a 40 cm
pole that is screwed into a flat plate which it turn is screwed to the
wall.


Perhaps you have chosen the wrong light. The one I have over the door of
our holiday let has a remote solar cell on the end of a 2m lead.

Mike

Muddymike wrote:
On 25/10/2016 12:20, NY wrote:
My wife is wanting me to attach a solar light to the brick wall of the
house. Because of a concrete "shelf" above the front door, which would
shield the charging cells from seeing any sunlight, the light would need
to be on an aluminium pole (supplied with the light in case it is
needed) to extend it forwards of that shelf. But I am worried about the
turning force of a weight of about 300 grammes on the end of a 40 cm
pole that is screwed into a flat plate which it turn is screwed to the
wall.


Perhaps you have chosen the wrong light. The one I have over the door of
our holiday let has a remote solar cell on the end of a 2m lead.

Mike



+1

I have one bought from Laldi with a 5 metre long lead for remote placement
of the charging panel.

Tim

--
Please don't feed the trolls