Coping on top of a garden wall

I want to place some coping on top of a garden wall. I've never done this before. A couple of simple questions. Also note that this coping needs to accommodate some iron railings.

1: What type of cement/bound do I need to use?
2: How to I make sure that they're level and square?

Thanks for any help.

Bricklaying mortar, if you aren't sure you can buy it premixed in bags. You can also glue them on and point them up later, you'll need a decent exterior adhesive like Ceresit PL.

If the top of the wall isn't level, then the coping won't be, otherwise you'll have to adjust mortar bed to suit.

The iron railings will need piers to sit between, just expecting them to fix into the top of the walls and stay there is a recipe for "no railings on top of the wall"

At the very least they will be easy to nick.

use a line and pins to keep 'em straight, (bed one slab on each end first and measure how long in between to see if theres a cut)
line back and front if necessary.
normal 5-1 soft sand and cement
build piers up at the ends first to fix railings to if there are not any already.
If you're not too handy with the old bubble, you can nail a length of 4x2 or 2x2 to the existing end of the wall, on the exact front corner and check it for plumb and mark the gauge up it, (75mm per course)
and lay to that. - - - - - - - - - - - - - - - -

What copings are these, as this will depend on how you lay them, and whether you line them on the top arris, along the front or line the bottom?

The mix should be a 3:1 or a 4:1 minimum as the top gets all the weathering and freezing

You can't run a line on both sides at the same time as the copings will invariably be slightly different widths and will be laid differently too.

You lay the copings to a line strung between each end of the wall, and if the copings are flat, then you would level every second or third in a direction perpendicular to the line.

Make sure the joints are full, and firmly ironed smooth to give them a weathering face

Hi, Woody,
The strength of the mix should theoretically match the mix used in the slabs, in order that the 'wall' sets as a single honogenous whole.
so 5-1 I think. perhaps 6-1.
I suggested lining both sides as nowadays these mass produced copings are very similar in size, and although I agree that it is not generally 'done' to line both sides of a wall, in this case, the lad isn't a bricky, and if he tries to tap the back straight he will bounce the front up and down, which will defeat the object of having a line on in the first place.
and loosen the copings.
Anyway he can slip a fold of card under the back line so that it runs a trowel width away from the wall if he wants.
regarding lining the bottom arriss, there are two reasons why I didn't suggest this,
(1) the bottom arriss is often spiky and uneven as these copings are cast upsidedown and the depth can vary and the edge can be uneven also.
(2) If there are going to be railings on top I deduced that the copings would be below eye line and the line on the bottom thing is only used if the coping is going to be above 6ft or so.

All valid points

But I wont agree with such a weak mix for copings. These get a tremendous amount of exposure and weather, and anything less than 4:1 just wont last

theroretically, a stronger mix would make the joints weaker.
however I secretly agree with you.
but stick to wood butchery in future mate