Bricklaying

[Deleted]

Does anyone know the composition of 'practice' mortar as used by apprentice bricklayers?

When wet it behaves like real mortar but dries back to a powder so it can be re-used, along with the bricks.

I've been given permission to build a brazing hearth so long as it resembles / acts as a barbecue when not covered in copper.

The last time I laid one brick on another, petrol cost under a £1 a gallon so I think a bit of a dry run is in order.

Thanks in advance,

Gareth.

[alanstepney]

I dont know, but would assume it to be a very weak lime mortar.

[Deleted]

Thanks Alan, that's a possibility.

When in College a few decades ago I used to watch the student brickies at work and wondered about the mortar but never asked!

[houstonceng]

Dragging the details out of my aging memory banks, 5 parts brickie's sand to 1 or 1.5 parts lime. It makes a weak lime mortar that can be very easily rubbed off the bricks.

When using, you can add water as it dries out on your spot-board to keep it workable.

"Victorian" houses were built using lime mortar and, often, then rendered or tile-hung. You usually find that, when such a house is demolished, the lime mortar can be rubbed off the bricks simply by rubbing one brick against the another.

I've never tried it, but I assume that a very weak (9/10 : 1) sand/portland cement and plasticiser mix would serve and be - relatively - easy to knock off vs a 4, 5 or 6:1 mix.

Just be careful when you build the final version, not to use too strong a mix of sand/cement. Depending on the type of brick, your sand/cement must "match" the strength of the brick. London Stocks like a soft (6/7:1) mix or lime morter. "Reconsituted stone walling" or flettons can stand a strong (4:1) mix.

[Deleted]

Tremendous - Thanks Andy.

I'll be using flettons left over from a conservatory build so 4:1 it is for the final version.

Thanks again,

Gareth.

[steam4ian]

G'day Gareth

For practice I would only use the lime mortar as Andy recommended.

Lime mortar can be used for practice because it takes a while to draw the CO2 from the air needed for it to fully harden.

Don't use Porland Cement in the mortar where it is subjected to heat, go back to a rich lime mortar or get appropriate heat resistant mortar.

My brazing hearth is a tray of fire bricks set on the BBQ.

Regards
Ian

Regards
Ian

[drjohn]

I was sent some vermiculite fire bricks from the UK - no need for any form of cement - I just build them into a hearth, do what I want to do then stack them away under the bench. Watch though if you're brazing stripped to the waist, stand to the side or the reflected heat burns your belly!!!

DJ

[Deleted]

Good evening Ian / Dr. John,

Sound advice on all counts: ta for that.

I have some vermiculite bricks, they've been drying in the shed for the last couple of weeks.

I agree entirely with the warning about semi-nude brazing especially as in recent years my arms seem to have shortened so my navel is nearer the flame than it used to be......

[Deleted]

Apr 7, 2010 8:29:26 GMT @walshg10 said:

...as in recent years my arms seem to have shortened so my navel is nearer the flame than it used to be......

So glad to hear I am not the only one suffering from this disease - and have you noticed how all the trousers in M&S menswear department are all wrongly labelled? The 33" ones all have 40" on them - really cannot understand it at all!!

Regards, A

[drjohn]

Gareth

I have to say that I only have 8 bricks 9" X 4.5", but I can build a little hearth on my plywood bench, do my brazing and the bench doesn't even get warm.

DJ

[Deleted]

Hi DrJ, that's encouraging; I haven't used my 'hot' bricks yet.

As to the size? Well, while I have a trowel in my hand I might as well make it a good 'un! I don't suppose I'll ever have to solder up the boiler of a 7.25 "King" but if I do then at least I'll have the hearth. **

Alisdair - I agree entirely with all you said and would add plastic lenses to the list. For twenty years I had glass lenses and the same prescription. A few years ago I changed to plastic ones and now my prescription changes every two years.

Cheers to you both,

Gareth.

** On the subject of soldering I've put the Newbie question of the year in 'Boilers' and would be grateful if you'd have a look.

G.

[smallbrother]

On the subject of bricklaying, I have made a proper start on the garden railway and have brick-edged about 13 metres of the ground level formation. Only 50 metres to go!

Will the back stand the strain?