Not setting Help quick

[cec]

I need info double quick ,

My home brew int setting very fast , the stuff I laid 2 days ago is still fairly soft , is this normal ?.
I'm making it 3 sand , 1 cement , 1 lime , 1 powder clay ,

Should I put mor cement in ,ie 1 1/2

Oh and what is laid is cracking a bit in between the joints

Help

[rivergirl]

Sorry I cannot help at all, would covering the new with damp sacking etc delay the set?

[cannyfradock]

cec

This homebrew mix should be setting after a couple of hours......with no cracking.

"I'm making it 3 sand , 1 cement , 1 lime , 1 powder clay".......I pushed this formula to a 4:1:1:1 mix, which if anything should have taken longer to harden.....but it didn't.

When I have used this mix, it hardens within a couple of hours and starts to form a crust shortly after. The curing process when using cement only starts after 7 days and is ongoing, but your homebrew mix shouldn't react the way you described.

I don't know what to suggest.....except that you are first using the correct materials......cement (normal (opc) or fondue. Hydrated lime, Powdered fire-clay....and building sand. Are you also making the quantities by volume.....i.e.....use a small bucket etc to measure your quantities.....3 level buckets of sand, 1 level bucket of cement....etc..

After 2 days your mortar should be hard enough so as that you must use a point of a trowel or wood chisel to be able to scratch the surface, but the body of the mortar should stay firm and solid..........it sounds like you are doing something wrong......or even better....something not quite right!!!

Please read over my words.......and if you are still in doubt, then please post again or send me a Personal Message (PM).......(The forum is starting to get a little busy and I sometimes miss critical posts.) If you want a quick answer to something and don't get a response, then PM me. If I can't answer a question, I can re-direct to someone who can.

Terry

[cec]

im using normal cement 1 of , 1 lime ,1 powded clay , 3 sand .
my sand is wet but i dont think that would make any differance ,
im using a kids bucket to get it in the right quantities aswell .
the bricks im using are a little damp , and a long way off from been dry , so i dont think they are sucking all the moisture in em .
heres a pic ,
to me its if its shrinking as its drying .
thursday night i put the 1st ring on and even today i could scrape at it and it still seamed soft .

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[cannyfradock]

cec

Your homebrew mix has me stumped. I could understand cracking.....if a lot of the mix was used in one area, and was drying too quick, but it shouldn't be as soft as you say after a few days.

Even in our current damp climate, the mix should be at least starting to harden after a few days. You say that your mix was measured by volume so even if the sand was wet it wouldn't really make that much difference. I could suggest adding plasticer (feb mix) or a drop of washing up liquid in the water used to bring the mix together. This will cut down on the amount of water needed to make a "mortar".

The only other things I can suggest is that, I used a cement mixer to knock up a small batch of homebrew.....you always tend to add more water if you make a mix by hand.......Is the cement "fresh"....it does have a shelf life............you say you are using powdered clay.....is this "powdered fire-clay"?....it needs to be.

If you were within travelling distance of Newport....I would willingly pop over to see if I could help as it's starting to niggle me that I can't solve your simple problem.

It has been a few days now......how is your homebrew doing now?

Terry

[turkey]

I think my homebrew is very much like cec, it took a long time to "set" and its now quite crumbly and I can chip at it easily and brush it, this is not so bad for me as its easier to clean my messy application. It was possible to indent it with my finger the next day for example.

I do suspect my cement is beyond its best and will be thowing out my sacks and getting some fresh stuff before going higher.

Now the arch is set say it has had my nephew climb all over it as he thought it was a castle and tried to kick it over to no avail so structually I am sure its fine however long it took to set. I suspect the clay as part of the mix really holds the moisture well and taked longer to go off as it where.

[cec]

Terry
The cement is fresh only a day old from builders merchant , the clay is fire clay from a local refactory firm , the sand is old , it's about 9 months old , it's been in its bag ( jumbo ) and it did get very wet .
I dont think I mixed it to wet as when I tried to do it dryer the bricks wouldn't tap down very easy ,
You say about adding plasticer but I was told that as I'm using lime there is no need for it .
I've not had a look today as I've been on my travels again but I will hav a look I'm the morning ,
The mix is hard but like turkey say you can still prod with your finger and dent it a bit .

Any how I cracked on and built it now so I will keep and eye on it ,
Oh 1 more thing it wasn't cracking on the inside joints , maybe the outer joints was just a bit to wide ,

Ps I will have a look on the clay bag and report back as to what it is

[cannyfradock]

So......on reflection (especially after Turkey's comment)....maybe damp bricks, damp climate etc....it needs that much longer to set. It sounds like both yourself and turkey are doing everything right.

So...on reflection....I was relating to my last build. It was a baking hot day and had to continually wet the bricks to keep some moisture in them for laying. I was also only knocking up small batches at a time as the homebrew was drying on me too quickly. I managed to build the dome in a single day and this is a picture of me 20 minutes after laying the keystone to the dome...



.....so maybe the difference in climate WILL make give the mortar a longer setting time?

I've been following your build on the other thread......great job!!!

Terry

[cec]

Well I was doing it in the rain like a mug , but when I want to do something I do it regardless . ;D
I think your right terry about the weather , it's been very damp , I've just been out and had a look and the 1st course is hard now but the rest of the dome is still softish ,
I'm going to do the porch tomorrow night ( if it's not raining ) .

Oh chimney ?
How high from top of dome ?
Could I use the old drainage pipe ( the sandy coloured , glazed type ) it's about 4" id ?

You will be sick of me soon asking all these questions