I'm trying to point up the gaps between some large slates that form the inner face of a wildlife pond. I'm using a Hanson M6 sand/cement mortar. But even though I make up the mix fairly stiff, the moment it goes into the water it goes fluid and just washes out.
What do I need to add to the mortar get it to stay put long enough for it to go off?
Make a dam around the area and run a small submersible pump (in a depression in the bed) to keep the area dry'ish. I did this a while ago, using quick-set cement and SBR, to build a series of water features in a stream.
Just to add - the dams were made of celotex offcuts and OSB, they were very unsophisticated.
It might be an interesting experiment to:
No electricity, so no pump available, but SBR looks like the magic ingredient to try. Thanks.
Having looked at some of the other responses they don't seem to have mantioned that cement isn't good for fish.
So I think you really do need to make some sort of mini coffer dam to enable you to do the cementing 'in the dry' and then let the water back after the cement has set.
Thanks, but there are no fish.
Well you said "a wildlife pond", even if no fish I assume there's something alive isn't there? :-)
I have seen repairs to river walls and moats where they use Hessian bags of concrete ... ram into place, water seeps into bag and sets the concrete ... could be an option
For a small amount you might find this Roman recipe of use:
Not yet. It's still under construction. Hopefully it will self-populate in a few months time, by which time any residual effects of the cement will have dissipated.
Food for thought - these are small leaks, but small natural fabric bags are an interesting possibility if all else fails.
Worth remembering this was basic Roman engineering :)
You need a dam to allow the bit you ae working on to be dry. I guess there might be some epoxy that might work, but other than that, surely mortar underwater is a bit of a non starter. Brian
But possibly using formers which contains the mixture and lets the "wash out" settle before curing.
OK, it will be fine then.
There are mortars designed for that job:
Might need to drape a bit of mesh down the side so that Toads and Frogs can climb out. Next stop visiting Herons!
Might also annoy the neighbours if they have to commission Crested Newt surveys before building development:-)
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Was expecting applying mortar under water to be compared to fixing nails onto rails, or pointing bricks in the sticks.
Any tips on stripping cable on a table?
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