Hi, Can anyone recommend what kind of glue would work best for repairing a broken 3m stalactite?  Cheers Beardy

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Something of that length will be heavy & will need support as well as a fixative, either internally, in the form of a pin, or externally while the glue is going off. If the latter, then you have a much wider range of possibilities as it need not be fast setting. Last time I was involved in this we used something imported from the US that was meant to be better in highly humid conditions, but the results were less than satisfactory.

I don't doubt that things have moved on in the industry since then & I suggest you talk to epoxy manufacturers & lay out your requirements, in terms of humidity, temperature range, strength etc.

3m is huge. Glue alone won't work for sure.

I would imagine that a grooved stainless pin and the type of adhesive that is used for P hangers would work. Simon is quite knowledgeable in that field.

Ship-badger said:

I would imagine that a grooved stainless pin and the type of adhesive that is used for P hangers would work. Simon is quite knowledgeable in that field.

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It could be done like that but it wouldn't be very good. The resin used for anchors is a specialist product for that job. There are much better products made for sticking stone together.

http://lmgtfy.com/?q=masonry+repair+epoxy

We brought out and stuck back together a 1.8m tall stal from Cow Pot, Matienzo. It's now sitting back under the drip, with a new layer of calcite eventually hiding the repairs, we hope.  Some of the repair details may help you Beardy. http://www.matienzocaves.org.uk/miscpics/conserve/pin-resin.htm

The current issue of Descent (243) has a short article on p.10 about the 1965 araldite repair to one of the the Colonnade formations in Lancaster Hole and states that "fifty years on, it is hard to spot the join".

Columns and stalagmites are easier, as the weight is either not an issue or is an actual help. One other thing I suggest is talking to SWCC & see whether there is any info on the repair of the Trident that was carried out quite some time ago, now. That's the nearest equivalent I can think of.

& yes, if the stal is still 'alive' then sufficient will have been deposited in fifty years to mask the join. I bet it can still be identified on close inspection, though, there will be differences in colour and texture, I am sure.

robjones said:

The current issue of Descent (243) has a short article on p.10 about the 1965 araldite repair to one of the the Colonnade formations in Lancaster Hole and states that "fifty years on, it is hard to spot the join".

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This website:

http://www.happywanderers.org.uk/

has two very useful articles about those repairs; one is by Dave Pickup (taken from the HWCPC 1966 journal) and the other is Derek Brandon's from Cave Research Group Newsletter No 95 (and also includes some photographs).

These repairs involved joints which were in compression, whereas your 3 metre stalactite's joints would presumably be in tension (both during and after the cement has cured). I suspect the advice above (i.e. to contact an epoxy resin manufacturer and ask for advice - and even help) would be the best bet.

There is also a certain member of the Northern Boggarts and BPC who advertised in Descent some time ago for advice regarding a stal repair in Wizard's Chasm. I helped him to pull together a load of references to stal repair techniques, all of which went into a single folder with the intention of it being available in future when questions like yours above cropped up.

If you've not sussed out who I mean send me a PM and I'll elaborate.

Well done for trying to effect this particular repair.

Dear All,

Many thanks for all the tips

(unfortunatley it is a stalactite rather than a column or a stalagmite)

The request originated from some friends in Spain, so hopefull they shall be able to put the advice to good use

Regards
Beardy     

For what it's worth Milliputs which is a mixable epoxy putty does work.  After some discussion with my brother in law Nigel, and based on unhappy experience of trying to fix a stalactite, I would think a fine drill which means you only need a light weight cordless, your choice of resin, some nails, and lots of electricians ties. You then drill cruciform style ie four holes above the break and on the broken stal apply the resin to the broken ends put the two pieces together and tension the joint by using the electricians ties around the pins you have inserted. When cement has well set return and remove pins and ties. We did one just with ties but using pins means you could repair a pretty beefy chunk of stal depending on size of pin (you keep the drilled out dust to fill the pin holes later on if you want).

Nice idea mrodoc, would it work using jubilee clips round both sections of stal to hold the tie-wraps?, would avoid drilling.

Standard school laboratory "stands & clamps" are very useful for supporting pieces of stal being cemented (but may be inadequate to support the weight in this case?).

You can also fix ratchet straps to both sides of the break, giving something to fasten big tywraps to (and these cause little or no damage to the stal pieces).

for what it's worth I'll make a contribution of my experience in this area.

About 10 years ago, I repaired a Stalagmite and a Stalactite (only about 0.5m) though.

The Stalagmite was easy, as someone said above weight and therefore compression are on your side. Make sure you have a clean break and then check you can position it accurately. Clean off both surfaces with a water spray and brush, then dab them with a towel to remove any excess water, then coat the base with superglue. Position and hold in place for a couple of minutes. Job done. (Superglue likes moisture which is why it sticks your skin together so easily.)

The stalactite was more tricky as you can imagine. As the bottom of it was about a metre off the floor I would have had to construct a wooden platform and maybe a jack to support it if using resin. I opted to use a pin, so I positioned the two parts best I could, made a small mark on the side of each half, then drilled a hole into each. This is the tricky bit of this method, getting the position of the holes in the right place. Anyway, I did it and again used Superglue. The trouble with that is, it doesn't allow for re-positioning and once the glue was applied to the pin it worked fine, but I'd cocked up and hadn't drilled the
holes deep enough, so the two parts didn't quite join up!

Damn. There was about a 3mm gap. If I'd have some appropriate resin I could have pulled the pin to drill the upper hole a bit deeper and tried again, but the Superglue had already taken hold and I didn't want to prise the parts apart for fear of causing damage.

It's still up there after all this time, just a bit wobbly! Something to inject into the gap would be great. Many lessons learnt...

Regards Mel. DCA Conservation Officer.