stalactite repair - some advice needed

[MSD]

Could somebody advise me how to best glue back a reasonably large stalactite which has been broken off? I understand that it's about 35cm long and about 5cm in diameter at the break (which was clean, leaving the broken off stalactite intact in a single piece). Topics which spring to mind are:

a) cleaning the stalactite
b) getting the surface to be glued dry and grease free (in case fingers have been at it). Alcohol?
c) what glue is likely to work best - some kind of reasonably quick drying glue obviously, but what? Epoxy? Superglue? The cave is quite cold (3-4 centigrade)
d) Depending on what glue is used it might be necessary to roughen the surfaces to get a better bond. Emery paper? Wire brush?

Any advice warmly appreciated.

Mark

 

[khakipuce]

Once did a job where we had to stick strain guages on to a concrete tunnel lining and then over-core them. We used dental cement because it sticks to damp surfaces and sets quickly. A quick google suggests that there are a lot of types available, I can't remember what the one we used was called, but it was pink!

 

[graham]

Lots of people can give different advice on this, but I am afraid that the quality of the results does depend wholly on the exact circumstances in each case; both ambient temperature and humidity will affect the rate at which a given cement will cure. We have used a variety of epoxies with variable results depending on those exact circumstances. Also possible is bone cement as used by orthopaedic surgeons, but it is very expensive.

 

[mrodoc]

I had to do this when somebody broke off a stalactite who was in my charge so to speak. it was in Hunter's Lodge Inn Sink. I was recommended to use MILLIPUTS which is an epoxy resin. We succeeded on the second attempt but it was fiddly because although the resin sets reasonably rapidly you have to keep the surfaces held firmly together. We succeeded by using electricians ties around the stal with something to act as a splint (cannot remember what but lollisticks or tongue depressors (if you are a doctor) would do.  The end result wouldn't have one prizes initially - after a few hundred years you probably wouldn't be able to tell the difference. there used to be a photo of it on the internet - v. embarassing!

I believe Araldite has also been used plus drilled holes and pins but that depends on the size of the stal.

Good luck!

 

[Duncan]

The NSS Cave Conservation and Restoration manual has an extensive section on speleothem repair.  It's far too long to summarise here, but to try to pick out answers to your questions:

a) cleaning the stalactite
and
b) getting the surface to be glued dry and grease free
- superficially dry with lint-free cloth and a can of compressed air
- rubbing alcohol to swab the mating surfaces
- don't apply heat as it can cause discolouration or spalling

c) what glue is likely to work best
- Epon 828 with Epi-cure 3243 (TETA) or Versamid 40 curing agent (Versamid 25 for wet applications).
- Drill and pin (with stainless steel) the repair.  Epoxy the pin into a close-fitting hole in the upper section first, then half-fill an oversized hole in the lower section with epoxy and fit it to the upper section (oversized hole to allow alignment adjustments).  Brace/tie in place until epoxy sets.
- For tiny stals don't pin, and use a pure cyanoacrylate adhesive
- I didn't see any mention of special glue for cold caves even though there certainly are cold caves in some parts of the US.

d) Depending on what glue is used it might be necessary to roughen the surfaces to get a better bond
- I don't see any mention of this.

There's much more detail and discussion in the manual, including lots of practical advice based on experience from a large number of repairs; if you can get hold of a copy it may be useful.

Duncan

 

[mandypoo]

Would this be of any use?

http://geography.lancs.ac.uk/Matienzo/miscpics/conserve/pin-resin.htm

 

[MSD]

Great, lots of ideas here. Thanks for the help.

Mark

 

[Pitlamp]

Mark - did you read that stuff in Descent about Wizards Chasm? A chap called Tony was asking for info. Circumstances put us in touch with each other and I told him about several articles on speleothem repair. He found others independently and I encouraged him to put all this stuff together in a big dossier which would be the definitive source on how to fix formations. He recently showed me this and it's actually a very valuable resource. Tony may well see this and post something himself but, if not, PM me and I'll put you in touch.

 

[Colin the Caver]

I think they once had to repair a stalagtite in White Scar Cave, might be worth contacting them for advice.

 

[gus horsley]

SWCC also had to repair the Trident, it might be worth asking them as it appears to have worked.

 

[bog4053]

I have just seen this item and the reference to myself and Wizards Chasm.  Our problem with the Wizards red stalactite is that we have a missing piece around 2 inches long which we have looked for very thoroughly twice now.  It really looks as if someone removed it and we are exploring fabricating the missing piece via a contact with the Natural History Museum.  Piecing together the broken bits that we have wasn't too problemattic because we took them out of the cave and time and damp weren't an issue.

As Pitlamp says, I compiled a collection of articles on stal repair and possibly the most relevant for you is the repair of the Marble Arch stals reported in Caves and Caving 36 which refers to John Wilson, a restoration expert from the Ulster Museum.

Apart from that the most helpful and comprehensive work I came across was the NSS publication Duncan referred to.  At the time I was compiling my references, the British Library didn't actually have a copy of this work but Lancashire County Libraries purchased one when I requested it so you can probably loan a copy via your own library if you want.