Author Topic: Merged topic - Spit and BP bolt removal/replacement  (Read 24710 times)

Offline cavermark

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Re: replacing spits with resin anchors
« Reply #25 on: November 18, 2014, 12:30:00 am »
It would be impossible to drill the anchor enough the get it out.


To clarify - I was suggesting that, in the case of Peco anchors, if the "Bolt"head is drilled off, the hanger would be removed. The shaft of the anchor would still be in the rock, but flush with the surface - the same outcome as grinding or hacksawing the head off.  Not ideal but much less noticeable than the resin splodge solution perhaps?

Bob - Rope access for tasks such as grinding would involve 2 ropes (as standard) with "hard links" such as steel strops, between you and your descender and back up device. You would also carefully position yourself and your ropes before starting the work so that any kick back or follow through would not be a problem. The position of the new P-bolts in the CNCC photos look like they could be useful for positioning too.

Offline andrew

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Re: replacing spits with resin anchors
« Reply #26 on: November 18, 2014, 08:34:08 am »
We really should not be discussing this. It is ever cavers moral duty to conserve caves to the best standards, while still enjoying access. Anchors should removed and the placement reused. This should be as an important factor, possibly more important than the strength. After all a 40 year life is very short, we are privileged to be towards the start of caving and have a duty to leave the environment in the best condition possible.

Offline Maj

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Re: Replacing BP anchors
« Reply #27 on: November 18, 2014, 11:32:32 am »
Thinking outside the box.
What happens if you heat the anchor up with a blow lamp first. Would this have a detrimental effect on the resin and hence provide the weakening required before pulling.
I'm assuming the thermal conductivity of the anchor would be greater than that of the resin, and so the heat will transmit down the anchor heating the boundary between anchor and resin.
 :-\ :-\
If it might work, I appreciate there are other factors to consider, for example:-
Affect on the surrounding rock.
Is there a risk of fumes from the resin?
Perhaps an aluminium plate to protect the surrounding rock and resin from direct heat, might resolve some potential issues.
 :-\ :-\

Maj.



 
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Offline Maj

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Re: replacing spits with resin anchors
« Reply #28 on: November 18, 2014, 11:45:40 am »
I didn't spot this second related thread before I posted. So I'll repost it here.

What happens if you heat the anchor up with a blow lamp first? Would this have a detrimental effect on the resin and hence provide the weakening required before pulling?
I'm assuming the thermal conductivity of the anchor would be greater than that of the resin, and so the heat will transmit down the anchor heating the boundary between anchor and resin.
 :-\ :-\
If it might work, I appreciate there are other factors to consider, for example:-
Affect on the surrounding rock.
Is there a risk of fumes from the resin?
Perhaps an aluminium plate to protect the surrounding rock and resin from direct heat, might resolve some potential issues.
 :-\ :-\

Maj.
Confucius say "War does not determine who is right, war determine who is left."

Online Roger W

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Re: replacing spits with resin anchors
« Reply #29 on: November 18, 2014, 11:58:56 am »
You might expand the bolt enough to loosen it when it cools. 

You might get it hot enough to degrade the resin (but watch out for fumes).

You might get the limestone hot enough to convert it to calcium oxide... (825 degrees or so).

Sounds like a suitable case for "try it and see" - preferably somewhere where there's plenty of ventilation and no danger of setting your rope on fire.
"That, of course, is the dangerous part about caves:  you don't know how far they go back, sometimes... or what is waiting for you inside."   JRR Tolkein: "The Hobbit"

Offline Bob Mehew

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Re: replacing spits with resin anchors
« Reply #30 on: November 18, 2014, 12:15:29 pm »
Anchors should removed and the placement reused.

We don't start from a clean sheet situation but have a range of different types of anchors which already foul up placements.  So I suggest we do not need to stop all placements of BP anchors whilst we determine if we an extract a BP anchor without fouling the placement location.  Perhaps we can make a stab at seeing if we can remove some resin from a BP anchor and then pull it using the BCA anchor puller.

I am free on Sunday 23rd Nov and currently have the BCA anchor puller.  If someone wishes to place an anchor in a convenient flatish surface location (concrete will do) I am prepared to drive where ever to pull it (I am in South Wales Saturday 22nd evening).  I don't have a battery drill to hand so someone will have to do the resin removal bit for me. 

The puller is booked for weekends of 29 & 30 Nov and also 6 & 7 Dec for use in South Wales.  I am a bit reluctant to offer to do it within that work as the existing plan is to pull 64 anchors which is challenging enoug!  The puller is then scheduled to go onto North Wales.

If we can get this underway, then people may wish to suspend placement of BP anchors, as few weeks delay is surely neither here nor there? 

Or can someone work on it with another puller?

What happens if you heat the anchor up with a blow lamp first? Would this have a detrimental effect on the resin and hence provide the weakening required before pulling?
Interesting thought.  As Roger says, trying it is probably the only answer.  Given the expected low heat conduction of resin, I don't expect the rock to get warm.  But heating the metal anchor would only damage the metal / resin bond.  For BP anchors the challenge is to extract the anchor without spalling the surface of the rock.  I am not sure if destroying the metal / resin bond will help that as one then has to remove the few centimeters of resin between the surface and the start of the BP anchor twist.  Another point to consider is the possible build up of CO2 if one is doing several anchors.  Being techi, I would want to place a thermocouple at the base of the anchor but that need not be done for the first suck and see.

Offline andrew

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Re: replacing spits with resin anchors
« Reply #31 on: November 18, 2014, 12:52:10 pm »
If you are in Wales, Mendip is not that far, and it is jrat evening on Saturday. I have al, the kit, just need to find a flat piece of rock, big enough, but we should be able to do that.

Online SamT

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Re: replacing spits with resin anchors
« Reply #32 on: November 18, 2014, 01:30:33 pm »
What happens if you heat the anchor up with a blow lamp first? Would this have a detrimental effect on the resin and hence provide the

http://www.bolt-products.com/SustainableBolting.htm

see the section on "melting out"

I think fumes would be a real problem.

I did wonder if you could warm the metal up using electricity -   Some sort of welder type setup.  I was thinking surface though. Not underground  :o


Online SamT

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #33 on: November 18, 2014, 01:49:39 pm »

Can I just say that before anyone gets too hung up (sic) on the subject of the removal, that if placed well in good rock, the BP bolts should NEVER need replacing (well - in theory)

The old DMMs on garlands in giants are probably the most frequently used bolts in the country and after ~20 years, are showing no signs of wear.

The only time we've had to drill out and replace bolts are where numbskulls have been lowering cavers down pitches directly off bolts causing them to wear thin.

I grant you the fact that having a bolt that is relatively easy to remove and replace is preferable.

Offline mmilner

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #34 on: November 18, 2014, 06:38:31 pm »
I grant you the fact that having a bolt that is relatively easy to remove and replace is preferable.

I agree wholeheartedly Sam.  :thumbsup: That's why I've been using Excalibur Screwbolts for years in the Manifold. There are a couple in Darfar Pot that are under water for much of the  year which I need to replace next year because of corrosion, but I can just unscrew them and screw new ones in using the same hole.

See:- http://www.excaliburscrewbolts.com/

Also, Excalibur are producing new Screwbolts now with corrosion protection that is apparently comparable to stainless steel... Will be trying them next year for the replacements I think.

Not covered by the BCA insurance scheme of course, but got fed up of waiting for DCA installers to install p-bolts. They get light usage too, of course...

I should also add that those eyebolts which will need replacing have been in there for 8 years and are still sort of OK, but I want to make sure they are safe. not that many people go down there. I may replace them with m12s as well instead of the current m10s, again just cos they'll last longer. The one above river level have hardly corroded at all and are all fine...
« Last Edit: November 18, 2014, 07:07:36 pm by mmilner »
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Offline Simon Wilson

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #35 on: November 18, 2014, 06:57:31 pm »

... got fed up of waiting for DCA installers to install p-bolts.


The full extent to which people got fed up of waiting and decided to install anchors outside the BCA anchor scheme is yet to come out.

Offline cavermark

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #36 on: November 18, 2014, 07:12:41 pm »

I agree wholeheartedly Sam.  :thumbsup: That's why I've been using Excalibur Screwbolts for years in the Manifold. There are a couple in Darfar Pot that are under water for much of the  year which I need to replace next year because of corrosion, but I can just unscrew them and screw new ones in using the same hole.

See:- http://www.excaliburscrewbolts.com/

Also, Excalibur are producing new Screwbolts now with corrosion protection that is apparently comparable to stainless steel... Will be trying them next year for the replacements I think.


Could be something to consider - I bet some git would just pinch them if using them as "fixed anchors" in popular caves though...

Online Pete K

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #37 on: November 18, 2014, 07:26:21 pm »

... got fed up of waiting for DCA installers to install p-bolts.


The full extent to which people got fed up of waiting and decided to install anchors outside the BCA anchor scheme is yet to come out.

I suspect that the various regional councils can only operate as fast as the volunteers who install the bolts do. Most of whom have jobs and lives to fit dragging drills and batteries into the deepest parts of the uk around. I don't think it is a failing of the BCA, more volunteers are required surely?
The volunteers who bolt for the DCA seem to get thinks done quickly.

Offline Grizzlybear

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #38 on: November 18, 2014, 07:32:07 pm »
Maybe before erasing all traces of previous exploration methods, including the repair of rock grooved by lifeline and wire tether. We could  reflect on Gibbons his account of Rome should be enough for most people ,however we still enjoy finding and preserving  Roman artifacts. To move on. I am sure most modern anchorage placers will consider the placement position of old spits ect. would be totally unsuitable for modern rope techniques These may often have been placed in a position for short term gratification rather than any long term considerations

Offline mmilner

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #39 on: November 18, 2014, 07:32:31 pm »

... got fed up of waiting for DCA installers to install p-bolts.


The full extent to which people got fed up of waiting and decided to install anchors outside the BCA anchor scheme is yet to come out.

True, but in my case the current anchors can be removed in minutes, the existing hole reamed out to the required size and a resin bolt installed in it's place. They have been placed in sound rock in good positions. Under the river bed level however it would be interesting to see how quickly they corrode as they would be submerged in acidic water for many months of the year. Down there I'd rather have anchors I could replace easily in minutes rather than having to go through all the faff that has been discussed in this thread. (Drilling out bolts and resin, etc.) Different situation to most caves in the country. about 25ft. below highest flood level.
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Offline mmilner

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #40 on: November 18, 2014, 07:39:30 pm »
Could be something to consider - I bet some git would just pinch them if using them as "fixed anchors" in popular caves though...

These aren't popular caves Mark, that's the point. And of course they could still be glued in place, but that sort of spoils the whole idea. These anchors will need replacing much more often cos they are under water for much of the year.

I'm quite happy for the above river level ones to be replaced with resin anchors and indeed have been asking for this to be done for several years, but everybody has been too busy doing caves further North as usual...  :coffee:
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Offline paul

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #41 on: November 18, 2014, 08:15:00 pm »
Could be something to consider - I bet some git would just pinch them if using them as "fixed anchors" in popular caves though...

These aren't popular caves Mark, that's the point. And of course they could still be glued in place, but that sort of spoils the whole idea. These anchors will need replacing much more often cos they are under water for much of the year.

I'm quite happy for the above river level ones to be replaced with resin anchors and indeed have been asking for this to be done for several years, but everybody has been too busy doing caves further North as usual...  :coffee:

Possibly because "These aren't popular caves " and therefore sit sowewhat lower down in the list of caves to be done?
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Offline cavermark

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #42 on: November 18, 2014, 08:49:53 pm »
Sorry, I meant the Excalibur type bolts could be considered instead of resin bolts for any given cave; but that they would be likely get pinched if said cave was popular...

Offline pwhole

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #43 on: November 18, 2014, 08:55:16 pm »
I've just bought a box of Excalibur bolts for a site specifically because they'll need to be removed again later, some (hopefully) to be resin-bolted properly at a later date - I'm quite pleased this option is available as it means we can use the 'best' spots to rig from without ruining them, rather than rigging around the best spots and making things much more difficult for ourselves. That said, even empty holes isn't ideal, so will still aim to use as few as possible, as it is 'kind of' virgin territory. Haven't used any yet, but I'm looking forward to trying them out. Wasn't sure how long they'd last in a wet environment, but it sounds like you're having no problems so far Mel.

Offline cavermark

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #44 on: November 18, 2014, 08:57:54 pm »
These may often have been placed in a position for short term gratification rather than any long term considerations

Now we have the internet I guess that won't go on so much?   ;)

Offline cavermark

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #45 on: November 18, 2014, 09:04:04 pm »
pwhole - they've been used quite a lot in rope access now - I've been surprised that they have passed pull tests at 7KN, even in soft looking sandstone or brickwork.
If placed well I guess they should be good until the bolts corrode. Obviously, if frequently removed and replaced the thread in the holes will wear and reduce holding power.

Online SamT

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #46 on: November 18, 2014, 10:42:06 pm »
Im a big fan of the exalibers. I've used them in baggers for short term stuff.  That's turned into long term as I've not been back yet to replace them. But it will be nice to be able to just unscrew them and ream out the hole for a resin.

Offline mmilner

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #47 on: November 19, 2014, 03:39:56 am »
yeah, hole wear would be an issue but the ones in the Manifold have never been replaced. I use M8s for deviations then M10s for main belays, usually in pairs obviously. If they were being screwed and unscrewed a lot and hole became worn just upgrade to the next size up, ie:- M12s. Beyond that then yes, you'd to replace them with resin bolts... or expanding anchors like Rawlbolts, but obv. they stress the rock so have to be placed carefully...
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Offline Simon Wilson

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #48 on: November 19, 2014, 04:13:06 pm »

... got fed up of waiting for DCA installers to install p-bolts.


The full extent to which people got fed up of waiting and decided to install anchors outside the BCA anchor scheme is yet to come out.

I suspect that the various regional councils can only operate as fast as the volunteers who install the bolts do. Most of whom have jobs and lives to fit dragging drills and batteries into the deepest parts of the uk around. I don't think it is a failing of the BCA, more volunteers are required surely?
The volunteers who bolt for the DCA seem to get thinks done quickly.

I don't think you appreciate what I said. There are a number of difficult potholes that are infrequently visited, that are the places where we would least want to have an accident and which have never had resin anchors installed under the BCA scheme. In these holes people would have to rely on 20, 30 or 40 year-old Spits or provide their own alternative. There have been people willing to install resin anchors but they have had no anchors available under the BCA scheme.

Offline cavermark

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Re: Merged topic - Spit and BP bolt removal/replacement
« Reply #49 on: November 19, 2014, 04:39:56 pm »
Simon - Would excalibur type bolts be a good interim measure for some of the sites you are referring to?  The holes can then be reused for whatever resin anchor gets decided upon and becomes available....

It does seem like things are moving forward now...