Techniques for removing glue in bolts

Purpose of post: Provide a central forum to talk about techniques for removing glue in bolts.

I have the opportunity to be part of testing to failure a variety of different types of glue ins and adhesives and I would like to include testing on the easiest way to remove glue ins.

I would love to hear from anyone who has an efficient method of removing adhesive anchors.

Methods: These are the removal methods that I have heard.

1. Heating the adhesive: Looks like most people recommend a torch to heat up the adhesive to allow the bolt to be removed. Has anyone used a heat induction tool like the Bolt Buster?

2. "Redneck Core Drilling" : This: I like this method but am interested to know the design on the puller. Is this something that we can adapt the current crop of homemade bolt pullers to do? Is that as simple as threading on a yoke and a clevis pin onto a Doodad type device?

Thanks in advance for your input all.

You need look no further than Jim Titt’s site, bolt-products.com. He’s done all the research.
Mal

Malcolm Daly wrote: You need look no further than Jim Titt’s site, bolt-products.com. He’s done all the research.
Mal

Thanks I have read thru that site several times. Anything specific you would like to highlight? Also your link doesn't work. 

Maybe the link doesn’t work but bolt-products.com does if you type itbin. Bolt removal is covered at bolt-products.com/SustainableBolting.htm
Mal

Induction heating doesn´t work on 304/316 SS as it´s non-magnetic.

Some bolts have fairly poor bonding anyway so you can just pull them straight out, the same goes if you are replacing glue-ins because the resin has deteriorated. It´s a balancing act between how strong the bond is to how strong the bolt is, you need a puller capable of at least several tons depending on what it´s like (mine is 80kN).
If the bolt is being replaced due to corrosion issues then it will just snap off, there´s no point in even trying to remove it.
Drilling around the bolt leaves a large ugly hole and usually still needs a substantial puller to get it out.
Heating with a torch is an "interesting" job! Epoxy will soften at fairly low temperatures so combined with a puller this can work. The problems are stainless steel is a very poor conductor of heat so  it takes ages to get any temperature down the bottom of the hole and stainless steel also weakens drastically when it´s hot so just getting the eye glowing red means it will probably break of rather than pull the bolt. The other commonly used resins (vinylester/epoxyacrylates) actually have a fire certificate and don´t soften particularly, you can burn them out if you are patient´and don´t mind the mess!

The alternative is brute force with a wrecking bar twisting them to and fro trying to work them loose, in the end they will come out if you haen´t gone mad and sheared the eye, like half an hour of wrenching them around and they succumb!

Normally either they are corroded in which case you probably can´t anyway or the resin has failed in which case they are easy to pull out, otherwise there´s no reason to remove them.

Wow! Jim, Thanks as always for sharing your expertise and experience.

Do you mind sharing pics or video of your 80KN puller?

Just spitballing here, but is it possible to artificially speed up the deterioration of the adhesive? 

They look like this;

With a half liter beer bottle for scale. This ones with a normal hydraulic pressure guage but I also use an electronic one.
I´ve thought about dissolving the resin, I even bought the solvents and planned drilling a small hole at 45° from above to the middle of the bolt and then filling it with epoxy remover. Then I stopped thinking about it! Another idea was using ultra-sound to break the resin bond or break up the resin.

I prefer this one:

My father-in-law used to try and foist that stuff on me, horrible sweet old-ladies beer in my opinion.

Bobby Hutton wrote: Purpose of post: Provide a central forum to talk about techniques for removing glue in bolts.
I have the opportunity to be part of testing to failure a variety of different types of glue ins and adhesives and I would like to include testing on the easiest way to remove glue ins.
I would love to hear from anyone who has an efficient method of removing adhesive anchors.

Putting the words "efficient" and "removing adhesive anchors" in the same sentence is a bit sketchy   

I assume you want to re-use the hole for the next test?   I know that at least one bolt manufacturer glues bolts into a steel block for testing.   The block won't fracture during the test nor when you heat it with a torch to get the bolt out.  

Testing to failure is difficult.  Do you realize (based on the DAV/UIAA tests done in 2001) that the bolts and/or rock will often fail before the glue?  (Is that what you want to know?)  Or your puller/test-rig will max-out before anything (rock/bolt/glue) fails?  

Methods: These are the removal methods that I have heard.
1. Heating the adhesive: Looks like most people recommend a torch to heat up the adhesive to allow the bolt to be removed. Has anyone used a heat induction tool like the Bolt Buster?

Jim's right.  Theoretically induction heating should work, but the Bolt Buster probably doesn't have enough umph to work with SS or Ti bolts.   However, both have reasonable thermal conductivity, so heating with a torch is going to be a lot easier.   Be aware that heating real rock like this will likely cause fracturing, so you can't use the hole again anyway.

Geez, someone should invent a bolt that doesn't require glue....

John Byrnes wrote: Putting the words "efficient" and "removing adhesive anchors" in the same sentence is a bit sketchy   

I assume you want to re-use the hole for the next test?   I know that at least one bolt manufacturer glues bolts into a steel block for testing.   The block won't fracture during the test nor when you heat it with a torch to get the bolt out.  

Testing to failure is difficult.  Do you realize (based on the DAV/UIAA tests done in 2001) that the bolts and/or rock will often fail before the glue?  (Is that what you want to know?)  Or your puller/test-rig will max-out before anything (rock/bolt/glue) fails?  

Jim's right.  Theoretically induction heating should work, but the Bolt Buster probably doesn't have enough umph to work with SS or Ti bolts.   However, both have reasonable thermal conductivity, so heating with a torch is going to be a lot easier.   Be aware that heating real rock like this will likely cause fracturing, so you can't use the hole again anyway.

Well we clamp them in a steel fixture to see if they break as it's faster for QC. We don't use any resin. 

 Kinda doubt anyone is going to get the rock hot enough to crack it!

mpech wrote: Geez, someone should invent a bolt that doesn't require glue....

Geez, someone with experience should teach you a thing or two about the ideal qualities of fixed anchors particularly in highly corrosive environs.

Current consensus in the development community is that glue-ins are state of the art.

The next 50 years will tell the tale.

Harumpfster Boondoggle wrote:

Geez, someone with experience should teach you a thing or two about the ideal qualities of fixed anchors particularly in highly corrosive environs.

Current consensus in the development community is that glue-ins are state of the art.

The next 50 years will tell the tale.

The current consensus is just group think.  

Glueins are the latest fad, and they have some real benefits.  However, the subject of this thread highlights the elephant in the room!
We do not have a sustainable method for replacing glueins.  Additionally, we lack a way to determine when a gluein that is not physically corroded needs replacement due to degradation of the glue.  Further, as seen in several recent failures, developers are much more likely to have a bad bolt due to glue problems.  The wave bolt may very well be hiding the fact that we have even more glue problems than we have seen so far.  The interference holding power may be covering up an otherwise weak glue in.  
The next 50 years will tell the story of how good of an idea our current fad is.

Harumpfster Boondoggle wrote:

Geez, someone with experience should teach you a thing or two about the ideal qualities of fixed anchors particularly in highly corrosive environs.

Current consensus in the development community is that glue-ins are state of the art.

The next 50 years will tell the tale.

I'm fine with glueins in the environments you referred to.

In normal climbing environments, it seems very useful to have bolts that can be easily removed and with reusable holes.  

Sandy Crimp wrote:

The current consensus is just group think.  

Glueins are the latest fad, and they have some real benefits.  However, the subject of this thread highlights the elephant in the room!
We do not have a sustainable method for replacing glueins.  Additionally, we lack a way to determine when a gluein that is not physically corroded needs replacement due to degradation of the glue.  Further, as seen in several recent failures, developers are much more likely to have a bad bolt due to glue problems.  The wave bolt may very well be hiding the fact that we have even more glue problems than we have seen so far.  The interference holding power may be covering up an otherwise weak glue in.  
The next 50 years will tell the story of how good of an idea our current fad is.

My thoughts exactly.

Wouldn't be surprised if more people end up dying from bad glueins than bad 1/2 inch mechanical bolts...

Sandy Crimp wrote:

The current consensus is just group think.  

Glueins are the latest fad, and they have some real benefits.  However, the subject of this thread highlights the elephant in the room!
We do not have a sustainable method for replacing glueins.  Additionally, we lack a way to determine when a gluein that is not physically corroded needs replacement due to degradation of the glue.  Further, as seen in several recent failures, developers are much more likely to have a bad bolt due to glue problems.  The wave bolt may very well be hiding the fact that we have even more glue problems than we have seen so far.  The interference holding power may be covering up an otherwise weak glue in.  
The next 50 years will tell the story of how good of an idea our current fad is.

Any mechanical anchor currently used has the same problems.

In an ideal scenario it may seem as though SS mechanical anchors are more sustainable (hole readily re-usable) but in actual practice are vastly more susceptible to corrosion issues leading to them snapping off at inopportune times and making removal problematic.

We lack any method of determining when a mechanical bolt has been placed improperly too even when it is not physically corroded.

I will take a glue in bolt with a simple interference fit over that next 50 years as my first choice, though I certainly use wedge and 5-piece more commonly for convenience.

Jim Titt wrote: They look like this;

I´ve thought about dissolving the resin, I even bought the solvents and planned drilling a small hole at 45° from above to the middle of the bolt and then filling it with epoxy remover. Then I stopped thinking about it! Another idea was using ultra-sound to break the resin bond or break up the resin.

Thanks for sharing Jim. Pretty slick set up. It looks like the the clevis rod end is welded on, is that correct? Any Advantage to that? 

So I will play the straight man. Jim, why did you stop thinking about using solvents to dissolve Resin? To caustic to work with?

Just carefully grind off the head/eye of the bolt until just below flush with the rock and patch with a two part epoxy putty. Finally camo the putty by dusting/dabbing with matching rock fines collected from the base of the wall. When I have done this I struggle to even identify the old glue-in location after the epoxy cures. I'm not sure what the issue with sustainability is.

Also, any bolt can be placed incorrectly and mechanical bolts get botched and fail all the time.

Using glue-ins correctly just calls for a higher commitment to excellence and integrity.

"If you don't have the time or money to do it right the first time, you don't have the time or money to do it"

John Byrnes wrote: 
Putting the words "efficient" and "removing adhesive anchors" in the same sentence is a bit sketchy   

I assume you want to re-use the hole for the next test?   I know that at least one bolt manufacturer glues bolts into a steel block for testing.   The block won't fracture during the test nor when you heat it with a torch to get the bolt out.  

Testing to failure is difficult.  Do you realize (based on the DAV/UIAA tests done in 2001) that the bolts and/or rock will often fail before the glue?  (Is that what you want to know?)  Or your puller/test-rig will max-out before anything (rock/bolt/glue) fails?  

For the purpose of replacing bolts ideally the hole would be reusable. Fire damage to the rock would be a valid aspect to add to the testing. These guys did some testing on fire damage as well. Do you have any experience with this in the limestone you work with?

The testing is being done by high liners who among other things are trying to find the limits of their anchors and configurations so rock or bolt failure are all valuable data. The goal for the testing rig we are building is 80 kn. 

Sandy Crimp wrote:

The current consensus is just group think.  

Glueins are the latest fad, and they have some real benefits.  However, the subject of this thread highlights the elephant in the room!
We do not have a sustainable method for replacing glueins.  Additionally, we lack a way to determine when a gluein that is not physically corroded needs replacement due to degradation of the glue.  Further, as seen in several recent failures, developers are much more likely to have a bad bolt due to glue problems.  The wave bolt may very well be hiding the fact that we have even more glue problems than we have seen so far.  The interference holding power may be covering up an otherwise weak glue in.  
The next 50 years will tell the story of how good of an idea our current fad is.

You mean glue-ins are the latest thing the USA has learnt from the Europeans. I was installing resin anchors in stone buildings in the early 1980's and they are still there holding the whole caboodle up. There are original stainless steel bolts from 1965 in the Frankenjura and I've climbed and fallen on them.

Testing resin bolts is easy, just clip a biner in and try to twist it.

All the research shows resin bolts are more reliable than bolt-ins. Removal is a problem but that has to be balanced against their longer life. There's plenty of bolt-ins that can't be removed as well!