glue in bolts

Glue in bolts are one of the two installation systems used on climbing routes. They are often referred to as Bühler bolts.

These fixed points belong to the so-called composite systems. Because the injection mortar connects to the rock on the one hand and the Bühler on the other.

Do you want to bolt a climbing route or set up a climbing route with glue in bolts ? Then you’ve come to the right place in our highly specialized Climbing Shop!

Largest selection of glue in bolts – Bühler bolts in the Alps

We are THE bolting professionals in the Alpine region. Consequently, you will also find a huge range of hardware here. Firstly, we stock all renowned manufacturers. Secondly, all steel qualities. And thirdly, we are the only retailer in the Alps to sell glue in bolt made of titanium. This means that we have the right glue in bolt for every application!

Here is an overview of the most common forms:

Pro’s and Con’s

Glue in bolts should always be preferred to expansion bolts. This is because composite systems have some clear advantages over so-called “friction systems”.

Below we give you a subjective overview. On the one hand, it is based on our decades of experience. And on the other hand on facts that are both logical and have been sufficiently researched in pull-out tests.

glue in bolt
expansion bolt

1 component
5 components (shaft, expansion element, washer, nut and lug)

Composite system = firmly connected to rock
Friction system = observe torque

Maintenance-free
Maintenance-intensive (e.g. retightening, if necessary, refitting nut, washer and tab)

No explosive effect
high explosive effect( notethe break-out cone!)

higher breaking loads
lower breaking loads

No bending possible
Tab can bend

for all types of rock
only “hard” rock types

No galvanic corrosion possible
Danger of galvanic corrosion (mixing steel grades)

Time-consuming installation
Installation is quick

not immediately loadable
immediately loadable

not suitable for roofs and very steep routes
suitable for all types of terrain

Installation must be very precise and careful
Installation relatively simple

Purchase and installation more expensive
Purchase and installation cheaper

Cheaper in the long term
more expensive in the long term

So why not always just glue in bolt?

If you look closely at the above table, you will immediately notice. The composite system has many advantages over the expansion bolt – bolt hanger combination. The following question therefore arises:

Why aren’t all climbing routes set up with the interconnected system?

The answer is relatively simple. Because expansion bolt can be installed much more quickly and easily, and also on steep terrain. In addition, expansion bolt can be loaded immediately!

In other words, the reverse is true. Firstly, the installation of Bühler hooks is slower.

Secondly, work has to be carried out much more carefully. Firstly, the drilling holes are much cleaner to clean. And secondly, filling the drilling holes and processing the injection mortar requires overview and experience.

As a result, the installation requires considerably more work steps and therefore more time.

Fourthly, composite systems are not immediately loadable. In addition, they cannot be used on very steep terrain.

A neatly placed glue in bolt is a much more sustainable solution than a expansion bolt with a tab! So why glue in bolt at all?
Given the predominance of expansion bolt in climbing areas, this is a good question.

However, the advantages are obvious. We have already listed them in the table above. In addition, we would like to point out further reasons why you still come across glued hooks time and again.
climbing area rebolting
Fortunately, the climbing area rebolting many places rely on glue in bolt. Firstly, the (old) anchor points are already in place. This means that the new bolts do not have to be loaded immediately.

Secondly, access is much easier and the final step of gluing can be done by rappelling.

And thirdly, the many advantages of composite systems have now been recognized. This is why this sustainable and maintenance-free option is increasingly being chosen for the renovation of climbing routes.
Climbing area construction
More and more climbing areas are being used for tourism. This means that very often we are no longer dealing with areas that have grown through the development of climbers.

As a result, aspects such as customer satisfaction and profitability play a major role sheave. On the other hand, the aspect of legal protection is becoming increasingly important for climbing garden operators.

The maintenance-free glue in bolt avoids some critical maintenance and therefore liability issues!

Prudent climbing garden owners opt for the best possible solution when building or renovating! Steel qualities
There are now glue in bolt with a wide variety of steel qualities on the market. These are intended for use in different environments. This is because different chemical influences prevail near the sea than in the Alps. It also makes a difference whether I am setting up a rope railing or a climbing route.

Consequently, you have to tailor your choice to the purpose.

Steel grades are usually indicated with the AISI* or A* designation. E.g. AISI 316L and A4 steel.

You can find more information on this topic in our technical article“Steel qualities at expansion bolt and glue in bolt“.

In any case, the piton must comply with the EN 959 – UIAA 123 expansion bolt standard.
Overview of steels at glue in bolt
AISI 304: CrNi stainless steel. Also known as A2 steel or V2A. Use of such Bühler hooks only in low-acid environments such as inner-alpine areas without air pollution.

AISI 316L: Particularly pure CrNiMo stainless steel. Also known as A4 steel. Use of such hooks in all inner-alpine areas without strong acidic fumes. Also up to approx. 50 km from the sea.

AISI 904L (HCR steel): Particularly pure NiCrMoCuN stainless steel with very high corrosion resistance. Suitable for bolting a climbing route even in acidic environments such as near the sea or next to factories with “acidic” exhaust gases.

Duplex steel: “Duplex steel is a steel with a two-phase structure consisting of a ferrite (α-iron) matrix with islands of austenite.” (Source: Wikipedia). The FIXE PLX steel is such a duplex steel. The main advantage of these hooks is their corrosion resistance. It is also less susceptible to stress corrosion. This means it is perfect for use near the sea and around industrial areas with lots of acidic exhaust fumes.

HCR steel: Only AISI 904L is a genuine HCR steel.

Titanium: The only true solution for bolting near the sea! These hooks are the most corrosion-resistant hooks currently available. Due to the metal properties, a titanium hook should not be welded. Consequently, they are perfect for bolting near the sea.

Only with us as the market leader can you get glue in bolt in all steel qualities! Round and oval shaft
Did you know that Bühler hooks differ significantly in their shank cross-section? There are two shapes due to production.
glue in bolt with round shank Cross-section
Firstly, the “round” hooks. In simple terms, they are manufactured as follows. Firstly, a piece is cut from a round steel rod. Secondly, it is bent into shape. Thirdly, it is finished at the end point using the TIG welding process.

The diameter corresponds 1:1 to the diameter of the base material (steel rod).

Hooks with a round shank require a drilling diameter of only +2mm. This means that they are much quicker and more economical to process.

Thinner drill diameter
Less battery consumption
Lower mortar quantity
Evenly enclosing the shaft with mortar
8mm hook diameter with 10mm hole already meets EN 959 standard

glue in bolt with oval shaft
On the other hand, there are the “oval” hooks. Here, a 6 mm steel rod is cut off. However, the piece is then “doubled” and bent and pressed.

This creates an oval shape of the shaft, as the press only presses from two sides.

The oval shape of the shaft has the following properties.

Drill diameter of 14mm required
more battery consumption
larger quantity of mortar
more irregular enclosure of the shaft with mortar

Setting glue in bolt (with grout)
Please familiarize yourself with the correct technique for setting the glue in bolt. This is a responsible task.

1.) Drill a hole wide and deep enough
2.) Do not forget the channel for the part of the carabiner eyelet on the side of the rock
3. blow out pumb or hole brush
4.) Insert enough injection mortar
5.) Insert the hook into the hole, turning it
6.) Spread any glue that has swelled out

Use squeeze guns!
We clearly recommend the use of a squeeze gun and cartridge mortar! This system is definitely preferable to glass mortar cartridges for systematic development.

Firstly, the amount of adhesive required can be controlled individually. Secondly, the injection mortar is mixed correctly straight away. And thirdly, gluing works with all hook sizes. This means that the Bühler hooks can be set perfectly even with just 2 mm more bored hole diameter.

How many glue in bolt can I process?

round shaft
oval shaft
drilling hole
300ml cartridge
360ml cartridge

8x80mm

10mm
20-22
25-27

10x80mm

12mm
18-20
20-22

10x100mm

12mm
15-17
17-20

10x120mm

12mm
13-15
15-17

12x80mm

14mm
16-18
18-20

12x100mm

14mm
14-16
16-18

12x120mm

14mm
12-14
14-16

12x150mm

14mm
10-12
12-14

12x75mm
14mm
18-20
20-22

12x90mm
14mm
16-18
18-20

12x110mm
14mm
13-15
15-17

glue in bolt Set with glass mortar cartridges
If you use glass mortar cartridges, there are a few critical things to bear in mind!
Firstly, you need to choose the right size or diameter. Ideally, the glue from the drilling hole should swell. You can then spread it under the carabiner eyelet.

Secondly, you have to drill the drilling hole larger than normal. Because with the coarse sand grains of the cartridges, +2mm is usually not enough. I.e. the drilling hole diameter = hook diameter +4mm!

Thirdly, you must rotate the stirrup hook at least 20 times through 360° when hammering in

For all these reasons, we do not recommend the use of glass mortar cartridges for larger glue in bolt. All Bühler hooks wider than 10 mm or longer than 80 mm should be processed with the squeeze-out gun.

Glass mortar cartridge recommendation

round shaft
oval barrel
Cartridge type

8x80mm

RM 8

10x80mm

RM 10

10x100mm

RM 10

10x120mm

RM 10

12x80mm

RM 12

12x100mm

not recommended!

12x120mm

not recommended!

12x150mm

not recommended!

12x75mm
RM 12

12x90mm
RM 12

12x110mm
not recommended!

Use the correct bonding mortar near the sea!
You need the right bonding mortar if you are installing near the sea glue in bolt. It is therefore essential that you check the specifications of your adhesive. We recommend the Fischer FIS AB 360 S.
Note: glue in bolt made of zinc plated steel
Climbing hooks of this steel quality do not comply with EN standard 959, which is why we strongly recommend that all climbing garden owners have their infrastructure inspected. In order to comply with legal regulations, annual inspections are mandatory anyway. Here, zinc plated glue in bolt should be removed quickly.

*Explanation of terms:

AISI: is the American designation for stainless steel classes;

A1-A2-A4: is the classic German designation of the stainless steel classes;