Glue Types

There are many types of glue

If you are placing ringbolts or U-bolts then you must use an injection glue system. Most bolt manufacturers produce high quality glue which is injected using a brand-specific caulking gun. The two parts of the glue are mixed through a disposable nozzle and the end result is optimally mixed glue which cures somewhere between a few hours to overnight (depending on the brand). It is very messy and requires diligent attention to detail and quality control. The easiest way to make an obvious, messy and bad bolt is to try and place rings without practicing first! Of all the bolting systems, this one requires reading in detail the manufacturer's installation guidelines.

Glue-in anchors transmit the load of the anchor over a wider area of rock than expansion bolts ever can. This means that the load is spread over the entire area that the glue bonds with the rock. This in turn means that the anchor is more reliable in general.

It's not about "strong enough"

Cheaper construction adhesives are typically polyester-based or vinylester-based. If used correctly, they are "strong enough" for climbing bolts. But that is not the issue. You read above that we have been using all types of glues for the past 50 years in Australia and we now know that these cheaper glues break down over time. We see this in cracking and flaking of the glue around the notch. This then leads to flexing in the bolt shaft, which will ultimately result in failure of the bolt (this has been tested and confirmed both on cliffs and in a scientific setting). Sometimes they can be pulled out by hand.

When we bolt routes now, they are not for today, or this year. Every route bolted produces a maintenance task for future climbers. We need to always be thinking 50+ years in the future and trying to minimise the route maintenance required. The way we do this is by choosing the appropriate bolt type, and critically, the best glue with the best lifespan. Epoxy is the only glue that will provide a 50+ year lifespan. We use and recommend the listed epoxy-based glues because they are non-porous and come with ETAG (European Technical Approval Guideline) certification giving a life expectancy of at least 50+ years for use in life critical applications. Some even come with a 100 year rated design life.

✅ 100% Epoxy Glues (best practice)

Ramset injection glue gun

Hilti RE-500 - the gold standard of epoxy

Epoxy. Only epoxy!

Epoxy wins. Source

Typical polyester glue breakdown.
This bolt was pulled out by hand.

Do not use capsules! Injection only!

❌ Polyester and Vinylester Glues (do not use!)

Half the strength of epoxy, and shorter lifespan - no longer considered good practice to use, despite widespread continued use due to the fact they are cheaper. Safer Cliffs Australia strongly recommend all route developers worldwide cease using non-epoxy adhesives!

Examples no longer recommended:

• ❌ Ramset 750ml 801 XTREM XC² (note that '801' was originally a 100% epoxy glue which was re-released in 2018 as a lower quality Vinylester)

• ❌ Ramset ChemSet 101 Plus (Polyester)

• ❌ Powers AC100+Gold (Vinylester)

• (Hilti: Have stopped producing polyester glues)
  

❌ Capsule Glues (do not use!)

Capsule glue ampoules in construction adhesives are pre-measured, sealed containers—often made of glass or plastic—that contain a two-part chemical adhesive system. Commonly used in the 1990s, they seemed like a good idea at the time, but no longer. They are fraught with issues including problems with insufficient mixing, but most notably, they do not contain enough glue to fill the notch required to properly recess a ringbolt. Do not use them.

The Book of Glue (Bolting Bible - howNOT2.com)

"The Book of Glue" is a comprehensive up-to-date resource from the guys at howNOT2.com and well worth reading. Please note we do not agree with everything in this guide (for example, we only recommend the use of epoxy glue), so do keep that in mind.

Read The Book of Glue here