Stainless Expansion Bolt with Fixed Hanger

Note: It is the considered opinion of Safer Cliffs Australia that glue-in bolts should be favoured over expansion bolts unless there is a compelling case otherwise.

Expansion bolts are easy to place, strong and readily available. Mechanical bolts work by either expanding of compressing - gripping the rock by pressing against the wall of the bolt hole. The pressing action creates friction between the anchor and the rock; for the bolt to pull out, the applied load has to overpower this coefficient of friction.

Expansion bolts are expensive as a unit as you have to purchase a commercial hanger on top of the expensive bolt. If you are only placing a few bolts then expansion anchors are the best place to start as the cost outlay for tools is very small compared to glue in anchors.

• Pro: You can use them immediately after placing
  
• Pro: Almost ‘fool proof’ to place
  
• Pro: Less tools to buy
  
• Pro: Hanger is replaceable
  
• Pro : Likely to show signs of working loose if in marginal placement
  
• Con: Bolt and hanger deforms after repeated falls
  
• Con: Hanger can be stolen and bolt tampered with
  
• Con: Bolt can loosen
  
• Con: Rust can occur when two grades of stainless (i.e. bolt & hanger) are forced together

Recommended brands/models for medium to hard rock only:

Ramset 12mmx75mm SS Hex-Head Dynabolt DP12075HSS
Powers Flush Head Sleeve 12mm SS FHS1275SS
Powers Power-Bolt Anchor 12mm SS RBHM1370SS
Fixe 12mmx75mm Triplex SS Expansion
Hilti 12mmx102mm SS HSL-G-R

Recommended brands/models for hard rock (granite)

Ramset 10mmx65mm SS Trubolt T10065SS
Powers Through Bolt 10mmx50mm SBA1050SS

Glue in Ring Bolt

Glue in rings are the strongest and most hard wearing of all the bolt types. They are complex to place however and involve quite a bit of expensive equipment to place. For a ring with a rod diameter of 10mm - a 12mm hole must be drilled and a large notch to recess the ring must be drilled. They must be recessed to stop the ring twisting out of the hole. You can only use injection gun glue with rings as the capsules never have enough glue to fill the notch. Historically, most ring bolts placed in Australia were homemade however this is changing thanks to greater availability and Safer Cliffs Australia now only endorse the use of commercially available EN959 certified bolts.

Before use it is important to prepare the ringbolt so it achieves maximum bond with the glue. Wash the entire ring with soapy water (or acetone) to remove any grease. This removes any residual chemicals left over in the manufacture of stainless steel. Ensure the the ring is appropriately recessed - this prevents the unit turning in the hole and breaking the glue bond. Do not over-recess as this can bind carabiners and snap them.

• Pro: Eye fits multiple carabiners and can be lowered off from
  
• Pro: Bolt cannot be stolen or tampered with
  
• Pro: Good in soft rock
  
• Pro: Longest service life
  
• Con: Messy to install and takes up to 24 hours before you can
  
• Con: Hard to replace
  
• Con: Tools are expensive (caulking gun)
  
• Con: Likely to pull out without warning if placed incorrectly

Recommended brands/models

Raumer
Fixe
Petzl

Glue in U-Bolt (aka Staple)

Historically, U-bolts were the cheapest of the bolting solutions for bolting steep rock. They are moderately easy to make at home using 10mm 316 stainless steel rod. Due to the ready availability of commercial ringbolts (and U-bolts), Safer Cliffs Australia no longer endorses the use of homemade U-bolts.

The biggest problem with U-bolts is the requirement to drill two holes per bolt, and they are known to be slightly more dangerous than ringbolts as they can cause carabiners to unclip. One of the biggest advantages is that they usually require light hammering to get them into the two holes which means they stay in the rock when the glue is drying - which is great when bolting roofs. You can only use injection gun glue with U-bolts as you cannot spin the bolt into capsules. U-bolts have been known to fail in extremely soft rock because of the close distance between the two legs. Most U-bolts have a minimum leg spacing of at least 45mm.

Before use it is important to prepare the U-bolt so it achieves maximum bond with the glue. Wash the entire U with soapy water (or acetone) to remove any manufacturing chemicals.

NOTE: Be careful to ensure that your holes are straight and the U-bolt fits without excess hammering required. The stress this places on the metal has led to premature stress corrosion cracking (SCC) and complete bolt failure.

• Pro: Eye fits multiple carabiners and can be lowered off from
  
• Pro: No welding required
  
• Pro: Stays in overhangs when drying
  
• Pro: Bolt cannot be stolen or tampered with
  
• Con: Hard to install and takes up to 24 hours before you can use it
  
• Con: Hard to replace
  
• Con: Tools expensive (caulking gun)
  
• Con: High visibility
  
• Con: Likely to pull out without warning if placed incorrectly

Recommended brands/models

Fixe
Titan Climbing

Injection Glue

If you are placing ring bolts 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 perfect mixed glue which dries somewhere between a few hours to overnight (depending on 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 systems this one requires reading in detail the manufacturers 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 bolds with the rock. This is turn means that the anchor is more reliable in general because it is usually impossible to visually identify internal rock fault lines.

✅ 100% Epoxy Glues (best practice)