Over the years we have worked with people across a vast range of sectors and in a huge variety of environments. Although each requirement often poses its own unique challenges, we have found common threads that are relevant to a large number of applications.

In this FAQ section we have cherry-picked a handful of the questions we come across most often, so that you can quickly learn and understand how a seemingly uniquely challenging situation might have a well-established path forward.

Diamond Chainsaws

Yes, diamond chainsaws are ideal for cutting brick, block, stone and reinforced concrete in order to create new door and window openings. Diamond chainsaws can cut materials up to 63cm thick from one side. For deeper applications more specialist equipment may be required. It's important to make sure there are no utilities running in the cutting path, so make sure you carry out the necessary checks before getting started.

Diamond chainsaws grind away at the material being cut using industrial diamonds. There are diamond chains for cutting construction materials such as brick, block natural stone and reinforced concrete.

There are also utility diamond chains that are typically used for cutting pipes made of ductile iron, cast iron, plastic and asbestos cement. Water is delivered through the guidebar to cool and lubricate the chain.

During the cutting process, slurry is created which can wear away at your guidebar and chain. The water supply helps flush the slurry out of the cut increasing the life of your bar and chain.   

Diamond chainsaws can create openings as small as 100mm square. Diamond chainsaws are designed to safely plunge the nose of the machine straight into the material being cut, so are ideal for creating small square or rectangular openings.

Diamond Chainsaws offer the ability to make deeper cuts in hard materials over alternatives like disc cutters and grinders. They are also able to cut square openings cleanly with no overcuts. 

Using a Diamond Chainsaw enables you to cut up to a depth of 630mm without requiring access from both sides of the cut.

Stone walls can be repaired safely and efficiently by using Diamond chainsaws to cut through mortar joints and remove individual damaged stone. This is a commonly used technique on historical buildings such as churches and castles etc.

Yes, for dust suppression, lubrication and cooling. Diamond chainsaws produce abrasive slurry which requires a continuous water supply to flush the abrasive debris out of the cut and the chain. A typical domestic water supply of at least 1.5bar and 4 litres per minute is perfectly adequate.

Diamond chainsaws can cut pretty much all masonry materials plus reinforced concrete. In addition, there are specific diamond chainsaws for cutting pipes used in the utility industry. These utility diamond chainsaws can cut ductile iron, cast iron, plastics and there is a hydraulic utility saw which is approved by the UK Health and Safety Executive for cutting asbestos pipe.

All chains have a tendency to stretch when used. Diamond chains stretch more than wood cutting chains because of the abrasive materials they cut. If the chain is too tight, a lot of the machines power goes into turning the chain and not into the cut. In extreme over-tightened cases, the power cutter may not be able to turn the chain at all. In addition, the bar, chain and drive sprocket can be damaged if the chain is too tight.

If the chain is too loose, the chain could be thrown off the bar, or allow the sprocket to turn without turning the chain, which will damage the drive links.

This depends on the manufacturer's guidelines, so it is best to consult an operating manual. Guidebars are designed to be used on both sides. If the cut is consistently leading to one side, turn the guidebar over. It is recommended to turn the guidebar over with every new chain. You will typically use 2-3 chains for every guidebar.   

A fuel/oil mix of 50:1 is recommended unless otherwise stated on your saw. That equates to 100ml of oil to 5 litres of unleaded petrol.

No you cannot. There are specific differences between wood cutting chainsaws and diamond chainsaws that prevent them from working interchangeably.

No you cannot. You should never enter a slot narrower than the diamond chain. There are some special pre-cutting blades available to use before a diamond chainsaw but the segments should be at least 6mm wide to avoid pinching. Never enter a slot narrower than your diamond chainsaw chain. 

Yes, diamond chainsaws can cut rebar embedded in concrete. You should cut concrete at the same time as the rebar by rocking the saw. This prevents the diamond segment from glazing.

A diamond chain can cut through up to 22mm rebar. Large amounts and larger sized rebar will reduce the chain life. Caution: rebar must be surrounded by concrete or aggregate material.

It’s time to replace your chain when the diamond segment is worn down to the welded pad on the chain chassis. Typically, a chain will cut 12-24 linear meters in 15cm concrete. If using hydraulic machines this range is most often doubled.

There are diamond chainsaws available that use special chains to cut ductile iron, cast iron, plastic and asbestos cement pipes. These utility diamond chainsaws use chains that incorporate a revolutionary grinding action which eliminates rotational kickback.

Historically, contractors used petrol disc cutters in the trench for cutting pipe. To cut the bottom of the pipe the operator pulls the wheel guard back to expose the top of the blade. If, whilst cutting the blade is trapped by the pipe the machine rotates instead of the blade, this is called rotational kickback.

Rotational kickback with disc cutters has resulted in serious injury and even death to the operator. Utility chainsaws if trapped simply stall, removing the chance of rotational kickback occurring.

For this reason, water and wastewater companies worldwide are utilising utility chainsaws for safe cutting of pipes. Other benefits of these saws include, reduced operator effort, reduced excavation size, straighter and faster cuts.   

Underwater Cutting Tools

There are generally two types of tool used underwater, pneumatic and hydraulic. Hydraulic tools are better than pneumatic tools for a number of reasons.

Hydraulic tools are typically more powerful, the system is sealed, therefore preventing water getting into the working parts and hoses etc.

When air tools are used underwater, water often finds its way into the working parts of the machine, scrapping the tool. Also, when air tools are used underwater the exhausted air can make it difficult for the diver to see what he is doing.

Hydraulic tools can be more expensive than pneumatic tools but when maintained hydraulic tools will last for many years. Remember, you cannot use any hydraulic tool underwater. Underwater specific tools have features that make them suitable for use underwater, at depth, such as special seals which stop water ingress into the tool.

Some tools such as breakers can ‘hydraulically lock’ when used underwater unless they have holes drilled in parts of the body to allow water to flow in and out during the hammer action.  

Hydraulic tools are typically more powerful, the system is sealed, therefore preventing water getting into the working parts and hoses etc. When air tools are used underwater, water often finds its way into the working parts of the machine scrapping the tool.

Also, when air tools are used underwater the exhausted air can make it difficult for the diver to see what he is doing. Hydraulic tools can be more expensive than pneumatic tools but when maintained hydraulic tools will last for many years. 

There are a number of hydraulic drills available for drilling concrete. For non-reinforced concrete there are SDS Plus and SDS Max rotary hammer drills capable of drilling holes up to 50mm diameter.

For reinforced concrete or holes larger than 50mm you need a core drilling machine. The core bits are diamond tipped and grind through the concrete and reinforcement.

There are underwater hydraulic core drills for hand held use which can also be mounted in a stand for larger hole sizes. These rig mounted core drills can easily drill holes of up to 250mm in diameter but larger sizes are possible.

Depending on the diameter of the hole and the depth required there are a variety of hydraulic drilling machines available. There are 2 sizes of rotary SDS hammer drills available for drilling holes up to 50mm in diameter and up to 1m deep. There is a Stanley hydraulic hammer drill which can drill holes 51mm in diameter and 74cm Deep. If you need to drill holes 6m deep and up to 76mm in diameter you can use a hydraulic underwater sinker drill.  

For reinforced concrete or for holes larger than 76mm you need a core drilling machine. These drills use diamond tipped core bits to grind through the concrete and reinforcement. There are underwater core drills for hand held use which can also be mounted in a stand for larger diameters. These rig mounted core drills can easily drill holes of up to 250mm in diameter but larger sizes are possible.

Hard marine timbers are commonly used in coastal marine construction. These timbers such as Greenheart can be incredibly tough to drill and cut.

Hydraulic drills offer lots of power and coupled with high quality wood auger bits can be very efficient. A hydraulic impact drill is very effective when drilling these materials as there is no rotational force imparted on the operator due to the impact action.

Greenheart is a very hard and durable timber, commonly used in marine civil engineering projects. Whilst tough, it can be cut using hydraulic underwater wood cutting chainsaws but the wood will often have marine growth and sand embedded into its surface.

These hard and abrasive materials will blunt a chain very rapidly making wood cutting chainsaws frustrating to use on this material. There is a relatively new diamond chainsaw fitted with a type of diamond coated chain which can efficiently cut Greenheart and similar timbers. Whilst the diamond chain cannot cut as fast as a new wood chain, the rate of cut is acceptable, 2-3 minutes for a 12 x 12” square section.

The diamond chain has several advantages, it is very safe to use unlike a wood cutting chainsaw, the diamond is literally unaffected by marine growth and sand on the timber and therefore one chain will last a long time.

The type of diamond chainsaw that can run the diamond coated chains for cutting Greenheart can also be used fitted with a different chain for cutting concrete, brick, stone and rock etc.   

There are two types of hydraulic drill which can be used to drill metal underwater. Pistol drills fitted with standard 3 jaw chucks are capable of drilling holes of up to 15mm when using blacksmiths or step drills.

Then there are magnetic drills which secure themselves to the metal being drilled by a permanent magnetic base. These types of drills use a cutter rather than a drill bit and can drill sizes from 12-100mm. 

Yes, depending on the hardness of the rock or concrete and how much material you need to break or chip there are two types of product you can use for this task. Hydraulic underwater chipping hammers are suitable for light breaking and chipping of rock etc.

For heavier breaking tasks you need to move up to a hydraulic breaker of which there are different weights of tool delivering varying degrees of blow force. In general, the heavier the breaker the more powerful it is.

First of all you need to understand the type of wood to be cut, is it a soft or hard wood. Soft woods can be cut by underwater hydraulic wood cutting chainsaws.

If you are cutting one of the very hard marine timbers such as Greenheart, you may be better to use a diamond chainsaw with a diamond coated chain.

Hard marine timbers when in water for some time will be coated in marine growth and often sand also. This will blunt a standard wood chain very rapidly. The diamond coated chains are pretty much unaffected by marine growth and embedded sand.

The other advantage of the diamond coated chains is that they are very safe to use in comparison to a standard wood cutting chain. 

There are a number of hydraulic tools you can use to cut pipe underwater. First of all, you need to consider the size of the pipe and the material it is made from.

Small diameter pipes of under 100mm can be cut using a 5 or 9” hydraulic angle grinder using abrasive or diamond coated blades but you will need access all the way around the pipe. 

Pipes made from ductile iron, cast iron and plastics can be cut using a diamond chainsaw with a special diamond coated chain.

Steel pipes can again be cut using angle grinders or larger pipes may be cut using a hydraulic cut off saw similar to a wood cutting circular saw. Larger, structural steel pipes are typically cut using specialist wire saws.

How deep do you need to make a cut in the rock. If you need to make a cut of only 80mm you can use a hydraulic cut-off saw fitted with a diamond blade.

If you need to make cuts of up to 63cm deep you can use an underwater diamond chainsaw. These saws use chains fitted with diamond segments that grind through the rock or reinforced concrete.

If you need to clean concrete underwater, for example so that you can pour more concrete on top and you need the two to key together, you can do this using pumps. A suitably powerful, hydraulically driven submersible pump fitted with a gun to the discharge hose has proved to be very successful.

Guns can be created with two opposing nozzles so that you can balance the forces created. If each nozzle has a valve fitted, this will allow the operator to play with the flow so cleaning performance can be fine-tuned.      

There are a variety of products available for cleaning boat and ship hulls and propellers. The area you need to clean will dictate the size of tool you need. If the area is not too large a hydraulic grinder can be used fitted with a variety of different brushes and wheels depending on the level of aggression required to remove the material. 

For large propellers coated in marine growth hydraulic underwater grinders and hull cleaning brushes are ideal. There are various brushes and wheels available depending on the level of aggression needed to remove the growth that are specifically designed for use by divers.

Scotchbrite type wheels can be used for gentle finishing, wire wheels for medium duties and barnacle bashing wheels for the heaviest of work. 

Steel chains can be cut underwater by using hydraulic underwater grinders fitted with abrasive or diamond coated cutting discs.

Heavy rope can be difficult to cut underwater especially if it is wrapped tightly around shafts etc. Hydraulic underwater angle grinders and straight grinders can be fitted with diamond coated wheels and will make short work of this task.

Some marine construction tasks can involve the tightening and loosing of many nuts. This task can be time consuming and tiring underwater. Hydraulically powered impact drills and impact wrenches can make light work of this task and depending on the size of the nut different sized tools are available. The impact action of these tools makes them easy and safe to use for the operator.

Sand, gravel and sludge underwater can be moved from one place to another using hydraulically powered submersible and trash pumps. The product to be moved can either be agitated by an air lance with the pump next to the lance or a suction pipe can be fitted to the base of the pump and plunged into the material. There are trash pumps cable of moving rocks up to 4” in diameter when suspended in water.

Buoys can be secured in place by either a very heavy weight or by using a ground anchor. There are a variety of ground anchors available and they are all inserted by using a hydraulic underwater breaker. The breaker typically uses an insertion tool, once inserted the anchor locks in place when pulling force is applied to it.

Pontoons and similar floating structures can also be secured in place using ground anchors. 

Depending on the size and shape of the plastic, diamond coated discs can be used fitted to hydraulically driven underwater angle grinders or straight grinders. For pipes or thicker material, you can use a hydraulic underwater diamond chainsaw with a diamond coated chain.

This product can cut plastic pipes from one side of up to 63cm in diameter. The chain has a course diamond grit coating which grinds away at the plastic. Use of these types of chainsaw are very safe as you have no razor-sharp cutters like you do with a wood cutting chainsaw.

You can cut and grind metal underwater using a hydraulic underwater angle grinder fitted with either abrasive or diamond coated discs. 

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