Diamond drilling porcelain tiles
Expert advice for professional installers on drilling porcelain tiles. By Richard Hazell
Richard Hazell standing outside the house at 7am. Its freezing cold with no natural light in this British winter so a fluorescent light is carried in.
Background: Recently I was asked to drill 150 holes into very hard porcelain tiles in four bathrooms over a weekend. This was an excellent opportunity to test our kits to destruction so I looked on it as a live exercise. Below are my experiences:
I decided to road test our product under the harshest of test conditions to make sure you - a professional tiler - can be totally sure I have experienced the worst a job can throw up. I also did it for myself because often I meet trade buyers in warm comfy rooms who want to pick holes into our kits. I want to be prepared. No surprises.
Property: The site was a new build with four bathrooms on four floors. One in the basement, One by the front door, one on the bedroom floor and one in the roof space.
General Conditions: The weather was bitter cold with sleet and rain.. There was no heating. Windows were fitted but external doors, garage and basement were open to elements and so working in freezing conditions meant thick layers of clothing. T-shirt. Jumper. External jacket and hat which obviously restricted my movement.
Most pipes can be bashed through in a less than elegant way
Working conditions: There were a mix of guys from chippies, electricians and plumbers competing for space, materials and basic utilities such as electric and water. In addition to the internal fitters there were guys outside working on a concrete pour with routine deliveries from cement trucks and others. Inside the rooms were dirty, poorly lit and had multiple power cables running from room to room. Each room had a mix of tools, materials, packaging and rubbish from old newspapers to unwashed coffee mugs. There was one outside portaloo but no tea or coffee facilities. A Dewalt radio played in the background and at certain times a loud sporadic burst of singing could be heard from one contractor to certain songs. His most popular "She's so lovely" By artist "Scouting for girls". shouting : "She's flirty, turned thirty Ain't that the age a girl gets really dirty?" (repeat). and insisting the song was written about Ulrika Johnson.
Fixtures of mirrors, first fix electrics onto very hard porcelain tiles
Morale: Was low from some of the thirteen people as they were working the weekend, it was dark with a lack of natural light and everyone was keen to be gone by 2pm each day. Morale was affected because the project was running at a loss for the contractors due to problems with the basement.
My timing estimate was that 150 holes would be 3 mins per hole or 450 mins of drilling or 8 hours of actual drilling times. This worked out to be accurate and equated to four hours of drilling per day. I was originally informed all areas would be pre-marked for me and I would simply drill the holes. However on arrival I was told contractors would mark the holes as I went. I asked if they could mark at least 12 holes per time.
First problem (for the contractors) was the drill noise. So they went off and marked holes in different bathrooms while I continued to drill. This meant following them from bathroom to bathroom so I had to travel light and carry everything from one room to another. This proved to me that equipment should be as portable as possible. I used a small paint kettle for water with a small sponge and put drill bits in my pocket. The heaviest item was the battery charger so I left that in one spot and went back to it for a recharge when I got a flat.
They were also keen to ensure the holes I drilled first were for heavy stuff like shower doors, sinks, cabinets and toilet pans so that they could do their job of fitting them. The problem (for me) came later because access to other holes was restricted by the fittings. So I had to take them back off the wall. For example I had to remove the loo pans, sinks and cabinets. It was easier to remove the items. Of course this added to (my) time on site. In hindsight it would have been more efficient to drill all holes first and then fit.
In order to test the durability of drills I did the opposite of the advice we give on site. I Drilled fast, applied pressure and used a minimal amount of water. Under the heaviest load the 8mm lasted about 5 to 6 holes before giving up. This is in line with our quoted pack life. So I am now confident that there is some redundancy in the drills if used correctly. But at least we can back up the 2-6 hole life with real field tests.
On the left is a clean hole that was drilled without breakage. On the right the hole has just started. In the middle the hole is being formed
After 150 holes I feel qualified to comment on drill tequnique. Over the weekend I adapted my technique The best way to drill is in bursts. Apply pressure to the drill bit then back off. Keep the sponge under the drill and withdraw it from the hole to cool it then push it back in hard against the tile for a few seconds. I found pulling the tip back until it was just at the edge of the hole but not completely out was the key to keeping it cool. Another must is not to break the core. This is the delicate part in the middle of the hole. If you snap it off its a bugger to poke out the core fragments. If you do manage to drill without snapping then it pulls out nicely in one smooth action. Word of warning is the core has a tendency to snap at about 90% into a tile. So you eject a broken plug then drill the final 1mm. But its this that gets stuck in the barrel and is a pain to poke out. The secret is not to move the drill too much. Hold as steady as you can. Believe me after 150 holes fatigue sets in so I found myself holding it in some funny ways. For example at waste height I pushed the drill with my hip and pushed the trigger with my wrist not finger. At the end of two days every bone in my body ached from cold, bruising and bumps. I think I had the equivalent to tennis elbow on my thumb from holding the drill for so many hours
Fitting items can restrict movement. This loo pan stopped the fixing of a loo brush on to the left tile. So it was refitted to the right tile
Final thoughts: At the end of the experiment I have a number of suggestions. If you drill aggressively change the cores every five holes because you can waste time getting the maximum life out of a core. It takes ages on hole 6. Try and stick with 8mm which give much more bite than 6mm. Its better to dump the rawl plugs supplied with the fittings and change to your own rawl plugs which are cheap enough to buy in bulk from many retailers. If you are going to drill that many holes then perhaps use a drill that has a button to keep it on. My figures were raw from the trigger. Dont be afraid to start off the holes dry. I used an old knackered core to start off most of the holes. Just dip it on a wet sponge to cool it.
Most fixing come with a cap to disguise hole drilling. If you are good enough then the caps can be removed...
I actually enjoyed my weekend and the guys on site were all good people. Having experienced the pain and the concentrated conditions myself I really appreciate what goes on in a job. One thing I was surprised at was the drill plate. I had put nice little thumb groove into the plate to indicate where to press it. But to be honest the plate can be held in any area. It was interesting to discover how little tile the plate needed to grip. I had that plate in all sorts of angles and working heights.