Surface
Preparation.
Surface Preparation – Nationwide
Sand Jet Cleaning – the Gentle Variation on Sandblasting
We provide a sand jetting service across all the UK, based in Yorkshire, we can easily reach all of Yorkshire, Lincolnshire, Nottinghamshire and Derbyshire, but regularly work further away than this. Sand Jetting is also known as grit blasting, sandblasting, shotblasting, JOS blasting, TORC Blasting, slurry blasting and vapour blasting; but we like to use the term ‘sand jet’ to identify this particular variation on the the theme of sandblasting; sometimes also referring to it as damp blasting, because it isn’t as dry as traditional grit blasting (and dust is suppressed as a result), but it also isn’t as wet as traditional slurry blasting (where dust is suppressed by a lot of water – resulting in a lot of water run off.)
Dry – Grit Blasting
There are occasions where traditional dry sandblasting systems have their benefits too; Generally these systems are more aggressive because, to obtain a consistent flow of sand, the valve on the blast pot has to be wider open compared to our wet system, but the lack of water means that the abrasive and debris doesn’t stick to a cleaned surface and so for some internal work, the end result can be less messy. So for some internal tasks we do recommend and use these dry blast pots. The picture on the left shows us using a tuned (low consumption, and very low pressure) sand blast machine to remove soot from plaster in a fire damaged house.
Traditional dry sandblasting (with the pressures turned down – and an eye on wood preservation rather than rapid cleaning) is the method we would normally use for internal woodwork.
Environmentally Friendly Chemical Paint Stripping
There are times when chemical paint stripping is needed. It can be considerably cleaner to use than abrasive cleaning, although generally the stripping agents return paint to its liquid state, and therefore reintroduce the mess potential of paint. The chemical we use isn’t the smelly traditional ‘Paint Stripper’ but a slow acting hydrogen peroxide based product, initially developed in Canada to strip paint from Aircraft. It is slow acting and works over around 24 hours. In general this is the technique to use for minimal surface damage. However as pressure washing is the most cost effective method for chemical and paint removal, some pointing etc. may be lost, more recently our Thermatec machine has provided a more gentle approach, which has worked well with projects in Leeds, Lincolnshire and Nottinghamshire.
Pressure Washing, rapid environmentally friendly cleaning.
We specialise in using a listed building approved low pressure sand jetting system used nationwide for property restoration. The system, in our trained hands, causes minimal damage to an underlying surface and is flexible enough to tackle most property restoration cleaning tasks.
That being so, there are times when pressure washing is an acceptable, environmentally friendly alternative. It is certainly cheaper rapid, and can be quite effective for surface contaminants such as algae and grime. Subsequent cleaning with the sand jet can remove stubborn stains. We have electric, petrol and diesel powered machines, and the big diesel machine will also generate high pressure hot water and steam. These cleaning techniques have been used effectively in projects in Lincoln and Derby.
High Pressure Water Jetting
While there are times when pressure washing is an acceptable alternative, for more aggressive work higher pressures become appropriate. 500 bar water jetting will rapidly and effectively remove paint from concrete and metalwork. One of the advantages of cleaning metalwork with HP water- Railings or fire escapes for example – is that there is much less flash rusting than when using grit blasting techniques. High Pressure water has the effect of removing loose paint and rust,but tends to leave well adhered primers etc alone. If necessary we can step up to clean metal with Ultra High Pressure water (to 2500 bar) which will remove all paint. But we mostly use these pressures to remove playground markings from school playgrounds.
Low Pressure, Superheated, Steam Cleaning
In recent years Stonehealth’s DOFF superheated Steam cleaning system has been widely promoted by conservation officers for the cleaning of surfaces with minimal damage. One of the developers of Stonehealth’s machine went onto form ‘Restorative Techniques’ and we actually use one of their ‘Thermatec’ machines – which provides the same service. Superheated Steam cleaning is very effective at dirt and grime cleaning – and will strip many paints – but much slower than our sand jet machine will achieve. This Listed Portico in East Yorkshire, for example, took nearly a week of (very wet!) cleaning to strip.
Dry Ice Blasting – grit free blast cleaning
There are times when alternative methods are called for, one of which is Dry Ice blasting. Here a surface to be cleaned is blasted with solid CO2 particles, and the surface is cleaned through thermal shock, the massive volume change as dry ice particles turn into gas, and some abrasion of the surface contaminant, making the process ‘grit or sand free’.
The advantage of this system is that the ‘abrasive’ evaporates on impact, so the only ‘debris’ is the material being removed. It is nearly ‘dustless’ – about as dustless as it is possible to get for an open blast system – however it will still blow cobwebs, birds nests, paint debris etc. fairly liberally!
It is used widely in the printing industry to clean print rollers, and for mould and weld cleaning.
Bristle Blasting – the hand tool that behaves like a grit blaster
One of the challenges we have faced over the years is to find a technique to safely remove the ‘stubborn’ patches of paint or dirt from a surface after we have used pressure washing, chemical stripping, sand jetting or even dry ice blasting. In 2013 we discovered that a hand tool we have had in our possession for a number of years – bought to clean up rust and ‘missed bits’ on blast cleaned metal (it is sold as a paint shop surface preparation tool) can be used on stone and brick as well. It has the advantage that the cleaning face is much smaller than with a sand jet, and can therefore be much more controlled. But the process is very like a hand held continuous belt grit blast – the teeth on the wheel act like particules of gri abd bristle blaster tool behaves like a sandblaster. It is however, still important to know when to stop!
Laser Cleaning
At long last, laser cleaning is becoming affordable for domestic and jobbing industrial applications. The system applies a scanning laser beam to a surface, and the contaminant is vapourised. We can now offer this service, it is possibly not the cheapest option, but if you are living in an open plan property then this could be the solution for you. It is very effective at removing smoke damage, less effective at removing white paint!
