Few things are worse than old hardened gum on concrete. The four most common methods to remove gum are heated water, sand-blasting, flame, and chemical removal. Let's look at the pros and cons of each technique.
Heated Pressure-Washing
As with many things, the most expensive option is often the most effective. This is no more true than with gum removal. If you have ever had gum and drank something hot like tea or coffee, then you know that an increase in temperature weakens the bonds of chewing gum. When it comes to cleaning gum, this is a gem of a fact to know.
"The increase in temperature is inversely proportional
to the decrease in the strength of gum's bond."
How then can one increase the temperature for effective gum removal? Well, if you have one gum spot on your front sidewalk, heating a kettle of boiling water might do the trick. If you own a strip mall, you would be boiling water till the cows and the cows' grandcows come home before all the gum is removed. This is where commercial hot-water pressure washers come in.
Fire up one of these bad boys and gum can be removed in seconds. While this is the most effective gum removal technique it can also be the most expensive. The cheapest hot water units start at $3-$4k up to $10-$15k for larger commercial units. This price does not take into account the equipment infrastructure required to run this unit which may include: a mount (truck or trailer), water tank, hoses, and nozzles.
For the most challenging grease and oil stains, there are pressure washers that heat up to 200-300 degrees by way of a saturated steam infusion. This setup is primarily for automotive applications where heavy removal is required. High-pressure hot water units are more effective than strict steamers as the added agitation significantly aids matter removal. Interestingly, the pressure-washing industry was born by a bootlegger and a still that was converted to a steamer called a Pressure Jenny. To learn more, you can read our article called, 'The History of Pressure Washing.'
Sandblasting
If you don't have a heated unit (or $3k-$10k to spare) and are looking for a more affordable option to remove gum, sandblasting is an affordable and effective alternative.
This sandblasting attachment ($30 on Amazon) connects to any 3/8 pressure washer gun tip allowing an easy conversion from pressure washer to sandblaster in seconds. This gum removal method is cheap and easy to use but requires a small to medium-sized pressure washing infrastructure. The downsides of this method are the bags of sand required and the bucket of sand you will need to lug around. This method uses the downstream injection method commonly used to add cleaning and surfactant agents to pressurized water. The high-pressure water creates suction in this tubing that is attached to the pressure wand, and the metal end of this tubing (which is in a bucket of sand) sucks up some sand creating what can be called 'Pressurized Cold Sand Water'. A title that I have coined for lack of a better term. This method does tend to create a lot of sand that must be either rinsed after use or blown off after the water dries. Lastly, it is important to not use too much sand in one place as this method can remove concrete.
Flame
If you are on a tight budget and don't have much gum to remove, there is another easy method that works well provided the gum is not decades old and has all but become one with the concrete. Stocked at all home-and-garden stores, a little propane flame torch can be used to apply direct heat and weaken the bonds in the gum enough to remove by scraping and/or a cold pressure washer system. And that is pretty much it for this method.These cheap tanks and added attachments might cost you $50 max and can also double as a firestarter, wasp killer, and firework lighter to name a few other uses. Just be careful not to hold the fire on the concrete too long as it has potential to discolor the concrete. If the gum doesn't come off relatively quickly, it is recommended to try another method.
Chemical
The last gum removal method on this list is chemical application. There are a myriad of chemicals that can be used ranging from $5 to $50+ dollars depending on where and how much you want. Some chemicals are designed to break the bond of the gum allowing for easy removal, other chemicals actually freeze the gum allowing it to be manually scraped off. This method is pretty self explanatory and is cheap but does require a little manual work.
In conclusion, there are several methods available for gum removal ranging from $10 to $10k. A lot depends on whether the removal is for commercial or residential applications. If you own or want to own a pressure washing business and don't have thousands to spare, sandblasting is the cheapest and most effective method that can be added to most any pressure washer. If you have a bigger budget, a hot water unit is a must as it is quick, effective, and doesn't require buying, carrying, or cleaning sand. Lastly, if you are a homeowner or businessowner with 1-10 gum spots to clean, chemicals would be the place to start.
Happy gum freezing, bond-breaking, scraping, blasting, and melting!
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