Dust Sealing

David Cook — 6 August 2018

If there is one thing that gets up the nose of every camper – literally as well as figuratively – it’s a fine layer of dust spread across the interior of the trailer after a day’s travel. And it’s not necessarily limited to the bedding and the floor – it can be inside cupboards, inside drawers, on the bench and even in your coffee cups.

Australia specialises in fine dust: intrusive, pernicious, sticky, red dust. It’s the type of dust that can seemingly infiltrate anywhere or anything; a dust that knows no bounds. It doesn’t have to be from the deep holes filled with bulldust in the far outback either, it can be a fine layer of dust across that short track down to your favoured riverside holiday spot. And just because you only had a few hundred metres to creep down, you just know that the steady rumble of traffic on that track behind your campsite is going to be kicking up fresh supplies as long as you are set up there.

There is not much you can do to limit the dust that arrives while you’re camped somewhere. You need the windows open to get air flow through – unless you’re one of the lucky few with a camper trailer which enjoys air-conditioning – and the door has to be opened every time you go in and out. And you just know it’s going to come in on your shoes and your clothes. But that fresh coating of red or beige you get when you first pull up is largely fixable, with a little care and attention to detail.

PINCHWELD SEALS

All camper manufacturers use proper pinchweld rubber seals on opening doors and windows these days – and if they’re not they ought to be – and we’re going to assume they’ve chosen the correct profile to suit each application. It is vital that there is no kinking of the bulb – the tubular section that is compressed by the closing door – or that the bulb is compressed no more than 25-50 percent, as failure to meet these standards will lead to dust and water leaks.

If your pinchweld has no tears and is not too old – so that it hasn’t started to harden – you should be fine. Give it an occasional wipe over with a silicon-based spray on a rag as this will prevent it sticking to the mating surface, which can result in it damaging the outer surface of the rubber and compromising the seal. Avoid using an oil-based spray as it will hold any dust it comes in contact with and become a problem all on its own.

COMPRESSION LATCHES

Most latches on doors to outer storage lockers and better entry doors to campers will have a compression factor to them, to assist in sealing. Compression latches are set at manufacture to seal the doors against the new pinchweld seals but may require fine-tuning (simply by adjusting the locking nut/s on the interior) after a year or two to slightly tighten the pressure on the pinchweld bulb. Remember, you don’t want to compress the bulb by more than 25-50 percent as it can over-compress and leave it without the resilience to make a proper seal with the door.

One of the issues with compression latches and keyed locks is that dust can and will build up inside the actual lock if you travel on very dusty tracks. If you’re in the outback and away from ‘civilisation’ you won’t be needing locks anyway, so tape up the latches to keep out the dust.

WINDOWS

Windows can be a prime source of dust leaks if not sealed properly. Sliding windows must seal against the stationary pane, and will require a good sealant material to maintain a dust-proof match. There are proprietary dust seals available that will dustproof all such points.

Any sealant around existing windows which has gone hard and begun to break up must be replaced. You can use silicon-based materials if you are clear of contact with bare metal (it will react with the metal) quite successfully but they will become quite dirty externally with exposure to dust. Some proprietary products such as Sikaflex or Bostik resist this issue.

Re-sealing around windows is not a difficult task, but is too detailed and lengthy for us here. If you don’t feel up to it, there are many professionals out there who can do it for you.

DUST ENTRY POINTS

Any hole cut in the external shell of your camper is a potential dust entry point, thus most of the better offroad campers will have minimal holes. Exhausts for heaters, hose entry points, heater ducts at the back of refrigerators, drains, gas hoses, electrical cables and many other such necessities create opportunities for dust to get in and make a mess.

Look for drain or other points which you have open while camped but which you don’t need while travelling, such as shower and sink drain points. Place plugs over the internal entry to these drain points or put caps on the external drain outlets to prevent dust ingress. Just remember not to forget to remove the plugs and caps you’ve installed when your camp spot is set up, and to reinstate them before you tow off.

Three-way gas fridges require vent covers to allow the heat to escape from the back of the fridge. Excess heat behind the fridge limits its effectiveness and having a vent permits you to usually be able to access and clean the evaporator coils behind to ensure they are best able to do their job of dissipating heat. Don’t leave the cover on when you light the fridge as you’ll simply melt the exhaust cover.

Leaves and twigs under dust seals on pop-top roofs can be a major source of leaks for both dust and water, allowing ingress of both. Check around the dust seals’ pressure points along the roof line and clean them off as necessary before lowering the roof, especially in leafy areas. A tennis ball on a length of light rope thrown over the gap point and pulling over an old towel will remove any unwanted matter, and a simple wipe with that same old towel along outer edges will complete the job. Alternatively, a small rechargeable leaf blower will usually clear all sticks and leaves, as well as external dust, and can be quicker and more convenient.

Make sure your roof on a pop-top or tilt-top is well clamped down as the capacity for a roof to ‘walk’ from side to side as the camper traverses rough road surfaces can permit dust to make its way past any seals.

PRESSURISED INTERNALS

One could argue that dust forces its way into the camper, but you can just as reasonably argue that it is only where the pressure outside is greater than that of the interior of the camper that dust can and will enter. To resolve this, some manufacturers and handy camper owners have taken to providing positive pressure principles in the construction or fitout of their campers.

This usually results in the inclusion of a fan on an external surface or an air scoop on the roof which forces air into the camper’s interior. These either draw air in or push air through an air filter – usually one from a popular motor vehicle for ready availability. The internal pressure only has to be the tiniest fraction higher than the natural external air pressure to ensure a dust-free environment inside.

Air scoops should be fitted towards the front of the camper and up high to keep them out of the dust from the tow vehicle. Snorkel scoops can do a good job of achieving this. One of the issues with unpressurised scoops is that they depend on the motion of the camper through the air, so that at low speeds – which is what you will be doing on rough tracks – they are less effective.

Fans for this use should have a 100 percent duty cycle rating as they will be running constantly for long periods of time. Boat bilge blowers can do a good job in this regard. But avoid high current draw fans so you can limit consumption of valuable battery power.

Some smart owners have connected the fridge box – which usually has a fan to pump in filtered cool air to assist in displacing fridge heat – to the camper body to ensure there is positive pressure to keep out dust. Remember, the interior only needs to be the tiniest bit higher in pressure than the outside.

Air-conditioner units, which have an entry point to the camper’s interior air space, can be a serious point of entry for dust.

Effective use of positive pressure solutions requires that you have a tight seal on exit points for air to retain the higher internal pressure. To make sure you’ve done a good job of minimising both air exit and entry points, place a bright light inside your camper and in the night look for pin-hole points of light, especially around inner guards, corners, where body panels meet or where any of those service cables and hoses enter or exit the camper. Then seal up everything. Expanding foam can do the job in hard-to-get-to areas which are out of sight, or adhesive-backed foam tape might be an answer.

And in the wash-up of it all you then hope for the best and that you’ve done all that’s necessary, because dust never sleeps.

 


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