Maintenance and repair
Due to a heavy-duty fabric shell and sturdy seams, Thermarest and other quality, self-inflating air mattresses are sturdier, less likely to leak than most inflatable air mattresses, and thus have a longer warranty.
Determining if the pad leaks
According to Thermarest, the following method can be used to determine if a self-inflating pad leaks:
This method allows campers to easily check a self-inflating pad for leaks before camping. It does not require that you sleep on the pad, use bubble soap, or immerse the pad in water.
Warranty repairs
Family campers may want to consider whether to find and repair a self-inflating mattress leak themselves, or to use the warranty and let the manufacturer deal with it.
Thermarest and other manufacturers of quality, self-inflating pads have a repair department and, if the pads have not been abused or neglected, can make free warranty repairs on leaking pads.
Campers who can do without the mattress for a week or two can ship it to the manufacturer's repair shop for them to find and repair the leak, or if the pad cannot be repaired, to replace the pad. This saves campers the time and effort of finding and fixing the leak and ensures that your self-inflating mattress will perform well for the duration of its life.
Since manufacturers of quality, self-inflating mattresses often offer a lifetime warranty, they can repair a mattress years after it was purchased.
If the warranty applies, the manufacturer may ask that campers pay to ship the pad to the factory for repair, and the manufacturer will pay to ship it back. The pad is light and ground freight should be reasonable.
A likely cause of a non-warranty repair is probably a puncture or burn on the fabric, or some other sign of abuse or neglect. Some manufacturers will do non-warranty repairs for a fee.
Manufacturers of less expensive, self-inflating mats should offer to exchange the mat within the warranty period for defects in material and workmanship. The warranty will extend a certain period of time, but not for the life of the unit.
Do-it-yourself, self-inflating mattress repair
Camping stores and Thermarest offer repair kits for those who prefer or need to repair their own self-inflating mattress.
The repair kit and its instructions may involve several steps including:
Do-it-yourself repair is suitable if a warranty repair is not possible or timely, campers are at the campsite or if they are comfortable doing such repairs themselves.
Finding the leak
If the valves are closed, and the pad is leaking at night at the campsite, it can be very difficult to effect a repair before the morning without a field repair kit. It may also be more difficult to repair at a campground than at home, where there is access to more equipment to find the leak.
Inspect the self-inflating mattress for an obvious puncture. Check both top and bottom fabric surfaces.
Check any clothes you wore to bed for any pointy items. Check the floor of the tent below the mattress for any sharp objects protruding from below. If you find any sharp objects, then check the spot where the pointy object may have pierced the mattress shell.
If there is no visual sign of a leak, try inflating the mattress, applying pressure, and listening around the valve and fabric surfaces for a leak.
Tip: Applying pressure to a thin self-inflating air pad generally means folding it in various positions and then pressing against it.
Blowing bubbles
If the above two methods fail to find a leak, the next method involves more work and preparation.
Start with the valve. Inflate the pad and either:
Then apply pressure to the pad and see if any air escapes from the valve.
Twist valves are sturdy and generally do not leak—they are more likely to fail from abuse. They are also easy to test and rule out, allowing campers to focus on the rest of the fabric shell.
If the valve does leak, one manufacturer (Thermarest) offers a replacement valve kit.
To check the fabric for a leak:
Repeat this process with different fabric sections facing the top until you find the leak. Check the bottom fabric, if necessary.
Because Thermarest self-inflating pads have a sturdy, wide, fully-bonded seam that extends 1/2 inch around all sides of the pad, the fabric is much more likely to fail (leak) before the seam does.
Either a defect in the fabric or coating has developed into a tiny leak, or the fabric has been punctured.
Taking the plunge
Campers who have access to a tub of water can inflate and immerse the Thermarest mattress instead. Apply pressure and watch for bubbles escaping the fabric.
Please note that lake water can be full of silt and algae, which can be difficult to completely rinse off of the fabric, and may later cause the mattress to mildew.
Once you find the leak, rinse and dry the mattress, then follow the instructions on the repair kit.
Using seam sealer for emergency repairs
If you don't have a repair kit, you can still effect an emergency repair on your Thermarest mattress by using Seam Grip tent-seam sealer, or other seam sealer with polyurethane, and a synthetic cloth patch.
It does, however, take Seam Grip sealer up to a day to completely set up, whereas repair-kit, patch adhesive sets up in as little as 10 minutes.
When using seam sealer to repair a mattress, be prepared to add a synthetic, fabric patch over the top of the sealer. It can be any excess nylon fabric that doesn't have silicone on it.
A patch is recommended to reinforce the fabric around all but tiny leaks. This will keep the adhesive from failing and the tear in the self-inflating mattress from spreading, due to the pressure build up of a camper lying on the pad.
Be sure to apply pressure around the top surface of the patch, so that it makes good contact with the fabric of the mattress.
Until thoroughly dry, exposed sealer is very tacky and adheres to anything and everything. If you are only patching a tiny leak and don't need to cover with a patch, you can apply a bit of talcum powder over the sealer to keep it from getting contaminated with leaves, dirt, etc., and to keep it from bonding to everything it comes in contact with before it thoroughly sets up.
Duct tape repair
Some campers have reported effecting an emergency, temporary, field repair of their Thermarest mattress by using duct tape.
Duct tape contains a fairly strong adhesive, which is useful for repair, but can dry out over time and be difficult to remove without using strong detergents or solvents and risking fabric damage. Duct tape was originally designed to be applied and not to be removed.
Once your camping trip is over, be sure to immediately remove the duct tape, and use a self-inflating-air-mattress patch kit.
Waterlogged self-inflating mattress
Keep the pad clean and dry. Try not to allow water to get inside the protective shell, or it will wick into the foam core, and mildew may form, which can deteriorate the foam core. This will probably qualify as neglect and invalidate the warranty.
If the valve is left open, and a lot of water does get inside the mattress:
It will take a few days for the moisture remaining in the foam core to evaporate.
Quality, self-inflating pads have mildew-resistant foam cores and can take some exposure to moisture without mildewing.
Conclusion
Quality self-inflating mattresses have sturdy shells and should perform well for years as long as they are not abused. Applying a quality patch takes several steps, but it is worth the effort in order for campers to maintain a quality product and to be able to enjoy a self-inflating mattress for years.