Mastic is sticky, messy and stinky, but it still is the best way to seal all joints in your heating and cooling system, no matter what type of ducting you have. It comes in a variety of containers and dispensers. It's been around for centuries and hasn't changed all that much. Use it with all other sealing choices as extra insurance.

One popular way of connecting flexible duct to other air-supply components is with cable ties. You want to pull the insulation back to expose the actual ductwork, and then pull it up onto the metal connection and install a plastic cable tie as tightly as you can. Apply a little mastic around the connection to ensure that it is as airtight as it can be. Now pull the insulation up over the connection and use another cable tie to secure it.

Tape also can be used, but use aluminum tape, not duct tape. Duct tape never should be used for sealing ducts. It won't hold at all. The aluminum tape does a pretty good job on metal ductwork, but not as much on flexi-duct.

If your ductwork is suspended or hanging, make sure that it isn't kinked or pinched. You can add more pipe strapping if you need to in order to prevent this. You even can use a piece of cardboard between the bottom of the strap and the ductwork to act as a wider support and prevent this type of pinching. Plastic strapping also seems less likely to cut or tear the ducts than the metal types.

In most cases, the insulation around these ducts is sufficient, but if you need to add more, you can. Just make sure they are sealed up tightly before adding it.

Q: We have an older home with glass shower doors that slide. One of them has been hard to open for a while, and the other one is starting to do the same thing. What can we do to fix these, or will we just have to replace them both? — T.E.

A: These type of doors have built-in wheels that slide on the upper part of the track. Try to carefully lift the door a little and remove it from the track. Then clean the wheels and track thoroughly, and apply a light lubricant to both. They should work much better after this treatment. If you have to replace the doors, it's not very difficult, but we would suggest trying this first.

If you are one of those people who likes to make things for the home or to give as gifts, you'll love our Hardware Chess Set. The plans are easy to follow, and use a variety of different hardware items to make the individual chess pieces. You may already have some of these odds and ends lying around in your workshop. If not, it won't cost much to put a complete set together. We'll show you how. Just send your request, along with $1 ($2 in Canada — no coins, please) and a self-addressed, stamped envelope, to The Super Handyman here at the newspaper and we will gladly send you a copy of the plans. Of course, you'll have to master the game yourself!