Most people like to make their own chutes if they can - others just want to improve the ones they have and some want to know what's the best chute to use. Well heres some tips from the Rec.Models.Rockets newsgroup, but a word on chute types for the newbie:

Why do some chutes have a hole in them? This is called a 'spill hole' and it allows air to 'spill' out of the canopy. This has two good benefits: Firstly it reduces the distance that the rocket will travel on it's way down and secondly it makes for a more stable decent (the rocket doesn't swing side to side like a pendulum). You might not want a spill hole if you are landing on hard ground, but if the ground is soft or there is a lot of wind, a spill hole is a good idea.

X-Form chutes - these are the same sort of chute that you often see being used for slowing down drag cars or jet aircraft. Why use one? Same reasons as a spill hole basicly. They give good stable decent rates.

What material should you use? The tips below offer some ideas. I've used shopping bags and black plastic rubbish bin bags but one of the best materials to use is rip stop nylon. If you can pick up an old tent from a garage sale or swap meet for a few dollars then do so - you can get quite a few chutes out of a tent!

Now, tips from r.m.r....

6.3 I'm fed up with tangled plastic parachutes with broken shroud lines. How can I improve on the standard chutes, or make my own?

From: soc1070@vx.acs.umn.edu (Tim Harincar)
Making your own parachutes is pretty easy. Start with the desired material (usually mylar or a light plastic). Make a cutting pattern out of cardboard by first drawing a circle that will be the maximum size of the chute (i.e. 16"). Take a compass [or] something that will give you an accurate radius of the circle. Pick a point anywhere on the circle and using the radius as a length draw an arc that crosses the circle. At the point where the arc crosses, reposition the compass on
that point and draw another arc. Keep doing that all the way around the circle - you will end up with six points including the starting point on the circle. Connect these points with a straight edge and Presto! a hexagon. Cut out the hex from the cardboard (I use artists matboard...) and this is your cutting template. Lay the template on the material and using an EXTREMELY SHARP XACTO KNIFE cut along the outside of the template. Make shrouds from a heavy gauge thread -
cut three equal lengths twice as long as the diameter of the chute and connect the ends to corner points adjacent to each other.

From: Roger.Wilfong@umich.edu
I usually build 12-24 line round chutes out of Estes material (just cut around the outside of the red and white circle and attach at the red /white boundaries) because they look more like real parachutes. I use embroidery floss for shroud lines and separate the 6 strands (for 12 lines - use two lengths for a 24 line). This makes a strong chute. With out crossing the lines over the top of the canopy, I've only had one failure of a 12 line chute (an EL that tipped off dramatically - i.e. cruise missile) and never had a 24 line fail. In the 10 years I've been back in the hobby and using this technique, my shroud lines have always come out the same length (within a couple of percent tolerance).

From: hal@HQ.Ileaf.COM (Hal Wadleigh)
1. Use fisherman's snap swivels for your attachments. It lets you store 'chutes separate from rockets and helps prevent fouling due to spin at deployment.[Note...modelers have always reported mixed results with snap swivels; they have been known to fail...Buzz]

2. Use nylon coat thread for shroud lines on homemade 'chutes (and plastic bread wrappers are the best cheap 'chute material).

3. Pay special attention to the security of the attachment points. Those standard stickers often look secure, but are actually not attached. A small knot in the part of the shroud line under the sticker serves as a good anchor point (with the rest of that part looped around the knot, as per standard practice).

4. Very small 'chutes should be crossform type. Cut about a 5" square, then take out about 1.25" squares from each corner. Attach 4 lobes of shroud across the flat ends and secure as above. Be careful to use small stickers for the corner attachments. These make good substitutes for streamers in .5" body tubes and can also be used as drogues to help in the deployment of large 'chutes [A note from cdt@sw.stratus.com (C. D. Tavares): Either round off the inside corner of that 1.25" square or reinforce the angle with something. Otherwise, it's a really handy place for the parachute to rip during a fast deployment.]

From: smith@mrcnext.cso.uiuc.edu (Greg Smith)
Nylon coat thread is very good for small, lightweight competition parachutes, but it's not real strong and does have a tendency to melt if it encounters a bit too much ejection charge heat. For sport and payload models with 12" - 24" plastic 'chutes, I use 15 lb. *braided* nylon fishing line. It's thicker than the coat thread, similar in diameter to the Estes cotton stuff, but tremendously stronger. In the last fifteen years, of the plastic parachutes I have built using this line (and always crossed over the top of the 'chute for reinforcement), I have had *zero* shroud line or attachment failures. The braided line has a hard, smooth surface that doesn't encourage tangling, and it doesn't unravel where cut.

From: whitman@nssdca.gsfc.nasa.gov (Rusty Whitman)
I've tried about everything to keep shroud lines from pulling off of plastic or mylar parachutes. Those little tape disks are just about worthless. Tying knots and cyano'ing the ends helps but you still have problems. I don't know why I never thought of this before but I ran across a roll of duct tape in my closet and knew immediately that was the answer. I cut out some little squares of duct tape and attached some lines to a parachute and they won't pull free without ripping the plastic. I don't know who invented duct tape but they deserve some kind of statue, its got more uses than a paper clip.

From: kaplowro@hccompare.com (Bob Kaplow)
1. Make shroudlines from Kevalr thread. This won't burn through. Tie a knot 1/2" from the end and fray the end. Attach that end to parachute.

2. Use the much stronger kite snap swivels instead of fishing swivels - make sure they lock, and don't just clip like a safety pin.