...A hinge can be used in two different ways depending on how far you want the door or lid to open. If you look at a hinge you will see the hinge post is prominent on one side and flat on the other side. If you hold the hinge with the post facing in, you can fold the hinge closed. If you fold it back the other way, it will only fold part way back.
...To determine which way you should place the hinge for your design, make this simple test. Hold one side of the hinge (with the hinge post towards the shell) against the egg and open the other side. You will notice that the hinge will only open back to 90 degrees. Use the hinge this way when you want to restrict how far the lid of a trinket (jewel) box will open.
...Now turn the hinge over (still holding it against the shell) so the hinge post is facing out. Again open the hinge. You will notice that the hinge will open right back against itself. Use the hinge this way when you want a door to open right out without the risk of breaking it off.
How do you get a door to open evenly?
...When you mark up a design make sure you place the hinge on the fattest part of the egg. (Unless you want the door to open at an angle on purpose) This will ensure that the door or lid opens straight to the body of the design.
...If you are hinging two doors on an egg, mark a girth line around the egg on the fattest part of the shell to ensure you get both doors hinged on the same level.
...Although some of these are personal preference, don't dismiss them out of hand until you try them - you may find it fixes some problems you have been having.
...When applying a hinge (with the hinge post in) cut a slot for the hinge post, extending the cutting slightly past either side of the opening. This needs to be at least the width of the cutting wheel you are using and will ensure that you don't cut into the hinge pin when you come back to cut the egg in two.
...Score the side of the hinge that will attach to the shell with an old craft blade. This gives the glue something to grip to rather than the slick surface of the hinge. Do the same on the shell.
Pref #1 - Initially, only glue one side of the hinge to the shell. Use Micropore or Magic Tape to hold the hinge in position on the larger portion of the egg and place another piece of tape across the other side of the hinge to make a flap. Apply glue to the side of the hinge which will attach to the small portion (the lid or door) of the shell. Close the hinge against the shell and press the tape down to hold the hinge secure while the glue dries.
Advantage of this method (as opposed to hinging on both sides)
........This way you are able to work with two separate pieces without having to worry about breaking the hinged portion off when lining the inside of the shell.
...Once you have completed all the interior work you can then glue the other side of the hinge into place and complete the outside decoration.
Pref#2 - Use more hardener (red tube or container) than resin
...It is advisable to use slightly more hardener than resin when mixing epoxy for a hinge (or stand) to ensure better adhesion. Do not apply epoxy right up to the post on the hinge or the glue may ooze into the hinge post.
Pref#3 - Vaseline on the hinge post
......Apply a tiny amount of Vaseline (petroleum jelly) on the hinge post to avoid the possibility of glue getting into the hinge post and gluing the hinge shut. (If this does happen, use heat to remove the hinge)
Step by step instructions for applying a hinge are included in our book 'Tis An Egg - Book One.
More from Maureen
When you put a hinge on an egg this becomes the weakest part of the shell due to the opening and closing of the hinged parts. You should always re-inforce behind the shell to prevent the piece of shell breaking under pressure.
To do this tear a small piece of paper (ordinary printer paper is fine) approximately 1" long x 1/2" wide - you will need two pieces for each hinge. Adjust the size of the paper according to the size of the hinge.
Use a brush and thin white PVA (Aquadhere, Sobo etc) to glue the piece of paper on the inside of the shell (longest side going around the egg, narrow side is the depth of the hinge flange) behind the hinge on both pieces of shell. Brush another coat of glue over the top of the paper (if I'm making a trinket box I coat all the inside of the egg for added strength to the shell)
...I hope the following will be of some help to you. I wrote this a long time ago and may have changed some of my ideas, but basically this is what I would do.
Applying a hinge
...Choose the size of your hinge according to the size of the egg you are working on. You don't need a cumbersome brass hinge for a chicken egg any more than you'd be justified in using a tiny hinge to support the lid of an ostrich egg. In my experience, hinging is easiest and most accurate if the line along the spot where the hinge will be positioned is cut first, plus about a half inch on either side of the hinge area, along the basic cut line that you've drawn. This extra bit of cut will allow you more room to accommodate the cut-off wheel of the Dremel tool without it catching on the edge of the hinge when you resume cutting after the hinge is secure.
... Scuff the area of the shell that will accommodate the hinge, or score it with 'xx' (especially when working with the slick shell of the ostrich egg). Sand the back of the hinge itself, with coarse sandpaper or a small sanding wheel of the Dremel tool. Removing the lacquer from the back of the hinge in this manner makes for a better bond when epoxied to the shell.
...Be careful not to get any glue on the hinge-pin or it won't work! This can usually be avoided if you apply just a tiny bit of vaseline to the hinge pin. Your hinge must be applied on the unpainted shell, making certain that it is set straight with the line of your cut. I find it expedient to hold the center of the hinge with small needle nosed pliers as I set it on the egg, then pressing it securely into position.
When your glue has set sufficiently (don't be too hasty - the epoxy must cure to create a permanent bond) continue cutting the rest of the way around the egg. In this way you have an exact match for the two parts of the hinged egg that is almost impossible to achieve in any other way. This is really crucial if you have designed a heart shaped door, or any door for that matter, and expect it to open and close precisely.
It is quite a feeling when the two sections open up as you expected and your hinge isn't stuck solid with excess glue! Of course it's also quite a feeling if you can't open it at all because the hinge is glued shut forever!
...With the heavier weight of the ostrich shells and their slick surface I've found that there could be a tendency for the hinge to snap loose from the shell after having been set with epoxy. In this respect I've had fairly good success marking the holes where screws would normally go in these larger hinges, then drilling small holes through the shell there. When the hinge is epoxied on, the epoxy goes through the holes, in the place of screws.
Then on the inside, I smear a little more epoxy for good measure. I've also had success cutting small brass nails off at about the thickness of the ostrich egg shell, plus the thickness of the hinge itself, and gluing those in place in the epoxied holes of the hinge. This gives a great deal more support. Whatever works best for you!
...Sometimes, for the sake of decorating convenience over absolute accuracy, the egg will be cut as for a jewel box and painted in two halves, to be hinged together afterwards. This is convenient, as you aren't bothered with the clumsiness of trying to decorate around two halves connected by a swinging hinge that invariably gets in the way, but you are definitely trading off the accuracy of fit.
You must be very careful that the trim around the cut edges doesn't bind, stick up too far for closing properly, or leave unsightly gaps. Although the 'hinge first' method may be a bit inconvenient, I invariably use it over the 'hinge after' method, simply to retain that degree of accuracy.
...You can work with an egg that is not blown. If you are going to make a diorama (with an opening in the front, and placing figures inside) you need no hinge. My advice to you is to use the trusty flame drill to do the cutting. The cut-off wheel will throw raw egg white all over! How about "egg in your face" literally? Simply dump the contents out of the egg in one swoop when you are finished the cutting.
...If however, you intend hinging the unblown egg, cut along the marked line where the hinge will go, the width of the hinge plus a wee bit extra to facilitate the cutting tool after the hinge is in place and so that it doesn't interfere with the hinge itself. Scuff the shell and the hinge in preparation for application, as mentioned in an earlier paragraph. Don't get any of the egg white on this area. Make sure it is clean, dry, and facing up.
...With a razor blade or x-acto knife, carefully cut through the membrane if it isn't already free where the hinge will be placed so you won't have any trouble opening the hinge later.
Apply the hinge and leave the egg completely alone until the glue sets. Don't chance getting any of the liquid from the egg coming out on the hinge area.
...When ready to finish the cut, as I stated before, don't use the cut-off wheel or you, the wall, the work station, everything, will be spattered with egg, although I do sometimes use the cut-off wheel to 'score' the shell along the line on which I will be using the flame drill to do the cut.
...If you prefer, the hinge can be applied with the hinge-pin facing in instead of out. This method will allow the door to be opened only so far and no further. Test the hinge in your fingers and you'll see what I mean. It can be useful, and makes it unnecessary to bother with a stay chain in some cases.
You will have to cut a little extra out where the hinge-pin will be set in and to allow the flanges of the hinge to lay flat on the outside of the egg.
...Always apply the hinge on the outside of the egg. The hinge, applied with the pin facing either way, will not likely conform to the rounded egg shell. Being very careful not to bend the hinge-pin, you can adjust only the flanges of the hinge with pliers so that it will more closely fit the curve of the egg, giving you a better bond.
I wouldn't dare take credit for thinking up any of these ideas. But I do take credit for remembering them. I know that I have complained about eggs breaking around my hinges. These are just tips that I picked up from people here and there. But I do want to emphasize that I have saved eggs from the trash can by repairing them with the acrylic nail kits. You mix up the nail powders, and brush it over the cracks. Guess it's kind of like putting bondo on the dents in the car. Sand it with a 400 grit sandpaper, and then doctor with acrylic paint. Heard this one at the Westlake Egg Show. I use aluminum to reinforce the hinges on the smaller eggs cuz I'm so rough with my stuff.
Don't know how others do it but here goes...I cut the space for the hinge, rough up the back of the hinge and the part of the egg where it will be placed, epoxy the hinge on then carefully drill the holes and epoxy the screws on. This is also the procedure for applying latches. Works like a charm.