Ah DRATS!! The hold broke!! Any time a hold breaks it is a bummer. However most holds can be repaired. If the hold repair is for your home wall, then who cares if you half ass the repair. That's up to the individual on how safe the repair is. But if the hold repair is for a rock climbing gym business, then possible lawsuits can come about if the hold rebreaks and parts of it end up hitting a customer, etc. Sometimes if the center bolt post of the hold breaks away, the best place for that hold may be the trash can.
Tools for holds repair may include a drill and drill bits, small wood screws, brackets of may different shapes and sizes, different size washers, thick gauge wire, epoxy, popsicle sticks for mixing the epoxy, Dremel grinder tool, angle grinder, sand paper and a flat belt sander is also nice to have. The epoxy I use can be purchased at a Home Depot store and comes in many mixes, some set up and dry faster than others, but still have great holding strength. Since the epoxy is a two part system, a glue gun is nice to have which costs around $100. The epoxy glue and gun also suggests to have a mixing tube, but every time you use the mixing tube, once the epoxy is dry, the tube becomes trash and the tubes are like $7 each. I just use the glue gun and squeeze out the glue onto a piece of cardboard, then thoroughly mix the two parts together with a popsicle stick. A small piece of plastic bag held on with a rubber band goes onto the glue cartridge which keeps it from drying out when not being used.
Okay let's play!! I purchased this awesome large smile face hold from Entre Prises and put it on the wall. The hold only lasted three weeks before the post cracked in 3 places. This could have been caused by the climbing wall not being absolutely flat, or the course setter over tightened the hold to the wall. However I want to note that the manufacturer that designed the hold only put 1/4" of material between the inner bolt washer and the back of the hold. A 2" bolt could have been used for this large hold, but a 1/2" bolt was still long enough to attach it to the wall. I am not sure why it is designed in this way, maybe for the rock gym to save money on the purchase price between a short bolt and long bolt. The good thing with this hold is that the post is still somewhat intact.
For this repair I drilled 5 holes and screwed in 5 screws around the post. Then taking a thick steel wire I twisted the wire around the screws as I ran the wire completely around the overall post while making sure the wire ends were twisted inward toward the post. This way once the hold is repaired and back into use, nothing sharp is sticking out which can cause injury to the course setter. Then use a popsicle stick to apply the epoxy onto the screws and cover the wire completely. 
After that had dried for a day, there is still the bolt depth of the post to be addressed. Once again I took the epoxy and filled in the bolt post leaving a depth of 1/2" for the top of the bolt to still be recessed within the hold. Once the epoxy is almost becoming dry, take a lock washer and shove it onto the top of the epoxy which will now serve as a new bolt stopper washer for the new hold. Without having the lock washer, over time the cap of the bolt will continually eat through the epoxy every time the hold is removed then replaced back onto the wall over and over for years. Let the epoxy dry for a day then use a 3/8 drill bit, drill out the epoxy within the bolt post and then Tada!!! the hold is ready to go back into use. Here I have Josh Kupfer showing his delight in having this fun hold back in action!!
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Oh NO! One of the ends of this amazing hold snapped off. This is a Halloween skeleton hand and black widow spider anchor hold shaped by Marty Karabin, and poured by Three Ball Climbing. The repair is not as easy as just dribbling some epoxy on one edge and then matching the edges back together. Since climbing walls are not all perfectly flat, the hold will simply break again with ease. So on this repair I drilled a few holes and creatively used a few metal brackets to use as a inner support that went across the cracked area. First spread out a load of epoxy to the area where the brackets are to be positioned, then screw the brackets into place using the predrilled holes. This way the epoxy is on the climbing hold, and on the underside of the brackets. Then spread out epoxy onto the top of the brackets and screws. After the epoxy has dried, flip over the hold and put a thin coat of epoxy onto the crack on the top of the hold. After the epoxy is fully dried, then get that amazing hold back into play!!!
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Awe Man! I just broke this massive Climb-It hold. (I think it is a early 1990s Climb-It?). But this presents opportunity! Once the hold breaks across the bolt area, it is not a simple fix of glueing the two pieces back together when the hold is being used in a high use rock gym. The hold will simply rebreak again along the glue line, and now you have two big pieces of big hold material falling toward the belayer. For this fix I decided to put a 3/8 threaded rod within the two broken hold ends to add strength to the glue line, and hopefully prevent breakage. Start by putting a small dot of paint on one hold piece, then perfectly match the pieces together so you now know where the exact spot is to drill the holes.
The tough job is to drill the holes perfectly parallel with the bottom (back) of the hold. I start with a thin drill bit, then progressively go larger in size until the holes are drilled deep and wide enough to accommodate the 3/8 rod. Drill the hole slightly larger than 3/8 to allow wiggle room so the two pieces of the holds perfectly fit together while the rod is within them.
Put the bolt washer and threaded rod into the hold and make sure everything fits perfectly together. I am also going to use a side grinder to make a channel on the bottom of the hold to add a smaller threaded rod to the thinner part of the hold on the opposite side of the bolt hole. I like to use a hole brush to make sure the holes are perfectly clean of loose drill dust, or simply wash the hold. Yeah glue time!! Put epoxy into both holes that the 3/8 rod is going into, and spread epoxy on one side of the hold ends. Use a bar clamp to squeeze the two sides together, and then clean up the extra epoxy that ooses out. At this time I add epoxy to the cut out channel, and put the smaller threaded rod within. Let the epoxy dry overnight.
Using a Dremel tool, grind the extra epoxy that is sticking up out of the hold, and clean out any epoxy that got into the bolt hole. Use the flat belt sander to sand the bottom of the hold to make it perfectly flat. Then its play time! Here we have Megan loving that the broken hold is back in play!
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Wow this is a totally awesome duel texture hold! But further inspection of the hold shows that the manufacturer only put 1/32 of hold material between the bolt washer and the back of the hold. So it was a guarantee that this hold was going to break within a day or two of when it is first placed onto the wall. The price of new climbing holds is getting up there so when I see this, I have to throw the red flag at the manufacturer. What happened to quality control? But this gives me a opportunity to get this awesome hold back into use. I am leaving the original washer in the hold and drilling out small holes within the side walls of the bolt hole above the washer. This allows epoxy to get into my drilled holes and prevents the overall epoxy plug from simply blowing out of the bolt hole on future installations.
Tape up the bottom flat side of the bolt hole, and around the top of the climbing hold to prevent epoxy from getting on the nice duel texture surface. Fill the bolt hole with epoxy but leave enough room to add a addition bolt washer to the top of the epoxy so it is not sticking up above the top of the climbing hold. Once the epoxy is setting up, (getting thicker), then add in the additional top bolt hole washer squeezing down enough for the epoxy to get around it, and try your best to make the washer parallel with the bottom of the climbing hold.
Use the belt sander to make the bottom of the hold perfectly flat while not sanding the tip of your fingers off. Drill out the bolt hole to accommodate a 3/8 bolt where now the hold will use a cap screw bolt which will still match into the original action the hold was designed to provide. And Wallah! Here showing is crimp master Jazzy Kvavle showing her psyche that this hold is back in play!
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What? No way!! I just broke my awesome Element Climbing two hand mini jug hold. Its a sad day at the gym for sure, but this can be easily fixed. This is the common hold break most seen at the gyms. The inner hold washer is causing the hold side to crack. The crack usually first appears during the course setting process, the hold being placed on a warped wall. Since the original hold washer is deep inside the hold, a new washer needs to be placed within the hold. The bolt hole needs a shelf grinded into it so the new washer is anchored on the shelf that sits slightly above the original bolt washer. Epoxy will fill the gap between the two washers.
Grind just enough so the larger washer fits into the hold. And grind deep enough so the cap screw bolt will be recessed within the hold. Wash the hold. Mix up some epoxy, put a piece of tape on the bottom of the hold to hold the glue in, place the washer in and glue the bolt hole. Once the epoxy is dry, drill out the bolt hole.
Put some glue on the small crack on the hold, and use the belt sander to make sure the back of the hold is perfectly flat ........ and then get that hold back onto the wall!! Here we have Logan showing total Excitement that the Element Climbing two hand mini jug hold, is rocking the crowd once again!!!
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Dude .....Noooooooo! I just broke my totally awesome small sloping florescent orange Wataaah hold. The bolt screwed   through and blew the back of the hold out. But no problem since this hold can easily be converted into a screw on hold. First drill a few more holes where the hold screws will be placed. Since the main bolt area of the hold isn't going to be a point of attachment, there was no need to fill the back of the hold so I added a penny to the hole to block the epoxy, and drilled two holes and added screws into the holes for the glue to form around and hopefully never break out while under pressure. Put tape on the hold surface around the bolt hole to prevent the glue from getting onto it.
Add the glue! When the glue is dry use a Dremel with a sanding drum to sand down the glue to match the hold surface. Adding artwork is optional!
Now get that hold back onto the wall! Here we have balance master Tom Taber showing good form on the totally awesome small sloping florescent orange Wataaah hold. To Tom, slacklines are so yesterday! He prefers walking on Coke/Pepsi bottles and Wine bottles.
Tom Taber, 1966
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Another sad day in paradise. The inner post cracked on the awesome white really large Thrive ledge hold. Noooo... But with a little love this hold can be brought back to life!!! On the hold top side a new larger washer needs to be installed being fitted for a button head bolt. The hold material that is above the broken post will support the new position of the bolt. First with a dremel tool carve a ridge out that will support the new larger washer. I also drill some small holes within the bolt hole which is above the broken post, so the glue that gets sandwiched between the now two washers has greater holding power. 
On the back side of the hold since the post is toast, it will be best if a few brackets are installed. First figure out what brackets will fit best, then drill in a few holes for the screws. 
Install the screws to make sure everything fits correctly. Then take the screws back out and put epoxy under the brackets, then rescrew the brackets in. Use more glue to cover the brackets and screws
On the top of the hold put tape around the bolt hole to prevent extra glue from getting all over the hold. Put epoxy in the bolt hole and place in the new larger washer and let the glue dry. Once the glue is dry, use a dremel to clean up the epoxy around the bolt hole and then remove the protective tape. Redrill the bolt hole, use the flat sander to make sure the post is not exceeding the back of the overall hold, and then get that awesome hold back onto the wall!!! Here we have Josic showing his confident climbing skills on the ​white really large Thrive ledge hold.