If you’re into playing squash then from time to time you may end up with a cracked frame on your squash racquet. A broken frame is usually the result of a manufacturing weakness, racquet impact with the floor, wall or another racket or, less commonly, thinning caused by long-term localised abrasion. A racquet with a cracked frame is usually buggered - but wait - maybe you can save it from the dumpster?
Figure 1. Severely Injured but not yet Dead!
Manufacturing defects usually occur early in the life of a racquet and many retailers will offer a full refund for a racquet that fails within the first month or so. If your racquet breaks very early in its life then I suggest you head straight back to the place of purchase for a refund or replacement. Here in God’s Own we have a piece of legislation called the Consumer Guarantees Act which requires that a product should be fit for purpose. Provided that the racquet has not been subject to extreme abuse (jambing in a car door is extreme abuse) then the retailer has an obligation to replace it.
Thinning occurs through grazing shots against the walls or floor. The grommet strip will be abraded away and the frame will be worn, usually on both sides. If the break has occurred at a point of significant abrasion then your racquet has probably seen years of use, is worn out, and not worth the effort of a repair because it will probably be near failure on the opposite side of the frame, and in any case you will not be able to get a replacement grommet strip.
If you frame has cracked in two places then it’s also time for a new racquet. Before attempting a repair inspect the frame carefully looking for any other signs of cracking away from the obvious break.
If you need a new racquet then I recommend that you buy two or three depending on how often you play. If you are prepared to negotiate then you will usually get a discount for more than one racquet. Then spread your use over the racquets (wear-levelling) so that they are all in similar condition. There is nothing worse than smashing your favourite racquet to death in an important game and then having to adjust to a completely different bat.
You’ll usually know at the time of impact, or within a couple of shots, when impact damage has occurred. Aside from experiencing the impact, the frame may be misaligned, the grommet strip may have deformed and the string tension may have reduced.
A replacement racquet will be relatively expensive (say >$200) and if your racquet is more than a year old then chances are you won’t be able to get an identical model.
Rather than consign a broken racquet to landfill it may be possible to repair it with just a slight change in balance and, depending on the location of the crack, minimal change in racquet dynamics. The following repair technique comes with no warranty but the dozen (or so) racquets that I have repaired have remained serviceable for extended periods (years) and have only failed after a second impact failure, usually resulting in a new crack somewhere else on the frame.
A word of caution. The broken edges of a crack are likely to be very sharp, and slivers of carbon fibre can cause splinters so handle the broken edges with care. Working with fibreglass results in tiny airborne fragments that can irritate your skin, eyes and lungs. Take appropriate precautions.
On with the Repair
Read through these instructions completely before starting the repair. The repair will only take an hour of actual work, but it’ll take a few days for the epoxy to harden.
You will need:
1. Side cutters.
2. A flat screwdriver.
3. A range of twist drill bits and a hand drill.
4. Some medium weight fibreglass mat at least 300 mm long cut parallel with the weave.
6. A smooth grade file and perhaps some needle files.
7. Some glass paper (1000 grit or finer).
8. A vice (handy but not essential).
9. Two clamps.
10. Fast setting Epoxy cement (5 minute Araldite – 1 ml mixed)
11. Epoxy resin (Marine West 105 - about 8 ml mixed).
12. A disposable 10 ml syringe with plastic nozzle.
13. There is no 13!
14. Plastic self-adhesive electrical tape.
15. Some lengths of cordage (nylon or whatever).
16. Some pieces of wood for the windlass and clamping
17. Some newspaper, a few rags, some vinegar and perhaps sawdust.
18. Rubber gloves, particle mask and eye protection for handling fibreglass and epoxy resin.
19. An ounce of patience and care.
Figure 2 shows a photo of what we are trying to achieve. I have sectioned an old racquet repair and you can see that the epoxy has filled the frame entirely about 50 mm either side of the original crack. The epoxy has bonded to the carbon fibre frame and has a significant fibreglass reinforcing in the core.
Figure 2. Sectioned Repair
Firstly cut through the strings with the side cutters and remove the remnants.
Now gently pry off the grommet strip (the plastic strip that prevents the strings from cutting through as they flex against the frame and protects the frame from grazing damage). Chances are that the grommets will have deformed so it may take a bit of effort to remove the strip. Work slowly from one end to the other, progressively applying leverage beside the next grommet with a flat screw-driver. If you start in the middle you risk stretching and deforming the grommet strip. If the grommet strip is severely worn, cracked, or missing grommets then you will need a new one, (particularly with a Type 2 frame – explained below). I am considering trying to 3D print a lap-sectioned general purpose grommet strip. If I ever get around to this I’ll post the results.
Inspect the frame looking for other cracks. Paint chips are not necessarily cracks! If there are other cracks then the racquet is toast and cannot reasonably be repaired.
Inspect the crack itself. It should be a relatively clean break extending right through the frame (usually at a stringing hole - a point of relative weakness). If the break hasn’t gone completely through the frame then you will need to flex the frame about the crack to complete the break. Do not use a saw because you will remove material as swarf resulting in an edge that will not mate cleanly under the frame’s pre-load compression.
With a pair of sharp side-cutters trim any carbon fibre spirals or strings that interfere with the joint between the broken edges. Clear any bent or flaking carbon fibre from the edges of the crack by hand with a twist drill or needle file. Now check that when the crack is pushed gently together that the frame holds its original shape and is flat when looking side on. You can make minor adjustments to the flatness by applying compression across the break and gently twisting the frame. Do not attempt to smooth out the ragged crack edges. The repair uses these to improve the bond of the existing frame. With the crack aligned the frame should stay closed under the pre-load.
Figure 3. A Nice Clean Crack
At this stage you should have a nice clean crack that seats under frame pre-load to the original shape and flatness with no stringy carbon fibre and maybe just a couple of chips missing from the crack edges.
There are numerous frame sections but I will deal with the two that I commonly encounter. These require slightly different techniques for application of the epoxy but otherwise the repair process is essentially identical.
The first type (Type 1) has the stringing holes separated from the frame cavity. You can only inject epoxy at the crack. Not all of the frame stringing holes will have mating grommets in the grommet strip.
Figure 4. A Typical Type 1 Cross Section
The Type 2 frame has stringing holes that provide direct access to the frame cavity. The grommet strip will have a grommet at every single stringing hole. This means that you can progressively inject epoxy into the frame about the crack through the stringing holes.
Figure 5. A Typical Type 2 Cross Section
(The string holes open to the frame cavity.)
Now we need to make the glass fibre reinforcing bundles. This is the key to the success of this repair technique. Epoxy is a great general purpose adhesive but the fibreglass reinforcing makes it strong, tough and resilient.
I strip about 30 strands of glass fibre from medium weight fibreglass mat to form a bundle about 300 mm long. The exact number of strands will depend on your particular racquet frame but you want enough to completely fill the frame void while allowing relatively easy insertion. Then I tie the bundle with sewing thread at four points to form two sections, each about 100 mm long. I mark the centre of each bundle with a pen to assist with positioning it in the frame later. I make both bundles at the same time so they will be of similar weight and cross-section.
Figure 6. Making the Reinforcing Bundles
Now I apply fast setting epoxy cement to the bundle at the tie points and twist the cord so that these glued sections form a tight plug. Now leave the cord for an hour or so while the epoxy sets. Then cut to the epoxy plugs giving you two equal length cords about 100 mm long. If necessary trim, squeeze and /or roll the epoxy plugs so they fit freely into the holes in the frame cross-section.
Figure 7. Finished Reinforcing Bundles
Separate the crack and lay one half of the frame above the other. Using a stout piece of wire push one end of each bundle into the holes on either side of the outer frame until the centre mark is just visible.
Figure 8. Inserting the Reinforcing Bundles with a Stout Piece of Wire
Figure 9. Two Bundles Inserted
Now adjust the frame so the inside section is now on the outside and push the other end of the bundle into the respective holes. At the very end of this procedure re-align the frame. When you are done you will have inserted the two glass fibre bundles on centre across the crack. The crack should close tightly under the frame pre-load with maybe just a few strands of glass fibre visible at the crack.
With a Type 2 frame cross-section you may also see some glass fibre through the grommet holes. Don’t be tempted to cut, pull or push this out the way because you risk moving the bulk of the bundle from the frame channels.
Figure 10. Bundles fully Inserted in a Type 2 Frame
(Note that they are visible through the stringing holes.)
Figure 11. Bundles fully Inserted in a Type 1 Frame
So far so good. Now it’s time to mix and inject the epoxy resin. This process is somewhat messy so find some bench space away from anything that you don’t want liberally coated in epoxy, and maybe put down some newspaper.
I use Marine West 105 System epoxy with a slow setting time. Mix about 8 ml of resin following the manufacturer’s instructions and load it into a 10 ml disposable syringe. Don’t try sucking the resin into the syringe because it will take forever and you’ll end up with small air bubbles that will not settle out. Remove the plunger and slowly pour the mixed resin in from the back of the syringe. Put the plunger back in place, invert the syringe, wait a few seconds while the air rises to the nozzle, and then press the plunger in to remove the air bubble.
If you are really concerned about the additional weight of the epoxy you can consider adding some glass micro-spheres. I haven’t tried this, but if you want to experiment then I suggest no more than 100% by volume to prevent the hardened epoxy becoming too brittle.
Figure 12. Mixed Epoxy and Disposable Syringe
Type 1 Frame Sections
- Gently separate the crack about 10 mm and insert the syringe nozzle as far as you can into the frame hole. Steadily inject epoxy while withdrawing the nozzle, saturating the fibreglass bundles. Then apply excess epoxy to both edges of the crack and close the frame. From here on out you want to try and keep the frame orientated so the crack is at the lowest point.
- Wipe any excess adhesive off the frame with a rag and apply a strip of plastic self-adhesive electrical tape to both the inside and outside of the frame.
Type 2 Frame Sections
- Apply epoxy liberally to both edges of the crack. Close the crack and apply a strip of electrical tape to the inside of the frame to seal the stringing holes. Now inject epoxy resin into the stringing hole immediately beside the crack with the syringe nozzle aimed at the glass fibre bundles until epoxy comes out of the stringing hole on the other side of the crack. Move to the next hole and inject more resin until it exudes from the hole closer the crack. Repeat on both sides until you are about 50 mm away from the crack.
- Wipe any excess adhesive off the frame with a rag and apply a strip of plastic self-adhesive electrical tape to the outside of the frame.
Place a few turns of tape loosely around the crack. Now lay some string in the grommet strip grove (enough to over-fill it) and bind tightly to about 100 mm either side of the crack with electrical tape.
Apply compression across the crack using nylon cord and a simple windlass. I also apply compression perpendicular to the crack using a second windlass but this probably isn’t necessary. Make sure that the frame does not visually distort due to too much tension. Finally, if the frame isn’t completely flat, gently clamp a couple of pieces of wood across the crack, then put the racquet in a vice with the crack at the lowest point on the frame.
Figure 14. (There is no Figure 13.)
Adhered, Taped and Tensioned with Crack at Lowest Point
Leave the racquet for 48 hours.
The epoxy will settle evenly about the crack and any air bubbles will migrate away from the crack leaving a solid fibreglass reinforced core bonded to the inside of the frame.
Clean up your hands with vinegar and/or sawdust. Vinegar is essentially dilute acetic acid which is an effective solvent for uncured epoxy resin. Sawdust just seems to work (an old boat-building trick). Once the epoxy has hardened you will need to scrape or file off any excess.
After 48 hours you can remove the clamps, windlass(es), the tape and the grommet strip recess cord. The joint should be completely secure and aligned with minimal excess resin on the frame.
The repair is essentially completed and the frame should now handle moderate abuse. It is a good idea to test it before going to the trouble of drilling out any blocked stringing holes, cleaning up the repair, and the expense of a restring. Try twisting or pulling the crack apart using your hands. Try taping the frame firmly against the floor. The patch should remain secure and the frame should be resilient – bouncing off the floor. The frame will strengthen even more under stringing compression.
Using a smooth grade flat file tidy up across the joint to the original profile. This may cut the original carbon fibre frame back slightly but you want a smooth finish. If there are any imperfections in the surface finish then you can lightly sand these, remove any dust, apply a further thin layer of epoxy, allow to harden, and rework to the original profile. This step is purely cosmetic and not essential.
Figure 15. Completed Repair with Grommet Strip Refitted
Some of the stringing holes will be partially or fully closed with resin. Drill these under-size and on centre with a hand drill and, in a second pass, drill gently to the original size. You can check the final size from the diameter of other holes or by measuring the diameter of the grommets on the grommet strip. Don’t use an electric drill for clearing the holes because by the time you realise that you have gone off centre you will have ruined the stringing hole. Elongated holes will require some needle files.
Double check that all of the holes are clear of epoxy. On my last repair my preferred shop telephoned and said that they couldn’t actually pass the string through one of the stringing holes. Oops! I raced down with a collection of drills and fixed the errant hole of stray epoxy.
Now polish up the repair with glass paper. I use 1200 grit. A useful check for profile smoothness is the Blind Man test. Close your eyes and run your finger across the crack. If it feels rough then you have some more sanding to do. If you want a perfect job then you might want to spray paint the patch once it is smooth to touch with a plastic or urethane based paint to match the original frame colour. A permanent felt marker will also work well.
Finally you need to replace the plastic grommet strip. If the grommet inserts have distorted then I gently heat them with a butane lighter and roll them between my fingers until they fit. The professionals use a heat gun.
Figure 16. Deformed Grommets.
Heat gently with a butane lighter and gently roll back to shape.
Figure 17. Another Repaired Racquet Ready for Restringing
And how good is the repair? To date only one of the racquets that I have repaired using this technique has failed at the previous crack. I had used that racquet several times a week for over two years (three re-strings) before it finally hit the dumpster.
If you are a top grade player then chances are you will feel the slight change in balance and action (we have added a few grams of resin after all) but your sponsor will probably provide you with a free replacement. For the rest of us ‘hacks and bashers’ you will have a completely serviceable racquet for a few years to come.