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Backpack DIY Repairs

Here are the instructions for some simple backpack and daypack repairs you can do in the field or at home. It's worth reviewing this entire page whether you have a particular problem or not. It will forearm you for situations that may arise in the future and give you an idea of the range of things you can deal with quite easily. Few tools are required and knowing a few 'tricks of the trade' can avoid the need, expense and inconvenience of sending your pack away for repair. That will also reduce our carbon foot-print.

Silicone SprayFIXING CONTINUOUS COIL ZIP PROBLEMS

The most common continuous coil zip problem is slider wear and distortion. It is caused by the use of excessive force to operate sliders on dirty, unlubricated zips, or where something is jammed in the zip. It shows up as the two sides of the zip not closing or meshing properly behind the slider (illustrated below). The single most important thing you can do to keep the zips on your gear trouble-free and to prolong their life is to regularly lubricate them. Spray cans of silicone lubricant like the one shown at the right are readily available from upholstering suppliers. Here are some notes on how to solve nearly all the zip problems that we have seen over the past 30-something years. Abrasion of stitching

ABRASION OF THE STITCHING that holds the zip coil to its tape flange is more common on packs than tents. It happens when a zip coil is not protected by a cover flap and the zip is typically dragged against a masonry or rock surface. Now that reverse slider fittings are commonly available many zips are now inserted with the coil side facing inwards. It is also common to see this orientation of zip with a PU lamination which adds greatly to water-repellency and abrasion resistance (but they are not waterproof). These developments greatly reduce the chances of the stitching that holds the zip coils to the flange tape failing. When the coil stitching is worn through and unravelling it may require complete zip replacement. If the problem is limited to a short section, often just a corner, it can be fixed by hand stitching with a fine needle and strong synthetic thread (#60 is ideal). Alternatively (and better), if you have access to a clothing weight sewing machine you can set the straight stitch length to the same pitch as the zip coils and work, hand winding the balance wheel, one stitch at a time along the damaged section. Start and finish a few centimetres over the stitching that is still OK. Use a needle size that fits between the coils but is not so fine that it may be broken. Be careful to keep the zip coil correctly positioned relative to the edge of the zip tape. Sealing the thread ends so they do not unravel is best done by melting them with a match or lighter flame. Do this quickly so only the thread ends melt. Press the melted endf with a finger tip to flatten it against the coils or tape.

SLIDER DISTORTION involves the upper and lower plates of the slider opening apart lightly at the trailing edge. You can see this with the left hand slider of the pair shown below. The extra clearance allows the zip coils to avoid each other (middle illustration). Provided the distortion is not too great a solution is to tap the trailing end of the slider closed again. First pull/force the slider to the 'zip open' end of the zip, as far as you can. In the end of a small block of wood cut a narrow notch just large enough to fit the arch that holds the slider pull tab (right hand illustration). Place the block over the back (narrow) end of the top of the slider so each side rests on the upper plate of the slider (just above the zip coils). Give the block a light tap with a hammer to close the gap between the top and lower plates where the zip coils run. Proceed with caution, checking after each tap! (In place of this tapping method it is possible to squeeze a slider closed by reaching over to the back end with pipe type pliers. Be careful! It is easy to go too far. In some cases it may be necessary to replace a slider that is weakened from distortion or badly worn inside. Zips should be regularly sprayed with silicon or teflon spray to lubricate them, reducing the force, heat and wear of operation.

Zip sliders: Pre-correction on left, Post-correction on right Zip coils not closing behind slider Using a block and hammer to fix the slider

BROKEN OR MISSING ZIP PULL TABS. If the metal pull-tab on a zip slider (on our travel packs) is damaged or Using side-cutters to open the archmissing it is often possible to fit a new one without fitting a whole new slider. Use side cutter pliers acting as a double-sided wedge under the back end of the metal arch that holds the tab. Squeeze the cutters gently to very slightly bend the arch up and open. Diecast will only take a small bend so go carefully. Bend it enough so a new tab can just be forced under the opening, into place. Use general pliers to bend the arch back down and retain the tab. If the arch breaks or feels weak a new slider will have to fitted.

REPLACING SLIDERS. Corroded and broken sliders will need to be replaced. Usually, badly corroded sliders have to be cut off since the action of salt on the diecast has frozen them onto the zip. To do this, grip one side of the tail end of the slider in a vise. Now carefully use a fine hacksaw to cut down through the bridge at the nose of the slider making absolutely sure not to contact the zip coils. Making the cut at 45 degrees will help. There is no need to cut fully through the bridge, just far enough so it can be broken with pliers. Once the slider is broken off, dust the remaining corroded material from the zip coils. Since 2003 we have fitted 'Slider Gates' on all the main #10 spiral zips used on our backpacks. This system means that only a few stitches need be unpicked to expose the zip end and easily fit a new slider. Slider replacement can be done, literally in a few minutes and the gate stitched closed  by your local boot repairman.  If the zip is not fitted with a slider gate end, for example, a short pocket zip, then you should send your pack to a recognised repair service. Email us for directions.

FIXING FABRIC TEARS, RUBS AND OTHER PROBLEMS

MESH. While fine mesh is not used on backpacks these illustrations from the DIY Tent repair page show the use of the PU all-purpose adhesive SeamGrip® in making neat, strong repairs to tears. (SeamGrip is sold at most specialist outdoor retailers). The same method applies to any fabric, although PU adhesive/sealant doesn't work on fabrics coated with silicone elastomer. In this case use a silicone adhesive/sealant. Transferring the SeamGrip to a 10ml syringe makes it much easier to dispense. Keep the syringe nozzle up to allow the air bubbles to rise out of the liquid before using it. What we do for all small nicks, puntures and tears is to simply using masking tape to 'back' the area to which SeamGrip will be applied. With tears be sure to make a good job of mating the edges. If you can, apply the SeamGrip on the inside surface. Keep the repair area flat while the compound sets (overnight). It will flow out to a thinner layer than you initially apply.

Seam Grip: Syringe provides better application control Attach masking tape to the back of fabric before applying Seam Grip Finished repair

LIGHT AND MEDIUM WEIGHT COATED FABRICS. For repairing rips in coated and other smooth fabrics a more immediate alternative to the glued repairs described above is the use of a piece of 'sticky back' self adhesive sail marking fabric, or similar - many outdoor retailers sell 'ripstop repair tape'. The adhesives on sail number fabric are unquestionably high grade so this is the material we choose. Sail makers usually have offcuts they will only throw out. Always round the corners of patches when you cut them so they are difficult to lift once in place. 'Sticky-back' is also good for repairing damage to down sleeping bag shells (when the alternative is a nightmare of hand stitching or reconstruction). Make sure the surface you are going to stick the patch onto is clean and dust-free. If the equipment comes in from the field with residual adhesive from gaffer tape or Leukoplast® stuck to it, first clean this muck off with white spirits (or methylated spirits, according to adhesive type) and allow to dry completely.

CANVAS, CORDURA® AND KODRA® TEARS, RUBS AND HOLES. The illustrations below show the use of SeamGrip on heavier fabrics, in this case canvas. You can also glue a fabric patch in place with this compound although the added fabric layer and thickness of the adhesive makes the patch area very stiff. Badly abraded areas, perhaps involving multiple layers of worn through fabric and a seam or two can simply be glued up with SeamGrip. To disassenble and stitch repair such damage could cost as much as half the original cost of the product and still not return it to 'as new' unless whole fabric panels are replaced. Several applications of SeamGrip may be needed. Always back the area with masking tape or a layer of a plastic that the PU sealant will not stick to (like a piece of polyethylene icecream container). In some cases we have wrapped a wooden block in cling-wrap, placed it inside the pack, pinned the repair area down flat using fine panel pin type nails tacked through into the wood. They are easily pulled out later.  PU uses moisture in the air for its curing process. You can place a piece of cling-wrap, PE or PP plastic sheet OVER the sealant (and weight it down) to produce a nice flat finish on the outside. Just allow longer for the adhesive to cure. Smoothing it with a wet finger before putting the cover on will speed up the curing time.

Seamgrip: Syringe provides better application control  Attach masking tape to the back of fabric before applying Seam Grip Seam grip over holes   Finished repair is tough, waterproof and flexible

SOFT OR STICKY PU COATINGS. In the DIY Tent Repair page we talk about trying to 'harden up' PU coatings that have gone soft with old age. The ironing method described there can not effectively be done on a backpack and it will be of little use anyway. The main problem for (synthetic fabric) backpacks once the PU coatings deteriorate is that the fabric yarns are much more free to move about and there is a risk of simple seam constructions simply 'combing' apart under load. Fabrics with failed coatings also leak profusely although, since all stitched synthetic bags leak to some extent, that is only a matter of degree. The only stop-gap remedy is to paint the fabric with something that will 'glue it up'. No commercial products that we know of are worth trying. What we can suggest is the silicone sealant and mineral turpentine emulsion described on the tent DIY page. Turn your pack bag inside out and make sure it is clean, free of grease and dust and absolutely dry. Mix up, in this case, say 1 part 'window and glass' silicone sealant with 2 parts turps, a thicker brew than for the tent application. Keep agitating the components until they emulsify then paint/spread the solution onto the inside of the fabric. Hang it up to dry in a well ventilated covered area for at least a full day of fine warm weather, longer if possible. After this if the finish still feels a little tacky or sticky a dusting with talcum powder will fix that.

REPROOFING CANVAS PACKS

The great advantage of canvas is that it will never suffer the problem described in the previous paragraph! Well used canvas packs benefit from re-treatment with a 'canvas dressing' solution, typically involving waxes and a solvent.  New packs will also benefit since the proofing with also soak into stitching, zip flange tapes, webbing attachment points and so on. The solution not only helps to repel water from these non-fabric components, it also serves to lubricate zips, important to extending their life. Use a firm brush to remove all loose dirt from the bag, inside and out! Follow directions on the packaging.

One formulation uses mineral turpentine as the solvent for the waxy polymers. It is flammable and you should avoid breathing the vapour and skin contact. Hang the pack bag in a well ventilated place where it can remain for several days while the solution dries. Using a spray bottle completely saturate the whole bag with solution so it soaks through to the inside of canvas panels. Pay particular attention to thick seams, zips and webbing attachment points. Treat only the bag - In the case of backpacks there is no real advantage in treating harness components. Do not use the item until the proofing is completely dry. Turps is slow to evaporate so this will take several days at least. As a guide 500ml can treat two full sized backpacks.

Another formulation uses silicone elastomer carried in a stronger solvent than mineral turpentine. The silicone content is nothing like the level of the mix we describe in the section above on sticky PU coatings, rather it is liquid enough to penetrate the fabric completely and coat all yarn fibres with the silicone compound. Fabsil from the UK proofings company Grangers is an example of this type of formulation.

REPLACING TAP-RIVETS IN THE LOWER ENDS OF ALUMINIUM FRAME BARS

The Synchro-FORM hip harness components on WE packs fasten directly through the pack bag into the bottom ends of the internal frame bars. These strong, direct, mechanical links are responsible for the excellent load transfer and stability WE packs are known for. The ends of the hardened aluminium-alloy frame bars are fitted with what is known as a 'tap rivet', an internally threaded fitting something like a pop-rivet - see the set of illustrations below. The tap rivets are steel with a gold colour passivated zinc protective finish. The 5mm x 16mm screws mounting the hip harness wings fasten directly into these tap rivets and are secured with high-strength Loctite® 262 thread-locking compound.

The tap rivet system has been in use on WE packs for more than 15 years. Depending on the age of your pack and where it has been used it is possible that corrosion and/or wear on the aluminium may make it difficult to remove the harness screws when maintenance is needed on harness parts. Up until 2005 the steel tap rivets were circular and, if they worked loose in the softer aluminium base they could turn when the time came to undo the harness screws. Since 2005 the tap rivets used have hexagonal barrels and, fitted in hexagonal holes punched in the frame bars, are unable to turn.

Failure of the tap rivets is extremely rare. If a rivet is turning in the aluminium frame bar, making it impossible to undo the harness screw there are two options: carefully use a 6mm drill bit to drill off the (countersunk) head of the screw so the frame bar can then be extracted from the pack, or use the clamp tool we have designed to hold the tap rivet from the inside, while the screw is removed (see your WE retailer for this). If you drill off the screw head be sure to place a block of wood inside the pack behind the frame bar so the turning rivet doesn't damage the pack bag fabric.

Once the frame bars can be removed from the pack bag it is not difficult to fit new tap rivets. We can supply all the parts needed. The steps are illustrated below. Use a 7mm drill to drill off the old tap rivet head. Be careful not to drill into the softer aluminium bar once you cut through the rivet head! Knock out the old parts. If the hole in the frame is circular use a small triangular file to make six corners in the circle so a new hex tap rivet will fit. Fit a new tap rivet into the hole making sure it protrudes towards the concave part of the frame (that is, towards the wearer's back). Fit a new screw into the tap rivet, winding it in say 8 turns. Now position the parts between the jaws of a vise - it needs to be a 100mm / 4 inch vise at least - and, making sure the aluminium frame bar is hard against the tap rivet head, gently crush the rivet in the vise. It only needs to be lightly crushed, just so it is no longer loose. If it is crushed too much it is likely to bend off-line. This will make it impossible to fit the screw fully into the tap rivet when the harness parts are attached.

When re-assembling the harness parts be sure to use a high-strength thread locking compound. Without this there is a risk that the motion of the hip harness wings will cause a screw to unwind. If you can not find Loctite® 262 then 5 minute Araldite® is an acceptable alternative. (Loctite is an anerobic-setting compound. It will remain liquid as long as it is in contact with air).Wipe a little compound into the end of the tap rivet as well as onto the end threads of the screw. Use a #2 point cross-head screw driver to tighten the screws BY HAND! If you use a screw-driver drill always start the screws by hand first (to avoid cross-threading) and make sure you have the drill set on a low torque, setting 5 or less. When the screws are done up there should be just a little drag on the rotation of the hip plates, no more.

Drilling off the head of a tap rivet  Setting the tap rivet Tap rivet clamp tool

 
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