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FABRIC DAMAGE 2 - Hole and tear repair in lightweight SIL-coated fabric

There are really only two options for repairing tears and holes in fabric that is finished on both sides with silicone elastomer. Almost nothing sticks to silicone except silicone itself so even temporary field repairs with tape aren't possible.

Large tears and extensive damage can only effectively be repaired with sewn patches or whole panel replacement. Anti-wicking thread should be used, the smallest workable needle size chosen and the thread tensions (top and bobbin) carefully adjusted. Once the patch is made, depending on its location, it may be a good idea to further treat the seams with silicone emulsion, described on the DIY page SEAMS 4 Restoring seam water-repellency using silicone emulsion.

Small tears and holes in locations that are not under great tension can be effectively repaired using silicone sealant, first smeared across the tear on one side of the fabric and then, once that is dry, on the other face. The adhesion of the silicone sealant to the fabric's silicone finish is not perfect but if the edges of the silicone 'patches' are smoothed out so they taper off to a very thin and flexible perimeter the applied silicone can be expected to hold well. It is important to cover BOTH sides of the tear.

Here are the steps for sealing the first side. Once that is done there is obviously no need to use the tape again.

This small tear in an outer tent was caused by a snag on the end of a nearby broken branch while packing up the tent. 

This cloth tape with its thick adhesive layer holds just well enough to the fabric silicone finish while the sealant application is in progress. Spend some time getting the edges in exact alignment. If the tear edge is ragged or has pulled yarns causing it to bunch it can help to work the torn edge flat by rubbing with a finger while holding the fabric out flat.

If a hole is being repaired, once the sealant is fully cured - wait a day at least, be careful when removing the tape from the sealant that is spanning the open hole.
(It is very rare to get a true hole where fabric is missing, particularly with sil/sil fabric. It has such a high tear strength).

Here the sealant has just been applied from the tube nozzle or if a cartridge is being used as was the case here, from the 'gun'. This looks a little rough. The next step is to spread the sealant out with a metal blade - an ordinary knife is fine - so it evenly overlaps the tear on each side and at the ends. Aim for an even thickness of about two millimetres. Don't worry about the look of the surface at this point just concentrate on spreading the sealant evenly.

In this step the sealant is smoothed out using a wet finger. Really, the best 'liquid' here, and also the most convenient, is saliva. Use plenty and work across the sealant to smooth the surface and taper off the edges, something that is done by applying a little more pressure there.

Leave the liquid to evaporate. Do not try to dab the patch dry with tissue or a cloth. That will comprehensively make a mess of a good job! 

Leave this first side patch to cure fully. To be safe allow 24 hours. Then remove the tape from the back side and repeat the sealant application steps on that side. It is VERY important to do both sides so no fabric edges remain uncovered by sealant. An uncovered edge is at risk of peeling away from the sealant.

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