Repairing Cracks

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Repairing Cracks

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fibernoob	fibernoob posted 8 Years Ago HOT Topic Details
Group: Forum Members Posts: 34, Visits: 134	Hi folks. I need to repair a cracked CF part (automotive rear spoiler /wing) and prefer to seek some wisdom before I start the job. The crack seems to be on the surface, but I am not certain if it has gone through the part (I do not want to pressure it to make it worse). There are in fact 2 cracks - one larger exposed one and another hair line crack below (see image) Unfortunately this part is NOT accessible from behind as it is one closed piece. I am thinking of sanding the crack with a small file by hand rather than using a Dremel not to risk cutting through it. Then filling the crack with a clear lower viscosity epoxy resin (using a syringe) and then polishing it. Any other alternatives to this ? I am concerned with cracks growing so I have considered drilling small holes on their ends to prevent further opening. Does this method (often used in metal) also work for Carbon Fiber ? (See image) I also will need to fill the holes afterwards. Many Thanks in advance Tags c/f cracked cracks repair repairing Edited 8 Years Ago by fibernoob
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Hanaldo	Hanaldo posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	The hairline crack is just the clear coat so that's fine, but I would be inclined to say that the larger crack is damaged fibres. Considering it is in such a load bearing area, I would want to be doing a structural repair there rather than just cosmetic. Unfortunately because it is a closed piece, there won't really be any way of doing a structural repair that is also cosmetically perfect. If it were me, I would scarf in the crack with a Dremel either until the crack is gone or you start to break through the skin. Avoid going all the way through if you can. Then lay some fibres into the crack and wet it out with resin, or chop up some fibres and mix them with resin to make a 'paste' which you then smear into the crevice. Either way, the use of some release film on top will help both in getting some compaction and with getting a flatter surface again. Also yes, drilling holes on either side will prevent the crack from propagating - the downside being that you will be left without any reinforcement in those holes. Best to use a filler powder or milled fibre to give the resin more strength and hopefully hold up.
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fibernoob	fibernoob posted 8 Years Ago HOT Post Details
Group: Forum Members Posts: 34, Visits: 134	Thanks again Hanaldo.
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