Those of you with a keen eye will see that I ordered uni-directional fabric, but haven't used it. These steps are the places where it would make the most sense to use uni fabric.
Well.... I didn't receive what I ordered, I got 2x2 twill. You keen folks are still saying... I don't see 2x2 twill.
My original thought looked something like this:
My plain-weave would only be the top-coat. My plan changed when I was happy with my test-pipe, and didn't want to deal with a return and wait for new fabric. I also decided that running several direction-changes of unidirectional can only lead to me making a huge mess of things. That layup lends itself well to vacuum bagging.
The next steps were not planned. It all came together quickly and would definitely had come out better if I had planned for it. I'm not displeased, but I'm not thrilled.
As we saw in my last pics, I have a top-coat of epoxy drying. I hadn't used heat, so it was drying slowly. It's two hours later, still tacky.
I decide "I'm going to put a final dress-coat on this". Something that is not there for strength, but instead to protect my repair. I grab my 2x2 twill (that I had decided not to use).
When people think of what carbon-fiber "looks" like, the image is usually 2x2 twill. While it has compromised in strength/weight ratio, it is easy to wrap around contours....close-up of my stuff
I want this to look nice. This layer is all bout looks. And covering up that bare spot we discussed earlier. But mostly looks. I've decided I am going to leave this repair visible (no frame-matching paint). It will be a "conversation piece". I'll lie and say I left it exposed so I can do a regular visual inspection, but really, I am leaving it visible as it's part of what this bike is, now.
This layer of fabric needs to be sized just right, with good clean edges. I decide to not use my roller-resin method. Instead, I'll lay electric tape on the edges of fabric, cut the fabric to the tape, lay the fabric on the tacky epoxy (from earlier) and peel off the electric tape. That was a mistake. Peeling the tape made a mess.
If I were to do this again, I'd use the roller-resin technique from earlier, and roll the crap out of it, leaving it resin-dry. I'd then put a very thin layer of new resin on top of my tacky resin, and wait 40 minutes for things to get good and tacky. THEN, I'd cut my fabric (while still sandwiched in the plastic).
Well, I didn't do all that. I laid my fabric on the tacky seatstay, pulled off the tape, made a mess that I tried to dress up using scissors, and ended up with frayed ended at each end of my repair. I'll get over it.
No pics of those steps. I then wiped on a decent layer of epoxy, wrapped with parchment paper, and taped. This time the tape is not pulled tight. Just snug and form fitting. Back into the heat for a day. Once out, I sanded it with 100 grit, and applied another layer of epoxy. This layer was just to give me a nice smooth surface to sand. No wrapping of any kind on this layer.
The result. Don't let those long lines fool you, they are reflections of the black-railing you see in the background. The reflections do show you the countours, but this is glass-smooth. Those aren't brush-strokes.
Remember when I wrote that there was no wrap on this layer (of course you do, it was in this post).... here's another angle. You can clearly see what way I had the frame laying while this step was drying.
Now, we are up to date. When I started this thread, I already had several days worth of pics. This is the current state of things. What's next?
Sand off the drips. Ride the bike.
Sure, There's more I can do. I could sand and polish the epoxy to make it look better. I could clear-coat it for UV protection. I could hit it with steel-wool or fine sand-paper to give it a matte look. But I think I will put it together and ride it.
Thanks for watching. I'll keep you posted with details. If I'm a good person, I'll come back to this thread in upcoming years, and tell you how it's holding up. It's not good if there is a carbon-fiber repair, then you never hear from the guy again..... doesn't inspire confidence that this is something you should try yourself!