Hongfu FM079

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MichaelK
Posts: 135
Joined: Wed Jul 04, 2018 4:50 pm

by MichaelK

Awesome work, thanks for the write-up.

Maddie
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Joined: Tue Oct 17, 2017 5:44 am

by Maddie

Good stuff!

by Weenie


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Kayrehn
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Joined: Thu Mar 24, 2011 6:06 pm

by Kayrehn

Inspired to do this as well!

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Klaster_1
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Joined: Mon Aug 15, 2016 10:25 am
Location: Russia, Saint Petersburg

by Klaster_1

Did a second hood too.

Before weight, without clamp:
IMG_20200804_182539.jpg
Hood only:
IMG_20200804_182604.jpg
This time I used a single layer of food wrap and a layer of Scotch tape:
IMG_20200804_184535.jpg
Deals on food vaccum bags (0.5USD for a pair) and a pump (0.75USD) served as a good reason to ride my other bike. Since Xshifter has died, it only has a single gear, last time I rode single speed (Velta Kama, used to be very popular here) was 20 years ago as a middle school student.
IMG_20200804_185555.jpg
IMG_20200804_190125.jpg
The cut pattern was modified: extra material removed, marked area where to place the lever for a proper wrap.
IMG_20200804_190507.jpg
Resin applied and vacuum sealed. Really love how neatly the bag pushes the cloth in, but in the end it ended as a failure. Like before, the resin was left to cure overnight, when I opened the bag I found it was still wet! Another 12 hours later, nothing changed, but the cloth at least stayed in place and didn't slide off, so I sprayed more resin on, wrapped the lever in food wrap and left for another night, which did the job. Next morning I spent more than an hour peeling the wrap off, I decided to remove all of it and the result turned out much better looking than the first hood. Some resin leaked under the first wrap layer and had to be peeled of the lever too, at least none got into the master cylinder bore. Scotch tape was easier to remove from the inner surface compared to food wrap.
IMG_20200804_192359.jpg
IMG_20200806_192641.jpg

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Klaster_1
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Location: Russia, Saint Petersburg

by Klaster_1

I expected for second hood to be heavier since I tried to use more resin, but even after multiple fix ups it came out slightly lighter. Probably because the wrap had less exposed fibers and no extra cloth patches.
IMG_20200807_113138.jpg
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IMG_20200807_113815.jpg
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On a bike, it looks rather ghetto, especially when paired with used cloth tape.
IMG_20200807_115143.jpg
IMG_20200807_115153.jpg
Will test it later after the wheels are rebuilt and a bleed job.

Takeaways:
1. A single base food wrap might cause leaks, wrap the lever at least twice.
2. Liquid resin (at least the brand I used) does not cure in a vacuum bag in room temperature.
3. Scotch tape over base wrap was a good idea.
4. Tight Scotch tape was not enough to prevent pits. If I were to do another hood, I'd fill the cavities with dense material.
5. Extra CF cloth increases weight, try to do the whole lever in a single cloth layer. This seems to match The Climb blog series, where two layers of CF yielded hoods twice as heavy as mine.

tomsneo
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Joined: Fri Jan 20, 2017 4:22 pm
Location: New Jersey

by tomsneo

Great job on the custom carbon hoods! Do you plan on giving it a clear coat to protect it? Or no to save some weight? I know wrapping in real carbon is no easy task. A buddy of mine made me a few parts on my car in carbon from sctratch very tedious process. Can't wait for more updates!
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Klaster_1
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Location: Russia, Saint Petersburg

by Klaster_1

tomsneo wrote:
Fri Aug 07, 2020 3:17 pm
Great job on the custom carbon hoods! Do you plan on giving it a clear coat to protect it?
Not sure a UV protection layer is necessary in my case, as far as I understand, it's the epoxy that requires protection, not the CF cloth itself. Since the hoods use liquid resin (resin in solvent that evaporates), there's no epoxy to protect from UV. I suppose the resin can degrade under direct sunlight and over time, especially when covered in sweat, in which case I can always make more hoods or put a fresh coat of resin. These are very cheap to make, I have enough material for at least three pairs.

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Klaster_1
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by Klaster_1

Off by 10g from the spreadsheet, but I suppose 1098g is good enough.
Attachments
IMG_20200812_180848.jpg
IMG_20200812_181019.jpg
IMG_20200812_181110.jpg

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godzuki26
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by godzuki26

Wow!!!! Those hoods are awesome. Thank you for the detailed write up. Those are huge weight savings. Let us know how they work out.
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Klaster_1
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Location: Russia, Saint Petersburg

by Klaster_1

Shimano RD-R9150 B-unit weight
Shimano RD-R9150 B-unit weight
Shimano RD-R9150 B-bolt weight
Shimano RD-R9150 B-bolt weight
Shimano RD-R9150 without B-unit and B-bolt weight
Shimano RD-R9150 without B-unit and B-bolt weight

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Klaster_1
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Location: Russia, Saint Petersburg

by Klaster_1

~20g off from the spreadsheet. Maybe it's time to add "grease and air" to it? 😅 Do you guys think 11-26 cassette would be considered as cheating? With remaining upgrades done (probably early next year), I can put the XG1190 on, remove the computer (30g) and source some Aerolites for sub-5kg disc build photos, but probably won't ride the bike in that setup much (especially during winter).

Regarding the DIY hood: one strip of tape held it in place only for a handful of rides in hot weather. I barely touch the hoods anyway, so not a very robust solution. For now, I did two wraps of tape, let's see how long it will hold, but going this way I can just remove the hood and wrap whole lever in tape.
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Hongfu FM079 weight (29.08.2020)
Hongfu FM079 weight (29.08.2020)

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Klaster_1
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Location: Russia, Saint Petersburg

by Klaster_1

Unlike SM-BCR2 from this video, BT-DN110 uses glue instead of clips to hold the case, so you'd either have to cut it off or unglue it somehow. Batteries are 570mAh 3.7 Li-ion, I'm going to order 14250 size 300mAh as replacements. The junction is lighter than claimed, but wires were heavier than I expected, about 10g per meter.
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Shimano EW-SD50 750mm weight
Shimano EW-SD50 750mm weight
Shimano BT-DN110 stock weight
Shimano BT-DN110 stock weight
Shimano SM-EW90-A weight
Shimano SM-EW90-A weight
Shimano BT-DN110 weight, without outer case
Shimano BT-DN110 weight, without outer case
Shimano EW-SD50 1400mm weight
Shimano EW-SD50 1400mm weight

takolino
Posts: 55
Joined: Sun Nov 13, 2016 9:11 am
Location: USA, SF Bay Area

by takolino

This just keeps getting better. Looking forward to see how you tweak the Di2 setup.

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Klaster_1
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Location: Russia, Saint Petersburg

by Klaster_1

takolino wrote:
Thu Sep 03, 2020 7:28 am
This just keeps getting better. Looking forward to see how you tweak the Di2 setup.
Will take a while longer, for some reason I assumed the junction A accepts a USB instead of a proprietary connector. And totally not looking forward to another bleed :x

DeRosa69
Posts: 24
Joined: Sun Jul 26, 2020 2:23 pm

by DeRosa69

Klaster_1 wrote:
Wed Aug 12, 2020 4:23 pm
Off by 10g from the spreadsheet, but I suppose 1098g is good enough.
Nice wheels!

by Weenie


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