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alevand
human power expert

USA
2937 Posts

Posted - 01/03/2016 :  18:00:39  Show Profile  Visit alevand's Homepage  Reply with Quote
I watched a video on filament winding driveshafts and they use a propitiatory matrix with silica in it to increase the compressive strength. It looks like white cream.

Is the BB shell composite or metal?

C:
Tony Levand

Edited by - alevand on 01/03/2016 18:06:09
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warren
human power expert

USA
6118 Posts

Posted - 01/03/2016 :  18:48:30  Show Profile  Visit warren's Homepage  Reply with Quote
The filament winders sound cool. Sounds like you are doing some serious investigation. If only there was a way to wind tubes that weren't straight it would be perfect for making bike frames.

The BB shell is titanium. I had it in my box of parts for several years and am happy that I have a project I can use it on. It was too thick and I sent it off to Rick to hsve him machine it down a bit.
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warren
human power expert

USA
6118 Posts

Posted - 01/04/2016 :  17:00:27  Show Profile  Visit warren's Homepage  Reply with Quote
Enter the doldrums of winter. I know I should go out to the cold, dark garage and play with carbon fiber, but it's warm in the house and the TV appeals to the animal hindbrain, providing a modern analog to the flickering fires that allowed our ancestors to survive the long and frigid nights of millennia past.
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Tom Schneider
recumbent enthusiast

112 Posts

Posted - 01/04/2016 :  19:57:02  Show Profile  Reply with Quote
I worked with a man who had an overhead gas heater installed in his garage, would keep the temperature at 70-75 degrees in a Minnesota winter.
His sons though it was great, they usually had one of their cars in his garage to repair.

Tom
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warren
human power expert

USA
6118 Posts

Posted - 01/09/2016 :  10:26:56  Show Profile  Visit warren's Homepage  Reply with Quote
Gluing on the boom. Fingers closed.
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Kragasaur
recumbent enthusiast

259 Posts

Posted - 01/09/2016 :  12:22:00  Show Profile  Reply with Quote
quote:
Originally posted by warren

Gluing on the boom. Fingers closed.



Presumably, you mean your fingers are crossed, not closed, unless you glued them together!

Glad to see you decided to brave the cold garage. I love this bike and you are making good progress. Keep on working! Those of us not currently building are building vicariously through you. So if you are not working, neither are we...

Eric
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warren
human power expert

USA
6118 Posts

Posted - 01/09/2016 :  14:54:25  Show Profile  Visit warren's Homepage  Reply with Quote
Yes, crossed. Stupid iPad autocorrect. I have to re-read what I write very carefully... I used the quartz halogen lamp up close to the head area to heat it up enough to cure. So far so good.
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warren
human power expert

USA
6118 Posts

Posted - 01/10/2016 :  08:40:06  Show Profile  Visit warren's Homepage  Reply with Quote
We had some nice above freezing temperatures over the past week so I took advantage of them and covered the boom with 1 layer of CF. I cut up some plastic grocery bags and used them to cover the resin impregnated CF. This seems to work better than the food grade plastic wrap as the plastic bag plastic seems to not wrinkle as easily and peels off better. I used the inner-tubes to compress the layup again. I won't use this method for the final layup as it leaves stripes in the epoxy that need to be power sanded off. I used the "oven" to cure the epoxy on the boom tube.

Before I added the boom to the frame I used 2 layers of CF to wrap around the head tube onto the down tube, then I bonded on the boom tube with a thick slurry of epoxy and micro balloons. After curing under the heat of the quartz halogen lamp and ensuring that everything looked straight I added a layer of CF to each side of the head tube area to fasten the boom more firmly.



In this picture the front wheel is turned slightly so the gap in front and back of the wheel appears larger than it really is.

Next step is to further reinforce the head tube area.
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mikes
recumbent enthusiast

Canada
155 Posts

Posted - 01/10/2016 :  09:12:10  Show Profile  Reply with Quote
Great job Warren,

However I think that you will need to instal the "cloak of invisibility" to see through the boom/headset!
Good Luck, keep posting.

Mike.
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warren
human power expert

USA
6118 Posts

Posted - 01/10/2016 :  09:52:11  Show Profile  Visit warren's Homepage  Reply with Quote
This bike was designed to have the same geometry as the steel bike and on that bike I was able to mostly see over the frame junk. My head will be up higher than it looks. Still lots of work to do before I can take a "Warren on the bike" shot.

I ordered a vacuum gauge and 1/4" ID polyethylene tubing for the vacuum pump that Rick gave me several years ago. It's a heavy, ancient oil filled pump, but it seems to work. The gauge will let me know if it pulls enough vacuum to be used for vacuum bagging.

Edited by - warren on 01/10/2016 11:14:27
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Kragasaur
recumbent enthusiast

259 Posts

Posted - 01/10/2016 :  18:55:45  Show Profile  Reply with Quote
Warren,
Can you explain what you mean about how you used inner tubes to compress the layup? Sorry, I'm sure you describe it earlier but I missed it or forgot.
And BTW it looks great. You've inspired me to a least think about building again.
FYI, when I need to do some aggressive sanding of CF, I have found that coarse drywall screens work pretty well. They don't clog up like sandpaper does. And, as you noted recently, do it wet, not dry to keep the dust down.
Eric
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Patrick Bateman
New Member

USA
69 Posts

Posted - 01/11/2016 :  02:02:39  Show Profile  Visit Patrick Bateman's Homepage  Reply with Quote
quote:
Originally posted by warren

We had some nice above freezing temperatures over the past week so I took advantage of them and covered the boom with 1 layer of CF. I cut up some plastic grocery bags and used them to cover the resin impregnated CF. This seems to work better than the food grade plastic wrap as the plastic bag plastic seems to not wrinkle as easily and peels off better. I used the inner-tubes to compress the layup again. I won't use this method for the final layup as it leaves stripes in the epoxy that need to be power sanded off. I used the "oven" to cure the epoxy on the boom tube.

Before I added the boom to the frame I used 2 layers of CF to wrap around the head tube onto the down tube, then I bonded on the boom tube with a thick slurry of epoxy and micro balloons. After curing under the heat of the quartz halogen lamp and ensuring that everything looked straight I added a layer of CF to each side of the head tube area to fasten the boom more firmly.



In this picture the front wheel is turned slightly so the gap in front and back of the wheel appears larger than it really is.

Next step is to further reinforce the head tube area.



Hey Warren,

Nice work.

I've found that that the plastic wrap for packing works even better than a vacuum. It seems to stretch more than Saran Wrap, and it's easier to work with. You can get it at Home Depot. It's located by the cardboard boxes and the packing supplies.
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warren
human power expert

USA
6118 Posts

Posted - 01/11/2016 :  12:27:49  Show Profile  Visit warren's Homepage  Reply with Quote
Cool Patrick, that should work well on the boom area. It will still be a tough layup. 3 or 4 layers of CF, Peel Ply, Absorption layer, then wrap on this stretchy stuff. I can't just do a big spiral wrap of the whole flame, so I'm thinking about doing each layer in 4 sections - left, right, top, bottom all overlapping.
http://www.homedepot.com/p/Pratt-Retail-Specialties-5-in-x-1000-ft-Stretch-Wrap-5005001/202029371

The rest will need to be vacuum bagged because of all the compound curves.

Eric - I slit several old inner-tubes lengthwise so they are like big rubber bands and then did a spiral wrap around the boom tube to squish it all together.

Edited by - warren on 01/11/2016 12:34:59
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Jeff Wills
human power supergeek

USA
1271 Posts

Posted - 01/11/2016 :  18:11:32  Show Profile  Reply with Quote
quote:
Originally posted by warren


Eric - I slit several old inner-tubes lengthwise so they are like big rubber bands and then did a spiral wrap around the boom tube to squish it all together.




Oohh... enough of the technical talk! My head hurts.

__________________
Jeff Wills
All my bikes:
(Site nuked by Comcast. Will return soon.)
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warren
human power expert

USA
6118 Posts

Posted - 01/16/2016 :  12:21:04  Show Profile  Visit warren's Homepage  Reply with Quote
The head tube is now reinforced. I was almost out of my several year old gallon of West Systems epoxy, so I took a trip to Rockler today to pick up another gallon of epoxy and some fast cure hardener and measuring pumps. The fast cure hardener will work better in the cooler temps. They had some "clear coat" hardener that was for top coat on wood and carbon fiber, but it $20 more expensive. I also have the hose and most of the connectors for the vacuum pump.

A vacuum pump test today showed the pump will draw 25 inches max with a fairly perfect seal. I will try another test later with air in a bag to see how fast it will remove the air.

Edited by - warren on 01/16/2016 12:50:20
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warren
human power expert

USA
6118 Posts

Posted - 01/18/2016 :  08:47:16  Show Profile  Visit warren's Homepage  Reply with Quote
I did a test today to see what kind of volume the vacuum pump would move and it is apparently very low. I put a paint can in a plastic grocery bag and sealed it up and it took several minutes to evacuate that small amount of air. This tells me that the pump will be good for small parts, but probably not for vacuum bagging the entire bike. I will probably just be using the wrap method and use foam to fill the concave sections as I have in the past. It's been hovering around 0 degrees F for the past several days so it's too cold to spend time in the garage.
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jjackstone
recumbent enthusiast

USA
232 Posts

Posted - 01/18/2016 :  10:44:14  Show Profile  Reply with Quote
If you have a good sized shop vac you can use it to pull down the bag. A well sealed shop vac can pull up to 5 psi fairly rapidly. It could be used in conjunction with your other pump. Or if you have a maybe a spare air compressor tank it can be evacuated in advance and used as a buffer tank. I used to use a 5 gallon backup pressure tank that I got from HF to help out.

JJ
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rickmantoo
recumbent enthusiast

USA
274 Posts

Posted - 01/19/2016 :  07:53:01  Show Profile  Reply with Quote
Warren

When I was using that Pump I used 1/2" ID tubing and I was able to bag the entire Great White frame and the sub frame and seat for the FnL, So maybe your tubing is too small.

Rick
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warren
human power expert

USA
6118 Posts

Posted - 01/19/2016 :  08:45:17  Show Profile  Visit warren's Homepage  Reply with Quote
Hi Rick,

Hmm. You may be right. I'll try to find some bigger hose.

Warren
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alevand
human power expert

USA
2937 Posts

Posted - 01/19/2016 :  15:24:24  Show Profile  Visit alevand's Homepage  Reply with Quote
Flow goes with the 4th power of diameter.

C:
Tony Levand
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Upright Mike
human power expert

USA
3803 Posts

Posted - 01/24/2016 :  19:40:49  Show Profile  Reply with Quote
Warren - seeing your build yesterday was very exciting! I'm as excited as I've been since seeing one of John or Thom's builds! I just read this whole thread!
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Tom Schneider
recumbent enthusiast

112 Posts

Posted - 01/25/2016 :  05:43:14  Show Profile  Reply with Quote

alevand Quote:
I watched a video on filament winding driveshafts and they use a proprietary matrix with silica in it to increase the compressive strength. It looks like white cream.

The main tube on recumbents could use this since the compressive strength is basically the epoxy. Did you find any more information on this white cream?

Tom
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warren
human power expert

USA
6118 Posts

Posted - 01/25/2016 :  06:54:09  Show Profile  Visit warren's Homepage  Reply with Quote
Here's a paper showing that mixing silica nanoparticles into the epoxy improves the compression strength of the composite material.
http://www.ipme.ru/e-journals/RAMS/no_13814/05_13814_kumar.pdf

Silica nanoparticles like MCM-41 are not something that I would want to mix into the epoxy myself due to difficulty of keeping the stuff out of the air (and my lungs) outside of a laboratory environment, and also it seems to be pretty expensive ($200+ for 1.5 grams?)

I have often used cabosil (fumed silica) to make a thick epoxy for bonding things together. It works well but does not add any strength to the resin.

Apparently plain old talc is a common filler for epoxy that also increases compression strength, but it is heavy.

I'm thinking that eventually we will be able to get high strength epoxy premixed with silica, or a liquid.

Other options:
Carbon nanotubes: http://www.playwithcarbon.com/multiwall-carbon-nanotubes-1l/

Here's some reinforced epoxy resin that claims 80% higher strength but it may be hard to get:
http://www.phenoxy.com/technical-data/tougheners.html
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warren
human power expert

USA
6118 Posts

Posted - 01/30/2016 :  14:04:22  Show Profile  Visit warren's Homepage  Reply with Quote
I laid up 3 layers of CF over the forward half of the bike. A large layup like that is a real ordeal. After laying up the CF I wrapped it in nylon peel ply and breather ply, then wrapped with that stretchy furniture wrap Eric recommended. I was concerned it was still not wrapped tight enough so I then wrapped it with the old inner tubes. The whole mess is in the foam box out in the garage, hopefully getting warmed up enough to cure properly by 200 watts of quartz halogen fury.

This is the minimum layup for this section, I may add more later if it's flexy.
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warren
human power expert

USA
6118 Posts

Posted - 01/31/2016 :  06:51:49  Show Profile  Visit warren's Homepage  Reply with Quote
Well, on the plus side, the peel ply does peel. On the minus side, I used way too much epoxy and the bleeder ply is saturated, which means I have a thick coat of tough material on top of the peel ply. This will take a long time to remove! I see at least one large wrinkle which will need to be power sanded off . Trials and tribulations...

This is where a female mold would have really been nice. Nobody cares how ugly it is on the inside.

As I am slowly peeling off the peel and bleeder ply I am seeing lots of large wrinkles on the sides where the sides where wrapping did not provide adequate pressure. Probably it would have been better to vacuum bag.

Edited by - warren on 01/31/2016 07:41:43
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