I was not sure where to put this but I have a question for those who have built a carbon bike. Do I need this stuff for my seat tube? Amazon.com : Finish Line Fiber Grip Carbon Fiber Bicycle Assembly Gel, 1.75-Ounce Tube : Bike Oils : Sports & Outdoors

I have read and they say never use grease on carbon, they also said that like steel or aluminum seat post they will bond to the frame over time. The article I read said to use something like I posted above. What do you do?

According to Craig Calfee there's nothing available at your local hardware store that will damage a carbon frame (at least no fluid). Mt experience starting with the first gen Specialized Allezs agrees with Craig's statement. Grease might leave a stain, might make slippage more likely, might require greater torque for binder aspects (which also speaks to the component's material) but will not harm the carbon's matrix, strength or laminations.

The more recent (then the early versions of carbon frames which often used AL interfaces with components) designs have more limiting torque levels of their binders and other interfaces. So using a carbon paste with a "grit" helps to contain the component, reduce the clamping or press in pressure and also reduce the galvanic reactions.

Carbon is electrically conductive enough so that other metals can and will galvanicly react with it. This is why when an AL insert is bonded to the carbon it needs some sort of insulation coating it (a layer of fiberglass is a common technique). (The early Specialized Allezs had a production run which failed to do this properly and had a high bonding failure rate). The carbon paste acts as a insulating barrier.

At work we now use carbon paste on all posts and many other clamping spots involving carbon to metals or carbon to carbon. Andy.

Thank You very much! I have ordered the carbon paste. I take it that it only needs a very thin coat?

Yes, a thin coat of both surfaces it best. Andy.

[MENTION=391685]Andrew R Stewart[/MENTION] Which carbon paste do you use? I will be assembling my first CF bike soon and will need to order some, your recommendation is good enough for me.

Thanks Andy! Another question. What do you use to put the thin coat inside the seat tube?

I do not know what his shop uses but I ordered this:https://www.amazon.com/dp/B0012RIEM6/...7OMI7EQW&psc=1

I'm sure that any carbon paste will be fine. I just use my finger to apply the paste to the seat post and inside of the seat tube.

Yup. That's how we do it at the shop I work for. Each carbon frame comes with a packet of carbon paste. Since we only need a small amount for assembly, we squeeze the excess paste out of the supplied packets into a jar. It looks like a jar of pink toothpaste!

Carbon paste can be used on non-carbon seatposts, if you have one that's a little undersized and tends to slip.
There are also specific formulas of Loctite for about any mechanical situation.

Yes, there are bearing and collar fit grades of Locktite that are used to make loose fitting bearings, etc. stay on their shafts and, of course, would work to take up the slack of a an undersized seatpost. It will also assure you will NEVER get that seatpost out without using a torch.

Here is a pic or two of my bike build on the Nashbar frame. I will answer a couple questions before they are commented on. (1) The fork is long because I have had cervical spine surgery and in order to see down the road comfortably I left it long. (2) The rear brake cable housing has been shortened. (3) i am waiting on a hangar for the rear mech. Please if you see something and have a suggestion, please comment. I have been out of cycling for a long time (early 90's) and new to bike building so I will appreciate comments from seasoned builders!

Use the seatpost for clamping into the work stand. It's designed to be compressed and easily replaced.

Yes yes yes. Don't clamp a carbon frame tube. It's good that you padded it, and I doubt that you've torqued the frame enough to do any damage. But, if that stand falls over then the top tube may crack. Seat posts, even carbon ones, are much stronger.

Ensure that the handlebar stem is clamping on enough steerer; it should be at least 75% filled with steer tube. I can't see well enough to confirm.

I see that your cables are rubbing the head tube. If you cross the cables over to the opposite sides, they won't rub any more. This entails running the shift cables to the opposite holes at the top of the down tube, and crossing them over somewhere (easy on frames with external cable stops).
I'm not sure how the internal cabling works on that frame, so this may or may not be possible. But it solves head tube rub. Some folks protect the head tube with clear stickers, like chainstay protectors.

Otherwise, your build looks fine.

How far is the top of the steerer tube below the top of the stem? The steerer should be nearly, or better yet fully, supported inside the stem and a gap of only about 3 mm left for headset adjustment. Full support is really recommended if the steerer is carbon and if possible have the steerer extend slightly above the stem and use a small spacer to get the required gap.

BTW, I count 70 mm of spacers below the stem and, if that's correct, that's more than any carbon steerer is supposed to have. A maximum of 50 mm is the highest stack I've ever seen any maker allow and that's with a 1-1/8" steerer. If you really need that much you probably need a larger frame.

It is no more than 3 mil, enough for the cap to fit properly.

The bike is not clamped. It is setting there. I will however move to seatpost, but my seat post is carbon also. Then again, I guess it is easier to replace a seatpost than the frame. I was going to put some lizard skin type material where the cables touch the frame, basically clear vinyl. The stem has just enough room for the cap to sit flush, 3 mil or less.

Thank You! Right now the frame is pretty much balanced in the stand with virtually no pressure on the top of the top tube. I have a carbon seat tube also. I take it the clamping will not affect it?

Put in a metal seat post , clamp That .. buy a cheap aluminum seat post in the right diameter for the Purpose.

+1 Unless you are really ham-handed you won't hurt the carbon post but a metal post is both cheap and impervious.

Question about the frame---what size and how much does it weigh?

I have been weighing Workswell or Nashbar, but Nashbar doesn't publish weight figures (unklike WW, whose figures are undeniably ultimately and wholly reliable. ) I have checked that specific frame (Y-seatstay) and am not sure any size really fits me (it goes like 52 cm, to 55 to 57.) About how tall are you? I have not had spine surgery---I use fat in front to keep me from bending down over the bike (so that info about max spacer stack height is Really useful.)

A wholly enviable build. Congrats and thanks for the pics.

I found the weight info on Nashbars site somewhere. I may have gotten it during a chat session. I can't remember now, I will look for the info again and post. The frame is a 58, which from measurements is closer to a 56. I am approx. 6'1" maybe a little less. I used to be 6"2" before my 5 surgeries. LOL
1025 grams for the frame and 351 grams for the fork. That would be 3.033561 pounds total. All I know is that it is much lighter than the steel bike I built a couple months ago. My wheels are heavy. I am using 36 14ga. spoked wheels. Both wheels without tires and tubes weigh 5.394712. I am heavy at 235 and used to break spokes climbing back in the 80's and 90's on my 86 Schwinn Super Sport. I'm sure wheels are stronger now but I will call it insurance. LOL
The biggest reason this bike is being built is because I like building stuff, but it will be used as soon as I can can go outside in bike shorts and ride.

I did not clamp the seat post hard. I do have quite the grip though but I did not use it in this instance.

Received tires and tubes from Merlin today, and installed on rims. I am still waiting on a RD hanger. The bike came with one but I did not check to see if it was tight when I installed the RD and it cross threaded the first couple threads. I learned something check everything! Assume nothing. Nashbar is sending a complimentary hangar and I also ordered an extra. They should be here Thursday.

Paint remover with methylene chloride (aka dichloromethane) can. It will dissolve/degrade epoxy.

That statement again makes that huge spacer stack very problematic.

I think Acetone would do a fair amount of damage on the clear coat also. It may not affect the carbon itself but any other adhesives it might or will.

I don't see where there will be an issue. The stem is fully on the fork tube except for 3 mil or tad bit less so the cap fits correctly. I am not an aggressive rider, I just ride. I do not see myself putting enough force on the front end to either cause damage to the fork tube or frame.
Maybe I am missing something?