Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Framebuilders Thinking about a custom frame? Lugged vs Fillet Brazed. Different Frame materials? Newvex or Pacenti Lugs? why get a custom Road, Mountain, or Track Frame? Got a question about framebuilding? Lets discuss framebuilding at it's finest.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 07-29-14, 06:09 AM   #1
alex jb
Senior Member
Thread Starter
 
Join Date: Feb 2012
Location: Leicestershire, UK.
Bikes: Orbea Ora, Klein Palomino, Planet X Kaffenback, Custom Bamboo build, 1964 Schwinn deluxe.
Posts: 215
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Bamboo build, advice on finishing.

Hi folks,

The frame is built and it was a fun but long and slightly stressful experience!
I would do it again though, lots of learning along the way.



My question is about the finishing of the bamboo surface and the joints.
Should I prep the bamboo lightly with 200 grit and paint epoxy over the whole lot or do something different with the tubes and the joints?
alex jb is offline   Reply With Quote
Old 07-29-14, 01:56 PM   #2
Canaboo
Senior Member
 
Join Date: Dec 2009
Bikes:
Posts: 321
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Sanding and total epoxy coating followed by more sanding and a UV resistant varnish coating is the way to go if you want it to last forever.
You have to get the gloss off the bamboo if you want anything to stick to it. You don't have to take it right down to the power fibers although it looks more finished if you do.
I have a frame sitting in my yard that's under the weather full time and it still looks like it was finished yesterday.
Here is a pic of a coated frame;

Last edited by Canaboo; 07-29-14 at 02:02 PM.
Canaboo is offline   Reply With Quote
Old 07-29-14, 08:03 PM   #3
RISKDR1
Senior Member
 
Join Date: May 2014
Bikes:
Posts: 490
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
the best builders of custom bamboo fly rods use spar varnish. Man O War in the red can (unless you are in California where it has been gutted) is popular. It is very tough. Bamboo rods are probably exposed to UV as much as bikes and certainly flex more. In addition to that they are exposed to water all the time. Over a period of years the varnish will darken from the UV exposure. As mentioned above, breaking the shine on the surface is a good idea since it give "tooth".
RISKDR1 is offline   Reply With Quote
Old 07-29-14, 09:09 PM   #4
Canaboo
Senior Member
 
Join Date: Dec 2009
Bikes:
Posts: 321
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
In this case the UV resistance of the varnish is solely to protect the epoxy, not the bamboo.
Canaboo is offline   Reply With Quote
Old 07-29-14, 11:28 PM   #5
MassiveD
Senior Member
 
Join Date: Jul 2011
Bikes:
Posts: 2,341
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
There are UV resistant epoxies, and there are some cheap epoxies that are pretty UV resistant like clarkcraft. I would have no concern about just using epoxy, if it starts to show any signs of problems then you can varnish at that point. But simpler is that if the bike spends all its time in the dark except an hour or two, and a week or two, here and there, you don't need varnish. But if it sees a lot of outdoor light, you can gloss varnish it, and it will protect the epoxy and the wood. Some theory holds that while the epoxy yellows the wood is affected by UV in such a way as to reduce the bond to the varnish.
MassiveD is offline   Reply With Quote
Old 07-30-14, 07:45 PM   #6
Mark Kelly 
Senior Member
 
Mark Kelly's Avatar
 
Join Date: Oct 2009
Location: Willy, VIC
Bikes:
Posts: 637
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
A Canaboo notes, you need to get the waxy cuticle off the surface before doing anything.

I disagree with MassiveD above: UV stabilised epoxies don't stay that way for long and by the time any damage becomes evident they're basically ruined, the UV radiation undoes the crosslinking which was the reason for using epoxy in the first place.

On my wooden bikes I use a five layer protection system. The first three layers are epoxy: one layer of a high temperature low viscosity laminating resin* (excellent penetration), then two layers of West System 105 / 207 (UV stable). Fine sand (320 or 400 grit) between layers of course.

I then top coat with two layers of 2k marine polyurethane*, again sanding to 400 grit between coats, to protect the epoxy. Attempts to use the 2k by itself have failed, it has lousy penetration.

IMO normal spar varnish is pretty close to useless, the yachties are used to applying multiple coats and replenishing them every couple of years.

* The products I'm using are Australian so there's not much point in naming them for you.
Mark Kelly is offline   Reply With Quote
Old 07-31-14, 04:35 PM   #7
alex jb
Senior Member
Thread Starter
 
Join Date: Feb 2012
Location: Leicestershire, UK.
Bikes: Orbea Ora, Klein Palomino, Planet X Kaffenback, Custom Bamboo build, 1964 Schwinn deluxe.
Posts: 215
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks All.

i have taken back the sharp raised edges left from the tape wrapping process but basically not cut into the hemp wrapping much to avoid weakening the structure and I don't mind the organic look (look at the wobbly bamboo I picked!)
I flatted the surface back with 120 grit an painted a layer of 2 PAC epoxy resin on the BB joint to see how it looks, it seemed to penetrate well and took the light spots back to the brown hemp color.
i haven't finished the joints yet, once I do if they are too my liking I will likely go
with the advice above and lightly key the tubes and use the epoxy as the first coat.

Last edited by alex jb; 07-31-14 at 04:38 PM.
alex jb is offline   Reply With Quote
Old 08-01-14, 02:08 PM   #8
alex jb
Senior Member
Thread Starter
 
Join Date: Feb 2012
Location: Leicestershire, UK.
Bikes: Orbea Ora, Klein Palomino, Planet X Kaffenback, Custom Bamboo build, 1964 Schwinn deluxe.
Posts: 215
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Bit of automotive polish to the layer of epoxy and it is looking a lot better.
tried the new BB in also.

alex jb is offline   Reply With Quote
Old 08-01-14, 05:26 PM   #9
Canaboo
Senior Member
 
Join Date: Dec 2009
Bikes:
Posts: 321
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
There is no reason why you shouldn't smooth the lugs completely. Are they strips of linen canvas for art?
Canaboo is offline   Reply With Quote
Old 10-16-14, 07:29 AM   #10
GreenstarBikes
Newbie
 
GreenstarBikes's Avatar
 
Join Date: Oct 2014
Bikes: Ecoforce 1 bamboo bike
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Nice job Alex. We use machined bamboo for uniform sizing, but looks like yours is natural. In that case you must sand the bamboo to scuff the shiny outer surface. You will want a minimum of 3 coats of varnish, sanding each time. Also pay attention to seal any gaps around the lugs. It helps if you can sand the edges of the lugs to be almost flush with the tubes. Happy Riding!
Attached Images
File Type: jpg ef1-green-2014-m1-crop-900.jpg (74.2 KB, 6 views)
GreenstarBikes is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 08:34 PM.