Brompton project

[12boy]

That seat post tube looks cherry except for the rust. Way to go dude!
I am building a mini vardo on a 4x8 light trailer, and really can't do much more until the temps get above 40 F and the wind below 20 mph. Still, it's been a lot of fun so far and while I may not get another shot till February I really am looking forward to painting it artistically, since the structure is pretty much built and primarily needs to be painted and put together some. These kind of projects are so much fun!

 

[tom73]

Nice one

 

[12boy]

Are we there yet?

 

[JhnBssll]

Haha no I'm afraid not. I haven't had a chance to get in the garage since the last update, the frame is still in primer and hanging from the roof timbers I finish work for the year in an hour so should be able to post some updates soon

 

[12boy]

What kind of paint? I have found rattlecan paint takes a couple of weeks to fully harden. In the summer months I put the frame in one of my cars as it gets about 140 F inside, sitting in the sun, but that won't do doodley squat at this time of year. One of my favorites for beater bikes is Rustoleum hammered bronze as the metalflakey finish obscures all kind of flaws.

 

[JhnBssll]

Yeah its rattlecan etch primer so will take a while to fully cure Heres a lineup of some of the paint that will be going on

I drilled a hole in the frame today then gave it another coat of primer

The hole will be for a Di2 wire to go into the main frame tube where I will be mounting the battery I've tried to locate it far enough away from the brazed joint so as not to weaken it, but close enough so the wire picks up the brake cable without too much slack. Only time will tell if I've succeeded

I've now run out of etch primer and the rear triangle hasnt even had its first coat yet Just ordered another can, and two more of laquer as I'm aiming for a nice thick protective layer over the top

 

[12boy]

What's the Di2 wire for? Must have missed that part.

 

[JhnBssll]

What's the Di2 wire for? Must have missed that part.

I'm fitting Alfine 11 Di2, I'm installing the battery in the main tube so need a hole to run the wire through to connect the battery to the rest of the system

I spent a few hours using the works shotblaster this afternoon, the rear triangle is now completely free of paint and I've started filling the dents All the brazing looks spot on after the cold setting so I'm pleased with that! I also pressed in a small depression in the chainstay bridge to give a little extra tyre clearance for good measure, I'd be annoyed to find I needed it after I'd painted it

More filling and sanding later, new primer arrives Monday but I might look at putting some colour on the stem and frame later

 

[12boy]

Do love that brass brazing. Thanks on the wire....so it shifts the hub?

 

[Drago]

You using a 2K lacquer such as spray max?

 

[JhnBssll]

I considered 2k but haven't used it before and was worried about reactions. Sticking with 1k satin laquer but have 4 cans of it so will put several coats down and hope its tough enough

 

[Drago]

I've used it many times, you'll be cool

It cures proper hard, and gives a glassy pro finish which doesnt dull slightly with time like 1K. It ain't cheap though.

Great project, keep the updates coming.

 

[berlinonaut]

Just stumbled upon this thread. Very interesting project! Before you start the final painting I recommend doing some quick checks to avoid running into issues with the final build. Until now you are still able to change relevant things and I think you maybe will run into trouble with your positioning of the brakes once you do the full build with all bits and pieces. The Brompton is a complex beast due to folding and tight clearances and the cables are part of that game...

1. Front brake: It is more comfy to have the break bosses on the rear side of the fork for two reasons:
- easier to deal with the bracket of the front light when the brake is on the back side of the fork
- with your build the brake cable will leave on the drive side which will probably let the cable stick out to the side in folded state, making it uncomfortable as it might get caught easily on obstacles when moving the bike around. In unfolded state you might run into issues regarding the cable routing to the bars, especially if you are using a luggage block with a bag on it.
All three no killers but I do not see any downsides with having the brake behind the forks but the upsides mentioned above.

2. Rear brake: Again the cables might be an issue:
- depending from your brake it might get into the way of the bold holding the stop disk to keep the bike folded. It mounts to the bracket that formerly did hold the original brake. I'd heavily recommend to check this as probably the clearance to the break will be very tight or not enough.
- the cable will again leave on the drive side and possibly come into conflict with the chain in folded state. ou won't have both issues with the brake mounted on the rear side of the seat stays.

Other than that: Brompton wheels with 135mm hubs are ususally spoked asyncronouly with shorter, straight spokes on the non-drive side. I am astonished that you have not run into issues with your wheel build yet, with the chain and sprocket as well as regarding tire clearance - but maybe your thankfully slight chainline issues are an outcome of the way you spread the rear fork. Typically 135mm rear forks for the Brompton are a bit asyncronous with the non drive side being spread more than the drive side.

Regarding tire clearance to the short stay in between the chain stays: You can gently dent it with the sharp side of a hammer to increase the clearance. Does no harm and is kind of common on Bromptons with spread rear frame. If you ever want to mount tires like the 40mm Greenspeed you will be thankful... 😊

Regarding the rear light I suspect I may have to come a little lower not to hit the ground. But this is something to change easily even after the build is finished. 😊

Amazing job! Especially the welding of the broken parts inside the seat tube is very interesting!

 

[JhnBssll]

Thanks for the detailed information - there are some points in there that I hadn't considered and a few that I had and chose to ignore

I wanted the cables all on the drive side hence the brake positions. I think this will make the cable routing easier overall when the dyno and Di2 cables are also considered. I'm sure there are some downsides to this but finding them is all part of the fun

The stop disc - I wondered what that was I also wondered why the rear did not lock in the folded position So you have helped me there, I still have the old parts in the garage and will have a play. I don't intend to move the brakes, but I may have to engineer a modified stop disc if the brakes are indeed in the way Thanks!

 

[Pale Rider]

Is your Di2 hole in the frame where you might want to put the Brompton graphic?