Bronze Age

[Bewarethemoon]

I recently undertook a little experiment with the help of my polishing guy, with the aim of determining the finish for my frame & swingarm (before coating). I think I mentioned in my build thread that I was considering raw steel with bronze brazed joints?

Anyway Gavin quickly knocked up a couple small test pieces, he brazed the joints & polished the steel.



So then my next move was to send them to my coating guy and have him powder coat them, the reason for powder over paint or Cerakote was it's durability, I asked for one to be coated in a flat/satin finish and the other in a gloss.



I've tried to take the best photos that I can, in natural, indirect but well lit sunlight to give a accurate depiction. There's an unmistakable green tinge to the brazing. Does anybody have any inkling as to what's caused this? It was less than a week between the brazing being carried out and the coating applied so I feel I have to discount oxidation. In regards to preparation prior to coating I'm assured the surfaces were cleaned with Acetone.

I'm at a little bit of a loss as to what's occurred here, all I can guess at is that's caused during the heat in the oven?

Daniel.

 

[mrtwowheel]

I'm guessing that it's caused by the heat of the brazing, changed slightly in color by the powder coat.

 

[Bewarethemoon]

I'm guessing that it's caused by the heat of the brazing, changed slightly in color by the powder coat.

That’s all I can surmise, it’s the heat in the powder coat oven adding the tinge.

I’m pretty sure I’ve seen some high end bicycle frames raw steel with brazed joints, I wonder what finish they apply to protect everything?

Daniel.

 

[Bewarethemoon]

Curtis Bikes in the UK make some beautiful frames and offer a finish very much like what I'm hoping to achieve.

https://www.curtisbikes.co.uk/frames/bmx-4x-dirt/motox-racelite-20/

They offer this polished and then clear powdercoated.

Daniel.

 

[Mailman]

Curtis Bikes in the UK make some beautiful frames and offer a finish very much like what I'm hoping to achieve.

https://www.curtisbikes.co.uk/frames/bmx-4x-dirt/motox-racelite-20/

They offer this polished and then clear powdercoated.

Daniel.

Yeah, that’s a good look!

 

[Bewarethemoon]

Yeah, that’s a good look!

Isn't it just?

They also offer a smoked clear coat finish...

https://www.curtisbikes.co.uk/frames/xc-supermoto-bike-packing/curtis-xc9/

It's small firm run by Gary Curtis, I'm going to give him a call on Monday and see if I can pick his brains a little. I'm hoping he'll be receptive, he's just up the road from me and I used to know a guy that raced BMX for him.

Daniel.

 

[Kevin Werner]

I am a little leery of a brazed frame. You could clean up the welds and then braze over them if you seek a look.

Welding or Brazing Which is Stronger?​

A weld is generally stronger, but this depends on the given situation as brazing is far from a weak metal joining method. Welding and brazing both serve different purposes, and this comes into play in the different situations that a weld or a braze would be considered stronger, however, we would conclude that overall welding produces stronger joints due to the heat penetration that it delivers. Heat penetration and the complete fusion of metal simply don’t exist when brazing; the subject metal does not melt as it does when welding.

Try to view the strength of welds vs brazed joints like this: brazing is a process where the bond is made on the surface of the joint while a weld can penetrate right through the material and bond the two together completely at all points of contact. Despite this, brazing is still considered extremely strong and it is the optimal choice in a variety of circumstances.

Advantages of Welding​

Strength​

When compared to the process of brazing, welding generally has the greater advantage of strength. As we previously discussed, welding produces intensive heat which forces metal past its melting point. Once the metal has melted and a “weld pool” has formed, the filler material is then added which allows the material to thoroughly fuse together.

Compared to brazing, welding is far more reliable in its structural integrity when the material thickness is thicker than 1mm. This is a big reason why welding is far more utilized today than brazing.

from
https://finemetalworking.com/weldin...lows the material to thoroughly fuse together.

 

[Bewarethemoon]

Hi @Kevin Werner

I should of been a little clearer, we’re just brazing over the top of welds that have been smoothed & blended. This is purely aesthetic work.

Daniel.

 

[Max Midnight]

I am a little leery of a brazed frame.

Norton Featherbed frames were brazed and you don't read of them falling apart...

 

[Kevin Werner]

Norton Featherbed frames were brazed and you don't read of them falling apart...

I know many frames are brazed. Many bicycle frames were brazed in the old days but the tubes were brazed into lugs giving a large contact area. Are Featherbed frames lugged?

 

[YamadudeXS650C]

I raced Formula Enduro Karts for many years, and I finished the bare chrome moly frames with just fine steel wool, then a simple wipe with WD-40.
Folks sometimes thought I had clear coated it.

This frame has been on display in my winter workshop for more that a decade, and it still looks like it did back when I was racing.

 

[Kevin Werner]

Hi @Kevin Werner

I should of been a little clearer, we’re just brazing over the top of welds that have been smoothed & blended. This is purely aesthetic work.

Daniel.

Hi @Bewarethemoon You have a cool idea and I like it. Forgive me for being a "debbiedowner" befor I understood what you meant to achieve. Post pictures if it works.