Easyflo flux as a substitute for Cycle Designs Stainless Light Flux?

[nikki]

Hi,
I'm currently building my first frame. Most of the build was done in the workshop of a couple of established framebuilders, however for the last stages I'll be working from a university workshop where I very much have to play by The Rules. That means no new substances to be brought in unless they've been through the university's Control of Substances Hazardous to Health (COSHH) evaluation process and approved.

The Cycle Designs Stainless Light Flux is not on the menu, and getting COSHH approval just for this one instance is highly unlikely.

There is however a Jewellery department based on another campus of the same university and it looks like they're using Easy Flo flux powder. (EASY-FLO products | Johnson Matthey)

Maybe, just maybe, the academic bureaucracy allows for transferring the COSHH paperwork between campuses...

But is Easy Flo something I could (or would want to) use as a substitute for Stainless Light Flux?

I've only very limited experience of the latter so far, and none of the former. I need to add a cable guide to the fork, and attach a couple of brass badges to the main frame. Sif 39 and 43 silver solders.


Thanks,
Nikki

[Eric Estlund]

I've never used that product, but looking at the page I suspect it's for soldering or low temp brazing of silver jewelry alloys. Looks like it's max working temperature is 800*C. That's a bit lower than the max temp of some other fluxes, but still higher than the melting point of many silver alloys (like 56 varieties).

I'd suggest mixing the powder in warm water to make a paste flux and running some practice to see if it will work for your needs.

Assuming the workshop has brazing supplies, what are they using for flux?

[nikki]

The workshop uses sif 101 rods with sifbronze flux powder mixed into a paste as you describe. Mostly the technicians doing odd jobs with it, whilst the students mainly use the MIG welder for their constructions (it's an art department workshop).

Come to think of it, there's also an introductory jewellery class that uses that space. Cones of borax sort of thing. We jostle in a polite manner for which torch head gets fitted to the oxy propane!

I haven't done any capillary style brazing with the bronze rods before, so I'm wary of trying that, although I suppose it's a fallback option with some practise. Some folks use it for lugwork, right?

[e-RICHIE]

I haven't done any capillary style brazing with the bronze rods before, so I'm wary of trying that, although I suppose it's a fallback option with some practise. Some folks use it for lugwork, right?

Are you referring to brass rod for lug brazing?
If so, far more people have used it for brazing lugged frames than have ever used anything else for the same task.

[nikki]

Points taken!

[Doug Fattic]

Nikki, I'm not sure I have a clear picture of what you are trying to attach to your almost finished frame. If you are brazing brass badges to your frame you will need to use silver of course. Like Eric said most standard white flux for silver brazing has an operating temperature of 1600º F. The Easy Flo stuff you mention is slightly lower although well above the temperature 56% silver (the most likely silver you brazed with) melts. Stainless Light goes up another 100 degrees to 1700ºF. Stainless steel requires a little higher temperature to braze properly and so having a flux that operates at a little higher temperature makes sense. This higher flux operating temperature works great for students brazing regular steels because they are less likely to burn it up by overheating it.

Brass brazing (American builders say "brass" but it really is bronze) is not difficult to do but it does take a different technique that requires practice when making the switch. 56% silvers melt around 1200ºF while brass (actually bronze) melts closer to 1600ºF. The kind of C-04 brass I use sold by GasFlux (that is a company's name) melts around 1450ºF if I remember right. The UK version of Sifbronze also melts around the same temperature. Anyway, it won't take much effort to practice/experiment with scraps with the flux available at your school and see if it works.

[Apollo]

Sif 43 is 55% silver with tin, Sif 39 is 38% silver with tin. Sif 43 has nearly the same melting temperature as 56% silver with tin brazing rod. Sif 39 has a a higher melting temperature. Sif 101 is very similar to American, "Low Fuming Bronze" brazing rod, colloquially called, "brass" brazing rod. Standard EASY-FLO for 800 degrees Celsius should be alright for Sif 43. You could also use 56% silver with tin brazing rod from another supplier. This has a similar low melting temperature and wets out well. Having everything clean is important. Some of the stainless steel type flux may be a touchy subject in Europe now as it often has higher levels of stronger fluorides that are considered more toxic. The bronze brazing would require the flux for its higher temperatures and would not be suitable for brazing brass badges.

EU industry decided to not standardize 38% silver with tin, because they claim 40% with tin is more popular and can do everything 38% can do. 55% silver with tin is certified for some type of high temperature electrical connections in aircraft. 56% silver with tin is often considered before it for brazing steel, but they both do work.

When I had my shop in Italy I knew a British frame builder that fillet brazed Columbus stainless steel tubing with 38% silver with tin. Columbus doesn't address fillet brazing, but recommends 56% silver with tin for lug brazing their stainless steel. Reynolds recommends 56% silver with tin for lug brazing of their stainless steel and 40% silver with tin for fillet brazing of their stainless steel.

The standard white flux for silver brazing should be alright for brazing with SIF 43 (55% silver with tin) or for 56% silver with tin brazing rod. There are some other fluxes I used in Italy, but there are also some to avoid.

[nikki]

Thanks Doug and Apollo for your detailed responses.

[And wider thanks to everyone who's made this forum such a valuable learning resource in general.]

Nikki, I'm not sure I have a clear picture of what you are trying to attach to your almost finished frame.

Yeah, I'm probably not making things particularly easy for myself for a first time around...

Badges


2mm thick brass, 2mm background grid.

The larger one with the poem is to go in the typical head badge position on the front of the head tube, the smaller one in an as-yet-undecided location elsewhere on the frame.


Cable guide
I need a cable guide for the front disc brake hose as it comes up the fork leg. Ideally matching these that are elsewhere on the frame:


This was missed off an order made by a third party, so I need to do a bit of detective work to get a definite ID for the part. I'm currently assuming it's not stainless, going by the rust that's on the one in the photo, but I'll wait until I've checked things with the supplier before making any decisions/actions.

Anyway, it won't take much effort to practice/experiment with scraps with the flux available at your school and see if it works.

*nods* I've got some offcuts I can practise on. The more challenging aspect will be persuading already stretched technicians from one campus to dig out paperwork for sharing with those from another campus, and then to get the permissions to have flux and oxypropane torch in the same space. I think I'm on the way to being able to put forward a reasonable argument for it now.

Brass brazing (American builders say "brass" but it really is bronze)

AH-HAH! That is super useful to know!

Some of the stainless steel type flux may be a touchy subject in Europe now as it often has higher levels of stronger fluorides that are considered more toxic.

Thanks for the heads-up on this - I'll see if I can find out more.

[Eric Estlund]

You could also silver solder those badges since they are no structural joints with high.surface contact.

[Blacklabbikes]

the cable guide is art 102 here: Brazeons

Peter is a great guy although the ordering process more involved than some online shops. Where are you based?

[nikki]

the cable guide is art 102 here: Brazeons

Peter is a great guy although the ordering process more involved than some online shops. Where are you based?

Yup, got that thanks - but even as a newbie I know I need to check there's not something similar elsewhere on the site or off-list somewhere!
Peter's been very helpful with seeking out the MSDS sheets for the Cycle Design fluxes.

I'm in Birmingham at the moment, relocating to the North West in a few months' time.

[nikki]

You could also silver solder those badges since they are no structural joints with high.surface contact.

Missed this earlier.

I'm really wary of slippery language now! Do you mean jewellery style with the strip solder where the silver content percent is up in the 60s and 70s?



Would you also consider that for the cable guide too?

[Apollo]

Missed this earlier.

I'm really wary of slippery language now! Do you mean jewellery style with the strip solder where the silver content percent is up in the 60s and 70s?



Would you also consider that for the cable guide too?

You may have to be careful in solder selection. There are some lower temperature types that are good for copper to copper, but not for steel or copper / brass to steel.

You are more likely to run into plumbing solder for copper only, rather than something suitable for attaching to steel.

You would really have to get selective to find the lower temperature solder suitable for steel I would think.

The original type you mentioned for bicycles would likely be more suitable, or at least easier to sort out.

[Blacklabbikes]

Too far north for me but you might find it easier to pop in to a local framebuilder - they might let you use their workshop if you can't make final progress with the uni.

[Doug Fattic]

Nikki, I second Joe's suggestion of finding a local frame builder to put on the final braze on. Even though I am located in the States (and Ukraine), several of my frame building class students have set them selves up with oxypropane brazing equipment in the UK. Btw, I learned at Ellis Briggs in Shipley West Yorkshire back in the day when Americans sought knowledge oversees. You might consider using adhesive to apply your brass badges. That way you won't mess up your Japanese writing with heat. There is a current subject thread about this over on the frame builders section of Bike Forums.

Do you need suggestions on how to bend your brass plates to fit around the frame tubes? One way is to split a piece of heavy walled tubing lengthwise (so it is a half tube) and squeeze the badge between that and another stout piece of heavy tubing behind it. Is the frame you made just a one-off custom for yourself or do you plan on making more in the future?

[nikki]

Yes, using a local framebuilder's workshop would simplify things considerably. Finding one would unfortunately not be as easy around here as it would have been 100 years ago, but I've got a couple of leads I could try. Joe, I have family in Exeter so you're not off the hook yet! ;-)

There's a case for doing it at the university if I can, but I have got this lurking at the back of my mind as a back-up option if needed.


Doug, thanks for the pointer to the Bike Forums thread. I did spend some time pondering adhesives and rivets as other approaches, but neither sat quite right with me. (Although, now I've got the badges made, I think I would consider adhesive if I really, really had to.)

I've given one of the smaller badges a blast with a torch to see how the text fared - and the one in the photo above was attacked with 60 grit and polishing mops - and it's holding up well so far. I haven't tried bending them yet though.

The current frame is custom for me, with the plan being to make more frames in the future. I'm about to start an art PhD which gives me 3 years to hunker down in a studio space and hone my skills on builds of varying practicality. I'll need to start again with the Health and Safety wrangling though, and make friends with the Engineering department for access to their torch! If that fails, I'll be introducing myself to the local framebuilders up there...

So, with that in mind:

* I came down on the side of brazed-on badges because I think that'll be a skill I'll want to keep coming back to in different applications.
* I've decided to push for brazing the current badges with the materials I want to be using in the future, so I'm about to put in an order for some Sif silver rods and some Cycle Design flux, working on the basis that if I don't manage to use them this time around, I will at a later date. In the meantime I've started asking around to find out what the Easyflo situation is and we'll see if that becomes a viable option or not. (Thanks Steve - I think our thinking is along similar lines.)

Do you need suggestions on how to bend your brass plates to fit around the frame tubes? One way is to split a piece of heavy walled tubing lengthwise (so it is a half tube) and squeeze the badge between that and another stout piece of heavy tubing behind it.

Short answer: yes please!
Longer answer: I've got a month or so remaining of access to some decent bits of equipment including lathes and a hand-cranked milling machine, so I'm using this to get as tooled-up as possible. Badge-bending tooling is getting pretty close to the top of the to-do list and a bit of my brain has been thinking about it, but not in any great detail yet.

For shaping the inner surface I can easily turn some aluminium down to size and cut a flat on one side, but the solution for supporting the outer surface has been less obvious without sacrificing a tube block or similar. I hadn't thought of using the inside of some steel tube - thanks!

[Doug Fattic]

In the States it is easy to buy tubing in inch fraction sizes. It is possible to purchase tubing that a bigger size will just slip over a smaller tube with just enough clearance for silver (or brass) brazing if the tube has a wall thickness of 0.058 inches. A specific example would be a tube with an OD (outside diameter) of 1 1/8” with a wall thickness of 0.058” will just slip over (meaning there is a few thousandths of an inch clearance between the ID of one and the OD of the other) a 1” OD tube. This is how bi-laminate frame construction is done. Claude Butler frames were famous right after the war for making bi-laminate frames when lugs were hard to come by. They look like a lug but in fact are 2 short sleeves fillet brazed together over the main tubes of the bicycle frame. Some of England’s very best classic era builders (like Bill Hurlow and Ron Cooper) came out of Claude Butler’s shop.

This slip fit is also possible with 0.120” wall thickness. A tube with this wall thickness (a common size that is easy to buy from airplane supply outlets) can become a tool to bend your badges. For example a tube with an OD of 1 1/2” and a wall thickness of 0.120” will just fit around a 1 ¼” head tube. Cut that tube length-wise into 2 parts (so it is now half a tube). This is the piece that will bully your head tube badge into a curve when the inside of it is placed against 1 ¼” round stock and the 3 pieces are squeezed in a vise. Get it?

For those in the States wanting to buy 0.058” or 0.120” tubing, it is available from Wicks Aircraft Supply or Aircraft Spruce. They also supply 0.035” tubing for brazing practice. For silver practice a short length of 1 ¼” OD tubing with a wall thickness of 0.058” can be brazed over a much longer length (so it is easy to hold) of 1 1/8” tubing with a wall thickness of 0.035”. For brass (really bronze) fillet brazing practice, short lengths of 1” w/0.035” can be mitered to fit on the end of a long piece of 1 ¼” w/0.035”. The advantage of having a long piece is that the non-active end can be turned with your hand to constantly keep the joint in the right position while brazing.

[nikki]

The university's been making cautiously positive noises about fluxes, so I'm optimistic something may have happened by the end of next week.

For those coming to this thread in the future, Tenacity No 5 has also been suggested on the basis of it having a slightly higher active temperature and a bit more stamina. http://www.jmmetaljoining.com/pdfs-p...x%20Powder.pdf (Not water soluble, though.)


Thanks for the badge-bending walk-though, Doug. All clear.
Metal listings in the UK are in a horrible mish-mash of mm, inches and SWG. ...Less clear!

I've spent time this morning with vernier callipers, various suppliers' websites, conversion calculators and some drawing software. I'll have to do a bit of shimming, but that should be easy enough. Mostly waiting for various deliveries now...


Side note: I'm not sure I'll end up doing much with lugs (non standard angles and all that), but I'm looking forward to the time when my learning curve takes me to the point where I give bi-lam a go.

[Blacklabbikes]

tw metals in southampton is a useful tip...

[nikki]

The badges are on!

Let's just say I can add no further information on possible substitutions for the Cycle Design flux *ahem*


Joe, how do you normally interact with TW Metals? Their website looks like it's set up for substantial orders of USA-held stock - are they generally amenable to being phoned up and asked for small quantities of bits and pieces?