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Sweating split bearing halves together

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G-Span

Swarf
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#1
My son & I are building a Wyvern Engine from the Hemingway Kits, which has a split Phosphor Bronze bearing. The procedure calls for the the two halves to the be soldered together, machined, then split apart again. I purchased a Benzomatic MAP / PRO TS8000 Torch, which cane with flux and lead free solder, for the job. But all my attempts, on a piece of test brass, have failed. Is the flux and solder wrong? I was getting the parts red hot. Tried to indirectly heat the flux coated area on one attempt. The flux turns black and the solder balls up and does not stick!
 

markba633csi

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#2
I think you are way too hot. If you are soldering it requires a much lower temperature than brazing or welding- certainly not red heat. Have you done any soldering before? You only need to get the parts hot enough to melt the solder and just a bit hotter than that.
mark
 
Last edited:

extropic

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#4
Those YT tutorials you mention may be about brazing copper tube. Flux for soldering won't survive the higher temps, as you've discovered.
I don't know the dimensions of your bearings but, pre-heating on a hot plate or using a hot air gun might be worth a try. What I mean is to get the parts to a uniform temperature but, not necessarily up to soldering temperature, so the torch doesn't have to do all the work. You want to use your heat source to heat the part (not the solder). Then apply solder to the pre-fluxed and heated joint. Don't put the solder wire directly into the flame.
Again, depending on the surface area, fit and finish, you might be better off pre-tinning the faying surfaces prior to final soldering together.

I thought the link below was an adequate tutorial for its intended purpose. At 3:11 into the video, for 5 seconds, a portion of the fitting is shown bright red but that is not due to temperature. It's a special effect edited into the video for purposes of calling your attention to that portion of the fitting.
Soldering Copper Pipe
 

Janderso

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#5
The bronze you are joining has an alloy make up that is an unknown correct?
In my experience and poor results due to improper flux/solder/brazing material, is due to using the wrong combination. Plus the pieces to be joined need to be very clean.
As an example, most go to solder has a melting point between 360-375 F.
The flux in the pic I have in my shop have the following operating heat ranges.
( I have always struggled with this stuff!)-Alphametals, liquid soldering flux-370 F.
White and black Stay-Silv are considered high temp brazing flux paste. Use between 1050-1800 F.
My point: You need to know the material you are joining, then find the correct solder/brazing/flux for the job.
My 2 cents anyway.
 

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chips&more

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#6
Red hot is TOO hot. And I would try a solder with lead in it. And a good paste flux. If you heat the part up beyond solder temp. IT WILL NOT SOFT SOLDER correctly, no matter how hard you try. You will then need to start over. Controlling the proper temp and keeping it clean are important. And try the lead solder, it’s easier than lead free to work with….Dave
 

ttabbal

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#8
Clean thoroughly.
Clean some more.
apply flux
heat evenly as possible until flux starts to smoke
add solder to the joint, it should start melting and flowing into the joint
When enough solder is added, heat for a little longer, 30 seconds max, but further away to make sure it flows nicely
Remove heat and allow to cool without moving either part.

As mentioned, you're too hot. You want to be just hot enough to melt the solder. Touch the solder to the part away from the torch once in a while to judge temperature. If lead based solder is available, use it. It's far easier to work with.
 

pontiac428

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#9
Is leaded solder still available in Cali?
Yes, you can buy 60/40 Pb/Sn solder in CA. It wets better and has a wider flow temp range than the 95/5 Sn/Sb used for plumbing, which flows in a very narrow heat window before balling and rolling off. For better flow and strength, I'd go with a 5% silver, but I do not know if that is too hard for a bearing. For non-electrical/plumbing applications, I like a stannic chloride ("acid") flux for better adhesion. Keep it clean, control the heat carefully, and you should not have any issues.
 

Lordbeezer

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#10
If solder isn't working for you and you have enough meat on your bearing could you epoxy .clamp if needed.machine.little heat to soften exoxy? Bet a picture would help ..
 

tq60

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#11
Contact the source of the material and ask for the suggested preferred solder.

Get correct solder as well as correct flux.

Solder requires absolute cleanliness to work properly and the flux is cleaner as well.

Assume it is black and sooty so clean it up.

Use very fine steel wool and light pressure to get it shiny clean.

If you made it red hot you may have altered metal chemistry so a light filing of mating surfaces may be needed.

In that case set dry paper face up on table and wet with just water and lightly drag the part across to make faces fresh.

Propane torch is more heat than needed and a Wagner paint removal heat gun is A PERFECT tool as it puts out a lot of heat in right range.

Sent from my SAMSUNG-SM-G930A using Tapatalk
 

junkcollector

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#12
If i am picturing this right , you are trying to butt two halves together?
What I'd do is clean as recommended and then tin both halves at the joint , and then clamp both halves together and heat till the solder just starts to flow .
I think things will go much easier tinning the parts first then trying to get solder to flow into a joint without any space for solder to flow into
 

whitmore

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#13
My son & I are building a Wyvern Engine from the Hemingway Kits, which has a split Phosphor Bronze bearing. The procedure calls for the the two halves to the be soldered together...
I've found that the most agressive fluxes (the ones for stainless steel) work well on bronze and brass; try some
acid flux (it only takes a little) with a length of flattened solder pre-loaded into the joint. You do NOT want solder
with builtin RMA flux (rosin flux isn't ideal for bronze or brass), but plain wire solder if you have it. Rosin flux will repel
the water-soluble acid fluxes, and since it doesn't work well on bronze... it's going to defeat the purpose.
 
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