I've been using MG Chemicals flux, with built-in syringe and plunger. It has been great. But with so many people constantly raving about AMTECH 559, I decided to give that a try.
Sadly, only the Chinese knock-off "559" is sold here in Japan that I can see, so I purchased 559 from Amazon USA and had a family member ship it to me to ensure it's genuine. Thankfully, I got the plunger and syringe needle included, but some people buying it on Amazon US seem not so lucky. Honestly, it's absurd to me to think a tube of flux wouldn't come with those 2 critically important items. But my tube of 559 came with them, so no complaints. However, the needle nose is much shorter than the needle that comes with my MG Chemicals flux. Not a big deal most of the time, but if comparing the two, I'll prefer the longer needle.
The 559 flux itself works well enough, but I did notice it sizzle 2 times very briefly (350*C, Hakko soldering iron) during my LC575 logic board recap, whereas my MG Chemicals flux never sizzles ever. The MG is a slightly darker brown, indicating more rosin is inside, so maybe less Rosin in the 559 is why I heard a couple sizzles. Overall, I don't see any big benefit to the 559 over the MG brand flux. 559 is not bad flux, but it certainly doesn't rock my world.
Here's the thing that rocks me in a very bad way...
THE 559 PLUNGER!
Let me first say that the MG guys really have their flux tubes thought out. The product clamshell pack is long enough to accommodate the tube with plunger pre-fitted. And there's a reason for that. The plunger on the MG product isn't easily removable, which is how it ought to be. Here's why. You push the plunger to get the flux out, but if you then don't pull the plunger back a bit when finished, the increased pressure inside the tube will cause some extra flux to spill out. It keeps spilling out until the internal pressure is alleviated. Sure, you can wipe it up and still use it most of the time, but the overspill can be avoided with the MG product simply by pulling the plunger back out a little bit. Not so with the AMTECH 559 plunger!
For the life of me, I cannot figure out how to fit that black rubber part of the 559 plunger deep into the white plastic slider that holds the flux inside the tube. I tried applying a huge amount of pressure, but the two pieces won't mate. And if I were to apply any more pressure, the flux would probably spew out the back end. (I am doing this with the needle removed and the stopper applied on the application end.) Since the plunger and white plastic part of the AMTECH 559 flux tube don't mate, when you try to pull the plunger back out, the whole plunger comes out, but the pressure on the flux remains the same because that little white plastic slider piece at the back of the tube remains in place. As a result, you see flux slowly trickle out and out and out the needle nose! And all you can do is sit there and watch it spill out. In other words, the AMTECH plunger forces flux out just fine but doesn't pull flux back in!
Surely, I cannot be alone in having experienced this. But maybe everyone just thinks 559 is the bee's knees and therefore the plunger issue doesn't matter to them. To me, the way the flux is dispensed and how you STOP it from trickling out is just as important as the flux itself. Maybe there are better flux syringes out there than the MG, but the 559 kit I purchased isn't one of them.
Sadly, only the Chinese knock-off "559" is sold here in Japan that I can see, so I purchased 559 from Amazon USA and had a family member ship it to me to ensure it's genuine. Thankfully, I got the plunger and syringe needle included, but some people buying it on Amazon US seem not so lucky. Honestly, it's absurd to me to think a tube of flux wouldn't come with those 2 critically important items. But my tube of 559 came with them, so no complaints. However, the needle nose is much shorter than the needle that comes with my MG Chemicals flux. Not a big deal most of the time, but if comparing the two, I'll prefer the longer needle.
The 559 flux itself works well enough, but I did notice it sizzle 2 times very briefly (350*C, Hakko soldering iron) during my LC575 logic board recap, whereas my MG Chemicals flux never sizzles ever. The MG is a slightly darker brown, indicating more rosin is inside, so maybe less Rosin in the 559 is why I heard a couple sizzles. Overall, I don't see any big benefit to the 559 over the MG brand flux. 559 is not bad flux, but it certainly doesn't rock my world.
Here's the thing that rocks me in a very bad way...
THE 559 PLUNGER!
Let me first say that the MG guys really have their flux tubes thought out. The product clamshell pack is long enough to accommodate the tube with plunger pre-fitted. And there's a reason for that. The plunger on the MG product isn't easily removable, which is how it ought to be. Here's why. You push the plunger to get the flux out, but if you then don't pull the plunger back a bit when finished, the increased pressure inside the tube will cause some extra flux to spill out. It keeps spilling out until the internal pressure is alleviated. Sure, you can wipe it up and still use it most of the time, but the overspill can be avoided with the MG product simply by pulling the plunger back out a little bit. Not so with the AMTECH 559 plunger!
For the life of me, I cannot figure out how to fit that black rubber part of the 559 plunger deep into the white plastic slider that holds the flux inside the tube. I tried applying a huge amount of pressure, but the two pieces won't mate. And if I were to apply any more pressure, the flux would probably spew out the back end. (I am doing this with the needle removed and the stopper applied on the application end.) Since the plunger and white plastic part of the AMTECH 559 flux tube don't mate, when you try to pull the plunger back out, the whole plunger comes out, but the pressure on the flux remains the same because that little white plastic slider piece at the back of the tube remains in place. As a result, you see flux slowly trickle out and out and out the needle nose! And all you can do is sit there and watch it spill out. In other words, the AMTECH plunger forces flux out just fine but doesn't pull flux back in!
Surely, I cannot be alone in having experienced this. But maybe everyone just thinks 559 is the bee's knees and therefore the plunger issue doesn't matter to them. To me, the way the flux is dispensed and how you STOP it from trickling out is just as important as the flux itself. Maybe there are better flux syringes out there than the MG, but the 559 kit I purchased isn't one of them.
