My Cheapo Chineese 3020t mini CNC Build (more like improvements) leanring all the way

[Lee Roberts]

Ravi,

Just a couple of notes:

1. There is to much solder on each one
2. Get yourself some soldering flux, liquid preferable

The flux and soldering go hand in hand, when the solder "flows" better (you'll see the diffrence) because of the flux, it just works and you'll see what I mean about there being to much on each joint.

Flux isn't cheap depending on what you get, however if you get liquid flux you simply apply a very small amount, so it last's a long time.

If you keep application to a minimum you wont need to do a lot of clean up, in fact look for no-clean flux, I like to use isopropanol alcohol to clean any soldering/pcb jobs I do.

Links below for what I use, just dip your tip in the Kalafonia tin before each pass.

ALCOHOL BASED SOLDERING LIQUID FLUX SMD/RMA REWORK, REFLOW, REBALL, NO CLEAN

COLOPHONY/KALAFONIA Limited offer 40g for the price 20g tin Solid soldering flux

IPA 100% | 1 LITRE | Lab/Pharma. Grade | Isopropyl Alcohol/Isopropanol (99%) 1L

Look forward to seeing the rework :)

[ravihotwok]

sakes lads ive just bought some flux but its hard stuff, will up load a pic in a mo. Im going to spend sat afternoon redoing these solders, thanks for explaining it in detail, I thought it balled due to me putting enough into the area and the solder had no where else to go so created the ball. Now I know this isnt the case and can revisit it with the knowledge of what im trying to achieve.

On another note, I want to buy new steppers a mine appear to be proper crap. Any recommendations for 3 motors that will fit my machine? budget of £120 for all 3?

[Lee Roberts]

sakes lads ive just bought some flux but its hard stuff, will up load a pic in a mo.

Ok, well the better value option to what I linked would be to buy some solid Rosin like this eBay - Rosin Resin and mix it with the Isopropyl I linked to above, brake the rosin up and add to the Iso untill your happy with the viscosity.

Here is a video on that:



Don't know what flux you've got but i'm sure you can change its viscosity, again the Isopropyl is what you want but nail varnish remover is made from Acetone and Isopropyl is what you get from the Hydrogenation of Acetone, if you've got some nail varnish remover you could try mixing some with the flux you have already, keep in mind though that they put perfumes and other softeners in nail varnish remover so it wouldn't be the purest of fluxes.

I would just order some Isopropyl, its so handy for other things, Hexa the company I linked don't mess about so it should be with you sharpish.

On another note, I want to buy new steppers a mine appear to be proper crap. Any recommendations for 3 motors that will fit my machine? budget of £120 for all 3?

CNC4YOU is still the best place both on price and service, the motors are of the lowest inductance we can find vs other things, link below.

Link: https://www.cnc4you.co.uk/Stepper-Mo...YGH301B-Nema23

[m_c]

If you're soldering new components, the flux in common solder should be more than enough to ensure a good solder joint. Any common solder you buy for electronics should be flux cored.

It must be over 10 years since I last used separate flux, and that was dealing with vehicle earth points that had been exposed to a couple British winters. I've certainly never used it on any PCB I've soldered.

[A_Camera]

If you're soldering new components, the flux in common solder should be more than enough to ensure a good solder joint. Any common solder you buy for electronics should be flux cored.

It must be over 10 years since I last used separate flux, and that was dealing with vehicle earth points that had been exposed to a couple British winters. I've certainly never used it on any PCB I've soldered.

I have been working with electronics since the mid 70's and as long as I remember, there have ALWAYS been flux in the solder wires I used. I never bought any separate flux ever in my life. As far as I know, flux in liquid or hard form is only used for soldering pipes and other very large surfaces, not PCB.

[Lee Roberts]

So far the only advice he's had is to get a solder sucker and start again, clearly there is more going on than that and he needs more experienced input, let's give him that instead shall we.

Flux cored or not something isn't right and it's probably a combination of things, additional Flux I think will help Ravi along in getting better joints, additional flux has been used in the SMD and rework/reflow arena's for years and for a very good reason!

What solder wire are you using?

Ravi, using additional flux cannot hinder the soldering process and can only assist you in doing a nice/better job, don't tell anyone this but that is the reason they put it in solder wire in the first place :).

Your soldering iron needs to be hot enough, balling up like that can come from the iron being too hot or cold, I'm betting yours is to cold, some lower end irons heat up but they don't do very well at staying hot once you start using them, this happens with low power irons too at around the 25w range, when you are trying to solder bigger components.

However my go to for most jobs is now a 12w Weller SP12, I inherited it along with technique from my grandfather who was a British telecom engineer, the iron is from around the 80-90's and still has the original tip, it along with a combination of technique, additional flux and a solder wire appropriately sized gets everything I solder just right for me - every time...Thanks Granddad!

40-60w is an average range on what allot of irons will be rated at, my other iron is a 25w similar to the Weller, I also have two gas soldering irons for mobile work. The bigger of the gas irons is handy with the tip removed as its basically a mini blow torch and works excellent on heat shrink and those jobs where you need a small flame with a bit more power.

What iron are you using ?

The tip of your iron needs to be "on point" Ravi, the problem comes from oxidation and not keeping your tip clean, once your tip becomes oxidized the solder will no longer want to flow or stick to it properly and this is a problem. Don't clean your tip in flux or water, this shocks the tip and damages the Iron and Chromium plating, just dip the tip in some pure Rosin after each joint and that should be good enough for the tips life time.

Solder to the tip of your iron and then to the area/joint to be soldered, your transferring the solder from one to the other, try and do this with as minimal amount of heat going into your component as you can and your now doing it correctly.

Soldering isn't rocket science Ravi, there are lots of options in terms of tools and technique but a few fundamentals need to be right for it to be successful, if left those balls of solder you've done so far could come lose and as such cause arcing, arcing not only damages components and equipment but it can cause fires too !!!!

[Lee Roberts]

Here is a video, the most relevant section about Flux starts at 7 minutes in, the astute of you will identify the difference in working with fresh unoxidized surfaces vs. oxidized surfaces such as those in the job Ravi is undertaking and the correlation in my recommendation of using flux.

I didn't recommend adding Flux to Ravi's game because it sounded good

[A_Camera]

So far the only advice he's had is to get a solder sucker and start again

Well, that's not very fair, is it? Did you not read post #53 and #56? That's all there is to it. Like you say, soldering is not rocket science, but needs some practice. He was given a google link but I did not pick any specific video, I think he should do that selection on his own.

My iron is a 24v 50W Weller from 1978. It still works well. Of course, it does not have the fancy temperature regulator and display, but I never really felt any need for that.



I have used up several tips and also have different type, depending on the purpose, I change when necessary. I would not use a high voltage type of iron, which the 12W you have been given is, on any electronics, but I know many people use tools which are not suitable. Anyway, while it may have a nostalgic value for you, I personally would only keep it as a memory.

Regarding flux, I stand by what I have said. It is waste of money. On electronics one should not use any other type of soldering wire than the one with flux in the core of the wire. As a matter of fact, too much flux can also cause problems, so it is not true that using flux can not hurt. Flux fluid is used only in industrial soldering, where the PCB is travelling through a flux foam first and then through the melted soldering wave.



Manual soldering of electronics don't need any flux foam or liquid.

My experience is that if there are balls then it is enough to heat them well up, until completely melted and either suck it up or in many case it will float out because there is normally enough flux around the points. If if does not float out and look like figure A in the picture I provided then there is nothing else to do than suck it out and apply new solder.

Takes a 15 minutes to half an hour practising and that's it. Really very simple.

[Clive S]

So far the only advice he's had is to get a solder sucker and start again, clearly there is more going on than that and he needs more experienced input, let's give him that instead shall we.

Lee you have not read this post from the beginning I feel. The questions you have asked have all been answered.