# Eggtimer Quark Destruction

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#### Motocrossman24

##### Well-Known Member
What about this one for $40? ttps://www.amazon.com/dp/B07RKMGPTX/ that’s the one I purchased...granted Iv only used it a few times, but it works as it should...I’m sure none of these cheap options are production worthy, but for someone putting together a few eggfinders per year, I’m sure they’ll last you a decade+...I bought a similarly cheap soldering station when I get into fpv drones7-8 years ago, and it’s been great for me, takes hakko tips and has been flawless, and used a lot. This is the solder station I use, you can likely get something better for 10-20$ more https://www.ebay.com/itm/937D-SMD-Soldering-Hot-Iron-Station-Digital-Adjustable-w-5-Tips-Japan-Heater/333525481432?epid=1955793516&_trkparms=ispr=1&hash=item4da7aaf7d8:g:uDYAAOSwB05eU5Fl

#### CalebJ

##### Well-Known Member
TRF Supporter
I've got a small variable power soldering station, but SMD is beyond anything I've done previously. This alternative looks like it would be worth every penny.

#### Greg Furtman

##### Well-Known Member
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I've got a small variable power soldering station, but SMD is beyond anything I've done previously. This alternative looks like it would be worth every penny.
@CalebJ If you buy it make sure you buy a practice board. I bought one of these.

#### CalebJ

##### Well-Known Member
TRF Supporter
You think that would be necessary even with the rework station?

#### Greg Furtman

##### Well-Known Member
TRF Supporter
You think that would be necessary even with the rework station?

#### Motocrossman24

##### Well-Known Member
For those interested in why 60/40 solder should be obsolete in the marketplace. Here’s a copy and pasted explanation

60/40 solder is made of 60% tin and 40% lead. It has a melting point of around 190°C, depending on the exact composition. Iron tip temperatures of at least 300°C are recommended. It is also very soft, meaning that cracks do not form so readily if the joint moves during cooling.

63/37Edit
63/37 solder is made of 63% tin and 37% lead. It has a melting point of 183°C, slightly lower than the more common 60/40 blend. The primary advantage of this solder is not the lower melting point, but its eutectic property. Non-eutectic solders, like the 60/40 solder, have a semi-solid state between solid and liquid. If a joint is moved during this stage, it can result in what is called a cold solder joint. Eutectic solders, like the 63/37, do not have this semi-solid state and are thus considered easier to work with as it produces fewer bad joints. However, these solders typically cost more than their non-eutectic counterparts.

50/50Edit
This is made of a half and half mix of tin and lead. Never use 50/50 solder for electronics — it is meant for plumbing. (There are brands[Worthington 50/50 leaded #331887], which is used for electronics and specifically not intended for plumbing). Otherwise, you may end up with failed joints, as the 50/50 solder does not have the same properties as 60/40, having a higher melting point and lower ductility. Also, it is very unlikely to have flux included in it like rosin core solders.

#### Motocrossman24

##### Well-Known Member

Or, maybe, templates that we can print on clear media and cut out ourselves?

I'd love to try the mask method for building a TRS!
because the circuit board hasa coating between the pads, you can literally draw athin line right down the pads for a micro processor. And when heating with the air gun, the solder will naturally move from the space between the actual copper pads, and collect only on the pads. The mask method simply isn’t necessary, it only helps to make sure that the amount of solder is consistent.The only real trick is finding the correct amount so that your not over doing it, and that amount is usually much less then you would think you need. A small practice board is rlly all you need to get the technique down. And at the end of the day, if you mess up a joint, just hold the component with your tweezers, hit it with hot air and it comes right off. Rinse and repeat

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
I can create the paste layer files pretty easily... it's been a "get to it" for a couple of years. We posted the one for the Proton when we released it (there are a LOT of parts on the board...), so maybe I can get the rest done since I have a little "down time" while I'm waiting for a launch to happen.

** UPDATE **
I've posted the cream layers for the Quark, Quantum, Proton, TRS, WiFi Switch, and Eggfinder TX. Due to the nature of the Eggfinder Mini assembly, it really doesn't lend itself towards reflow assembly, and the other kits don't have enough SMT parts on them to make it worth reflowing them.

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#### CalebJ

##### Well-Known Member
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@CalebJ If you buy it make sure you buy a practice board. I bought one of these.
Greg - is there any trick/technique to applying the paste to the board? The practice board and hot air system came in so I gave it a quick shot at lunch. My first reaction was that the paste tends to stay on the toothpick or syringe unless I really push down, at which point I get way too much. Just curious if you'd found a better way.

#### Motocrossman24

##### Well-Known Member
Greg - is there any trick/technique to applying the paste to the board? The practice board and hot air system came in so I gave it a quick shot at lunch. My first reaction was that the paste tends to stay on the toothpick or syringe unless I really push down, at which point I get way too much. Just curious if you'd found a better way.
you really just need a small smudge of paste. If you think about what they’re doing when using a screen to apply the paste, it’s basically just wiping the paste a little thicker then the thickness of paper over the pad. Make sure the paste has warmed to room temp for 3-4 hours before working with it, or it is a lot more difficult to apply.if you weren’t aware, paste needs to be refrigerated or the flux evaporated away and makes it even harder to use.

#### CalebJ

##### Well-Known Member
TRF Supporter
I didn't know about refrigerating it - thanks for that.

The issue I'm seeing is that I basically get none at all or a tiny glob. Is there a better tool for application, perhaps the edge of a blade?

#### Motocrossman24

##### Well-Known Member
I didn't know about refrigerating it - thanks for that.

The issue I'm seeing is that I basically get none at all or a tiny glob. Is there a better tool for application, perhaps the edge of a blade?
I personally have only used the tip of the syringe, but I don’t see why a blade wouldn’t be good, just be careful not to cut through the epoxy coating on the board. If you have many small traces in a row, you can just take the blade and wipe it right down the pads, and because the paste’s flux is attracted to heats it will take the paste between the pads and pull it towards the pads(they heat up faster). Another thing I learned is that there are 3 different classifications of paste (t3/t4/t5) which is the diameter of the solder balls in the paste, with t3 being the largest and t5 being the smallest. I recently purchased some sra t5 paste, and it is much easier to work with then my t3 kester paste. The solder joints also look a lot smoother and more uniform. T5 paste is a bit more expensive, but it’s all I will buy from now on.

#### CalebJ

##### Well-Known Member
TRF Supporter
I'll definitely keep the solder ball size in mind the next time I resupply. Looks like the tube I bought based on Greg's recommendation above was T4. Thanks for all the info. Will give it another shot this evening.

#### Motocrossman24

##### Well-Known Member
I'll definitely keep the solder ball size in mind the next time I resupply. Looks like the tube I bought based on Greg's recommendation above was T4. Thanks for all the info. Will give it another shot this evening.
I would assume t4 is good stuff.

#### CalebJ

##### Well-Known Member
TRF Supporter
Probably so. It seemed to work perfectly on the one component I did attach.

#### Joe Bruce

##### Well-Known Member
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Last night I used this hot air rework station and Kester EP256 solder paste to build my first EggTimer Quark. That was board #2 for the station -- I built this cheap practice board first.

I thank the many posters on this thread for the inspiration and product suggestions! Though hot air rework is its own art, my solder joints are MUCH cleaner than on my hand-soldered Quantum. The build was much faster, too, with my only issue being a little solder in the "Tx" hole for the header pin (an issue I only made worse before I fixed it). I could generally paste & place 3-6 parts at a time.

I was even able to fix a hand-soldered practice board from a few months ago where I had installed an LED backwards. It is amazing how 75% of the time, the parts just move into position. Of course, the other 25% they tombstone or flow together into a small mass of resistors, etc.

Still learning the new art, but I have much more confidence in (successfully) building the remaining Quark, Quantum, and EggFinder Tx / Rx boards! Thanks as always to Cris for designing and selling these kits!

#### CalebJ

##### Well-Known Member
TRF Supporter
I ended up attaching maybe ten components onto the practice board last night. I'm still pretty rough at handling the tiny things (even with tweezers they're frustratingly small), but the hot air system is magnificent.

Joe - since you just did the practice board and the Quark in close succession, how would you compare the two projects?

#### Greg Furtman

##### Well-Known Member
TRF Supporter
Greg - is there any trick/technique to applying the paste to the board? The practice board and hot air system came in so I gave it a quick shot at lunch. My first reaction was that the paste tends to stay on the toothpick or syringe unless I really push down, at which point I get way too much. Just curious if you'd found a better way.
@CalebJ Sorry for the late reply. I found heating up the PCB pads a little bit with the hot air gun made it easier to apply the soldering paste. And I applied it directly from the syringe with the fine tip. I also found out right away that syringes are like caulk guns, it you don't take the pressure off right away they continue to ooze.

#### CalebJ

##### Well-Known Member
TRF Supporter
Thanks! I encountered that for sure last night. Oozed a surprising amount of paste onto the table that I mostly managed to recover. And the second round of placing components went dramatically better with a warm board. Lots of learning opportunities. The suggestion to get the practice board was a good one for sure.

#### Greg Furtman

##### Well-Known Member
TRF Supporter
Thanks! I encountered that for sure last night. Oozed a surprising amount of paste onto the table that I mostly managed to recover. And the second round of placing components went dramatically better with a warm board. Lots of learning opportunities. The suggestion to get the practice board was a good one for sure.
The practice kit was fun. I might pick up another kit just to play with. And isn't it cool when the soldering paste finally melts and the component self-aligns?

#### Joe Bruce

##### Well-Known Member
TRF Supporter
Joe - since you just did the practice board and the Quark in close succession, how would you compare the two projects?
The practice board was great practice for the Quark! I did the entire practice board except I gave up on those teeny 0402 parts halfway through. Even with a lighted magnifier they are TINY, and fortunately Cris uses 0805 and 1206 parts in his designs.

On that 858D clone, I've used 380 degrees C and the air flow at about 4. Some of the parts on the Quark are a bit closer together than on the practice board, but it wasn't a huge difference. The group of 3-4 resistors to the left of the processor clumped together when the solder paste started to flow, but they were easy to coax into position (or for one, remove and re-place after things had cooled).

I had no solder bridge issues other than between IC pins -- not the pads, but the pins themselves. That was usually easy to clear with tweezers, though one time I removed the part and vacuum desoldered the excess and sort of started over.

I carefully inspected joints with a 10x loupe as I went, and reflowed or added a bit more solder paste when it wasn't up to par. Though it's a new skill, the solder joints are "professional quality" versus some obviously-not-pro joints on my hand-soldered Quantum. Overall, I agree 100% with you that the hot air is "magnificent" and I wish I hadn't delayed getting one for so long!

For the solder paste, I pressed the plunger with my right hand and "aimed" with my left hand, since I hold the board in a Panavise (elevated). When I'm done with the few parts I'd place at a time, I pulled back on the plunger to avoid the oozing. That two-handed reflex bit me ONCE during the Quark build, though -- put my left hand BRIEFLY on the hot air gun (OUCH!). Won't do that again (I hope)!

#### CalebJ

##### Well-Known Member
TRF Supporter
On the practice board I noticed some issues when I tried to do a set of nearby components at the same time. If I got too close with the hot air, it would occasionally blow them around a bit even with the air turned all the way down (I'm using an 898 from eBay, for whatever that's worth).

This whole process really is like magic. I've done plenty of hand soldering and I'm perfectly mediocre with it. This allows me to do things that are a fraction of the size with exponentially better results and in less time.

#### Joe Bruce

##### Well-Known Member
TRF Supporter
This whole process really is like magic. I've done plenty of hand soldering and I'm perfectly mediocre with it. This allows me to do things that are a fraction of the size with exponentially better results and in less time.
Agreed 100%. The practice board I hand-soldered months ago before attempting my Quantum wasn't functional and I had problems with the 0603 parts. With the same board and hot air, I no issues until I got down to the 0402 parts and I could do half a dozen resistors or capacitors at the same time. ICs are fun, too -- you can just draw a line of paste down each row of pins and watch the solder flow to the pads (and hopefully NOT bridge the pins).

EDIT: ...and the voltage regulator was a HUGE pain hand-soldering on the Quantum, but was a snap with hot air on the Quark!

#### CalebJ

##### Well-Known Member
TRF Supporter
Re drawing a line down each row - I did that but added the quick step of drawing a toothpick through the gap between each pad. Just takes a few seconds to do and definitely groups the sections of paste to the appropriate pads. Not sure it guarantees results, but it ought to at least decrease the odds of an accidental bridge.

#### Joe Bruce

##### Well-Known Member
TRF Supporter
@CalebJ I'll have to try that on the next board!

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