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zlab

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Everything posted by zlab

  1. Anyone remembers that i started a rebuilt few weeks ago? Well yeah, a few hours job resulted in 3 weeks 😐 The parts that were ordered a week before the rebuild showed up yesterday, after 4 weeks 🙄 package lost on the way and obviously found after some time... Now it's in perfect condition again: -new diff gears -diffs filled with oil, 70k front and 30k rear -all new slipper clutch parts -replaced damaged bearings -rebuilded shocks -new front skid plate Still need to reinforce the new bodyshell, but it is drivable now and i can use an old one... While waiting for the parts i got an idea of selling it and buying something bigger (maybe a kraton 6s or E-revo 2.0)... The problem is just that the market here in my country is really small and i can already see that selling it would take ages... Unfortunately the shipping to UK is quite expensive also and i guess that Brexit is not making it any easier... 😒 But i think we could sort something out... And i don't even know what the value is, anyone has a clue about the price? -a lot of spares (at least 100€ in there) -brand new bodyshell -Alu suspension holders -Alu wheel hexes -strut bars -CF top plate -48DP conversion -MAX10SCT combo with a 3660 motor -XT90 conversion -Turnigy 12kg servo -Turnigy Nano-tech 6000 mAh 65-130C hardcase - 1x -Turnigy Nano-tech 5800 mAh 30-60C hardcase - 1x -set of UNUSED Proline trencher LP tyres on raid 6x30 wheels -sanwa MX-V radio system I am sure i forgot something, but just to give you an idea... Is there anyone to make an offer for the whole set?
  2. I also have carbon fiber top plate, everything open and plastic acetal spur gear... When i was using plastic top plate and spur gear cover, i tried everything to close all the holes, but nothing helped, i think i had to change at least 4 spur gears due to damage from trapped litle stones... since mounting the cf top plate and opening everything (also the hole on the bottom) i have no problems with this anymore. And it has been a year since i did it. It seems to me that closing it all around just make it worse, not mentioning the troubles when cleaning and checking the mash...
  3. eh, just some concrete at full speed 😄 well i don't remember when was the last rebuild and i have some spare time now as i am positive to covid... after disassembly i found out that both diffs have damaged gears...again 😐 luckily i have most of the spares on stock and some on the way
  4. Well i think i need to make a new protection plate... it was some serious accident, luckily no one was hurt 😆
  5. I had a really nasty head on colision on saturday, it was full throttle... What really suprised me, that none of the usual stuff broke... But the impact was so hard that it broke both battery posts and launched the battery out of the car. What do you guys think about this battery? It's been sitting now outside the house since saturday and nothing strange is happening...Do you think that it is still safe?
  6. zlab

    diff grease

    Any general use NLGI2 lithium based grease should do the job for the gearing on the rc car. For a few bucks you will get a 400g of quality grease in a cartridge. Those fancy named RC greases are pure rip off, charging big money for small amounts. Same as bolts and nuts in rc shops... you can get better qualitty for 1/10 of that price...
  7. It will be difficult to measure the output from the ESC, you would need 3 channels on an oscilloscope with insulated inputs. Measure the resistances between windings. All 3 measurements should be about the same. The easiest way is a cross check with another motor/ESC
  8. At choosing the battery you must look for those parameters: -number of cells (depends on your ESC and motor, what is maximum for it) -capacity (it will affect your runtime) -discharge rate (as mentioned in previous post, for example if you have a 60A ESC and let's say a 5000mAh battery, this means that you need a battery with at least 12C discharge rate. 30C battery would be OK for this.) -physical size to fit in your battery compartment Having a 60A ESC does not mean that the motor will draw 60A. It is maximum current that ESC can handle without risk of damage.
  9. C rating of the battery telly you the maximum current that can be safely drawn from the battery. Current [A] = Capacity [Ah] x C rating For example, if you have a 5000mAh (5Ah) battery with the 30C rating, this means that it can safely be loaded with 150A max.
  10. About that front bumper riping out the screws from the main plate... I did this modification quite some time ago and it is still doing its job after MANY bumps and crashes... You can see on the picture from today how beat up is this alu plate today... i am sure that i would break about a dozen bumpers and few chassis plates without this modification. All you need is a piece of aluminium sheet metal (1mm) and some basic metal working skills. I recommend longer screws for the diff housing. You cut it to desired shape and bend it on the front to match the counture of the bumber. Then some additional screws into the bumber and it is done, half an hour of work...
  11. Maybe i was a bit too close to the curb
  12. there are 2 possible problems with that. First is, that when you pit it on it must be oriented correctlly, otherwise it may bind into the top plate when you turn and push it off. Check with your top plate on. Other problem may be that the plastic is torn around the groove. This is a very bad design, looks loke an engineering joke. You must change the servosaver, but it will happen again soon. I changed 3 of them and then finally decided to make it better. You can see on previous pages, i made the servo saver one rigid part and inserted a bearing there for the elimination of freeplay in steering. I am using a direct mount servo saver to protect the servo. It works perfectly, no more problems with that since the modification.
  13. I ordered some in the past 6 months and they could all be taken apart. Any pictures?
  14. @Alex97 well the bearings tolerance don't affect much here. The problem is the plastic diff casing which causes runout of the gear. Then you have problems when adjusting the gear mesh. Just right on one spot and then to tight when you rotate it for 180° But if we talk about bearings in RC, i can see that they are all crap. All are made out of chinesium and in bad tolerances 😐
  15. Well i is never to late. I went to school for an electronic engineer, but because of the nature of the work i had to get a lot of mechanical knowledge. In the era of the internet it is relatively easy to learn the theory, then it's just practice. On first steps you make a few expensive misstakes and that is how you learn 😁You learn how to rebuild the CNC mill spindle after you destroyed a set of 4 precision bearings, 300€ each 😂 About the diff, here you can see the front one, which still needs a bit of love with the sandpaper
  16. @Paul Busby Honestly, no precision machining involved here. Factory diff casings are moulded quite out of tolerance, when i measured factory assebmled diff, the runout was more than 0.3mm! I measure it and mark the spot where the high spot is. Then i just carefully remove some material with fine sandpaper and measure it again when assemled. Fine tuning with tigtening the screws to get it straight as possible.
  17. adjusted the diffs to run straight. Now they are bellow 0,05mm. It should be good enough 😀
  18. 7. Stupid exercise When i started my high school i can say that i already had quite some practice with soldering. In the first year we had 4 hours per week for the practical part of the knowledge in the school's workshop. After many hours of basic drilling, grinding it was finally time for some soldering. I will never forget when the teacher said that we will do some soldering for the evaluation. I will never forget how stupid was that particular exercise to us. So here you have it. The stupid exercise. You will learn how to hold your soldering iron for precise moves and how to hold it where it needs to be. It will also help you to build your pain level, as it will burn your fingers probably. You will learn, that even if it burns, you must wait for the solder to solidify. When you do it, make the cube smaller. And then again, smaller than the previous one. With this you will learn how to heat just right, as if you will overheat, another joint will melt... First find a solid copper wire. They are used for domestic installation in this part of Europe and i had some laying around. I used 1,5mm2 wire, which is around 16AWG. Strip the insulation and make sure that you used a straight piece. Cut 12 pieces of same length, you can start with 5cm long pieces. Then make a cube out of it. That one was done in around 10 minutes, so don't take it for reference. Make it better. Watch for cold joints.
  19. 6. Soldering two wires together Easy job that can be frustrating if you do it wrong. Twist the wires in the way that takes the least thickens, otherwise you will end up with fat joints. Don't take the video for the reference, I'm sure that you can do it better. I was in a hurry and now i see that it really doesn't look good on the video 🤦‍♂️ Make it thinner and straighter.
  20. 5. Soldering the wire to connector This is where you really don't want to overheat. I will use XT60 and XT90 connectors. Base of this connectors is made from nylon. I don't know exactly which nylon, but keep in mind that PA6 has a melting point of 220°C and PA66 melts at around 270°C, so we are pretty close here to melt everything. On the first video you can see XT90 connector and 12AWG wire. Again, i add solder first to the tip while holding it on the wire, and then adding solder directly on the wire. Because there is a lot of heat distributed on those pins it takes quite a long time to reach the temperature where the solder begins to melt. You can see, that i check it with the soldering wire and when it begins to melt on the connector it means that we reached the temperature there. Then the solder quickly flows to the pin itself. On the end i wait a second or two to be sure. Let it cool on the table, don't move the connector and wire, if the plastic started to soften around the pin, you will deform it and you have a bad connector. Just let it cool so the plastic around the pin hardens again and keeps it's original form. If the wire is relatively thick for the hole in the connector pin, you will need to do it with the bare wire, so you can squeeze it in there. On next video we have a XT60 connector and 6mm2 wire (10AWG). You can see that i added some flux there for faster distribution of the heat. Yes it takes quite some time, but first the wire must heat up, as it is quite a lot of heat distribution there. I am always keeping the tip on the wire and not on the connector itself. This will help you not to damage the connector, as the temperature on the pin will be just right, when you see solder flowing there.
  21. 4. Soldering the end of the wire Soldering the end of the wire is the basic and the easiest job here. If you have the tip of the wire soldered it will help you later for easier soldering to the connector. As you will see in the video i first add some solder to the tip to get the flux flowing into the wire. This will help to quickly transfer the heat through the rest of the area we want to solder. Later you can see that i don't add solder to the tip, but directly to the wire, because we want to solder that as quickly as possible, not to damage the insulation. As soon as the copper heats up enough, the solder will melt. If you cannot melt the solder like this, then you don't have enough power on the soldering iron/to much heat distribution from the iron. You can see that i wait for the solder to simply flow to all the areas i want to solder. Keep in mind that this is a 6mm2 wire (10AWG) and 60W soldering iron, thus it takes a little longer to do it. DON'T use soldered wire for screw terminals! I have seen many people to solder the end of the wire for the screw type terminals. There is just everything wrong with that and is prohibited on all power electrics in industry or at home. Because solder is relatively soft it will deform under the tension from the screw over time and cause a bad connection. The best scenario is a malfunction and the worst one is the fire... Always use wire ferrules and appropriate crimping tool.
  22. @RCJC no it's just an original body shell, reinforced with the drywall tape (i don't know the exact name in english) and elastic glue. You have guides for that all over the internet, where people do it with shoegoo glue. I used somwthing else, better glue for my opinion and cheaper. Will make a photo later. 1) it all depends on how much you want so spend. First thing i did, were aluminium arm holders, as those plaatic ones breaks quite easily. Also a must is the sway bar upgrade. I realised latter that also CF top plate is a very nice upgrade as it makes the whole car much more rigid. 2) more is better spur gear, suspension arms, body posts, wheel hexes (i recomend upgrading to alu), front CVDs, rear dogbones, central shaft. Also a nice stock of bolts, which i recommend buying at a specialised local store and not in RC shop. They are like 10x to expensive in RC shops. 3) first thing to do when you get a new carnage, open both diffs and clean that peanut butter out of it and put some proper grease in there. Also the gearmesh between the diff and diff pinion is really bad out of the factory. Take some time and shim it correctly.
  23. 3. Do's and don't s Do it comfortable I see many people holding the soldering handle extremely uncomfortable. It is not a screwdriver, it's not a hammer and it will not run away from you. Hold it gently, with your fingers, there are no forces others than the weight of the handle involved in the soldering process. Take a comfortable position on the chair and choose correct height. It doesn't help you if your back is in pain, neck twisted and fingers white. Do not overheat Putting the temperature to the MAX will do more harm than good. As we discussed, 350°C should be more than enough for most jobs. If you go to high with the temperature, you will experience problems with melted connectors and burned flux. If you burn the flux, it will not be able to perform its function and the result is a bad joint. On the picture bellow you can clearly see the result of too high temperature/too long exposure to the heat. You can see the damaged connector and burned flux (it is the dark residue on the solder). When you will overheat the solder you will also experience problems with the solder sticking to the tip and not forming enough surface tension. Use the right amount of solder If there is not enough solder, the joint will probably mechanically fail in a short time. If you use too much, it will form a bubble which is there only to make it harder for the heatshrink to put over and also harder to inspect for joint defects. Don't be afraid to heat Some people could be afraid of that "DON'T OVERHEAT". They are afraid of melting the connector or damaging the PCB and use too short time of heating the work piece. The result could be a cold joint. If you don't heat it enough, the joint will be mechanically and electrically bad. Not necessary to fail right away, but some vibrations will break it sooner or latter. Watch how the solder flows and sticks to the surface, you will quickly see where is that point where the work piece gets the right temperature and the solder just flows everywhere. On the picture there is a typical cold joint. You can clearly see that it just sticked on top of that wire and connector just like a chewing gum and waiting to fail. Solder the workpiece I have seen many people melting the soldering wire on the tip and than putting this on the work piece. This won't do anything. Only melt a small amount in the initial stage of the process, but later melt it on the workpiece itself. You will see it later on the videos. It will help to distribute the solder and flux. Keep your tip wet You want to keep your tip wet all the time, as this will prevent the tip from oxidation and increase it's lifetime. Right before you start to solder, clean that old solder away with the wet sponge. Don't modify your tips People have many ideas when it comes to modifing and repairing stuff. Don't grind your tips, that is a bad idea. Tips have a coating which is preventing it from oxidation. If it is damaged buy a new one. If you need a thinner one, buy a new one
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