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Soldering issue on ctb16k pc kit


MikeLand
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First time building a kit and I'm working the ctb16k kit. I'm having problems with the neutral spade lugs. Can't get the solder to flow.

I purchased the CSI soldering station because I was having trouble the 30 watt iron I had. I got the 3.2mm chisel tip and am using it but the solder is not flowing. I have station set to 800 and seems like I'm holding on there for long time, like 5 minutes before solder flow. However, the solder doesn't flow to the other side. Am I going to have problems because solder didn't flow all the way through to the other side of board?

What am I doing wrong? Do I need to turn the heat up all the way to 896?

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Richard Hamilton

I'll be interested in seeing what people say about this. It is hard to visualize what you are doing, but I hope it is not the fact that you are holding a soldering iron onto a circuit baord for 5 minutes. YIPES ! I smell problems if you do that.

Are you trying to solder a spade lug that is aready mounted to the case? If so, the case is going to "sink" away the heat and you probably will not get enough heat to solder it. If that is the issue, remvoe the lug from the case to solder a wire to it. Again, I can't visualize what you are trying to do. Can you include a photo?

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As you solder does the solder flow a little first?
If it does this is a "heat bridge" once this forms the solder should flow much better and faster. Generally a solder joint should "take" within 2-3 seconds. However with a larger mass joint like the spade connectors it will take longer 10 seconds at the most. Maybe you trouble is with the iron or just the tip. The tip should be nice and clean "shiny" with solder to the point. If there is black crud on it take a damp natural fiber sponge and wipe the tip on it while it is hot. This will clean off the black crud and allow more solder to stay on the tip and also allow more contact area to heat the parts to temperature.
When soldering you should have some solder on the tip to create the heat bridge. This heat bridge is the only way to heat parts efficiently. You know you have one when you pull the tip of the iron away from the parts and the solder tries to stretch between the iron and the part. Once this happens it won't take long to solder the parts together (1-2 seconds).

On those bigger connections I use a 50 watt soldering iron. You just have to be careful not to over heat the board. This will be seen when the traces of the board start to delaminate from the surface.

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LightORamaDan

At 800 degrees it should get through to the other side. Make sure that you have the tip clean and tinned. When you start to solder those neutrals start in a corner and do one pin on the spade connector. Make sure when you touch the tip to the pcb that you also take the solder and touch it to the tip and the board so that you have a bubble of solder to help transfer the heat from the tip to the board.

5/10 minutes is too long for the tip to be on the board and not get a good solder joint. 3 sec on a regular lead and 10 sec on high sink areas such as the neutrals should be enough.

You an try cranking up the temp but if the solder is not flowing after 10 sec then there is something wrong.

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I've even used a 125w soldering gun on those connections. You just have to be very careful with how much heat and how long you heat when using something like that. A 50w or 60w would probably be perfect for those connections.

You have to remember, the entire ground plane acts like a giant heat sink on those connections and it dissipates the heat away from where you are heating. Sounds like you just need more heat. :)

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Dennis Cherry

Jeffrey wrote:

I've even used a 125w soldering gun on those connections. You just have to be very careful with how much heat and how long you heat when using something like that. A 50w or 60w would probably be perfect for those connections.

You have to remember, the entire ground plane acts like a giant heat sink on those connections and it dissipates the heat away from where you are heating. Sounds like you just need more heat. :D


The answer is no, do not wait for the solder to flow on the other side.

Put as much solder tip as you can in contact with the lug and PC board, apply some of the large solder between the tip and the lug/board, wait a few seconds and the solder should flow onto the lug and solder pad. If it flows and covers both surfaces you are done, remove the soldering iron.

LOR uses extra heavy duty PCB's, it is hard to get the heat to flow through the holes so solder will flow to the other side, just make sure your solder joint is fine on the solder side and your done.
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Richard Hamilton wrote:

Are you trying to solder a spade lug that is aready mounted to the case? If so, the case is going to "sink" away the heat and you probably will not get enough heat to solder it. If that is the issue, remvoe the lug from the case to solder a wire to it. Again, I can't visualize what you are trying to do. Can you include a photo?

Its not a spade lug to the case. Its the spade lug to the pcb board however I think the heat is sinking away in the block that the lugs are going into. I have better luck with spades that are by themselves or with the fuse holders.

The tip is new and I clean it with the wet sponge that came with the station. However, I was not putting solder on the tip before heating the joint. I'll try that.

I apply the iron tip on one side touching the hole and lead at the same time and then touch the solder to the opposite side of hole and lead. With the solder should I touch the iron tip to get the solder to flow or am I doing it right by not touching the iron tip?

Thanks for the help. I'll those tips try. I wish I had pictures to post but I didn't take any.
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LightORamaDan

MikeLand wrote:

Richard Hamilton wrote:
Are you trying to solder a spade lug that is already mounted to the case? If so, the case is going to "sink" away the heat and you probably will not get enough heat to solder it. If that is the issue, remove the lug from the case to solder a wire to it. Again, I can't visualize what you are trying to do. Can you include a photo?

Its not a spade lug to the case. Its the spade lug to the pcb board however I think the heat is sinking away in the block that the lugs are going into. I have better luck with spades that are by themselves or with the fuse holders.

The tip is new and I clean it with the wet sponge that came with the station. However, I was not putting solder on the tip before heating the joint. I'll try that.

I apply the iron tip on one side touching the hole and lead at the same time and then touch the solder to the opposite side of hole and lead. With the solder should I touch the iron tip to get the solder to flow or am I doing it right by not touching the iron tip?

Thanks for the help. I'll those tips try. I wish I had pictures to post but I didn't take any.


Here is the way I do it... It may not be the NASA standard for soldering (not that I know the NASA standard) but I get good results.

With small connections I do it much like you describe. Tip against the PCB and the lead and then solder against the other side of the lead. On the Tip I keep a small bead of solder as I move along and it provides a good contact. Once in a while the solder will not melt immediately (within 2 seconds) in which case I move solder to V that forms where the tip meets the lead and that way the solder is touching both the lead and the solder and it melts instantly.

Now with big connections, place the tip against the lead and the PC and i immediately put the solder against the tip and the PCB and lead and make sure there is a bead of solder big enough to bridge the tip, lead and iron. Sometimes that bead does not immediately flow and the solder even sometimes gets stuck. I just wait for the iron to do its thing and heat everything up. Then I move the solder over to the other side of the component lead and wait for it to melt. With some big things I will sometimes put the iron on the PCB only (with a touch of solder) until i see the the solder on the PCB is melting then I slide it up against the lead and apply solder.

Dan
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What are you using to hold the spades / fuse clip? Could that be absorbing the heat?

my trick for the 16pc's- i create a little solder joint on the top side - just enough to hold the spade, then flip over and finish the job`- Do all the spades on one plane at the same time - the plane will stay heated and the others will allow the solder to flow better

For the 16k's - clip all the terminals together then solder all the hots - this will keep the neutrals all in one place.

Make sure you contact both the terminal and the pad at the same time with the iron, this will ensure a good solder connection

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Watch out for temperatures. If you get high enough temperature, it will boil away the rosin and can lead to bad joints. More wattage is probably better than more temperature.

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Dennis Cherry

The idea of getting the solder between the solder tip and the lug/PCB is to help make the contact area larger so the heat from the tip will transfer better. The solder tip sometimes does not make enough contact due to angle of the iron, the melted solder helps.

Yes I do also insert the components and add just a touch of solder on the top side to hold it in place before flipping the board over to do the final soldering.

This will also let you adjust the parts before doing the final soldering also. Only solder one lead on each device on the top side except the IC sockets, connectors, and headers these have to be soldered on the bottom side but just solder two pins only, one on opposite corners, then check that the device is flat against the board, if not just touch the soldering iron to the required lead and push the socket flat to the board once it is flat then solder all the pins.

I hope this helps you.

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Sorry for the multiple post but couldn't figure out how to post pictures in one post.

I wasn't using anything to hold them in place. I had it upside down and did the best I could to keep it straight. Since the fuse holders are the tallest part already soldered I stuck one of the low power heat sinks under it to apply pressure from the bottom. If the spade got leaning to one side I used pliers to straighten it.

I wonder if the heat sink it was sitting on was drawing the heat away.(light bulb going off).

Now my question is do those joints look ok?

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Dennis Cherry

MikeLand wrote:

Sorry for the multiple post but couldn't figure out how to post pictures in one post.

I wasn't using anything to hold them in place. I had it upside down and did the best I could to keep it straight. Since the fuse holders are the tallest part already soldered I stuck one of the low power heat sinks under it to apply pressure from the bottom. If the spade got leaning to one side I used pliers to straighten it.

I wonder if the heat sink it was sitting on was drawing the heat away.(light bulb going off).

Now my question is do those joints look ok?

From your picture they look very acceptable on the solder side, should look like mini volcanoes.


GOOD JOB
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I cant tell from the picture, but it looks like one on the right (second column, third row) looks a little suspect

otherwise looks good

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Dr. Jones wrote:

I cant tell from the picture, but it looks like one on the right (second column, third row) looks a little suspect

otherwise looks good

I took a closer look at that one. I compared it to the rest and it looks ok. Looks like the light or lack of light in the picture made it look suspect.

Thanks for the critique Dennis and Dr. Jones.
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Dennis Cherry

MikeLand wrote:

Dr. Jones wrote:
I cant tell from the picture, but it looks like one on the right (second column, third row) looks a little suspect

otherwise looks good

I took a closer look at that one. I compared it to the rest and it looks ok. Looks like the light or lack of light in the picture made it look suspect.

Thanks for the critique Dennis and Dr. Jones.

You are welcome, hope this also helps others out in improving your soldering skills.
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MikeLand wrote:

Since the fuse holders are the tallest part already soldered I stuck one of the low power heat sinks under it to apply pressure from the bottom.

I wonder if the heat sink it was sitting on was drawing the heat away.(light bulb going off).

I went back over a few joints that looked suspect from the top side. This time I didn't have the low power heat sink under it applying pressure. Things went much better. I guess that heat sink was drawing the heat away from the spade lug.

I'll need to find some other way of holding those spade lugs in place on the next one.

Thank you for everyones help.
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  • 3 weeks later...

MikeLand wrote:

I'll need to find some other way of holding those spade lugs in place on the next one.

Thank you for everyones help.

Sorry for the late tip, but I use masking tape to hold all my spade lugs in place. I do a strip of tape length wise across all of them and then I do a few at 90 degrees to those to hold all of them tight to the board. Only burned myself a few times this way. :(

Oh, and if you do try using tape, do not try and re-adjust the tape once it's made contact with the spade lugs... otherwise you'll be taking the tape off of all of them and re-doing everything. ;)
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I've only done one PC kit, but I too just used the blue tape as recommended in the instructions. Other than the issue Jeffrey mentioned about don't try to readjust the tape or you'll be cursing and pulling countless little spades from the tape one by one and starting over ;)

Also, as mentioned in the instructions, try to work in such a way that the heat from the previous joint helps preheat the next joint. Those neutral pads are very large and will hold a lot of heat, but also take a lot of heat to heat up .

-Tim

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I changed the tip on my soldering station to a chisel point giving more surface area. This helped transfer the heat more quickly.

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  • 3 months later...

John Hertig wrote:

Watch out for temperatures. If you get high enough temperature, it will boil away the rosin and can lead to bad joints. More wattage is probably better than more temperature.

John makes a very good point. Also as I have been reading down to this point I am screaming that by cranking up the heat. You are oxidizing the lead on the tip. This will also lead up to a dirty solder joint (read cold). I would not go much over 650 and if that is not enough to do the job, then you need a higher WATTAGE iron.

My technic is to as someone else mentioned. Is to wet the iron tip with just a little solder. Then apply the iron to the lead and solder pad on the board. And apply the solder to the oppisate side of the lead till it flows. Hold the iron on for another second, to insure all parts are hot enough for the solder to flow onto the junction. In a few cases I have put jut a small dab of flux on the tip of the solder wire and then touch the joint. The flux helps clean the joint and promotes the flow and adhearsion of the solder.

Good luck

Max
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MikeLand wrote:

Here is another.

In the top row, 3rd & 4th look like they could be cold solder joints. I am seeing a black line between the solder and the post. In the 3rd row and 3rd from right, looks like a blob around the post and a copper pad below. This appears to me that the pad was not hot enough to allow for the solder to flow onto it.

Now even though you took good photos. I could be mistaken, without the ability to give each solder joint a good 3D inspection in person. All other joints look real good. I presume this is one of your first kit builds and soldering is new to you? Pat yourself on the back. Hell I have almost 35 years of soldering and sometimes mistakes slip by me. Not all wires take to being soldered easly. Here is a tip. Take one of those large pink erasers we used in schools. Give the back of a PC a good rubbing. Then use either the eraser and give resistors, caps, diodes a good rubbing on the leads so that they shine. Dont try this with IC chips as their leads are easy to bend and break. This will help the solder to flow onto the leads.

Max
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