Cutting Flex Strips

[drlucas]

Two pictures attached:

1 -  what I think I need to do (the goal image).
2 -  what I did (the hackjob image).

I think if I splice right in the middle of the solder joints, then I just solder new wire on it, it will work, but I want to take two strips and join them together and just overlay the one strip on top of the other...but without de-soldering the old one off first I'd end up with three strips deep at the one end.

anyways...see the attached and let me know if what I think I need to do (just and solder) or if i'm on the right approach with the hackjob and just need to desolder each one of the four joints one at a time

[zwiller]

Ok, the hack job is bad but salvageable.  Worst part is it looks like you may have pulled the the soldering pad off the 12V line (+VC).  That's cool, just use the solder pad on the bottom to hook up... 

On the remaining joints, add some flux to your desoldering braid and remove the solder from the other joints.  The braid should easily wick up the solder and you should have no solder on the strip.  The torn piece from the other section of strip should just fall off. 

The goal image has some issues.  First off the section you want to keep is the "IN".  Also, you don't necessarily need to throw the "OUT" part away just realize you can't start a section with it. 

Not sure what you mean about splicing and overlaying but we'll get there!

I will be up a while as I am sick and bored.  So post away! 

[twooly]

The best thing I found when doing the flex strips was to tin the wires you want to attach and also put a little on the flex strip pad.  Once you've done that place the wire on top of the little solder you put on the pad and just heat the wire a little and they will bond together.

[drlucas]

ok...i'm getting there....and I think you are right about the direction....I just remember something...as both ends of the flexstrip has a long lead of three conductor wire on it...I cut the other end and this is what is left...so, right, I got the wrong end. that makes sense...not a PCB issue rather a PMB issue (past my bedtime)

I have the rosin core solder so I will need to pick up some flux to help with the desoldering process. I've tried solder suckers and braids in the past....still learning to master that technique...done my etherdongle jack after a separate PMB issue.

Tonight I've kept the keys to the soldering station locked and made a commitment i'll wait until the weekend when I've got lots of time and energy to try my luck again, but this thinking process before I go to work again on the reuse of the flexstrings will prove to be valueable to me in the long run. thanks for the help along the way!!

Including my ramblings when i'm tired!  the overlay - all I was thinking if I have two flexstrips if I cut the left hand side of one and solder the right hand side of the other together from the spare strips and if I don't clean the part of the strip that I don't use then I can just put the two strips together. I guess I was thinking the strips were kinda like tongue and groove wood where one fits into the other, then you solder them together...I think I need to see what two "clean" strips look like and then I bet I can figure this out better. 

Ok, the hack job is bad but salvageable.  Worst part is it looks like you may have pulled the the soldering pad off the 12V line (+VC).  That's cool, just use the solder pad on the bottom to hook up... 

On the remaining joints, add some flux to your desoldering braid and remove the solder from the other joints.  The braid should easily wick up the solder and you should have no solder on the strip.  The torn piece from the other section of strip should just fall off. 

The goal image has some issues.  First off the section you want to keep is the "IN".  Also, you don't necessarily need to throw the "OUT" part away just realize you can't start a section with it. 

Not sure what you mean about splicing and overlaying but we'll get there!

I will be up a while as I am sick and bored.  So post away!

[zwiller]

Go to bed, man.  We'll regroup.  I will give you a good thought to sleep on.  I think the flux will help more than you realize: desoldering braid does not work for me at all, without flux...

[jnealand]

How are you using the desoldering braid?  I put the braid on the joint and then put the iron on top of the braid and it just sucks of the solder.  If you are trying to heat the solder and stick the end of the braid in the melted solder forget it.  Just make a sandwich with the braid in the middle between the iron and solder you are trying to remove.  I've been using it a lot this week as I upgrade all my SSC v1 and v2 to v3.  I even put the braid on the end of the resistor leg and use the iron to push the leg down flush with the pcb and it picks up more of the solder as it pushes down.  Only 8 more SSC upgrades to go, but I still have to flash the last 10 with the v3 firmware and test them.  So far all have worked fine.

[thestig]

Quick question and it may be stupid but...

Can I cut the flex strips wherever I want to end the flex strip. for example. I am lining my house with flex strips and have flex strips that are too long and hang over the house. can i just cut this at any of the connectors where I see solder pads? or do i have to cut it before the Diode that starts the next 1 meter strip. I understand that cutting these in the wrong place will leave the extra flex strip useless *unless i still have over a meter left and can start on that certain diode.

[zwiller]

How are you using the desoldering braid?  I put the braid on the joint and then put the iron on top of the braid and it just sucks of the solder.  If you are trying to heat the solder and stick the end of the braid in the melted solder forget it.  Just make a sandwich with the braid in the middle between the iron and solder you are trying to remove.  I've been using it a lot this week as I upgrade all my SSC v1 and v2 to v3.  I even put the braid on the end of the resistor leg and use the iron to push the leg down flush with the pcb and it picks up more of the solder as it pushes down.  Only 8 more SSC upgrades to go, but I still have to flash the last 10 with the v3 firmware and test them.  So far all have worked fine.

Jim, I use the same techniques as you, but I am using Rat Shack braid.  I could swear there is something coating the wire as it burns off smoke...  If I don't use flux it just gets hot and smokes and the solder doesn't flow.  Just a little flux and the braid works well.  Someone here recommended using the flux as I was frustrated with it when I first used it. 

Best of luck on the upgrades to v3.  I did that mod so often last year I could do it half asleep.   

[zwiller]

Quick question and it may be stupid but...

Can I cut the flex strips wherever I want to end the flex strip. for example. I am lining my house with flex strips and have flex strips that are too long and hang over the house. can i just cut this at any of the connectors where I see solder pads? or do i have to cut it before the Diode that starts the next 1 meter strip. I understand that cutting these in the wrong place will leave the extra flex strip useless *unless i still have over a meter left and can start on that certain diode.

You got it.  End anywhere you see the solder pads, start at the solder joint/diode/R1 (actually every 1/2 meter or 15 leds). 

[drlucas]

Clearly I was tired last night...tonight's attempt was ALOT better. Attached in this shot is the results.

Now...the only issue I have run into is the plastic casing. I wanted to get the two strips to butt up against each other. So, I cut both ends about 1/2" from the solder joint and peeled it back. then took one of the plastic end caps that come in the reel packaging and cut the one end off, and was going to put silicon under where the two strips meet with the new little cap over top of them. all would be good, but I can't for the life of me get the flex strip to slide within the plastic casing.

How do I resolve this, do I get some sort of lubricant and slide on the back of the strip and slip it in then, use baby powder, or something else like just wiggling the strip back and forth until it goes in? Anyone run into that problem, or did I use all my energy with the soldering that my other skills of inserting strip into plastic covering won't come back until I recharge in the morning? 

Progress at least!!

[jnealand]

In my early attempts at cutting and resealing I cut the tube exactly over the solder joint, then slit the sides about an inch so I could peel them back.  I was just putting 3 pin connectors on the ends and not reconnecting strips.  I put the end cap over the wires on the connector before soldering and when I was done I just used copious amounts of RTV in the cap and over the cut edges to reseal everything.  On later attempts I slid the tube back after cutting the tube over the solder joint.  Just keep working it starting two feet back and putting pressure on the tube.  Once I got if far enough back I soldered the connectors on as before and then worked the tube back so that it would cover the solder point and let me slide a cap on.  Again copious amounts of RTV.  After the RTV dried I went back and looked for voids and filled those with RTV.  Seems to have worked good.  I've just ordered more strips and asked Ray to send them not in the tubes and then I ordered a bunch of tubes so I could cover the strips after cutting them.  I'm going to make a small matrix so there will be lots more cutting that I did when I cut last years strips in half to make a 7ft tall pixel tree.   Now I am trying to get everything else done so when the new strips arrive I will have time to work with them.  The matrix will be an addon and not a critical part of the display so if I don't finish it before Thanksgiving I will just keep working on it until it is ready.  I didn't add my pixel tree to the display last year until mid December.  So much to do, so little time (and I am mostly retired).

[zwiller]

Yep, much better!  Just a thought, the SSC limits you to 1 full strip(120 leds).  You aren't joining 2 strips or making the strip longer that 120 leds, right? 

Anyway, the silicone sleeve can be a trying but I have been told that I am a patient guy when it come to matters such as this.  I will say that I unrolled the strips a day or two before hand to keep them flat before I worked on them.  Maybe try using something inside the sleeve to straighten it and move the strip along gently.  From memory you need to be more gentle than aggressive and only expect the strip to move a little at a time.

Jim has a good point, if you will be splicing alot you might benefit by getting some extra sleeves to eliminate this problem.  I was "fortunate" that all my cuts/splice/joints were for corners with and never went directly sleeve to sleeve.  I could see that being fun and agree with Jim the RTV should do the trick.  I have also seen some guys put clear rtv in the sleeve and heat shrink the outside. 

I have been procrastinating on making the final decision as to what will make the show this year...  I am hanging out here more often hoping to get some inspiration.   

[jnealand]

I ordered WS2811 12v strips and will be putting them inside of 1" 200psi PVC.  My test using an extra TM1804/9 strip looks really good.  This will help me get rid of my last incans.  Yay.  I am going to try the 2811s since others have reported they work well and they are much cheaper.  $30 for 5m vs $42 for 4m.  My arch strips will be 3m and fit in a 10ft piece of PVC very easily.  Also with the 1" pvc the SSC fits right inside the arch.  Looks really simple and is much easier to store than my old incans.  I will end up with a couple of 2m pieces that I could solder together, but I am going to make a small matrix that I will be able to use the cutoffs on and cut up some other strips that I have ordered.  Now just waiting for them to get here.

[zwiller]

Hoping to lose the incans too.  Please let me/us know about the 2811 strips.  I would really trust your input.  I admit I am also unsure what direction I am going with everything and your post is very timely! 

[drlucas]

I'm joining up a few extra pieces from the mega tree I put up...I have 12 part strands and want to make 2 full strands....I'm respecting the law of gravity, pixelnet and any others that might be in jeopardy as a result of my hacking these strips

As for extra shells....I'd definitely be up to getting two new ones if I can find them somewhere local.