Stripping the plastic off headers, an easy way?

[Infraviolet]

I've got some specially sized 90 degree male 2.54mm headers for which I need to fully expose the pin and remove the black plastic joining structure.

This is because how they are to be used they need to be soldered on the "wrong" side where the plastic currently is as a means to mount together boards at an angle, only after mounting is it possible to take some angled supporting jigs away and solder the other side.

Ideally I'd solder one end of the header to one board, then strip away the plastic part, then place the board and the other board in the holding jig, then solder the "wrong side" from where the plastic must be removed, then take off the jig and finish up by soldering the "right side". But if absolutely necessary I could extract the header pins from the plastic frst and use other means to align them during the soldering to the first board of the two they join.

The trouble is I can't find a nice quick way to remove the plastic. I can remove it, but it takes ages and lots of effort and risks bending the header pin out of the desired 90 degree shape (which is necessary else I could just use plain pieces of stif wire).

Anything involving cutting it off takes a lot of work with side-cutters, coming in at funny angles time and again until enough plastic is gone to expose the header pin. And can only be done to lone header pins before any soldering is done to them, trying it in situ after the first soldering would mean the cutting would force header pins apart whilst the other ends were soldered fixed in to holes, and would bend or break something.

Trying to forcibly pull the plastic off has similar issues. Trying it a pin at a time for lone pins needs a lot more force than is easy to apply to such small places where snipe nosed pliers struggle to grip, and trying to tug on the plastic with one set of pliers and on the angled sction of the header with another set, is as likely to bend the pin as it is to liberate it from the plastic. And again, too brutal a process to do in situ after the first soldering, I'd be more likely to damage something than to remove the plastic.

Melting isn't too easy either, the plastic used is obviously designed to be somewhat fireproof and to char, and when trying to heat it with a soldering iron it leaves a terrible black gunk on whichever part of the iron touches it (I tried touching with the side of the hot barrel section of an iron to avoid getting the gunk on the tip). As doing the first soldering before this melting is the only way to be able to get the header pins held firmly whilst apply the iron heat to them this has to be done in situ.  And it only therefore melts on the side of the header, after much iron prodding, which faces outwards and can be reached with the side of the iron's not-quite-tip-area. So the gunky remnants, which cool immediately in to something almost as solid as beforehand, need tugging off with quite a bit of force with pliers or cutting at with side-cutters some more.

I did this by a mixture of the means for enough header pins for my initial use, about half an hour to expose 8 pins and in the process wrecking 4 pins. But this is for a project which will later on need a fair few tens more of header pins stripping in this way.

Is there a nice easy and quick way to get the plastic off? Without having to try to find weird chemicals (most chemicals being more likely to dissolve metal pins than plastic surrounds anyway), and without processes more likely to bend the pins or damage the board than get the plastic off.

I am not looking for an alternative to these headers, as the metal curved piece is exactly the right shape and has the perfect length on both sides of the bend for joinging board at an angle in this scenario. And I doubt lone header pins without the plastic are sold with the same dimensions.
Thanks

[langwadt]

easy to pull pins out of a header if you do it one at a time

[JustMeHere]

Post a photo

[Dan123456]

If they aren’t attached to anything currently, just use a heat gun / soldering iron

Just heat the crap outta the pins slightly melting the plastic and it should come off real easy 

I usually have the opposite problem where I accidentally remove the plastic that way when soldering them to a PCB 

[jpanhalt]

Lacking a picture...

Headers differ in how hard it is to remove the pins.  Some headers have the pins slightly distorted ("staked") where they are in plastic.  That makes them harder to remove.  Pins in the cheaper (?) ones without the distortion can sometimes be almost loose.

When I want to remove the plastic from multiple pins or, more often, relocate the plastic, I use a small, 2" machinist vise.  See: Palmgren.  With a slight cock of the header, the plastic can rest on one jaw and the pins can be pushed out with the other jaw.   

Some alternative ideas:
1) If you have a mill, you can mill one side of the plastic off after soldering without damaging the pins.  It should them come off easily.
2) Pre-remove all the pins, then reinsert in the plastic as a spacer.  They should then be looser.
3) A variation of #2:  Make your own spacer -- I use wood -- or drill the holes in a plastic one slightly larger.  Then use that spacer for your loose pins.
4) Isopropyl alcohol has good wicking and wetting properties.  That might help as a lubricant, but I haven't tried using it.

[chickenHeadKnob]

If they aren’t attached to anything currently, just use a heat gun / soldering iron

Just heat the crap outta the pins slightly melting the plastic and it should come off real easy 

I usually have the opposite problem where I accidentally remove the plastic that way when soldering them to a PCB 

I would exercise some skill and caution if applying heat. Yes with the cheap headers the pins can be pulled out, but if you apply too much heat for too long you can get separation of the tin coating from the underlying steel pin core. It can be very subtle and not easily seen. Same with soldering wire wrap pins to a board.

The mechanism is the thermal expansion of the steel core on heating then shrinks back and separates from the coating on cooling. I had this very hard to diagnose intermittent failure on a wire -wrapped proto board because I had soldered the diagonal corner pins of wire wrap sockets to fix the sockets to the board before beginning wrapping. Only on one pin I had applied too much heat. You could not see the separation but it caused the modified wrap to float on the pin. A real bugger to find that one. When I removed the wrap parts of the plating came off with it and I had an a-ha moment. 

Edit; maybe with the modern really cheap plated parts this no longer is a risk as the plating is much thinner these days. Back in the golden era when this happened you got a more generous  helping of tin.
Note the difference in expansion ratios is what also causes the heavy tin plated steel leads of inductor/transformers to eventually develop what looks like a cold solder joint on single sided phenolic paper type circuit boards after many years of thermal cycling and normal functioning.

[T3sl4co1l]

May be a place where actual cheap Chinese parts are preferable.  I've seen a few boards with really cheap heater stock on them that melts readily at soldering heat (it's probably glass-unfilled LCP, or even like, freaking ABS), and doesn't stick much to the pins.  So, it's ridiculous to solder, the pins drift everywhere, they don't stay at the same height or angle... but it's also easy to reposition them lengthwise (if not otherwise fixed, like when soldering pigtails to header stock), or to pull off the bracket entirely.

There are also, I think, water-soluble plastics that can be removed afterwards; and low-profile stock for jumper and board mounting purposes.  Not sure offhand about sources for these though, I haven't tried shopping for them.

Or the clip-style / edge / wraparound like pins that are IC-socketable, that could be used just as well for soldered-in application.

Tim

[Infraviolet]

jpanhalt: "When I want to remove the plastic from multiple pins or, more often, relocate the plastic, I use a small, 2" machinist vise.  See: Palmgren.  With a slight cock of the header, the plastic can rest on one jaw and the pins can be pushed out with the other jaw."

Thanks, that seems the best solution. Works much better than trying to pull with pliers. And as an advantage, it turns out merely moving the header right to the tip of the long side of the L shape is enough, I can feed the curved part of the L the "wrong way" through a plated through hole (it barely fits, but it does get through round the curve) to get it to the desired position and leave the plastic at the end to help keep the pins steady during soldring.