Problem and solution - circuit board blank

[CaptainJane]

Thank goodness for The IAP.

I turned 2 of the PSI 3/8 circuit board blank to put on Smitty V2's. The blanks (1 red and 1 green) came out beautifully, and all that was left was to press the components on. Even though I was gentle, BOTH blanks cracked when I tried to press the components on. Crap!

Then, I remembered a post a couple of days ago about wrapping a blank in electrical tape to keep it from shattering when using a barrel trimmer. I repaired one blank, marked the edge where the crack was, then wrapped both ends tightly in electrical tape. I then carefully pressed the components on, putting the clip over the crack. When I took off all the tape, no more damage.

Next time I turn a circuit board blank, I will try wrapping the finished blank with electrical tape for sure.

Since the blanks are 5 inches long, I will be able to get another pen out of those blanks.

I hope this helps someone else.

 

[ed4copies]

Additional information: Once a circuit board blank cracks, trickle thin CA over the end of the blank, at the crack location.

Leave standing upright overnight--many times the crack is gone. CA will "wick into" a crack and repair it.

(This does NOT work if the pen is already sold or it is a very expensive blank, so don't tell your blanks if they are sold!!:biggrin::biggrin::biggrin

 

[CaptainJane]

good to know

Thanks Ed. That is kinda what I tried, but the crack had actually split open, so I had to use a buildup of medium CA. I did not do the overnight upright part. Thanks for the tip.

 

[WriteON]

Why did they crack. Any thoughts

 

[magpens]

Why did they crack. Any thoughts

Cracking may be due to expansion forces in the brass tube when you press the end components in.

I have had problems like this and have decided to routinely ream out the brass tube ends with an adjustable, parallel-sided reamer and then glue in the end components with epoxy. I try to keep the reaming to a minimum so that there is still some resistance to the pressing.

If anyone can see an undesirable aspect of this procedure, please let me know about it. Yes, disassembly could be a problem ... any suggestions to a glue that would be more appropriate than epoxy ? Blue Loctite ?

 

[WriteON]

Why did they crack. Any thoughts

Cracking may be due to expansion forces in the brass tube when you press the end components in.

That happened to me with the bottle stoppers. I relieved the metal posts slightly with a Dremel and stone wheel.... used Epoxy for retention.

I had good results with Circuit blanks used with PSI Steam Punk Pens. Obviously kits are not created equal and adjustments are sometimes needed