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HP Forum Archive 15

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Repairing Classic Series battery compartment cover
Message #1 Posted by Gordon on 17 Feb 2006, 7:16 p.m.

The sliding latches on a few of my Classic series are broken. The common problem tends to be the plastic tab in the inside of the battery cover (where the rubber feet would attach to), they are often broken in half.

There is not enough material for crazy glue to grab on to, and since it occurred on three of my Classic series, I presume it is a common problem.

I had thought about replacing the internal plastic piece with a custom machined/drilled thin metallic tab, and attach the plastic feet (on the outside of the battery cover) to it. But that can get quite involved in making it. Does anyone has a better idea?

      
Re: Repairing Classic Series battery compartment cover
Message #2 Posted by John Garza (3665) on 18 Feb 2006, 5:14 p.m.,
in response to message #1 by Gordon

Gordon,

I've come across this problem a couple of times. What I do is line up the two pieces of broken plastic, then glue a thin strip of plastic over the joint, see below.

Battery latch ====== ====== New plastic -------

I find old plastic collar stays from dress shirts work great! Just trim to fit.

-John

            
Re: Repairing Classic Series battery compartment cover
Message #3 Posted by John Garza on 18 Feb 2006, 5:16 p.m.,
in response to message #2 by John Garza (3665)

Somehow, the text in my last message was not wysiwyg...

Lets try it again...

Battery Latch ====== ======

New Plastic ------

      
Re: Repairing Classic Series battery compartment cover
Message #4 Posted by Vassilis Prevelakis on 18 Feb 2006, 8:00 p.m.,
in response to message #1 by Gordon

If you have all the pieces from the old latch, you can simply add two metal wires to reinfoce the join. Here is a picture of the latch on my HP-97 (the only difference with the HP-67 latch is the colour).

If the latch is broken you arrange the pieces so that they are in the correct positions relative to each other and also correctly aligned (the tops must be level).

You place thin wires (the ones shown in the picture are wires from a resistor pack) on top. You then gently touch each wire with the tip of a soldering iron and wait till the heat allows the wire to sink into the plastic.

**vp

Edited: 18 Feb 2006, 8:02 p.m.

      
Re: Repairing Classic Series battery compartment cover
Message #5 Posted by David Smith on 18 Feb 2006, 11:42 p.m.,
in response to message #1 by Gordon

If you have the piece, you can reattach it as good as new with plastic welding solvent (methylene chloride) available at any hobby shop. Lay the pieces of latch on a stone or metal table top. Paint each end of the latch with the solvent and hold them together for around 10 seconds. Let dry overnight. The bond will be as stong as new... something no glue will do.

            
Thank you for all your great suggestions
Message #6 Posted by Gordon on 20 Feb 2006, 9:02 p.m.,
in response to message #5 by David Smith

Thank you so much for all your ideas. I think I will try the welding solvent first and see if I have enough pieces to put it together (part of the middle section is quite crumbled). If that does not work, then I will try the metal wires.

Come to think of it, is there enough clearance to put another thin piece of plastic on top, then use the welding solvent to create a new piece. So in the picture below, F stands for the rubber feet, O stands for the old crumbled piece, and N stands for the new piece.

NNNNNNNNNNNNNNNNNN OOOOOOOFFFFFOOOOOO

My concern is there may not enough clearance to do that. If it may work, is there any place that I can go and buy that thin piece of backing plastic? Do they sell stuff like that at hobby shops?

                  
Just realize John Garza has the same idea
Message #7 Posted by Gordon on 20 Feb 2006, 9:07 p.m.,
in response to message #6 by Gordon

John,

After I post my last reply, I realized my second alternative is the same as your suggestion. I will give that a try, I think you are right, the collar tab is just about the right thinkness.

Do you use crazy glue, or the welding solvent? I think most of my collar tabs are plastic-like, but not exactly plastic, as they do not snap when you bend them.

                  
Plastic for latch repair
Message #8 Posted by Randy on 20 Feb 2006, 10:14 p.m.,
in response to message #6 by Gordon

Collar tabs: They're usually made of polyethylene, very hard if not impossible to bond to. The solvent welders will not work, you need something made of a styrenic material.

Some hobby shops sell styrene plastic in strips, rods, tubes and other shapes. It's used primarily for model railroading and many of the shapes are scaled to real world things like 4x4 timbers. Several of them come in real handy for calculator repair :)

I use strips that are 0.25" x 0.010" for the top cap on the battery latches - it reinforces the tab and doesn't add much in the way of thickness. Evergreen Scale Models is what my local shop carries. If you'd like, send me an email and I'll snail mail you a chunk.

IMO solvent welding is the **only** way to repair anything plastic in an HP handheld - throw the crazy glues away, they only make things worse.

Edited: 20 Feb 2006, 10:17 p.m.

                  
Re: Thank you for all your great suggestions
Message #9 Posted by Marcus von Cube, Germany on 21 Feb 2006, 8:52 a.m.,
in response to message #6 by Gordon

Gordon,

Quote:
NNNNNNNNNNNNNNNNNN OOOOOOOFFFFFOOOOOO

I think you mean this:

Quote:
NNNNNNNNNNNNNNNNNN
OOOOOOOFFFFFOOOOOO

The forum has some formatting capabilities. If you want to force a line break, hitting the return key is not enough. Add a special tag after the line: [NL] and your line break will be preserved.

Marcus


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