SPICE repair problem

[PANAMATIK]

There are two common repair problems with SPICE calculators like HP-33C/HP-34C

If you try to insert todays AA Batteries or NiMh accus, the case will break at the weakest place, which can be seen here, because the AA NiMh accus are slightly longer than older NiCd accus. I tried to fix it with a 2mm x 10mm plastic sheet strip and Epoxy glue at the inner rim, but without success. How can you fix this problem?



For another reason sometimes one (or both) of the screw holes are broken. I tried to add lots of epoxy and drill a new hole there, but without success. How can you fix this second problem?



Bernhard

[ijabbott]

Have you tried solvent welding? The stuff used by model makers, not plumbers.

[grsbanks]

(11-28-2019 08:49 PM)ijabbott Wrote:  Have you tried solvent welding? The stuff used by model makers, not plumbers.

That's a good call. I've fixed several cracked calculator case elements using a few drops of acetone. You just have to be careful with the stuff because it'll knock you out if you don't have proper ventilation where you're working. It'll also completely dissolve any plastic parts you drop in it...

[Paul Dale]

The case is ABS and I expect solvent welding is the way to go. Most glues don't stick well to this plastic. I've not tried this mix but it seems reasonable: https://www.matterhackers.com/news/how-t...and-slurry. Straight acetone ought to work as well but might be a little less forgiving.


Pauli

[albertofenini]

Hi everyone,
I have always had very good result with this product :
Plastic weld Poly-Weld glue adhesive perspex abs acrylic hips polycarbonate
https://www.ebay.it/itm/Plastic-weld-Pol...2749.l2649
take care !
Note :
I'm not affiliated by any mean with the seller nor the producer and if it is not appropriate post links to commercial products please remove it immediately

[PANAMATIK]

Thanks a lot for all your advice. I will try acetone and other ideas and inform about the results.

Any ideas about the screw?

Bernhard

[Maximilian Hohmann]

Hello!

(11-29-2019 11:31 AM)PANAMATIK Wrote:  Any ideas about the screw?

If you can find an adhesive that sticks to this awful „Spice-plastic“ (personally I am not convinced that the Acetone method will work, at least it didn't for me in similar repair attempts) then you can glue a metal nut (M2,5 or M2) to the remains of the old screw hole. Or drill it out almost to the bottom and fix an "Einpress-Säule" (like eBay Germany item number 400999452325), sorry, no idea about the english translation for that... in the gap. This should hold quite well because you can attach the glue on two sides and on the bottom.

Good luck
Max

NB: I have already tried "UHU Allplast" (an adhesive available here in Germany which is supposed to stick to "all" types of plastic) but it does not work very well.

[albertofenini]

With the glue i have mentioned in my post I have melted and soldered successfully the plastic of which are made both the Woodstock and the Classic,
Not sure how will work on the Spice
It weld very well and it exists for three different size of filling gaps, thin, medium and big
That one is for thin
In rebuilding battery packs you can not spot the difference and is very strong
This should allow a you to weld in place some plastic and rebuild the post
Take care

[ijabbott]

If using thin, volatile solvent (although I think some of the commercial "plastic weld" solvents have some polymer chains dissolved in them too), use a nylon syringe suitable for organic solvents, with a stainless steel needle (preferably round-ended, not sharp hypodermic) to apply the solvent to the edge of the joint, and let capillary action draw it into the joint. Hold the pieces together for a minute or two while it sets. Don't press it together too hard or you'll start to deform the softened plastic.

[striegel]

With several recent plastic repairs that kept re-breaking, I discovered that when I glued on a piece (or 2) of a broken jeweler saw blade, it held up better.

The blades are very inexpensive, so I have lots of them (the package of very fine ones came with 144 blades for around $6.00).