HP Forum Archive 15

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HP 15C metal trim refinish ?? Message #1 Posted by Rick Opp on 11 May 2005, 9:58 a.m. Has anyone had any luck trying to straighten/refinish the metal trim around the HP Voyager series calculators? I recently got burned by a deceptive seller on Ebay. It's my own fault, I ignored some red flags and purchased it anyway. There is a small dent in the metal and quite a few light scratches and wear. Can the metal bezel be removed from the calculator without destroying it? If I can get it off, I think I can straighten it and restore the finish. Thanks Rick

Re: HP 15C metal trim refinish ?? Message #2 Posted by Vieira, Luiz C. (Brazil) on 11 May 2005, 12:57 p.m., in response to message #1 by Rick Opp Hi, Rick; the metal trim you refer to is the aluminun frame in the display? If so, removing it is possible, but it should be used some material to melt the glue used to hold it in place. Other contributors in here succeed using some harmless chemicals, but I actually do not remember the main component used. In time: if anyone reading this post knows, please, what is the best plastic gule that's used to melt plastic in calculators cases? I know that there is an active component that melts the plastic so it fuses the parts with each other, but I don't remember which, too... Thanks and success, Rick. Please, consider that if the HP15C you bought is working fine, you have a workhorse in your hands. The scratches are easier to deal with than a deffective unit. Please, consider that this words come from someone that has a daily-used HP15C that has scratches since the day it was bought. Best regards. Luiz (Brazil)

Re: HP 15C metal trim refinish ?? Message #3 Posted by bill platt on 11 May 2005, 1:13 p.m., in response to message #2 by Vieira, Luiz C. (Brazil) Hi Luiz, Acetone will dissolve ("melt") the polystyrene case. But acetone evaporates too fast and so is a very poor choice for fusion welding. It also has a high wetting coefficient and so tends to spread quickly acrossa surface, tending to damage it. Styrene monomer will also dissolve the plastic,and is more viscous and so tends to stay put a bt better without spreading, but I am not sure you would use that as it is slow evaporating. Many other solvents will also attack it: ketones especially such as Methyl Ethyl Ketone. I believe the benzene relatives will all go after it, too such as toluene, vinyl toluene, (and as previosly mentioned ) styrene. Methyl and ethyl alcohol seem not to damage it--though I have never tried straight methyl alcohol--it may damage it. Hexane does not damage the plastic, and is a good choice for dissolving the adhesives without damaging the plastic. Randy suggested hexane to me. It is the solvent used in making "rubber cement" and it is nasty for your brain! It is slow acting and of medium volatility. Regards, Bill

Thanks! d8^) (was: HP 15C metal trim refinish ?) NT Message #4 Posted by Vieira, Luiz C. (Brazil) on 11 May 2005, 1:26 p.m., in response to message #3 by bill platt

ouch Message #5 Posted by Frank Boehm on 11 May 2005, 2:33 p.m., in response to message #3 by bill platt you really should take cae of yourself when using the suggested chemicals, except for acetone (which is "rather harmless") you should wear gloves, eye protection and better inside a closed working place designed for chemical experiments I would rather suggest a two-compound glue, which takes a bit to harden, but it works well (much better than usual glue) and won't cause cancer :)

Re: ouch Message #6 Posted by bill on 11 May 2005, 3:05 p.m., in response to message #5 by Frank Boehm And you wonder where all the cancer comes from? I don't. We evolved bathed in low-level ionizing radiation, but we did not evolve in a benzene environment. (Interestingly enough, styrene is not considered a carcinogen, even though it is a benzene ring withj a side chain, as is toluol and vinyl toluene). Neoprene gloves (latex, nitirle and other disposables will not work) and eye protection are all you need if you work outside and you are using small quantities--I try to make the air go in such a way that I don't have to breath it--or I put on a half-mask carbon filter respirator. Regular old paint thinner is just as bad for your brain as these "powerful" chemicals, and yet most painters do not wear resiprators (I did). REGARDING GLUE: The glues sold for plastic models should work--though the "non-toxic" or whatever versions do not work well at all--you really need the ones that "contain oil of mustard" or whatever..... Regards

Re: HP 15C metal trim refinish ?? Message #7 Posted by Charlie O. on 11 May 2005, 1:57 p.m., in response to message #2 by Vieira, Luiz C. (Brazil) Look here at a 15c still in use which some would call cosmetically challenged. http://www.geocities.com/cjoxford2/johnscalc.html

Re: HP 15C metal trim refinish ?? Message #8 Posted by Giancarlo on 11 May 2005, 3:44 p.m., in response to message #7 by Charlie O. Hi everybody. I'd like to enlarge the problem: what about re-building the entire metal bezel? Is it possible to make / get a technical drawing (with dimensions) of the metal piece to try to build it from scratch? Thanks for inputs. Cheers. Giancarlo

doing your own bezel... Message #9 Posted by Hans Brueggemann [GER] on 14 May 2005, 3:14 a.m., in response to message #8 by Giancarlo giancarlo, good question! i never did that, but would go this way: there is a 2-compound silicone named "CHROMASIL" (that's how it is called in germany. dentists use it to cast teeth models) which i use to cast copies of small parts. i would simply copy the complete display area of the calc, without disassembling anything. after that, just cast a new display area as a model where you can get all necessary dimensions from. it is that easy and it works, because the silicone makes absolute perfect copies. it also reproduces the surface structure of the bezel. cheers, hans

Definitively yes! Message #10 Posted by Artur on 13 May 2005, 9:54 p.m., in response to message #7 by Charlie O. Hi, I have succesfully worked on many bezels for voyager series. You have to use a very strong alchool (absolute) and a small dentist spatule. So, slowly, put some drops of alchool between bezel and plastic calculator body and gently force the bezel up. In almost 1 hour it is done. Try to not damage the plastic over display, but, if it happens, eschange it with a new one cutted from a CD case. Use a sand paper to remove the scratches and apply a new car varnish. Use a contact glue to put everything back and you will have a new one calculator! Good work! Artur

Re: HP 15C metal trim refinish ?? Message #11 Posted by Hugh Evans on 11 May 2005, 6:08 p.m., in response to message #1 by Rick Opp It might be easier and more effective to make a replacement. Fill the dented part with bondo, scratch it up a bit for good measure and attach the replacement with some epoxy. Hypothetically, you could get good results with aluminum foil using this method. Good Luck, -HDE

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