HP Classic Calculator (HP-65) back label

[burkhard]

(05-31-2019 01:09 PM)rprosperi Wrote:  Although often there is not much feedback on your rescue/repair posts, I really appreciate reading them and I'm sure lots of other folks do too.

Yes I am one of these! I have a couple of HP-65s myself that need a little attention and I'll be referring back to your posts when I finally get to them.
Thank you again!

[albertofenini]

here we go, we did a couple more labels today, and here are the pictures, one is English, one is German
The English was in better shape so the result is absolutely better, not good as the first one in this post, but good enough.
We know that there are replicas for sale, but we try to re-use as much as possible the original materials,
it is not better or worse, right or wrong, is more a way of thinking what we intend for "restoration".
First the materials, we usually put the label in a badge holder, than we wood tools we flatten it
as much as possible.
Some tools have a rounded corner, some a sharp one, depends how deep the wrinkle we use onw or the other.
All are from domestic recycle, you will also see a manual de-icer for car glasses ...
In the video, we will post it on YouTube soon, you will see how we use them.
You also will see that the initial status of the label obviously makes the difference.
Given the same tools and same skills you will notice that the German label gave a worst result.

   
   

Then you will see how we protect the back of the cal, and how much glue we put on both sides

   
   
   

[albertofenini]

and now the results ...
we usually apply a final touch of polish or car wax just to give a uniform look to the label

   
   
   
   

[[kby]]

I'd encourage people not to sell the original "spoon" technique short—with a bit of practice it works really well. I say this as someone who tried it half-heartedly a few years ago, with predictably half-hearted results. Recently, I've tried again, and worked on my technique a bit. The attached was from a cosmeticallly pristine machine, but I'll point out that it's been removed and replaced at least a half a dozen times in the past few weeks (not that I would recommend that practice—I mention it to show that with some patience it need not be fatal to try again!).

I use GEM Teflon coated razor blades in the removal; these are the this are the thinnest and sharpest razor blades I know of (I have a bunch because they are used to make oboe reeds). The part number is 62–0178; they are aluminum and .23mm (.009") thick. That is just so you can get the corner/edge of the blade under the label. Once that is accomplished (after the heat), then it's best to (gently) apply the pressure along the side (not the sharp edge) of the blade to work more and more of the label loose enough to grab. It's best for someone with small fingers and short fingernails, so that you can grab the label without making a dent with your nail (although that is not fatal if it isn't too bad).

I then like to use label remover to remove all of the old adhesive. The original is usually the harderst in this case. The label should be smooth and shiny (not quite a specular mirror, though) on the back when done. I quick wipe with either isopropanol or acetone is good to degrease the back at this point (the paint in my experience has seemed resistant to both, but I would not push it with acetone, but you shouldn't be getting any on the front. Degrease the back of the calculator (after removing the adhesive with label remover) with an isopropanol wipe.

The glue I currently use to replace the label is Elmer's Craft Bond. I'm sure there are many other things that will work; this one is one of those that you are supposed to be able to have it act as both a permanent and temporary bond. I use it in the more "temporary" sense, although it seems pretty stuck then. It removes easily with label remover if you need to do a redo. To use it in this way, I spray a very thin coat (essentially one pass) on just the label. The nice shiny label now has an even matte finish on the back. Let it dry 3-6 minutes, then attach the label. You might need to use the spoon again over the next few days to get all of the bubbles out from underneath pernanently—just put something between the spoon and the label like a piece of paper. I do not spray any glue on the calculator—just the label.

Either before degreasing or after attaching if you're careful, I have used a black paint extra fine marker (it's actually paint, not just an oil sharpie) to touch up minor scratches if they are away from lettering (such as one you might get when trying to get the razor blade under the first corner and having it miss). If you let the paint just barely dry and gently wipe it with a tissue, you can get it to be prety invisible—your eye only sees the surrounding texture and color as long as it's not distracted by a glaring glint of silver.

I will try to post more pictures with more "realistic" cases over the next few days.

[rprosperi]

(06-04-2019 05:42 AM)[kby] Wrote:  I'd encourage people not to sell the original "spoon" technique short—with a bit of practice it works really well. I say this as someone who tried it half-heartedly a few years ago, with predictably half-hearted results. Recently, I've tried again, and worked on my technique a bit. The attached was from a cosmeticallly pristine machine, but I'll point out that it's been removed and replaced at least a half a dozen times in the past few weeks (not that I would recommend that practice—I mention it to show that with some patience it need not be fatal to try again!)....

Thanks for the comments on your successful techniques. Your detailed notes and precise description of the steps is very useful, particularly things like how log to wait between steps, etc. Also, including specific product names and descriptions is helpful; often, products considered 'almost the same' don't work nearly as well, or sometimes even at all.

Could you please specify which label remover product you use, as this is an essential component of success? This is an example of where using the exactly correct product could make a big difference in the results. Knowing the manufacturer, brand name, etc. should make it easy to locate a source to acquire it locally, or if not available locally, then to find a suitable product as near the original as possible.

Thanks!

[[kby]]

(06-04-2019 01:12 PM)rprosperi Wrote:  [

Could you please specify which label remover product you use, as this is an essential component of success? This is an example of where using the exactly correct product could make a big difference in the results. Knowing the manufacturer, brand name, etc. should make it easy to locate a source to acquire it locally, or if not available locally, then to find a suitable product as near the original as possible.

Thanks!

I use 3M Adhesive Remover in a spray can. There is a comment of “Citrus Base” on the label and it does have that limonene smell. Contents says “citrus extract” and propane. The propane is just the propellant; the particular citrus extract they listed has what looks to be a CAS number of 8028-48-6. You kind of have to scrape a bit with fingernails to get the original adhesive off of the label. Usually most of the original adhesive (and any replacement if it was done by the method I outlined) stays with the label when it’s removed—not so much with the calculator. The original adhesive is kind of rubbery and more rolls up like removing chewing gum, rather than dissolving off like the craft glue I use does.

The paint pens I used were the store brand “Craftsman” at Michael’s.(Definitely not the same as the old tool brand at Sears!).