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sexta-feira, 8 de março de 2013

One Fix for the Red Glue Problem

JD800 by Marcos Carrera from Taiwan.

This was posted by Shupac800 at the JD-800 Tech Group:

My Fix for the Red Glue Problem
Posted By: shupac800  Sat Aug 4, 2012 8:10 pm 

I posted this tutorial to last year and thought it might be
helpful to republish it here.

* * *

There are two kinds of JD-800 owners: those who have already experienced the
red glue of death, and those who are going to...

As we all know, the red glue that holds the key weights to the keys did not prove to be stable over a period of decades. When it gets old, and especially if the synth is kept someplace warm, the red glue softens and seeps out, making a God-awful mess.

The best way to fix this problem is to remove all the red glue, under the mildest conditions possible (NOT boiling water, as some have tried), and re-glue the weights into the keys. The keybed comes out better than new. Here's my technique.

Sodium hydroxide (NaOH, lye) solution works great to dissolve the red glue without harming the plastic. It is caustic, so WEAR SAFETY GOGGLES. Even dilute NaOH can permanently damage your eyes, and it's very likely your lye solution will be splashing about. If you get any of the solution on yourself, wash it off promptly with a lot of water.

The sodium hydroxide I like to use is granular NaOH, which I've bought on eBay. If you can get Red Devil lye or some other pelletized NaOH at your hardware store, that will work too, but the granular NaOH dissolves faster.

In a plastic bucket, mix 80 grams NaOH with 2 liters of water until all the NaOH is dissolved. (The bucket will get warm.) For you chemistry types, this recipe makes a 1-molar (1 mole/L) solution of sodium hydroxide.

Immerse the keys in the lye solution. You only need to soak the part with the glue on it, so don't worry if keys aren't completely bathed in the solution.

Leave the keys soaking in the solution for 18-24 hours. After this time, no traces of the red glue should remain, and the weights will simply fall out of the keys into the bucket.

Carefully pour the NaOH solution down the drain. Don't let the weights get poured down the drain too.

Rinse everything with a lot of water. Dry the weights as best you can. It's normal for a bit of rust-colored oxidation to form on them; don't worry about it.

At this point I soak the keys for another 24 hours in a bucket of soapy water. This bath helps eliminate the fishy odor left on the plastic by the reaction of the lye solution with the red glue.

When everything is dry and clean, re-glue the weights into the keys. I have had great results using a popsicle stick to apply a dab of 5-minute epoxy to each key. Make sure the weights are properly centered.

To remove any red goop that has seeped onto your chassis, I have found the best method is to blast the goo with freeze spray (available from Radio Shack or Fry's). Then, while the stuff is frozen hard and brittle, chip it off with a single-edged razor blade.

And that's it. Have fun.


Here is another topic about the Red Glue problem: Sorting Out Flats JD800 Sticky Key - Red Glue


7 comentários:

  1. Just wanted to post here because it shows up close to the top of google search results - I have had good results with just sodium bicarbonate (baking soda) and vinegar. I just poured it in the part of the keys where the weights sit for a couple of hours until i could remove the weights, and then let both the keys and weights soak in it over night. It dissolved a lot of the glue and the remainder was very easily scraped off. I also found that it would now come off the weights just with hot water.

    It's probably not quite as effective as the sodium hydroxide, but a lot safer and more accessible. Hope that helps someone!

  2. Dear ibbod0. Could you share how much baking soda and how much vinegar? What is the ratio?

  3. hello everybody

    got here through google search results.

    Instead of baking soda with vinegar i used simple washing soda (sodium carbonate).
    Approximately 300 grams on 4 liter of very hot water. Within a couple of hours the epoxy begins to transform into a non sticking jelly-like consistence. Now the weights (those that haven't fallen out already) can be removed easily. Bear in mind that the hotter the solution is the easier the weights will come out.
    Then you should let the weights and keys soak in the solution over night. After that the epoxy leftovers can easily be removed from the keys and weights.
    In general it is the same procedure as described by ibbodo just with a different solvent: sodium carbonate instead of sodium bicarbonate & vinegar.

    There is one important thing that you should bear in mind: DON'T soak the keys and weights in some kind of soap solution until you have removed the "epoxy-jelly".
    In my first test with a few keys i put the parts in a dishwasher detergent solution before removing the "jelliyfied" epoxy.
    It turned out that the detergent somehow transformed the jelly-like epoxy into a stiff and hard consistence which was more difficult to scrape off.

  4. Man this worked great. Got the Lye (NaOH) from the Ace Hardware store.

  5. Man, this worked great. How did you figure out sodium hydroxide or lye? I have a lot of goo (lots and lots) on the flex board and it is fragile. Any suggestions?

  6. The flex board is very fragile, must be carefull with that.
    I remember someone commented about at the JD-800 group, need to search there:


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