Hi all,
I’m servicing an Alesis QS8, and while the keys all work, I’ve noticed that a lot of the plastic parts of the weights are cracked on one side and will probably fail eventually. (Makes one think of late 90s Rolands, right?)
What type of plastic is used here, and is there a cement that I can apply to the cracks to bond the plastic together? It’s not ABS, since it’s flexible. I’ve heard people mention nylon…?
And… has anyone actually managed to repair Roland weights, or do we have to continue buying them on eBay from Turkey?
I’m giving this product a try: J-B Weld SuperWeld Light Activated glue. It’s a CA glue that cures when you shine the little UV LED light at it for a few seconds, which is handy as it means I can put the part down after gluing it! I’m using it to fill and cover the cracks in the plastic parts of the hammers of this QS8, and I think it’ll work to stabilize those cracks. I also had a broken Roland hammer lying around and used the glue, with great results: that metal head isn’t going to come off any time soon!
I put a blob of the glue onto a non-broken section of the plastic, and cured it with the light. I was able to peel it off, so the bond isn’t super strong. I think the plastic is probably polyethylene, which is notorious for being hard to glue. But I think the mechanical hardness of this glue when set will go a long way to preventing the cracks from getting worse, especially as in most cases the crack goes down to the metal component, to which the glue should bond really well.
For this QS8… I’ve inspected 48 hammers so far. Every one has cracks in the plastic.
I not long ago repaired a Roland Digital piano which had the same issue.
First used superfic to glue the metal weights to the hammers, this kept the 2 parts together.
Then used 5min 2 part epoxy to coat the area and into the cracks.
Once dried had to give a light sand so the hammer weight end would fit back through the slot.
Worked a treat keys all weighed within in grams of eachother.
My daughter now has a fully functioning digital piano for 10$ initial purchase and about 50$ worth of epoxy.
Threw in my time for free
light weight cyanacrolate glues need to absorb into the materials for it hold at its maximum strength, They do not absorb into abs plastics (such as keys) and lead weights, instead it sits on the surface and does not have its full strength. Hard knocks can crack and separate those parts.
Use a 2 part epoxy and sand and isopropyl alcohol the areas to be glued, works the best. it does not take gobs of epoxy to work. It is a heavier glue so some feel it might throw off the keys balance, That’s why I say it does not take gobs if it to work. It can be used thinly on a prepared surface as described.
