[pianotech] Glue study-Tight bond 50 and Assembly 65 PVA

[Dale Erwin]

   Hey all
  Last month there was a discussion fueled by Doug Greggs  wanting to know about what was in the PVA glue sold under the Bolduc name by Piano -tech. Well... Its a PVA which stand for poly vinyl acetate. If y'all recall,  that glue was my glue of choice for Bridge caps, hammers hanging, making soundboard panels (edge gluing), gluing on ribs and gluing the board in the case etc.. The problem is, we couldn't get it for 4 months in the winter because its not freeze thaw stable(see MSDS sheets) Changes chemically. So I needed a viable all weather alternative.
  Ron N made some comments about doing some research & I did. 
  At his suggestion I went to the Franklin Glue site and did some research on aaaalll their product line. ..So many, that its a bit confusing as to the properties they possess.  
    I ended up talking to their glue expert, Barry, who has been studying this stuff for 25 years said, that" how glue is made,... is amazing and confusing"
     I relayed my satisfaction with the PVA glue used previously & explained to him what we were using it for. We discussed clamp pressure and applications. After splaining it all to me he steered me strongly to the tight bond 50,  an aliphatic resin glue (whatever that means). He said it was by far the strongest of the tight bond family and can also be used in radio frequency applications. It has a light creamy color.
 I wanted to try the their "Assembly 65" Pva as a replacement to the Bolduc glue . He convinced me that the tight bond 50 was the glue that would best meet my application. It is freeze thaw stable though the MSDS sheet says it isn't. 
   Barry said, if it freezes, it doesn't change chemically, but it may dehydrate a bit. Just add a small amount of water if its too thick. Sounds like a great solution for a multitude year round glue up applications in our small shops

  Dennis & I set up some test pieces for simulating bridge cap drilling. We tested the T.B. 50, the Assembly 65 and the Bolduc on pieces of hard maple glued together.
 After drying overnight we drilled all three and all three drilled beautifully with no build up in the flutes. I had some dried droplets of the 50 left over on the bench top so I placed it on the vice anvil and tapped it with a hammer.  Its as hard as hide glue. Perhaps they were trying to mimic the properties of hide glue. That would be desirable.

 Also I used both glues to hang 2 different sets of hammers and both are really good for this. The 50 had a slightly longer working time. I would use either depending on the hammer bore to shank fit. The solids and consistency of texture is about the same as the other PVA from P-Tek

 The last two days I was making soundboard panel blanks for clients. The first one I glued up with the T.B. 50 was a B panel, & its important to get the glue on quickly, get it clamped and then tweak the planks for level. This glue excelled.  It has a slightly longer working time than the Bolduc which is very desirable and the stuff dries hard over night. After the blanks went thru the panels sander the glue joint were invisible just as with the PVAs
  Today I glued up a M board for a client and used the 65. The set time is too fast and it allowed almost zero time to tweak the planks for level. The temp both days approx 75 degrees.

   The T.B. 50 or the Assembly 65  are NOT sold in small quantities in the local craft or hardware store. The short story is I had to buy 5 gallons. It has a 6 to 8 month shelf life depending on how it  is stored. So I bought plastic quart containers and if you'd like to take some off my hands it can be purchased for 10.00 per quart plus shipping. Thats HALF the price of the Piano-tek product.    Please take some off my hands.... :)
 I will probably carry the Assembly 65 PVA as well if there is interest from enough of you.
   I can get that by the gallon and for approx. the same price as the T.B. 50

The conclusions for me are that there are many types of wood glues out there that will work for many of our purposes but I like what I'm seeing so far.
 Its a sticky wicket out there
Dale


Dale Erwin RPT-
 Mason & Hamlin/Steinway/U.S pianos
Pre-hung Ronsen hammer sets/Abel parts
Sitka Soundboards & Supplies
WWW.Erwinspiano.com
209-577-8397

 
  



 
 
 
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