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backwoodsmark
01-14-2014, 09:53 PM
Hi folks, I wondered if anyone uses dap's weldwood plastic resin glue for instruments? I was using luthiers merc. white glue and its great but it can easily get frozen during shipping here to Montana. I had used titebond for years but when I started putting on z-poxy then lacquer finishes the finish sinks into the titebond. The weldwood I could buy localy. I don't know if the weldwood dries completely hard like the lmii glue. any thoughts on this stuff?

Michael N.
01-15-2014, 01:45 AM
It should dry a lot harder than LMI glue, that's if LMI is a PVA. The Weldwood is a powdered resin glue (ureaformaldehyde), sometimes known as the boatbuilders glue or Cascamite/Extramite here in the UK. It comes as a powder and is mixed with water. It dries glass hard. It's not reversible. Nothing touches it, even extreme heat. I used to glue purflings with the stuff and then bend them on a hot iron. They never, ever gave way. You can char the wood and the glue will still hold.
I wouldn't use it on an instrument that I thought might need repairing sometime in it's life. That means virtually any instrument of value.
I can see PVA/Titebond being problematic in Montana. I'm fairly certain that those types of glue are supposed to be stored above a certain temperature - but then again there must be thousands of woodworkers using PVA in states that are very cold/Canada. Alternately look at using Hide glue. It's virtually the only glue that I've been using for over 20 years.

Chris_H
01-15-2014, 11:19 AM
Hi folks, I wondered if anyone uses dap's weldwood plastic resin glue for instruments? I was using luthiers merc. white glue and its great but it can easily get frozen during shipping here to Montana. I had used titebond for years but when I started putting on z-poxy then lacquer finishes the finish sinks into the titebond. The weldwood I could buy localy. I don't know if the weldwood dries completely hard like the lmii glue. any thoughts on this stuff?

are your joints tight? If they are there shouldn't be any problems. If there are glue lines I would work on tighter joints before switching glues.

Kayak Jim
01-15-2014, 01:37 PM
I use UF resin for bent laminations where I need long open time and no springback. As Michael said, it makes a very hard glue line. Can't see the need for instrument building. There is a load of furniture made with PVA glue (or hide glue), yes even in Canada, and all kinds of finish applied with no problems.

Moore Bettah Ukuleles
01-15-2014, 04:20 PM
If I'm not mistaken James Goodall uses (used) this glue for gluing purflings to bindings prior to bending. Sheets of b/w/b would be laminated onto sheets of ebony or whatever, then cut to make binding strips with purflings attached. I think it's a great use for this glue in this case as the glue survives the heat bender very well.

Tarhead
01-15-2014, 08:04 PM
Weldwood has a shelf life of one year from manufacture. The container has a sticker with a 7 digit code. Ignore the first 3 digits. The 4th digit is the year and the 5th-7th digits are the Julian day. It becomes gritty and doesn't set up in a smooth consistency when it's too old. The 4 hour pot life at 70F is another consideration. You're not going to use very much per build session so you'll have some waste and it's not cheap.

I would be using hot hide glue. Make up a small batch in a small squeeze bottle (ask your Pharmacist for one) like pediatric antibiotics come in. Heat it in a hot water bath. I use a baby bottle warmer...~$5.00 at a kids consignment shop or on Craigslist. Store the leftovers in the freezer between builds.

backwoodsmark
01-17-2014, 06:59 PM
about the cold weather I was referring to the shipping. The glue has to be shipped in the back of a ups or fed ex truck across the rocky mtns. Lmi recommends waiting for warmer weather to order. I did read an article somewhere about the possibility of lacquer sinking into titebond glue. cant find it now of course. I was trying to find a substitute for the lmi glue that was available locally. I sure put a lot of work into the glue joints. I've built 47 guitars, 6 mandolins and 4 ukulele's. It seems the shrinking or sinking is so perfectly even all around the instrument, the binding,purfling, end graft, soundhole inlay. I must have gotten the joints to go together somewhere. Just thinking.