Weldwood Plastic Resin Glue

[Matt P]

I was watching David Marks, and he assembled the main pieces of a computer desk using "plastic resin glue." On the same desk, he applied 1/4" walnut edge banding to plywood with yellow wood glue and blue painter's tape to hold it in place.

When is it best to use plastic resin glue, and when best to use yellow wood glue (pva)? I know that plastic resin glue provides a much longer set time, so pieces can be adjusted. E.g. Could I always use plastic resin glue to glue up mitered jewelry boxes? Would it be stronger than yellow wood glue?

tx,
Matt

[Peter Quinn]

I did some research and asked around a while back about weld-wood but have yet to use it. It needs a minimum operating temperature of 70 degrees, so the glue and wood needs to be maintained at or above 70 throughout curing process for proper adhesion. For comparison Titebond III will work down to 55 degrees safely according to their website, and my experience confirms this.

Somewhat careful measuring/mixing are recommended to insure proper strength and apparently environmental conditions like temperature and relative humidity can affect mixing ratio (mixed with water).

It does not have gap filing strength so joints need to be tight and precise, like most adhesives. It creates a bond stronger than the wood like most modern adhesives. It is fairly water resistant, type II I believe. It is a mess to clean up squeeze out and gloves should be worn when using to avoid skin contact as it has some nasty stuff in it (urea formaldehyde I believe) Sanding dust is quite dangerous as well, so a mask must be worn if sanding squeeze out, better option is to clean up before its cured.

It is not recommended for food contact surfaces (cutting boards). At 70 degrees it has roughly 45 minute working time, 12-14 hour clamp time. I'm told that by raising the temp over 100 degrees after clamping the cure time can be cut to 4 hours, and this can be done using an electric blanket.

It is used primarily for complex glue ups requiring long adjustment time and or water resistant properties. It is related to Resorcinol glue, though resorcinol is 100% waterproof suitable for marine submersion applications (below the waterline), and resorcinol is even nastier to work with still.

I am planning to try it this spring on an interior five panel door that is nearly impossible for me to glue up alone with regular PVA (yellow glue). Thus far I have avoided it for all other work due to minimum operating temperature and apparent difficulty of cleanup.

[Mark Singer]

The plastic resin is very good for laminating curves in a vacuum bag and other long time glue ups. Strength is very good. A mitered joint does not have any mechanical qualities for strenth use keys or other splines.

[Bart Leetch]

Weld-wood has held my Dad's 32' roof trusses together for 40 years or more. We used either 1/2" or 5/8" plywood & Senco staples & Weld-wood glue on both sides of the joints of the trusses. 25 years later he decided to use the building for a garage & wanted to sheet rock the ceiling we had to cut & push up the bottom web on one truss about 1/2" to make the whole ceiling flat to hang the sheet rock on.

[glenn bradley]

E.g. Could I always use plastic resin glue to glue up mitered jewelry boxes? Would it be stronger than yellow wood glue?

If my main concern was mitered corners I would key them.

5th-ann-boxes-3.jpg

This can be hidden or decorative. The mess of plastic resins and the concern over the sanding (when dry) and handling of it (when wet) would keep it an "only if absolutely necessary" product in my shop.

[Rich Schneider]

Plastic resin glue is more commonly known as urea formaldehyde glue..DAP seemed to popularize the name Plastic Resin glue...UF is a rigid glue which is why it is nice for bent laminations...

[Jamie Buxton]

I mostly use PVA, and occasionally use urea-formaldehyde. PVA is convenient, quick-setting, and strong. I use PVA for standard joinery, and for veneering. Urea-formaldehyde is a hassle -- you must mix it up. UF is slow-setting, which may be good or bad depending on what you're doing. In a properly prepared joint, UF and PVA are both stronger than the wood surrounding them. I use UF for bent laminations and molded plywood because PVA is said to creep, and UF does not.

[Cliff Rohrabacher]

Resourcinol is not as strong as Titebond. It's a pain to work with, Requires high clamping pressure and has a temperature issue.

I have found that it will set up lower than 70 Degrees F. But it can take more than a week. Longer even. I haven't determined if the bond is weaker when cured at low temperatures it seems about the same but, I haven't done more than tear the joints apart by hand.

It's great for things that are going to experience a lot of heat. It cures in a non-polymer structure - more like a phenolic. All other glues I've used cure up as polymers and all polymers creep when cold and a they literally flow when heated.

[John Hain]

I use plastic resin/UF glue alot actually. I like the long open time and also like the darker color on some projects. My shop sits about 65 degrees year round and I haven't had any problems with curing as far as I can tell. I also haven't had a problem with using it in joints that aren't "super" tight. Someone will probably tell me not to do it -- but I also use it to fill wood defects on darker projects if they are small and I want them hidden. I started with the Weldwood/DAP product and have switched to Urac 185. They both have worked well for me. That said, the only time I use it instead of TBII or III is usually for longer glueups and sometimes for very dark wood when I worry about the glue color showing (rare). Just my opinions.

[scott kinninger]

Well I'm pretty much sick of the glue creep from TB II, so the next time I glue up a table top (or most other things that require more than one board width) I'm going to be glueing it with DAP plastic resin glue. It may take longer to dry and I may have to do the glue-up in a spare bedroom with an electric space heater running, but a year from now I'll be glad I took the extra time and effort.

I've also used plastic resin glue for bent laminations because it is supposed to be more rigid and therefore have less spring back.

[tom ruth]

Plastic resin glue is worth the extra time spent mixing and drying. No creep and it doesn't clog sand paper like some others. Just make sure you get a fresh source, as it only has a shelf life of about a year.

[Chris Padilla]

Tom,

Welcome to Saw Mill Creek as I see this is your first post. Also, note that you are replying to a thread that is almost exactly 7 years old.

[Mel Fulks]

.....but they still make the glue and obviously it still gets good reports! Welcome !

[John Donhowe]

I've also used plastic resin glue for bent laminations because it is supposed to be more rigid and therefore have less spring back.

+1 I had a project with bent laminations- no spring back at all with Weldwood. Not all that difficult to mix or work with.

[John McClanahan]

Tom,

Welcome to Saw Mill Creek as I see this is your first post. Also, note that you are replying to a thread that is almost exactly 7 years old.

Yep, that's a detail thats easy to overlook! Welcome, Tom.


John