Replies

1. 
   Jamie_Buxton | Jun 09, 2003 04:02am | #1

   That is the product name for a urea-formaldehyde glue sold by DAP under the Weldwood brand.  Urea-formaldehyde is used in bent laminations because it does not cold-creep, unlike the common yellow glue.   Online, one source is http://www.thehardwarehut.com.

   
   

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   Edited 6/8/2003 9:05:59 PM ET by JAMIE_BUXTON

1. 
   Kevin | Jun 09, 2003 07:16am | #2

   What do you mean by "cold-creep"?

   Regards,

   Kevin

1. 
   Jamie_Buxton | Jun 09, 2003 07:59am | #3

   A few solid materials slowly deform if kept under constant strain.  That's cold-creep.  Yellow glue has a reputation for cold-creeping.  The glue line in a bent lamination is subject to constant strain.  If the glue cold-creeps, the lamination's shape will change, and at worst the glued joints will fail.   The usual fix is to use a glue that doesn't cold-creep.   Wood glues that don't cold-creep are urea-formaldehyde, epoxy, and hide glue.

1. 
   Kevin | Jun 09, 2003 08:09am | #4

   That makes sense. Thanks for the explanation. I keyed on the word "cold" because my employer is doing part of a multi-agency visitors center inside the Arctic Circle in Alaska. Because of the extreme temperature changes none of my paint/finish suppliers wanted to go out on a limb and say that any given product would for sure withstand the temperature swings from summer to winter. So, anyway... I wanted to make sure what you were describing wasn't something related to extreme cold temperatures.

   Regards,

   Kevin

2. 
   AlanTurner | Jun 09, 2003 04:25pm | #5

   VAcuum Pressing, out of Maine, sells Unibond 800, which is a 2 part, urea resin glue.  It has no water in it.  It dries by chemical reaction insrtead of evaporation, so it will cure in a vacuum press.  It is quite waterproof, non-creep, gap filling, and tintable.  I love this stuff, and use it for things well beyond vacuum bag operations, which called for.

   I glued up the top of my workbench with it because I didn't want to be feeling a glue line someday, and because it has a longer open time.  It can be worked like wood since it is brittle when dry.  Won't melt in a drum sander or planer.  I don't think it is hard on knives, either.  Daryl Keil (SP?) is a real gentleman to deal with.  Very knowledgable and quite willing to chat it up a bit to help others.

1. 
   Jamie_Buxton | Jun 09, 2003 08:52pm | #8

   s4s, are you sure there is no water in Unibond 800?  I agree that it cures by chemical reaction, not evaporation, but that doesn't prove there's no water in it.  Other urea-formaldehyde glues are distributed as powders which you mix with water, so it is possible for urea-formaldehyde glues to include water.  I ask because I've seen thin wood bow when I put Unibond 800 on it, just like it would behave with yellow glue.

1. 
   AlanTurner | Jun 09, 2003 09:32pm | #9

   In the context of shopping for a vacuum system, I disucssed with Daryl the differences between Unibond 800, his formulation, and the Unibond 2000.  The difference, he explained, was that there was water in the 2000, but not in his.  If I recall correctly, the 2000 is  aa powder, mixed with water.  His is the liquid resin, and a powder.  This is all I know on the point, but a call to Darly might be informative.  I am certainly no adhesives pro, I would be the first to admit.

3. 
   HowardAcheson | Jun 09, 2003 06:18pm | #6

   Either the Unibond 800 or the DAP/Weldwood Plastic Resin would be the adhesives of choice. They are both urea formaldehyde adhesives. However, both can be somewhat hard to get these days unless you know of an industrial distributor. Some Home Depots stock the DAP/Weldwood product.

4. 
   Quickstep | Jun 09, 2003 06:23pm | #7

   I believe polyurethane glue (like Gorilla glue) is also resistent to creep. I've used it for laminations before and liked it because it cleans up easily and since in a lamination, glue goes everywhere, this is a big plus. It's also easire on tools if you have to do any subsequent planing etc. Even though it foams to fill a gap, it has little or no strength in the gap, so be careful of that.

1. 
   HowardAcheson | Jun 10, 2003 05:54am | #11

   Here's why I don't like poly glue for laminations. When it cures, it expands forcing the surfaces apart. As a consequence, any joint glued with poly glue needs to be firmly clamped along its whole length. With some laminations, it can be difficult to get it clamped correctly.

5. 
   alias | Jun 10, 2003 04:25am | #10

   jim- i just laminated these ellipse's with 4 -3/16's soft maple w/ the dap urea formaldahyde was pretty easy. but DO NOT starve the glue joint. i paint the glue on let it sit 5-7 minutes then assembled. be generous and allow for spring back with tightning up the radius some . i'm sure this radius is not as tight as yours, so gauge accordingly. with thickness and more laminations. have fun... bear