Hassles with Urac....am I screwed?

[Eric Krewson]

My friend George was a chemical salesman before he retired so he was interested in the properties of Urac when he started making bows.

He called the tech rep at Nelson to find out more about the stuff. The tech rep said the exact mix of hardener to resin wasn't critical and a wide variance worked just as well as a perfect mix.

[No-sage]

I stopped measuring a while ago too.  If you read their spec sheet (available on their website), they list a bunch of different mixes and cure times and temps.  I've mixed a bunch, so I kind of know what it should be like.

I've had old stuff not bond before, but it didn't bond the second time either.

The time for a full cure did surprise me though, several days IIRC.  I don't work a glue up for a full week now to get a full cure.

[Roy from Pa]

Scoot, ya didn't by any chance mix up yer beer instead of the glue did ya?

[scootsp1]

Haha, nah not that silly Roy!!! lol
Glue up went well last night the Urac cured up fine this time round,but one of my clamps must have let go last night.I have a gap under one of the nodes.
Haha if not one thing it's another!!! I think i just wasn't meant to build this bow! I'm going to treat this bow as a test piece and practice my shaping and tillering techniques. Not going to worry too much if this bow explodes on me,I'll just put it down to experience.

[Roy from Pa]

You need to clamp the heck out of them Scoot.  

 

[horseapple]

Ok heres my take on urac glue, I've only used the volume method, never the weight method when mixing, built hundreds of backed bows and have had zero come apart from urac, also urac is the only glue that I've used and I always use heat to cure, to me its a failsafe glue.

JD

[Flinttim]

Yep, lots of clamps. I made frequent visits to the local Big Lots Store here and kept buying until I had 3  five gallon buckets full of clamps. They might not be optimum clamps for most work but for bow making they are just fine.

[Flinttim]

Hey JD, what ever happened to that great build along you had on a BBo ? The print is there but all the pictures are gone ? That thing was a classic.

[Roy from Pa]

I have never had a bow come apart with URAC either. Used the volume method for years, now I measure it. Only takes a couple of minutes to measure it out, to each their own I guess. I also put the bow in the heat box after glue up. I used to cure my bow limbs at 140 degrees for 2 hours. Then again for 2 hours when I did the riser section. Seems that gave me problems as it was drying out the Bamboo too much, which caused a few splinters in the boo on a few bows. Now I cure the bow at 92 degrees for 2 hours and the glue gets just as hard, but I also let the bow sit for 24 hours at 70 degrees before doing anything else to it. I don't know if it's true that curing wooden bows at high heat makes the glue joint  stronger or hold together better if left in a hot vehicle. Bow's shouldn't be left in hot places anyway. But I recently had a bow splinter up the boo and I tried to remove the boo with a heat gun and I had a heck of a time getting the glue joint to break free. Gave up with the heat gun and cut the boo off.

I love URAC..

[Eric Krewson]

The onlys thing I glue on with regular epoxy are arrow rests, Urac is bullet proof in my opinion.

I like being able to heat a handle and bend it even after it has had multiple parts glued on with Urac. The Urac won't turn loose.

Tim, here is my clamp storage/lay-up/glue up table. This is an old picture, the clamp bar is completely full now.

   

[horseapple]

Hey Tim, lost all the pictures when MSN groups bellied up, I still have a CD with all pictures and captions, funny you can never have to many c-clamps, got 2 bucket fulls myself  

JD

[mullet]

I've never had a problem with Urac except in cold weather or raining non stop. I've just moved it out in the sun and it usually kicks off.
 David, I'm a cheap ba$#&^ also. I've got a can in my refrigerator I forgot when I bought it. Just used it a month ago with no problems.