Urac 185 question.

[Prarie Bowyer]

Hi,

I glued up a bow night before last.  Glue is still gummy.  It got kinda cool both nights but the days were warm.  Bow was wrapped up in shrink wrap.  I've done this before and it only took about two dys to dry.  Was it the cool or did I get my mix significantly off (eyeballed it 2:1)?  Will it dry ever?

Thanks,
PB

[Pat B]

How old was your Urac? If older than a year and not stored properly is may be stale and may not set completely.    I always mixed by volumn(2:1) and not weight and never had a problem. Urac cures by chemical reaction so wrapping it in plastic wrap shouldn't be an issue and Urac will cure at room temp over about a 24 hour period.

[Stingray45]

It coulda been old like Pat said and I'm not sure if the cool would have played a part. I haven't used it yet but I just ordered some up to try my first tri-lam but the directions say it has to cure for 24 hours at 70 degrees.

[Josh]

i think it only has a shelf life for a year or so... Mine usually cures in a few hours if I put it in my hot box. I can usually get my hot box up to 100 degrees or so with just 2 100 watt bulbs.    I have glued one up and tillered it all the way out in the same day with fresh Urac before even though I wouldn't really reccommend doing it.  I just got a little impatient that day but it worked.   

[Prarie Bowyer]

It's about 3 weeks old and the liquid has been kept refirgerated.  I generaly cook bows in my car which gets full sun.  But the night got pretty cool.  I checked it a bit ago and some parts are more solid now.  I'm wondering if my measurements were considerably off or if it was the cool.  the instructions say that no curing goes on below 65* I think.  Maybe it's 55*.  Need to double check that.  I poked several holes in the wrapping for what ever good it will do.

I had a poser lam in the bow and It turns out that my clamp shifted in the night.  One side is pretty gappy.  How do you get that joint clean?  I think I can just fill it and use the bow if it comes out.  Hoping to do better on the next one.

[Prarie Bowyer]

Yea, end of the third day and some areas are still gummy.  However I was able to clamp that gap spot and take the heat gun to it to close it up.  funny thing.  Those parts solidified afterwards.  I'm wondering if the temp has more to do with it than anything?

[mikekeswick]

You've had it for 3c weeks but how long had it sat on the shelf of the shop....! Some places you can trust some you can't....
I would say the temperature is the problem - most glues don't like the cold. If you don't have a hot box get yourself some G2 boat building epoxy as this stuff will still give a great bond in the cold, you just have to leave it long enough.
Your heatgun fix sounds risky to me...but you only learn whats posssible by trying!

[Prarie Bowyer]

Well the hickory was cheap (swallow ) and the bamboo might be reclaimable if it goes badly.

[Mark Smeltzer]

Could be either or both of the reasons the guys mentioned.  When I want to save left over glue i put it in the fridge and I have have a can go bad from keeping it too long.
Mark

[Jboyd]

only had one failure with urac and I guess it was old , I had kept it in the frig but it was on
a splice on a set of slats.  It never set up and it was hot during the summer time.

Jamie

[Prarie Bowyer]

Otherwise I think I like Urac as compared to what I was using.  A thinner epoxy system that is crystal clear.  I wish Urac were less tinted but it's easier to see where you have glue and it dosen't run all over the place as easily.

[Prarie Bowyer]

Took the bow out of the form today.   Which meant unwrapping all the rubber clamps.  I had a considerable amount of squeze out.  then my boo lam delaminated in the center.  I think because I didn't glue the riser right on and thus the bow began to try to go straight.  I took a heat gun and melted the glue to remove the backing.

So, I had a considerable amount of squeze out in some areas.  I make sure I get glue in every single milimeter of BOTH glued surfaces.  Yet some areas were nearly dry.  Strange I thought.

I discovered that I don't need the power lam if I cut the riser into the limb fades.  So what I did was to clamp just the bow body into the form and use a heat gun to heat up the thick part (center) pretty thoroughly and let it cool over night like that.  Then I'll use it as the template while on the form to cut the riser block curve.

My other hickory R/D bamboo backed bow was much shallower but came out fine.   The car got hotter.  I'm wondering if Urac really needs heat to cure properly.  When it's truly dry it's like glass hard.  But on this bow it was dissapointing to say the least.  I like the consistancy, and the color I guess.  I'm ok with the refrigeration of the glue component.  But I need to pin down what caused teh bad set.  The next glue up I'll make the bow spend the night in the house by the boiler.  Or break down and make my oven.