A question about curing Urac.

[wood carver 2]

I glued up a R/D bamboo backed longbow yesterday using Urac. It has been about 20 hours now and when I went to check up on it I found that I could push my fingernail into the glue that squeezed out. I glued it up in the basement where it's cooler than the rest of the house, but not that cool. It's at least 65 degrees down there, near the minimum for using Urac. The glue I used has been stored in the fridge for a few months, but it looked and smelled ok and I let it warm up to room temp. before mixing it.
Any thoughts? Should I just leave it clamped for another day?
The anicipation of having a bow in the clamps is killing me        
Dave.

[fujimo]

i would leave it clamped, and bring it up into the house, after mom has left for work!!- it does not smell- well at least i cant smell it after a few guinnesses- i glued some up last night, and it was hard after 5 or 6 hours -i just had it in the house where its abvout 18 celcius.

[wood carver 2]

Thanks Wayne. I guess I'd better move it to a warmer place. The only other times I used urac was in the summer when temperature is not a problem.    
Dave.

[wood carver 2]

Well, I got it moved to a warmer room. The temp. in the basement is right on 65 degrees and it says on the can not to use Urac below that. Now I'll leave it another 24 hours just to be safe.
Dave.

[PEARL DRUMS]

I put work lights on mine and it cures hard in a few hours. I have a basement shop that is 63 degrees year round.

[DVSHUNTER]

The thicker the glue joint the longer those cure times get.  The first time I used urac I mixed the whole can for one bbo!  The left over took a LOOONGGG time to cure.  I glued up some things last night in the shop and then remembered that it was going to be below freezing that night so I built a fire and kept it abouve 80 overnight and the squeeze out is still a bit soft.  The handle is completly dry and hard though.  

Thicker = Longer than normal cure times. imo
Leave it clamped.

[jtbluefeather871]

How long after curing can you start to tiller when using urac?

[wood carver 2]

Pearls, I still have to glue up this bows' sister so I'll be adding heat when I do it. I just never thought to check the room temp. first.
DVS, I'm leaving it clamped for another day to be safe plus I moved it up to a warm room.
I also glued up a couple of risers to use up the leftover glue and they cured up ok - but they're just flat glue lines with no tension on them.
Thanks guys.
Dave.

[wood carver 2]

JT, I'm no expert, but once the glue is hard I cut the blank down to size and shape and start tillering. Normally I wait at least 24 hours.  That's about as much as my limited patience can usually stand. This time I'll wait a lot longer.
In my experience as a woodworker, I find that most glues reach 90% or more of their strength after about that time. That is under optimal conditions. My glue up was too cold so it will take longer to cure.
Maybe some more experienced bowyers can add some clarity or correct me if I'm wrong.    
Dave.

[PEARL DRUMS]

If its cured hard through, its ready to work.

[psychmonky]

When I glued up my first, I built sort of a tent with a comforter and put a goose-neck-type desk lamp underneath with a 100w bulb, just to keep the temp up a bit. I was running into the same cool basement problem as you. I left the light on for about 6 hrs and then just let it cure at room temp.

I had to work the next two days, so it was actually clamped for close to 72hrs, but when I uncovered it, the glue was as hard as could be. Definitely cured lol.

[SEMO_HUNTER]

If I do a glue up with Urac in the winter or early spring I build a tent like others have suggested and put a heat lamp on the floor shining up into the tent to provide warmth, then leave it for a long time before working with it. If I do a glue up with Urac when it's warm outside and sunny, I'll carry the whole thing outside to sit in the sun. It cures pretty fast in the direct sunlight. Urac likes to be warm when it cures, not cold. So your basement probably wasn't the best place to leave it to cure. Upstairs in warmer temps would have been a better option.

I've got a hot box now that I can put my glue ups in for curing and I just keep it around 80-90 deg. or so for Urac.

[wood carver 2]

Until it gets warm out, I'll be tenting my glue ups and adding heat.
Dave.

[milehi101]

An important thing when using epoxy is to be sure to mix it well if you dont that will cause it not to cure also

[wood carver 2]

Had that happen before!        
Dave.

[SEMO_HUNTER]

Originally posted by wood carver 2:
Had that happen before!          
Dave.

Me too! It never hurts to add a tad bit more of the hardner (powder) to Urac especially when it's cool, it will only cure faster is all.

[Roy from Pa]

Woodcarver ya need to build a hot box so momma doesn't whoop up on ya:) I cure my bows with urac for 24 hours. I start out at 90 degrees for about 6 hours then cut it back to about 80 degrees till the 24 hours is up.

[fujimo]

hey guys, what adjustable thermostats are you guys using in your hot boxes- i only have the one from binghams that is preset.
i need to change mine out.

[wood carver 2]

Roy, I'm planning to build a hot box but that will have to wait for now. I'm tripping over things in the garage as it is. I'm hoping to move sometime in the near future and one thing on the shopping list is a bigger work space.
I brought my bow upstairs and left it another 24 hours and it cured well.
Semo_Hunter, I read that you could use more powder in the mix - after I did this glue up. next time, I'll add extra powder when it's a bit cold.
Oh Roy, there is no momma to whip my backside.      :(      
Dave.

[Roy from Pa]

Ok Dave, then the dog is gonna whoop ya, lol.