Hey guys,glued up a bamboo back bow last night with Urac 185.I checked it this morning and the squeeze out is still really tacky.The temp dropped here last night and I'm thinking that could be the cause of my problems.How long should it normally take to cure a room temp?
This is my first bamboo backed bow and my first time using Urac.
Has anybody had similar experiences with Urac?
Starting to wish I had of just used Titebond!!
Any help or advice would be greatly appreciated.
Cheers
James
should still be ok once it sets. i always use a hot box with urac. You can let it set at room temp, but it takes forever (24 hrs) and is not as strong.
You could place it over or near some heat source to cook it a bit. I've placed Urac glued bows over the heating vents in my house and draped a blanket over the whole thing to hold in the heat. Worked pretty well.
Thanks for the fast replies fella,I haven't made a heat box yet.I was hoping that it'd eventually cure.Can't get out to get the stuff to make one either,I've only got a motorbike and Melbourne is experiencing some pretty wild weather.Yesterday we had hail the size of cricket balls(about the size of a baseball!!lol)and today it's blowing a gail!!
It's a public holiday today here aswell and I'm stuck at home!!
I have built a heat wrap using wires for some structure, foil for reflecting heat and sleeping bags for insulation and heated it with a couple shop lights to cure URAC in a cold shop. It worked well.
The Bow will be fine, let it sit for another day. Take it inside where it is warmer. Urac is good stuff.
Thanks Roy,that's exactly what I've done.I think i was just stressed that I'd screwed up somewhere along the way.That and I'm anxious to see how it's turned out!
I know the feeling. So does my liver:) LOL
Haha nice one Roy!!lol
Nope must have screwed something up along the way.
just checked on it after 24hrs and the squeeze out was still tacky.
I must have screwed up the ratio or the temp was just too cold.....
Gonna clean up my stave and give it a go later in the week when the weather is gonna be alot warmer.
Oh well ya live and learn
Put a tent over it and put a 100W bulb under your tent. I can maintain 90 degrees under my tent in 30 degree weather.
It does sound like you mixed your Urac wrong. I bring handle glue-up in the house and cure overnight at the 70 degree temperature in the house, hard as a rock the next morning.
Here is my tent(yard sale comforter) thrown over a BBO glue up.
(http://img.photobucket.com/albums/v181/ekrewson/bow%20making/cookingabbotent.jpg)
Are you sure the URAC wasn't past its shelf life? That's what happens when it is bad. Did it stink?
Thanks for the idea Eric,I'll look into it.
The Urac was brand new,I got it from 3 Rivers about a week ago.I'm pretty sure it was me screwing the ratio up.
I scraped of all the un-cured glue of my bamboo and Spotted gum last night and I'll try again tonight.
Thanks everyone for your help!!
Good luck on this go round. Lets see it when it's done
How long did 3 Rivers have it though? There should be a date on it.
Do you mix the URAC by weight or volume? Volume is a guessing game, I like to weigh my URAC out on a scale. Little tip on buying URAC here. You can buy it direct from the factory for less than half the price you can other places, and it's fresh..
http://nelsonpaint.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=UA
I just checked on the can and the bag of hardener and neither have a used by date on them.
I'am going to try again after dinner with a make shift heating rig with a few halogen shop lights.We'll see how I go this time around.Going to be a lot more precise with the ratio.
Fingers crossed for a better out come!!
Oh I found out about buying direct after I'd already bought it from 3 rivers.
I've never had Urac with a date on it. A code , maybe , but without knowing the secret to the code it's useless. I always date mine once I get it, that helps some.My best guess is you messed up the mix. If you don't have a scale, wait till you can borrow one or buy one. Don't use volume measure. It's not precise enough.I put the parts in small paper cups that I have zeroed out on the scales. I generally use "grains" for small batches. It's more precise for the weighing.. Once weighed up I mix the two and get busy. I set my glue up on a rack along my wall right above the baseboard heater. No problems.I believe it does say on the can to not mix below60 deg or something.
You could also heat it up with a blow dryer and let it set, this should kick off the curing.
I mix by volume and seem to be able to get away with not very precise measures. 2:1 by volume. I've also use glue up to 2 1/2 years old (stored in the fridge) without incident. Not the recommended, but I'm a cheap bastid and got away with it.
I think you need at least 70 degree F or better for the mix up and the whole cure period, up to 24 hours. When in doubt mix up a small batch, stick two pieces of whatever together and then put it somewhere warm for a spell. No point risking the materials and effort required to get a full bow glue up going when it's easy enough to proof the glue first.
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.
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.
Scoot, ya didn't by any chance mix up yer beer instead of the glue did ya? :)
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.
You need to clamp the heck out of them Scoot.
(http://i47.photobucket.com/albums/f165/ROY-CHRIS/IMG_5419.jpg)
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
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.
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.
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..
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.
(http://img.photobucket.com/albums/v181/ekrewson/100_0022.jpg)
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
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.