Author Topic: Bending ambient cured smooth on  (Read 1930 times)

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Offline Eric Krewson

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Bending ambient cured smooth on
« on: October 19, 2017, 10:46:03 am »
I glued up a BBO with smooth on and have a slight string/handle alignment problem, this is the first glue-up I have used smooth on.

I could bend a handle glued on with Urac with no problems with the glue turning loose but don't know about smooth on.

Any of you guys do a little heat correcting on a bow glued up with smooth on and had the glue turn loose?

Offline leonwood

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Re: Bending ambient cured smooth on
« Reply #1 on: October 19, 2017, 12:46:33 pm »
I tried it once on a tri lam elb, slowly with the lowest setting. Had both gluelines separate at the handle :-[

Offline Dances with squirrels

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Re: Bending ambient cured smooth on
« Reply #2 on: October 19, 2017, 01:33:04 pm »
Eric, I've made a couple dozen heat corrections on bbo's and trilams. All were glued up with Smooth On. I've cured most of them with heat, but done several at room temperature back in the day. To be honest I can't be positive any I've adjusted the alignment on were room temp ones... but I've never had one delaminate... knock on wood.

I should add, when I make corrections on such bows, I study it in depth to determine where it actually needs corrected. Usually it's one limb or the other that strayed, so I prop it up solidly sideways in the vice, hang a weight from the tip, measure to the floor, then slowly heat all sides of the limb for its full length (or wherever it needs it most). It will gradually bend toward the floor as the heat affects the wood and glue joints. When it goes far enough, I stop heating it, prop it there, and let it cool... then remove it. I have used a gallon of water, or an 8 lb sledge with an eye bolt and S-hook in the end of the handle for a weight, hung from the limb tip.... or wherever, to make the correction you need. I like to stand a big sturdy tape measure up on the floor, locked in position, with the end of the tape positioned against the bow's limb tip, to indicate how far the limb is moving. With it as a reference, once you get the limb warm enough, you can watch it start to move. Then you can stop precisely when you need to without overheating or damaging the bow.... Maybe part of the reason I've never had one delaminate. Works for selfbows and such too.

Dean got me rolling on this technique.
Straight wood may make a better bow, but crooked wood makes a better bowyer

Offline Dances with squirrels

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Re: Bending ambient cured smooth on
« Reply #3 on: October 19, 2017, 01:47:22 pm »
Sometimes a bow needs a limb twist correction, or both a limb twist/alignment correction made.... say in a pronounced d/r trilam. In such cases, I may position it in the vice as above, then clamp a pipe clamp or bar clamp to the limb, padded of course, and then hang the weight from the pipe or bar. The farther you move the weight away from the limb, the more leverage it has. This too can be propped where needed and measured with the 'standing tape measure' to affect and indicate the needed changes. I don't know how well I'm describing this stuff. Can post pics if it'll help.

If you can heat the entire limb, I would consider that.... especially since this bow was a room temp cure. That way less heat is needed per inch to affect the same degree of tip movement, which should mean less chance of delamination.
Straight wood may make a better bow, but crooked wood makes a better bowyer

Offline Eric Krewson

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Re: Bending ambient cured smooth on
« Reply #4 on: October 19, 2017, 03:47:46 pm »
I got the string aligned by reducing the strong side a little.

I shot the bow a bunch today and really need to toast the limbs as the bow is a bit sluggish and I missed poundage by about 4#. I used beautiful osage but it was very light weight, not the hard, dense stuff I usually use for a BBO. I didn't realize how light it was until I cut and spliced the billets.

Anybody toast limbs glued up with smooth on? I usually give this type of bow a superficial toasting.

Offline Dances with squirrels

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Re: Bending ambient cured smooth on
« Reply #5 on: October 19, 2017, 04:41:40 pm »
Not me.
Straight wood may make a better bow, but crooked wood makes a better bowyer

Offline sleek

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Re: Bending ambient cured smooth on
« Reply #6 on: October 19, 2017, 05:29:22 pm »
I have done it with tight bond 3. I used a wet rag over the back to keep things cool, and did it quick as I could. I didnt want a deep heat soak to affect the glue. Then after i turnded the bow belly up ( heat rises ) and put a damp rag on it wiping it to cool it off asap, to keep tje heat from soaking further.
Tread softly and carry a bent stick.

Dont seek your happiness through the approval of others

Offline PatM

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Re: Bending ambient cured smooth on
« Reply #7 on: October 19, 2017, 07:34:39 pm »
Apparently Epoxy can be post cured at any time. You just need to re-clamp it if you try that.

mikekeswick

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Re: Bending ambient cured smooth on
« Reply #8 on: October 20, 2017, 02:53:17 am »
I use the same method for removing twist/sideways bends as above.
I would make a small hot box to cure EA40 as it's properties are greatly improved by a heat cure.
Send Smooth-On an email they are very helpful and get the datasheet at the same time.
No way would I attempt to heat treat a lam bow...sure you could probably change the colour of the belly but not enough for a proper heat treatment.

Offline BowEd

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Re: Bending ambient cured smooth on
« Reply #9 on: October 20, 2017, 09:16:55 am »
Yes the comments by DWS & mike sound good but I would never try to heat treat the belly of a smooth on laminated bow because I run the temp clear up to 350 to 400 degrees slowly for the best treatment.Sadly that stuff should of been done prior to glue up.
BowEd
You got to stand for something or you'll fall for anything.
Ed

Offline Eric Krewson

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Re: Bending ambient cured smooth on
« Reply #10 on: October 20, 2017, 01:49:18 pm »
It is rare for me to have a poor performer when I make a BBO, this one is. The last poor shooting BBO I made was glued up with Urac, I heat treated the belly and turned a dog of a shooter into a rocket launcher. I have made over 50 BBOs but never used smooth on before. Looking back, I agree I should have heat treated before glue-up but I wasn't expecting a sluggish bow.

I have a lot more of the same wood so it will get heat treated before I glue up next time.

Offline Badger

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Re: Bending ambient cured smooth on
« Reply #11 on: October 20, 2017, 06:43:43 pm »
   Eric, sluggish bows happen now and then, did you figure out why it was sluggish? Too much set? Moisture?

Offline Eric Krewson

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Re: Bending ambient cured smooth on
« Reply #12 on: October 21, 2017, 07:37:17 am »
Very light weight, soft osage, not the hard, dense stuff I usually use. I suspected it would be whimpy but thought the bamboo would even things out.

All from this tree I salvaged from a road right of way with permission from the city office;



Beautiful wood and I have a lot of it;



This is the only tree that I owned a tractor to assist me with the loading and the last osage tree I will ever cut (too old and too busted up from injuries). I sure wish I owned it when I was cutting the 40 or 50 other osage trees that made up my stash and wrestling the logs to my truck or on a trailer by hand.

« Last Edit: October 21, 2017, 07:54:51 am by Eric Krewson »