Primitive Archer
Main Discussion Area => Bows => Topic started by: DLH on September 08, 2013, 11:26:14 am
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Got around to removing some twist yesterday and I thought everything had went well. I had been given advice to use a caul and it worked great. I forgot one crucial detail didn't seal the back before I started. The stupid part is that I have read multiple times where everyone recommends to seal the back before any corrections. Guess some things are learned the hard way by making the mistake yourself. I'm just going to load the crack with super glue and seal the back before anymore corrections.
(http://i1120.photobucket.com/albums/l491/dnl17694/10C09482-74EB-4961-A6DA-0134B25ABD66-1112-000000F1CC7DEB86_zps4d9d6f98.jpg) (http://s1120.photobucket.com/user/dnl17694/media/10C09482-74EB-4961-A6DA-0134B25ABD66-1112-000000F1CC7DEB86_zps4d9d6f98.jpg.html)
Thanks,
Daniel
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What do you mean by seal the back? I've never heard of doing this before and have never had a problem?
Jon
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What do you mean by seal the back? I've never heard of doing this before and have never had a problem?
Jon
Probably like how you seal the ends on a stave when you cut it
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If your stave was dry & cured(osage) bein sealed wouldnt matter IMO.. I scrape all of off usually by this point in my build.... Most likely what you have here is caused by forcing it without enuff heat.. could have been a crack already there that just showed itself under pressure also...
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.....or it could have had a tad too much moisture in it too
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I always seal a newly exposed back no matter how well seasoned it is and especially if I am going to make coorrections with heat. I use spray shellac because vI can easily remove it if necessary or just add a finish over it.
Fill the crack with super glue like you said. Scrape the excess off the surface after it is cured out and seal the back.
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I always seal a newly exposed back no matter how well seasoned it is and especially if I am going to make coorrections with heat. I use spray shellac because vI can easily remove it if necessary or just add a finish over it.
Fill the crack with super glue like you said. Scrape the excess off the surface after it is cured out and seal the back.
What is the point though Pat? If the stave is well cured, what does sealing the back do? Just curious.
Jon
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Jon, I've had well cured staves(some 10 years in my shop) check when I exposed a new back. Even a well cured stave exchanges atmospheric moisture as the R/H changes. Apparently that is enough moisture to cause a check as it dries.
It is so easy to spray a quick coating of shellac on a bow back and just as easy to wipe it off with alcohol and a rag if I want to that it is not worth the risk on having a bow stave check. I keep a spray can of Birdeye Shellac on my work bench at all times just for this. If I want to shorten a stave I spray shellav on that newly exposed end too. Do I need to? Who knows...but I do anyway because it has saved a few staves or extra work chasing another ring over the years.
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Its another level of protection and prolly not a bad idea to boot ;)... Only reason i scrape mine off is i just seal with cheap school glue and it makes a gummy mess when it gets hot, lol... I am gonna get some of that Pat... I dint know it could be removed that easily ;D
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If you are buying a stave, Pat's can of shellac on the bench is cheap insurance. For those uf us that are a 12 hr drive from osage, it's money well spent.
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I've never sealed a back and never had one crack like that and it's a thousand degrees down here all year. I concur with Blackhawk, I think it still had moisture in it. Anyway, it still won't hurt anything.
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I always have my wood's MC down low to begin with so I don't seal my backs either. Bet that check was already there and the heat shrunk the wood around it causing it to open up.............Art B
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And from the looks of the check, it isn't headed anywhere I'd worry about. Pretty much right down the middle of the limb. Appears also, that you carefully followed the grain of the wood. Good for you! To me it would rate up there some where between "who cares" and "so what".
Sic 'em Daniel, show that stave who's boss!
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It may have been moisture but I'm not sure I don't have enough experience yet. This is black locust that was destined to be fence posts and set in a barn for years but that's a guess I had them atleast a year before getting to this point. I also have had it inside reduced to this point for atleast two months now. Am I looking for a color change for corrections or more too hot to the touch? I had it start to change color and was afraid of getting too hot so I tried the clamps at that point.
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That stave checked because it had to much moisture in it.
All this talk of staves being ten/twenty/thirty years old don't mean anything if the combination of temperature and relative humidity where the wood is stored aren't hot enough/low enough then the wood will never get to a low enough m.c. to become a bow!
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Every bow maker should have a copy of this....store it in your favourites!!!! Use it and bingo...no checks!
http://www.csgnetwork.com/emctablecalc.html
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Yep, or to heat gun it without checking.
Seasoned and dry don't necessarily mean the same thing.
I love my shellac, but once a piece of wood is dry, I don't reapply it.
You should not have to change the color of the wood to get it hot enough to bend.
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Fill it with super glue and proceed Daniel, you're still good. If you want, bring it up to Scottsburg and work on it there .
Tracy
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I'm with Pat,ya it probably had some moisture but sometimes it's hard to tell even
on a seasoned stave,so for me it ant worth the chance,I mean really how much trouble is it to seal it , 5 minutes and a little time to dry,and then it is very unlikely you will have a problem with checking. :) JMO I have found that a little prevention with selfbow building is worth the time,if you think their might be a problem try and do something to prevent it before it really is a problem. ;) :)
Pappy
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It was probably still wet. Takes sometime for wood to loose moisture unaided.
I never seal a whitewood just osage and BL.
Looks like the crack is with the grain and that should be fine. Superglue it and clamp it.
Jawge
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Every bow maker should have a copy of this....store it in your favourites!!!! Use it and bingo...no checks!
http://www.csgnetwork.com/emctablecalc.html
I'm a little thick this morning, can you explain how to use this???
Don
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Every bow maker should have a copy of this....store it in your favourites!!!! Use it and bingo...no checks!
http://www.csgnetwork.com/emctablecalc.html
I'm a little thick this morning, can you explain how to use this???
Don
Seems to me this would be most accurate when kept regulated indoors since an unregulated and uninsulated garage/workshop changes constantly as day and night and weather changes. Say I kept my stave in my house where the temp is 72F and humidity is 20% I could expect the moisture content of that stave to equalize around 4.5% using the chart. At the same time if I kept it in my garage where the temp is 100F and 80% humidity in the summer it would equalize are 15.1% moisture content. For more precise calculations you can feed your humidity and temp into the calculator. I had been storing the stave I'm working on in my garage but lately I've had it in the house when I'm not working on it.
I hope I explained that in a coherent manner. Sometimes things make more sense in my head than the do in words.
And @ Mike- Am I right about a unregulated garage/workshop stored wood?
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I think your on the right path there Marks.I've never had the supposed problem of the subject of this thread because I'll bring my roughed out bows inside where I keep it 45 to 55 % humidity at 75 to 80 degrees F for at least three weeks before I start to work on them.Especially if I know I'm going to heat treat the bow.Done lots & lots of bows that way too.One of these days I'm gonna make a hot box.
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And is there an ideal EMC for all woods or does it vary?
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Another question. How does this stop checking? I was under the impression that checking was caused by drying too fast.
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Thanks for the replies everyone been a lot of help moving forward. About how long would be a good time to bring it inside after its been roughed out before heating to be on the safe side? Assuming its dried atleast a year outside? Is this too relative of a question? What should I do from here leave it inside and put it on hold for now?
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Yes DC checking is caused by the outside surface of wood shrinking too fast for the inner wood to keep up.If the wood is the same moisture throughout the thickness it won't check.If you get the wood say below 15% at least you can hurry it with a hotbox.
I find that out by weighing the roughed out bow at a certain controlled temp and humidity untill it quits losing weight for at least a third of the time that I started weighing it.It'll take as long as it takeswhich is usually for sure in 4 to 5 weeks.You can put a fan on it too if you dare.The closer to tillering profile you have your roughed out bow the quicker it will get ready.The last 1% can take a while,but every 1% of less moisture gains the wood about 6% in strength.Add it up.I'm quoting Tim Baker's findings in the TTB4 book on bow wood[which you should look at if your curious] and have done it this way with lots and lots of bows.I tiller my bows to the average humidity that is in my area.I find that to be around 45 to 55 % at 75 to 80 degrees.Then my moisture I estimate is around 8%.I try to keep my bows at those numbers while I'm not shooting them.I only use wood heat in my place so it can get dry here.Winter dry air will gain poundage on self & especially sinewed bows.At that moisture I have never had wood check on me from heat treatment.
While heat treating limbs that have shellac on them I've seen the shellac on the back get so hot it boils and crusts up.Through 1/2" of wood.This is with no kick back up from the heat guns heat onto the back of the bow.I'd rather make bows without the heat gun myself but most times it seems that's not what happens with all of the recurving going on.I've got a few hedge staves in my shed are natural profile reflexed some type of staves that I think I won't put a bit of heat to.Let them be natural.I'm learning all the time yet too but pushing the envelope more.Hope this clears things up for you a bit.
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Thanks Beadman. So far I seem to be doing it right. Most of my staves are Ocean Spray and in my shop 60-65 degrees@ 75-80% RH I can get away with them losing 25 grams or so a day. I got a little pushy yesterday, put one out in the sun for the day, lost 45 grams and got a small check.
Thanks again and sorry for the hijack Daniel
Don
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Yes sorry Daniel and to that after I debark and remove sapwood of staves like BL or hedge I coat the back with a sealant.The ends should be done right away before this.Then I like to keep them in a shed for maybe three to six months 60 to 80 degrees.I like to do it in the spring.Temperastures cooperate with me then.Then rough out the bow but keep it at least 2" wide and mabe 3/4" deep on the limbs.You can rough em out sooner but that's the way I do it.I've had em warp before.Build up your inventory of wood so you are'nt waiting all the time for wood to dry.Then I take em inside at the humidity and temperature that I want and wait.Take more than one inside.I do.In 4 to 5 weeks you should be able to tiller your bow.
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Your good guys sorry for opening a can of worms. That's similar to what I did Beadman I may invest in a hot box to get that extra moisture out for the future. I've got a stash started in my apartment it's getting in the way and everyone I know ribs me about it haha
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I like to store em horizontal DLH.Off the floor.So each limb is at the same height.Just makes me feel better.I'm sure someone will say it did'nt make a diff and I guess I could say it too,but it still just makes me feel better......LOL.
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I like to store em horizontal DLH.Off the floor.So each limb is at the same height.Just makes me feel better.I'm sure someone will say it did'nt make a diff and I guess I could say it too,but it still just makes me feel better......LOL.
Oh yes it does!!
Like Beadman syas weighing the staves is a great idea too.
Shellac isn't actually a very good sealer anyway and certainly won't hold excess moisture in a stave whilst heat correcting.
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Alright I'll store them horizontal across the dresser too I think I have seen where others do that as well. Thanks for all the advice.
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DLH.....It may sound like we are preaching to you but we want to see you get a nice bow made and be happy happy happy.
Ill give you an example of what when on here in the last 2 months with my BL future bow[I HOPE].Ive always got to say that to cover my hinny.
I cut the tree 7/13/13.Shellaced my ends.Immediately pulled the sapwood and bark off.Shellaced the back.Within a couple days I reduced the staves to 2 to 3 inch wide by 1and1/2" deep.Let it set in my shed at around 80 degrees for a short week.Picked a stave out and roughed it out to a bow.Within 1/4" of final dimensions.Let it set a few more days.Took it inside by my dehumidifier with a fan on it for a few weeks.Reduced it more to floor tiller.I'm weighing this all the time while I'm doing this now to get a guage on it's moisture according to the graph Tim Baker shows in the TTB 4 book on Bow Wood.After a couple more weeks of drying I tiller it to 20" checking for set to see if it is dry enough.It was so I heat treated it.No checking.Now I'm waiting for the wood to equilliberate.I'm waiting 10 days.I'll tiller this bow within a couple of weeks.That'll be 9/16/13.Almost 2 months since I cut the tree.I've done this quite a number of times with bows.A hot box can cut off a couple of weeks I'm sure.Letting wood season I think makes a better bow most times by a certain degree and that degree will show itself in the amount of set your bow takes while tillering.That's why if a person gets enough inventory of staves they can season longer and why moisture content is very important in making these bows.
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Your fine everyone's post have been informative and your not preaching just helping out and giving advice to end up with a nice end product.
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Hey DLH, I saw a comment ealier about bring it to Scottsburg. That the ITBA 3 day Tracy's refering to? If so, I'll see you there too. Not that I'm all that helpful or anything, just happy to find a fellow ITBA shooter in the midst. Mark B.
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DLH...this bow making is not magical like Mike said earlier somewhere.A number of things have to be right for a lesser stressed type of bow to be made that holds a good reflexed or flat profile after tillering and shooting in.I'm not going to speak to you in half truths here.It is not a secret.Wood moisture before tillering is just as important as tillering in my book.I can't stress it enough.