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Main Boards => The Bowyer's Bench => Topic started by: Scott F on March 20, 2016, 07:46:00 PM
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Today I glued a bow and it is in the oven as I type this. When I take it out of the oven and clean up the glue I am hoping for an ASL with ash limbs under clear glass and a purpleheart riser.
I have no idea what it will look like because this bow is seemingly possessed.
First of all, it is a little cool today and my garage felt like a meat locker. I didn't warm my glue so it felt like I was trying to spread silly putty on my lams. Should I bring it inside and warm it up? No way, that would be too much like defeat - I decided to just press on, but after the SECOND time that I had to come inside to mix up some more smooth on I began to wonder what the heck was going on!
I use innertubes for my press; I found out where all the glue was hiding after I squeezed it to the bow form. This one is going to be fun to clean up...I may need a chain saw to hack off the blobs of glue.
Lastly, my hotbox seems more like a lukewarm box. My light bulbs are keeping the box slightly warmer than the inside of my house is right now. I'll pull it out tomorrow evening if it doesn't warm up much tonight. I've heard of people not using any heat with smooth, I guess I am trying that theory out tonight.
Wish me luck.
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What is your heat source?
As long as it's at least warm you should be all right. And, only thing worse than too much glue is not enough :)
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I run four 100 watt bulbs most of the time. in the winter I have to run two 200 watt bulbs and two 100's if it gets below 60 degrees in my shop. can you put a blanket over the oven to insulate it? If you do keep checking on it, dont want a fire..
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Heat source is a couple light bulbs on top of some 2" thick foam insulation board. I only make the occasional bow therefore I take my 'oven' apart after each build. It is fairly warm so I don't think that it will be a loss, it just isn't as hot as I like it to be. I usually cook my bow for about 4-5 hours, this one will be in the form all night.
I just check and the squeezed out glue is hard on the sides so it should be okay.
I am definitely going to heat up my glue prior to my next build. This stuff was not fun to work with.
Question -- does the working time for smooth on diminish rapidly if you warm it up prior to applying it on the lams? Also, is it better to keep the glue and hardener in separate containers while it warms up or is it better to mix it, then toss it in the oven to warm up?
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I am thinking that Kirk (Bigfoot bows) said he heats separate parts for a few seconds in a microwave, then mixes.. I have a small heater in my shop for cold days. I have put the seperate glue parts in 3 oz cups near the heater for a couple of minutes before mixing but it didnt get hot just very slightly warm. I'm not sure about pot time on mixed glue but I think the warmer it is the faster it could set up.I run an AC unit in the shop during glue ups if its warmer than 72 degrees..I'm a sweater anddon't want to drip sweat onto my lams during glue up.. if your squeeze out glue is hard then thats a good sign
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Yep heat the glue separately.
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A word of warning from someone who's been there. Don't get the glue too warm-hot, or it will start to setup before you finish glueing up the bow.
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Smooth on will set up in 24 hours at 70 degrees, however I would give it longer if you can. You will be just fine :)
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Originally posted by Jon in North Idaho:
Smooth on will set up in 24 hours at 70 degrees, however I would give it longer if you can. You will be just fine :)
Yep! My last 5 bows where done without any heat. No problems with any of them. Over 10,000 shots on my personal bow and counting! ( not really counting, just a conservative estimate)
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Thanks for the encouragement.
I pulled the bow out of the form because the glue boogers were solid. This was a straight form so I was confident that if the massive glue squeeze was solid, the thin glue lines must be cured.
All looked great so far.
I am going to warm (not heat) my glue prior to my next build to see if it is better than what I did with this bow. I've never had my smooth on act so stiff. It lathered up just fine, but it was a PITA to do so. In retrospect, it may have been because I am not used to building bows with so many laminations. This one has (3x) core lams of ash along with my glass back and belly. I don't know if I have the patience that some folks demonstrate when they use multiple core laminations with veneers and glass - that is too much material to butter up with glue for me.
I need to try a roller someday, for this glue up I used a piece of flexible plastic like I normally use.
Pictures will follow in time, right now this thing is U-G-L-Y.
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I got the boogers knocked of and it is looking way better than I anticipated.
The glue lines are very tight, everything seems square but I had one of my belly glass laminations slip down about a full 1/4". My grip was set to be around 2 1/8" to 2 1/4" deep, I may have to sand it off to about 2". I was thinking of gluing flat piece of wood over this area to thicken it a little, but the 'clear' glass would be visible on both the top and bottom if I were to do that.
I need to get a better process down for this area of the bow. I learned a to string a couple new cuss words together when I was clamping this area on this bow...
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:clapper:
Glad it's a bow.
I attach stoppers on the form that won't allow the lams to travel. For a flat bow like yours and using rubber bands, you can build the form exactly 72" and put solid permanent stops on the end of the form and cut all of your lams to the exact length needed. If for any reason you decide to work with shorter stock you can fit solid spacers in front of the permanent stops. It can be done with the air hose too but the stoppers need to be just a Frog hair taller than the stack.
Sorry, no pics. Probably as clear as mud!
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Actually your explanation is perfect but I elected to temporarily glue a wooden block on the riser instead of the form. My thought was that I could butt the end of my glass up to this block and force it into position by bending the glass. It worked out well, but I needed to grow an additional arm (or three) to press the glass into form while I attempted to wrap my tubing around the bow. When I did, it slipped a little and my lams were obviously already glued and in place in the stack so there was no turning back.
I will use end blocks for the next bow as you suggest.
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Next question --
Straight taper from the fades to the tips or is it better to keep a consistent length from the fades for about 10" or so, then taper it to the tips?
I really want a skinny limbed longbow but I think that the little bit of added width may help if the limbs start to get squirrelly on me and want to twist.
Right now the bow blank is squared and full width (1.5")
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I keep mine 1 1/8" wide from center out to 14" on each limb, then a straight taper to the tips.
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I haven't had much time to work on this bow but I've managed to head to my garage for a little bit each evening.
I cleaned up the blank and rough profiled the limbs with my belt sander. I don't have an edge sander so I ended up making a profiling board by using some heavy grit zirc sanding belt glued to some flat stock material. I clamped my bow blank to the bench and made sure that it was eyeballed square to the bench and used this profiling board
to essentially plane off (sand) the limbs to shape. I made a quick string last night because I didn't have any strings this long at my house.
Today, God willing, I'll have time to cut some string grooves and tiller this one.
I took jsweka's advice on the profile but I kept the tips a little proud so that I can move them around a little if it wants to twist while braced.
I was a little disheartened when I read a post where apparently Gregg Coffey once said that a straight limbed longbow was a difficult bow to make. If an expert bowyer says this, I may have my work cut out for me!
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My shop is not heated, so I try not to do any bow building in the winter. It will take half again as much smooth-on for a glue up if it is cold.
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Glad to hear you are making progress on it. I find straight limbed longbows much easier to build compared to recurves.
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Trux, I haven't built any recurves yet, but I'll certainly agree that there is little mystery to building straight limbed longbows.
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Despite my initial apprehension I would agree that straight limbed longbows are easier than d/r longbows. I've made some d/r longbows and a couple bingham pronounced td longbows, this bow is easier than them all. Hopefully I didn't just jinx my daughter's soon-to-be bow...
I reduced the width somewhat today and put (2x) 36" metal rulers parallel to each limb to determine the rate at which the limbs tapered their width from the fade outs to the tips. When that was even I cut some string grooves to get it strung up.
When braced at a low brace height the string tracked perfectly down each limb and it was a perfect even tiller as measured from my fade outs (15" riser). I'm putting it up tonight so that I can figure out what tiller measurement is an appropriate start point for a 69" AMO bow. I'll be shooting it 3 under. I'm guessing that 1/8" - 3/16" positive tiller should do the trick.
Tomorrow I plan to glue some overlays on the tips and begin to shape the handle. I'm planning on a straight grip at first, but I'll probably create a dished grip when push comes to shove.
jsweka -- thanks a million for your stack recommendation. I draw over 28" but I wanted it to be ~50@28. I think that this will come out right where I wanted it to be. Super happy right now.
I can see some more toys - I mean tools coming to my house in the near future. Rough cutting a 2" thick purpleheart riser with a 7" coping saw is not much fun. Grinding it to shape wasn't bad however because I bought an oscillating spindle sander when I made my last bow. The next tool for me with be a bandsaw. I read EVERY thread that discusses them.
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Coping saw :scared:
That would be a project.
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Scott - I'm glad it's coming along and the stack thickness seems to have worked for you.
These straight longbows just scream "classic longbow" and really are the easiest bow to make. And I've dabbled in all wood laminates, r/d, and one take down recurve. I never have had any problems getting the string to track down the middle and usually have little to no tillering work to do.
Now...when are we gonna see some pics?
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Pictures - I'll take some tomorrow for sure regardless of whether the bow is finished or not. Right now I am gluing some tip overlays on it with some smooth on.
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I know we mostly have different ideas about shelf height etc, but with mine on my flat longbows being 1 3/4'' above static center, I find for 3 under somewhere around neutral to 3/16'' negative tiller works for me.
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Mine are set up for split finger and usually 1/8" to 3/8" positive. Also about 1 3/4 above center.
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that is where mine are too if using split, but 3 under is usually neutral or negative.
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This bow is still neutral tiller. The photo makes it look sort of funny, I guess because I am canting the bow somewhat.
You don't want to see any close ups yet because it is still not finished, but here it is at full draw.
I draw 30" and this bow is 57lbs at my draw. It will lose a couple pounds but it is exactly what I was hoping for.
I'm already thinking of making another one with black glass and increase the stack but significantly reducing the limb width. This current bow is 1 1/8" at the fades and slightly over 1/2" at the string nocks.
(http://i872.photobucket.com/albums/ab287/Pictures4scott/ASLnumber201.jpg) (http:// [url=http://s872.photobucket.com/user/Pictures4scott/media/ASLnumber201.jpg.html) ]photobucket[/URL]
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Looks real good, Scott.
Can't wait to see some close up finished pics.