Primitive Archer
Main Discussion Area => Bows => Topic started by: superdav95 on August 08, 2023, 01:08:51 pm
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Hey guys. I’ve had a few enquiry about my bbh bows so I figured I’d do a build along while I’m building my current test bows. So it’s Another build along sort of…. It’s a series of tests and ideas I’m trying with these two. So they are not actually twins bows but pretty close. One will stay slightly wider further up the limbs. Only slightly. As far as the reflex both will be very close. Both will be boo backed with toasted boo strip. I’ll post some dimensions here as we go but generally one will be 1.4” wide out of the fades narrowed to about 1.25” for about 16” up the limb then narrowed to about 1/2” at the tips. Finished tip width with be closer to .4” or less when done. As far as the other one it will be similar but limb width will got from 1.4” out of fades to about 20” to where it is narrowed to 1.25” then narrowed to 1/2” tips. Both will have toasted boo strips as my other test bows. The strips dimensions are as follows. Same outline top profile of the bows with the tips at .090” thick tapering up towards the handle to about .13. This is repeated for both limbs. I space out the nodes to match up on back of bow blank. I orient the bottom limb B with the nodes that are slightly closer together which happens to place the first node out of the fades area closer and thereby stiffer slightly due to that node. This planning ahead of time my not be necessary but that’s what I’ve done. Anyway more to come. You can see in the pics so far that I’m using a belt sender to make short work of these. I’m using a 36 grit 6x42 table top sander. For those who want to do one of these it’s indeed still possible with rasps and file and drawknife but I’m wanting to get these done quickly. The glue I’m using smooth on ea40 epoxy for my glue up. I use a vice and various clamps to add reflex on glue up. As like many do here I use narrow 26” inner tube from bike tires as my wrap up. Some use a wrap that’s cut lengthwise up the tube but I like the extra strength of the full inner tube for my wrap. Just my preference but I’m sure as long as you get good glue up with minimal glue line your good. I also tape up my boo backing node side to protect from glue. Before I wrap a put a layer of Cir-an wrap to protect my inner tips for most of the glue squeeze out. Doesn’t stop all of it but works pretty good. I no longer do hot box for ea 40. Didn’t find it made any difference for me. I do mix 2 parts a and 1 part B when mixing my glue. I just eyeball this. I do also make sure I degrease my glue surfaces with acetone wipe down prior to glue up and also ensure I glue the same day I grind and flatten my glue surfaces. You can see that in the last pic I’ve stayed within 1 growth ring to getting the back prepped for glue up. Not sure if this will make any difference we shall see. Hopefully this helps someone out there think of one of these builds. They make great bows. Stay tuned 🌝
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I’m watching!
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yes sir, me as well.
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I'm watching with curiosity as well.
BBH = ??
Mark
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I'm watching with curiosity as well.
BBH = ??
Mark
Sorry mark. I should have clarified that in initial post. BBH = bamboo backed hickory
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Here you can see me splitting off my boo slat. I use a big knife for this like a machete working my way down the length of the pole. I make sure I inspect my boo for any checks and cracks. Most bamboo will have some minor scuffs that don’t affect anything functional but is more aesthetics. I split out my slat to about 1 and 3/4” wide. I use a hammer on the back of my large knife to split through the nodes. I use large diameter moso bamboo pole. At least 4-5” in diameter if you can get it. Using large well seasoned moso pole bamboo will yield better results as the crown will be kept to a minimum. More to come. Stay tuned 🌝
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Let’s talk bamboo a bit. As mentioned earlier I use large diameter moso bamboo. The poles I get are in 10’ lengths seasoned about 2-4years. I’ve used greener poles too but it’s more work to get the moisture out. It’s doable but more work. Here you can see some poles showing how the nodes are closer together as you go down the base of the pole. In the last pic I show a slat that I bought online. It’s not usable in my opinion. You can see the uneven back on this slat. Obviously this will be an issue getting an even backside that gives consistent bend if used. Watch out for this. I find that using poles and making my own slats gives me the quality control I need. I have found that commercial slats 2” wide can be good but it’s hit or miss depending where you order from. Lots of guys here use them just fine. Just look them over well. For me I use the large poles for other bow projects anyway so it works out for me.
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I toast my slats after I grind them down to about 1/8” thick. For a length of about 69-70” it takes about 20mins each side. I use radiant heat source. A hot plate like a stove top or single burner type would work. I go till I see steam coming out the ends hovering over the heat source about 3-4”. I keep it moving and pay attention not to hover over an area too long to scorch it. This will make it too brittle. Heat tempering boo strips I believe has a performance benefit. I’m still testing out some theory on this with these bows. I also weight my bow strip just prior to heat tempering it and after. I’ll see a drop in mass of around 30-40 grams. This is seasoned 3yr dry bamboo. If using greener stuff be prepared to lose a lot more mass in the form of moisture. The last pic you’ll see how the boo strip swells a bit after heat tempering it. This is due to the loss of moisture. This is not a problem and this is why I start this process at 1/8” thick. I’ve tried heat tempering the strip thinner but found it checks and splits more in me. Keeping it at least 1/8” saves this for the most part. A very light Color may be seen on the belly. This is fine and won’t affect anything.
Here’s video link for the heat temper process.
https://photos.app.goo.gl/NS34tXRfrtpwbNt8A
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For this slat I went with a taper from about .090” thick at the tips to center line of .125” thick. You can see that I used clamps to get my outline penciled on from my hickory bow blank. I do this step when I get the thickness of entire strip down to about .150” thick. I use my 36grit belt sander for this. This gives a good glue up surface too. Once I draw on outline and head back to the sander and get the outline shaped out. This is where I then taper down to my finished thicknesses. For this one I went .125-.090. Center to tip. My other test bow I went a little thicker .150”-.100 center to tip. I’m testing out some theories with various boo strip thicknesses. After I get my tapers done and outline the way I like I tape up the back in prep for glue up. This protects the boo back from epoxy squeeze out. The 36grit belt sander gives good glue surface but I’m sure other hacksaw blade methods or rasps or files work too. I thin use a clean rag with acetone to wipe down both back side of hickory bow blank and the belly of the boo strip. I also mark the A and B as a reminder which side it which along with a center line for alignment on glue up. Trust me you’ll only forget to do this once. Don’t t ask me how I know this 😉 Epoxy is messy slippery stuff! Where gloves. I’ll post more tonight when I get back of the glue up set up I use. Stay tuned. 🌝
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Thanks for taking time to document your work. Very helpful
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Looking good
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Ok here’s my glue up. I clean the sanded and prepped surfaces with acetone and let it dry. As mentioned before I use ea40 smooth on 2 part a and 1 part B for my mix ratio. I’ve done it with 1:1 ratio without issues too but the can says 2:1 for best resistance and performance. I mix it well for about 5 mins. Then I spread it on both glue surfaces ensuring proper alignment.
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This is what your 2:1 ratio mix should look like mixed. This is an eyeball quantity that gives enough glue for good squeeze out. I put a liberal amount of glue on both surfaces then lay them in place. I tape around the fades and tips and at the bends to hold slat in place while I lay the Curran wrap over it. It protects your inner tube wraps from squeeze out of excess glue.
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I wrap with two 26” long inner tubes. Some may think this is overkill but I like the results and gives nearly nonexistent glue line. The coarse 36grit belt sander marks in the glue surfaces give plenty of grab. You’ll notice that too that I wrap the limbs with 1/8” gaps to allow for squeeze out. Will it work well without doing this? I suppose it would but I made sense to me to do it this way and I get good glue ups. I use the full tube also and don’t split it in two halves lengthwise. I use a ruler to measure the height of the tips from the table to ensure they are the same. In this case I added an inch to existing reflex. Should have about 5” reflex after glue is cured. I’ll clean up bow a bit tomorrow stay tuned. 😁
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Thanks for sharing this. I'm definately following along!
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Here’s the bow out of the glue up and wrap. I hit it with the belt sander to save time and then to the rasp. Glue lines are good! About 5” reflex. We shall see what I end up keeping when I start tillering. More to come.
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That is looking good Dave!
The problem I always had with the inner tubes is that the glue sticks to the tubes making it hard to remove and often damages them when removing. I often could use them only once therefore. Don't they? I therefore bought silicone rubber bands which dont stick with the 2k - this worked much better. But since I'm glueing my bows with white pva carpenters glue this anyways isnt a topic anymore.
Wonder how much of that reflex you are going to save....the heat treating sure will help you a lot!
Best of luck!
Cheers
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looking good so far Dave. I'm watching when I can.
Thanks for posting this. A boo backed bow is on my list.
bjrogg
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That is looking good Dave!
The problem I always had with the inner tubes is that the glue sticks to the tubes making it hard to remove and often damages them when removing. I often could use them only once therefore. Don't they? I therefore bought silicone rubber bands which dont stick with the 2k - this worked much better. But since I'm glueing my bows with white pva carpenters glue this anyways isnt a topic anymore.
Wonder how much of that reflex you are going to save....the heat treating sure will help you a lot!
Best of luck!
Cheers
Thanks Simon. Ya it’s an issue with the glue sticking to the inner tubes. I usually get 4-5 bow glue ups with each set. Ever since I started wrapping with cling wrap just prior to wrapping with inner tubes. This saves the tubes in large part to get more uses out of them. The reflex I’m hoping will retain at least 3-4” of it. These 2 bows are slightly different from each other so there may be some variations in reflex retention too. The secret to retain more of this reflex is more to do with the reflex induced with the heat treatment more then the Perry reflex part of this build. We shall see what happens. Thanks again for watching and following along.
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looking good so far Dave. I'm watching when I can.
Thanks for posting this. A boo backed bow is on my list.
bjrogg
Thanks BJ. I recommend trying one.
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Watching with interest (-P
Del
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I tape my bamboo as you did . Tape with strap tape as you did then wrap in plastic wrap to keep glue off fire hose or inner tubes.
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Did a little more work on both of these bows. As mentioned earlier they will have similar dimensions but will vary slightly. I haven’t decided quite yet how many variables I want to include between these two bows. Too many will make it difficult to determine what made the difference in performance if any difference at all. I admit that it’s not terribly scientific but we are dealing with wood after all. I have thrown in 3 known variables so far. 1. Limbs width. 2. Boo strip thickness. 3. Darkness of belly wood. This last one was varied by flattening more of the back of the hickory blank in prep for boo strip glue up. Taking down more from the back of the blank allowed me to keep more of the toast compared to the second one. I’m debating on a 4th variable of bow length. The first one is 68” while the second is 69”. Today I got both tillered to about 15” with long string on my inverted tiller device. This allows me to scrape and pull without removing the bow. I’ll take it to the wall tiller set tomorrow for getting to around 27” at 50lbs. My goal for these is 48-50lbs at 28”. We shall see. The bend so far on both looks good. More to come.
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Got one of these tillered to low brace. Bow bend looks good to my eye. It’s at 50lbs at brace so I have plenty of weight to remove yet at full draw. I’ll work on the other one tomorrow and get them both to brace and go from there.
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those are very nice and look fast just sitting there... I'll bet they do well in the testing. Congrats! :OK
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Thanks Bob. I’m hoping they will be.
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Great information! And nice looking bows. I will have to try the inner tube wrap on my lamination projects. I can never seem to get enough claps at the correct positions.
David
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Very nice work, Dave. Very helpful information.
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Strung profile looks great. Should be very fast.
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Thanks guys. Fingers crossed.
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Just a couple updates. I got both tillered to about 50lbs just passed brace height with bend looking good on both. No issues or anything yet. I also cut in the shelves and added the string knocks. I went with Buffalo horn nocks. They are very durable and I kept them pretty light. Tips will narrow more upon finishing from here. I like to shape up my nocks to an angular shape to get them both the same dimensions then glue them on and shape and round them on the bow. As for the shelf I cut with a pull saw my shelf line and then use a chisel and chip out the pass to that line cut. Files and rasps do the rest of the shaping. I’ve been taking my time to get my inners moving early on in my tiller. I find this helps me avoid whip tiller. At least for me. I also do not go over my intending final draw weight during the tiller process. I usually get to my intended draw weight at brace height about 6” or so in this case 50lbs. Then I brace it and continue my tiller from there strung at low brace. Thanks for following along on this journey.
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Looks good Dave!
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Some bad news guys. I developed a bad hinge on the upper mid limb while tillering out to 26”. I found the likley cause. It appears to be a thick glue line section next to it. I’m guessing it was creating a stiff spot and partially causing a hinge. As I attempted to balance this out it just ended up too underweight. I abandoned this one and moved on to the next one. I may end up trying to salvage this later with a belly lam of bamboo slats on each limb. As for the second bow it went well all the way to 28” at just over 52lbs. It looked balanced and had just a little under 1/4” positive tiller upper limb. This bow is an asymmetrical bow. I shot it in and it shot very well. It shot hard and fast and worked my way up to 28” draw. After about 20 shots I noticed a more pronounced bend right near a knot on the belly of the upper limb. I had figured it was ok as it was mostly removed during tiller but it may in fact be an issue after all. Bow still shoots amazing but I worry about it lasting and blowing up eventually. I think I’ll belly lam this one first with boo slats on each limb belly. This will allow me to remove more of the issue at the knot on the belly and salvage the bow (3rd pic shows this knot). I’ll get to work on this one first as it shot so well. It still held 4” reflex after all this too which is promising if I can do the belly lams. I’ve drawn a pencil line on the delay to show where I’ll start removing wood to prep for belly boo lams. (See second pic) The other one I’ll wait a bit in for now and save it for another project down the road. Oh well all good for learning. My take away on these bows as they stand now is incomplete really but one observation I made is the bow that had the thicker boo strip had a tougher time getting tillered. It caused for more belly wood removal then ideal for stability. Here’s a few pics
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That is pushing the limits. Amassing you kept so much reflex. The knot is the culprit for sure. This design requires real good wood . The design has more inner limb stress due to the reflex. Especially when most of it is in the last 10” or so. Your going to do it Dave. Your right there.wont be long and the task will switch to arrows.
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Hey gang. Here’s an update on these bows. As you know if you e been following this thread both these bows had issues. The second one shot very well up until it started failing a bit near a belly knot. It basically was stressed around the remnants of what was left of the knot and threw the tiller off. Still shot ok but looked funky. I set it aside until recently. I decided to boo laminate the belly. I’ve done boo laminated bellies before but have always scraped and sanded the nodes and re tilled much the same way a self bow. This proof of concept bow is nothing new but had checked a few boxes for me as something I wanted to try anyway and this bow was a great candidate for it.
I was very careful to pre tiller this bow after removing about .150” thickness on the belly of each limb. This allowed me to get rid of most if not all of the troubles around the knot that had caused issues. I pretillered the bow after removing this belly wood to good looking balanced brace and then to about 20”. At this time it was about 32lbs at 20”. I then proceeded to prep my belly slats. I decided to go with a very slight taper from the tip at .120” down to about .140”. I went thinner at the transition fades around .100” to allow for the bend at the fades. I decided to stagger the nodes and place nodes midway of the nodes on the back to spread out the irregularities of nodes somewhat. You can see the pic where I’ve marked with arrows of node placements. Glue up went good. I used the usual inner tubes and double wrapped the area at the bends in fades. I clamped this down with several clamps after wrap. I took a good look at the bends to ensure even bending in the boo slats prior to glue up. The one slat had slight more crown then the other so comparing bend is important I think. Keeping tips aligned after glue up is important too. As far as tiller after the glue up of belly lams I did a little side tiller only. This allows me to keep the surface of the belly slats untouched. I think this made the difference on this bow. Tiller isn’t perfect but fairly decent considering side only scraping. Time will tell. I’ve got about 50 arrows through it now and it seems great. It is around 67”ntn and pulls about 55lbs approx. the new mass of the bow is 629grams. It was around 600 before. Not a deal breaker. I need batteries in my digital draw weight reader! I took the rare opportunity with my wife around to take a couple short vids. Sorry about my scruffy appearance. I’m a all day work clothes kind of guy 😀. I’m sure you guys get it! The bottom pic shows the reflex at about 4.5”. This was bout 30min after shooting today out to full draw for about 50 shots. The reflex was about 4” immediately after unstringing the bow. I was quite pleased with this!
Anyway the speeds are very good. The bow shoots very straight no matter what I fire through it. The chrono readings seen in the video are promising even at only 27”draw. I later had slightly better readings at 28”-29” draw but my wife ditched me and thus my camera person.
At 27” draw at 10gpp the video shows readings of 186 and 187. Very respectable I would say for all wood bow.
At 27” draw at about 7gpp arrow the video shows reading of 195fps. Not too bad.
Later in the day I shot a 202fps with the same arrow at 7gpp and was closer to 28-29” draw.
Also shot a 188 and 189 with 10gpp at 28” draw later also. Not a ton faster but a little bit and it was a nice cloudy day for my chrono.
I’ll post some pics here too but here are the two video clips of the above readings for interest.
https://photos.app.goo.gl/LiHDU9pxXU9JXadi7
https://photos.app.goo.gl/Y2LgnrZD8cqfz1sL9
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More pics…
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Couple more…
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I’m just catching up on those thread - Dave those are fantastic bows, even after problems leading to design alterations at the last minute, which has to be the sign of a true expert. And those speeds are exceptional. I wish I had a grain scale and could tell when I’m actually throwing for speeds (but my t-Rex arms don’t allow for a great draw length for speed). Either way keep up the great work and thanks for sharing.
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Thanks kidder! Much appreciated and my pleasure. It’s what gets me up in the morning.
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So one last update on this test bow. I decided to try a Massey finish on this one. It went ok I guess but not quite as I hoped. I did my usual stain job first which has a nice blend of Colors and fading. When I went to apply the home made Massey finish all my Colors started bleeding together and results were more subdued Colors and transitions. Fine if that’s what one wants but I was going for something different. Oh well. Will give it a few days to see how it grows on me. Here’s some pics anyway let me know what you guys think. The tan Color bled onto he white hickory core and made it look yellow like Osage of something. Kinda weird it did that. I did not take a picture before the Massey finish to compare but trust me it was tan Color prior to the finish.
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Few more…
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One more
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I don't think it looks bad at all, Dave. I'd hunt that dog.
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I don't think it looks bad at all, Dave. I'd hunt that dog.
Thanks PD! I may just do that this year!
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Looks good to me too. Impressive speeds ,lots of reflex. Yeah that will work.
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Looks good to me too. Impressive speeds ,lots of reflex. Yeah that will work.
Thanks mike. Yes I’m pleased with the speed and the way it shoots. It’s silky smooth to draw and no handshock. The finish will work.
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You know me I like yellow! That’s smoking speeds.well done my friend.
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Thanks Arvin!