Missing draw weight record

[Kirkll]

Ya know..... even experienced bowyers that have built many, many bows miss draw weight some times. But i think i hit my personal record for missing weight today.  I was shooting for a target weight of 48 @28" and really like coming in about 5 pounds heavy so i can do some fine tuning and sanding to balance the limbs.

This set of #2 Bare recurve limbs i just strung up came in 82 @ 28".     I knew i missed my mark pretty heavy just trying to get it strung.... But 30 pounds heavy????  WTF???

Part of it i know was this fossilized bamboo i've been using. It's a woven strand bamboo impregnated with an epoxy resin, and it's the one core wood i've seen that actually bumps up the draw weight on same stack height using anything else, including vertical grain bamboo. When i went back into my bowyers log to get a stack height, i forgot to factor in the F-boo.

When i first started using this material i was concerned about mass weight in the limbs... But... What i found that it was much stronger in tension, and that i could use much thinner lams. This mitigated the mass weight, and my performance testing was excellent.  I just bought another case of it from Cali Bamboo through a commercial flooring supplier i have.....

I thought you guys might get a laugh out of my 30# boo-boo.   What are some of the biggest weight misses you guys have made?

Kirk

[Jerry Gille]

I like to build a mild D/R longbow that has the bottom limb 1 1/2" shorter than the top limb.  I have monkeyed with the bottom stack thickness many times trying to get me close to tiller at glue up.  When I first starting doing it I had some serious negative tiller "learning curves" to show for my guesses.  I'm talking an inch or more of negative tiller.  I love wasting money and time disguised as "learning." 

[Mad Max]

30# boo boo    I like that


Can't think of anything for now but I like to use the 1" mark on a tape measure alot, so sometimes my measurements are off because I forget    I'm a big Fabricator of steel, so 
When bending steel make sure you are making a left and a right, not 2 left's

[Longcruise]

I targeted 65 and hit 105!!

I managed to get it down to 85.  It was difficult finding someone who wanted it.  I just got careless in checking my lams or they may have been mismarked by the vendor.  NOT KENNY!

[wood carver 2]

When I first started learning to build bows. I had already built three wood/bamboo bows, all of which turned out to be shooters. Two of them not the greatest. The next bow was to be a lot more deflexed/ reflexed. I can’t say how much over weight it was. I never did get it strung… 🥵
Dave.

[garyschuler]

Kirk, i used to build a few of the woven strand Bamboo ASL bows, if you are referring to that. It was Caramelized Bamboo, woven strand. It was years ago so can’t speak much on it now. I’ve came in 39+ lbs over on Recurve bows before though. Not Happy about it either !!! Lol 😆

[Kirkll]

Kirk, i used to build a few of the woven strand Bamboo ASL bows, if you are referring to that. It was Caramelized Bamboo, woven strand. It was years ago so can’t speak much on it now. I’ve came in 39+ lbs over on Recurve bows before though. Not Happy about it either !!! Lol 😆

This stuff is called  Java "Fossilized Bamboo"  and is T&G flooring. The way they make this is by impregnating the woven strands and pressing it together under pressure and heat. So its carbonized woven strand. You might have had the same stuff bro... It's pretty cool material.... Very consistent in deflection, and it has the highest janka rating for hardness of any wood in the world. But... its not brittle... The nature of the woven bamboo keeps its flexibility characteristics..... I have not tested it under compression yet. i typically just use one layer on the back site and try to keep it in the tension side of the core. But i think it might do well on the belly side too.....  As a matter of fact.... This material might work well with no glass backing at all. It might be worth trying it on a tri-lam some time....

Well i found my 30# boo boo..... I obviously grabbed the wrong lams when i laid up the limbs.  My stack height was supposed to be 210-215 at the fades,   and its measuring 254 .

I did a reverse calculation on my lam stack calculator and it confirmed  my original stack calc was right on.
Keep in mind my target net weight is 48@28 and i like 4-5 extra pounds to play with.

[Mad Max]

This is the one I THINK you are talking about??? I can't  see the horizontal lines but I think they are there
Click the link
EDIT on the link this is the wider boards
https://www.lowes.com/pd/Cali-Bamboo-Fossilized-5-in-Java-Bamboo-Solid-Hardwood-Flooring-25-88-sq-ft/1000000470
CALI Fossilized Java Bamboo 5-1/8-in W x 9/16-in T x 72-in Smooth/Traditional Solid Hardwood Flooring (25.88-sq ft)
Item #759152 |

Model #7004001900





This one shows some horizontal lines
CALI Fossilized Antique Java Bamboo 5-5/16-in W x 9/16-in T x 72-in Handscraped Engineered Hardwood Flooring (21.5-sq ft)
Item #1218884 |

Model #7014001100



If that link is the one, WE are back to order it from your local lowes and NO shipping charges.

[kennym]

Or maybe this? I bought a couple pieces once , not here tho.

https://www.ambientbp.com/products/strand-tiger-wide-plank-bamboo-floor

[garyschuler]

Yep thats it. I have a partial box  left in the shop. I’ll take a pic if it. Same color and i remember it was woven strand. I might still have a bow i made out of it. I’ll check.

[Mad Max]

Yep thats it. I have a partial box  left in the shop. I’ll take a pic if it. Same color and i remember it was woven strand. I might still have a bow i made out of it. I’ll check.

Kenny or me??

[Mark R]

I've had a box of the woven strand Bamboo flooring for years but decided against using it, I thought being impregnated with so much epoxy would be dead weight and slow but hearing what you guys are saying I'll give it a try and keep my cores thinner. If anyone can give me a rough estimate how much thinner compared with vertical bamboo flooring I would very much appreciate it.

[Longcruise]

How does this woven/epoxy Treat your saw blades?

[Kirkll]

How does this woven/epoxy Treat your saw blades?

Its no better or worse than cutting most high janka rated hardwoods. It sands very consistently in the drum sander without burning. Bamboo is nice in the drum sander.

[Kirkll]

This is the one I THINK you are talking about??? I can't  see the horizontal lines but I think they are there
Click the link
EDIT on the link this is the wider boards
https://www.lowes.com/pd/Cali-Bamboo-Fossilized-5-in-Java-Bamboo-Solid-Hardwood-Flooring-25-88-sq-ft/1000000470
CALI Fossilized Java Bamboo 5-1/8-in W x 9/16-in T x 72-in Smooth/Traditional Solid Hardwood Flooring (25.88-sq ft)
Item #759152 |

Model #7004001900





This one shows some horizontal lines
CALI Fossilized Antique Java Bamboo 5-5/16-in W x 9/16-in T x 72-in Handscraped Engineered Hardwood Flooring (21.5-sq ft)
Item #1218884 |

Model #7014001100



If that link is the one, WE are back to order it from your local lowes and NO shipping charges.

Hey max..... The first link to the 5 1/8" wide X 9/16" thick is the right stuff, but you want to make sure you order T&G , and not the "Click it" style.

Here is the stuff they just sent me, and they screwed up and sent the 7/16" thick with the click milling instead of T&G...... I am still able to get 144 lams at .080 from a case just using a table saw with a thin kerf 8" blade. But the 9/16" thickness would be better. I prefer rough cutting my lams at a bit over .100 thick before running them through the sander. I rarely use lams over .80 in a bow. but having a few thicker lams for tapers is nice to have on hand.  On the click style milling i get 4 @ 1.75" wide & 2 @ 1.5" wide for each board.  If a guy uses a small portable table saw and uses a 7 1/4" thin kerf Freud framing blade. Those small saws will rip 1.75" and have a thinner kerf cut than the 8" blades do.  The thin kerf 8" is needed for my big saw to rip the full 1.75" in one pass but it's kerf cut is a wee bit wider.

I typically get set up and Rough cut the whole case with a brand new blade, (144 pcs) and then bundle them in groups of 20. Total time is about 2 hours to do all the ripping and have them on a shelf ready to sand...

The drum sanding takes more time for milling tapers, so i run a few 20 pc bundles at different taper rates as i need them. As long as they are stacked tight and taped the will not oxidize. But i always freshly sand all my lams before lay up anyway.

BTW..... I get this material for less than $100 per case.  This comes out about .70 cents per lam hard cost.

https://photos.app.goo.gl/XiqP7PNZLVz2gPTLA

[Kirkll]

I know a lot of guys use bandsaws to rip their lams, and this material is going to be really tough on bandsaw blades me thinks.   I've always prefered the consistency of ripping my lams on a table saw with a fresh thin kerf carbide tooth ripping blade.

Resawing thin lams on a bandsaw is tricky to get good consistency. Once everything is set up perfect, you don't dare touch it until you are done.  I've screwed up some beautiful hardwood trying to mill veneers on a band saw in the past.... Never again....

You guys can have it... Using a table saw i know exactly how many lams i'm going to have when im done, and id bet good money i still get more lams in the long run than using a band saw that takes forever to set up perfectly and get a thinner cut, just to save a bit of saw dust.

[garyschuler]

When running thin lams in Table saw. Pay attention to everything. Here’s a Boo Boo from a few years back.Had to drive myself to the Hospital, was really hard to hold my Beer and drive at the same time !!! 😂

[Mad Max]

Thanks Kirk

Be careful gary

[Kirkll]

Running a table saw correctly and using the right kind of push stick is very important, and can be dangerous ripping 1.75” thickness on thin lams.

 Most table saws have a wood insert that the blade comes up though on the table. I have several that I use with different types of blades that keep thin material from slipping down below table depth…. Using fresh blades, and the right kind of blades for different materials is critical on a table saw. I’m constantly changing blades to rip glass or carbon , and save my nice blades for hardwood. Dull blades get tossed or resharpened. Those are the blades that get you.

Most home owner saws do not have a lot of power, and if you bind up a blade it will stop the motor. With a commercial grade saw with a 3-5 hp motor, if you bind up a piece of wood it will kick back on you hard and you are not going to hold it. So it's important to shape the type of push stick, or push block so it it does kick back it doesn't push the stick through your hand.  Look at these blocks i use.

 There is a lot more to using a table saw than meets the eye and requires experience to run safely. They are man eaters……But…. It’s a great tool.   

[garyschuler]

Yep, it was not the Saw, but when i went to pull the piece away from the saw, i got distracted for a second and did not clear it from the blade all the way. the tip if the lam caught the blade and pulled my hand down and into the blade. Freak accident, and no one is allowed in the shop until i’m done cutting. Be aware at all times. I’ve cut hundreds of lams on the Table saw, just lost focused that one second.
As Kirk stated, A dull setup and worn clearance plate is your worst enemy.