Building A Laminate Bow W/Hand Tools & Scap Staves

[Springbuck]

I think you COULD use locust for a backing.  A perfect quartersawn-style clean-faced split would be the exactone to use, too.   My thinking is that thin BL belly/boo back, the locust is unnecessary, unhelpful, and too thin.  BL as a backing is a sketchy unknown, too thick, and too heavy.  EITHER of those start to add up to a very thick stack.

Heck, looking at that BL, split-off pic, I'd say clamp that straight smooth it and find a backing for it!!

[Springbuck]

 Ok, couple of criticisms just to keep it on the rails for next time!   

Yes, the BL QS backing was doomed.  I could tell you by looking it wouldn't hold because of those dark lines where knots wiggled the grain.

Juniper is different than the STRONG woods Asharrow mentioned. ERC and juniper is ELASTIC, not bend resistant, in compression.  However, I looked at your juniper belly slat a bit closer, and I'm not entirely convinced of its grain structure.

Yes, osage and mulberry are both heavy and slightly underutilized as core woods.  No big.  But, thin slat of softer wood (juniper) on the belly, with mediocre grain might be too much for the belly.  Keep this core thin and belly lam thicker.

[Limbwalker]

Springbuck now we're getting somewhere, thanks so much for the no bs answers. For the record when I talk about what I 'think' or 'thought', I m not necessarily disagreeing with you, I am thinking about if someone is just starting out, five years from now, and reads this, that they get they're answers. Make sense. Just discussing ideas and experiences is helpful. Then you come in from behind and one by one, knock the questions out. Thanks. I'm regrouping and I will show you the new stack and you can tell me what you think, I did get rid of the whole double belly a while ago, thanks to you.  I have a feeling Asharrow is smart. You see I didn't go to school, I paid my dues in other ways.

Asharrow, I hear you, I do. I admit my scientific process is no process at all. Been winging it from the jump. Your right. How will I know who the culprit is if it breaks? For a while I was kinda talking to myself here, until people chimed in, so I was working it out. My mind has changed since the beginning. I tossed an idea out about the double belly thing and it was shot down more than once, I'm over the idea, it's dead.

So should I be building two bows at once with one being the control? Joking, you don't want twice as many questions do you? lol. I have learned a lot so far and if stopped now it would have had value for me. I'm not going to stop obviously, but that's why I'm messing with the BL and doing samples. I know I need to do muipule samples to get a real accurate average. Not enough time.

Mikekeswike said it's important to use a backing with interlocking grain. Here is a thread about BL back https://www.primitivearcher.com/smf/index.php/topic,29125.0/nowap.html Since BL does not have interlocking grain, I'm concluding this is why it is better plain sawn.

The bow is a trilam, that will not change, done, backing undecided, I made new bellies with better grain and am processing a bamboo and a BL back and will decide soon. I just have to get e glue lines and triple check the thickness on the sides of belly lams; I don't want any twist now. When I complete that, I will post a pic, you and Springbuck can tell me what you think if you want. Anybody for that matter. Quick question, two Knots on one belly lam, issue? Not on the edge and I very well might work right past them.

So I have the core and Belly established. I would like to glue them up first. Then glue the back on that last. Because I may want to add reflex/deflex or just flip the tips w/steam/heat to the core and Belly first and then try to store more energy by tightening it all up with the back. I do like to keep my options open. I produce the best results not being tied to plan and then missing an opportunity because I was hell bent on a plan.

In closing I feel like the core and Belly kind of already have been proven to be sufficient in the past. Adding a BL back would be stepping more into the unknown for me. Oh the splices, I have learned a ton so far about that too. I feel like if a splice fails it would be quite obvious. Ashjim, your saying if the back fails I won't be able to distinguish because they may all break and which one went first kind of deal?

I appreciate all the thoughtful responses and helpful tips/answers. I do not want to rush this next bit, but I do want to put the poor thing out of it's misery as well. Soon enough. Well, good evening and please, ideas; thoughts

[Limbwalker]

I decided on the back and it will be Bamboo. I have a couple other staves I feel will be fun experimenting with a BL backing. I have a white oak stave that had checked all along the back so I had to violate the back of it to remove the checks. So I with be doing a plain sawn BL backing on that another time.

I haven't had time to work on bows the past few days, but tonight is free and I'm going to be getting things in order. This bow should be glued up by the end of this week. Thanks for all the helpful advice so far.

Springbuck, I'm going to do exactly as you said and trap to the bamboo. I will post pics of a dry run as soon as I touch up glue lines and finish processing  the bamboo. Any additional advice for the bamboo? Before I narrow it to dimension and thin it?

[Limbwalker]

Update, I am finishing up the Juniper belly laminates. I decided I'm going to have the tips flipped and some deflex off the riser, which will be done when glueing up.

One of the Juniper belly pieces cooling off, dry heat bent.

The tips will be static, so after things are glued up and the bow is shaped the tips are going to be as narrow as I can get them and not bend. I have already prepared underplays if they are needed. If I can get away without them, I will.

Another thing that changed is the core is now 5 pices spliced together. My daughter 11 was messing around with it and she broke 4" off of the Mulberry tip. She said she was bending it, I certainly was not mad, it became a good opportunity to let her learn a bit about wood. Now she wants to make her own bow. She picked one of my Osage staves of course. I gave her a yard stick & pencil, lets see what she comes up with 

Anyway, I have another much better old old Osage log that I have split up and found some scraps from it and made a new tip on the Mulberry side and did the same on the other side to match. In the end, that hard Osage will aid in keeping the tips static so oppritunity lies in every little "accident"
Be well, until next time.

[Limbwalker]

can someone help me out real quick? How much does the wood variety matter in the power lam? I can use Osage, BL, Mulberry, Juniper, Hickory or Ash.

I'm going to go with BL unless that is a bad idea, thanks

Never mind on that one, I know what will work just thought of it.

[Jim Davis]

About any wood will work between the belly and back. hardly any energy storage there. Lighter is better, since that layer is just along for the ride. "Power lam" is just a hype term, probably originated in some sales department.

Jim

[Limbwalker]

Thanks Jim, that frees me up to pick something pretty much based on color alone. My main concern was stiffness to thickness ratio and if a stiffer wood was better, but after research what I read is congruent with the above answer. I do need one because the belly wont be thick enough to start the fade into the riser. Thinking about the function of the PL, I would think as long as it's not incredibly brittle anything will do.

I have a about a century old scrap piece of Osage that will slightly accent the bow, thanks again Jim

[PEARL DRUMS]

Its not a hype word derived in an office, Jim. They use the term "power" because it is meant to stiffen up and strengthen only a certain section of the bow.

[Limbwalker]

I wanted to double check something, I've used bamboo before and from my understanding, after the rind is removed it is a tan color, correct?

I don't want to harm the good fibers; it can get concerning because I'm noticing two color changes as I remove the rind. I suppose leaving the rind on is an option, but I would like it gone on this bow. I put bamboo on an Ash bow before, but I think I didn't get the rind all the way off in that one. I gave it away so I can't remember. Doe my question make sense? I have searched the web and read contradicting things. Anyone with experience please feel free to let me know, thanks

[Limbwalker]

Almost

[Limbwalker]

I glued up the belly and core. I planned on that for reasons I said days ago. I'm glad I did it this way so far because it gives me a chance to better tune the profile. Since I'm working with laminates I made from scraps, they are not the same. I will sort of floor tiller it before I put the bamboo on. That's the best way I can describe the next step. Basically I'm going to get each limb closer to final before I put the back on, but not too much, just a couple spots. I have knots to deal with on belly so it's been a process this far.

I will have pictures soon and after the bamboo goes on, I will do the final tiller and that's that. The final tiller will take time, I'm not in a rush. Juniper can't be rushed. It took time and convincing to heat bend the Juniper, but with patience I was able to do it and it will be the same drawing the bow.

I am going to temper the bamboo. Wait I shouldn't temper the bamboo if it's the back. I'm going to do it and I will tell you why. There is a report done by for bamboo rod makers about this subject. Rod makers have to deal with elasticity and set as well. After years of testing a report was finally made and if done correctly, tempering at no more than 200C (392F) increases MOE by about 2-4% but increases resistance to set by a much higher percent. Also there are some good tips in there about water reduction in the bamboo, things I never paid attention to. I'm going to be sure to seal the ends of it immediately after tempering it. The article is 30 pages and if you use bamboo and can get through the article, read it. I will leave it for anyone to read. There is good info in here https://www.dropbox.com/s/edxnj4ujc0qdtnz/Bamboo%20in%20the%20Laboratory.pdf?dl=0

[Limbwalker]

Here is a pic gluing up the belly and core, I added a few wedges after I took this pic. 8 pieces of wood so far. I did this two days ago, glue lines came out very well. I will add pics when I glue the back on maybe later today. Note this is not the final profile of the bow. Working my way there.

[Jim Davis]

Its not a hype word derived in an office, Jim. They use the term "power" because it is meant to stiffen up and strengthen only a certain section of the bow.

But it only stiffens the section by making it thicker. Internal layers add almost nothing to stiffness by virtue of the material used. That's why some bows can be and are made with foam cores. The foam just adds thickness. So one kind of core material or internal lamination can really only be better than another if it is lighter. Not be cause it's some proprietary material.

[PEARL DRUMS]

Power lams aren't in limbs, they are situated in the handle and fade section only to stiffen it up, or "power" it up, if you will.. Foam would do no good in a riser as a power lam. Works great in a limb as a core.