Author Topic: struggle to bend recurves  (Read 3350 times)

0 Members and 2 Guests are viewing this topic.

Offline backtowood B2W

  • Member
  • Posts: 574
struggle to bend recurves
« on: April 08, 2019, 12:26:08 am »
hi guys!
Something I am doing wrong, but what?? This is maple, I did 2 test trials - first failed totally - second was almost okay - at the bow the first failed badly second was almost okay too.
the radius of the caul is 3"
I bring down the bending zone to a growth ring. Sometimes I don't have even thickness because of that.
This tips have been very even - bit less than 1/2" thick.
I steamed about 40 min. The first trial 30 min.
Doing the first bend at the bow, I think the metal strap slipped a bit.

Offline backtowood B2W

  • Member
  • Posts: 574
Re: struggle to bend recurves
« Reply #1 on: April 08, 2019, 12:34:25 am »
this is my next victim
I wanna use the same caul, but without the vice - I will try to bend it by hand and clamp it down.
This is ash and it should become a molle design.
I hope I didn't rough out the fade to early!

I hope you guys will have some clues what I´m doing wrong
Please help!!! Thank you!!!!!
B2W

Offline Del the cat

  • Member
  • Posts: 8,322
    • Derek Hutchison Native Wood Self Bows
Re: struggle to bend recurves
« Reply #2 on: April 08, 2019, 02:12:58 am »
That's rather a vicious bend. I'd suggest reducing the tip to a this slat and bending that (on a softer caul) cutting some thin slats, steam bending them first then laying them up onto the pre-bent tip.
I've had similar on a Hazel bow, rasped out the fractured part, and overlaid a pre-bent section.
https://bowyersdiary.blogspot.com/2013/05/radical-recurve.html
Del
Health warning, these posts may contain traces of nut.

Offline Ryan Jacob

  • Member
  • Posts: 427
Re: struggle to bend recurves
« Reply #3 on: April 08, 2019, 04:11:25 am »
I agree with Del. That’s asking too much from the wood. If you calculate it, the circumference of the back is around 2.35 inches and the belly is 2.74 inches. I’m not saying it’s impossible because it isn’t but maybe by bending a larger portion of the wood into the same amount of reflex would increase your chances of success. Just my 2 cents.

Offline PatM

  • Member
  • Posts: 6,737
Re: struggle to bend recurves
« Reply #4 on: April 08, 2019, 04:40:27 am »
The guys making composite bows using Maple will soak and boil the wood to achieve sharp bends with thicker pieces of wood.  Get your supporting strap snugged up a bit better.

Offline Eric Krewson

  • Member
  • Posts: 5,432
Re: struggle to bend recurves
« Reply #5 on: April 08, 2019, 05:28:46 am »
A guy I know that almost never has a problem with a bend soaks his wood in a bucket of water for 24 hours before steaming.

Offline Pat B

  • Administrator
  • Member
  • Posts: 37,633
Re: struggle to bend recurves
« Reply #6 on: April 08, 2019, 05:33:45 am »
Also, try to get the area you are bending even thickness and smoother. I've never worked maple but the others advise sounds good.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline ohma2

  • Member
  • Posts: 960
Re: struggle to bend recurves
« Reply #7 on: April 08, 2019, 07:59:01 am »
Your caul looks a little complicared to me once out of the heat you need to make the bend quick and clamp it .and when using a strap keep it as tight as possible during the bend.evenly dementioned wood makes for a better outcome to.

Offline maitus

  • Member
  • Posts: 310
Re: struggle to bend recurves
« Reply #8 on: April 08, 2019, 08:30:23 am »
Seems like You underestimate the importance of metal support stripe. It looks very loose. Hook one end of this stripe across the bow tip (bend it to 90 degree) and clamp correctly the other end. If metal support is secured correctly You cant brake the outer curve, because of it cant stretch but You can crush the inner curve. And use clamps as much You can in every part which is down against the form to not let some part to lift up.
« Last Edit: April 08, 2019, 10:31:30 am by maitus »

Offline DC

  • Member
  • Posts: 10,396
Re: struggle to bend recurves
« Reply #9 on: April 08, 2019, 08:33:20 am »
I don't know if you did, but I clamp the strap in position before I steam it. Steam them both. I fold the end of the strap over itself 2 or 3 times to form a lip that hooks over the end of the piece. Camp the other end tightly to the piece. The caul should be firmly attached to the vice jaw and the vice should be open enough to put them both in. Do a dry run. Round the outside corners and smooth the outside of the bend. All that said some woods bend tighter than others. I can bend Yew down to 1 1/2"-2" radius if it's clear but even perfect Ocean Spray is risky with a 6" radius. Practice with scraps but prep them like it was the real thing. Keep the successful practice bends, you can splice them on future bows. Steam the wood close to the vice. Don't try to steam it in the kitchen and then run back to the shed to bend it. ;D

Offline goomba

  • Member
  • Posts: 67
Re: struggle to bend recurves
« Reply #10 on: April 08, 2019, 08:36:14 am »
I don't know how much value this list is
in bow building but maple is dead last.

Stock Selection
The U.S. Forest Service has evaluated 25 hardwood species for relative bending quality. In their testing, the best 17 woods were:

Hackberry (Best)
White Oak
Red oak
Chestnut oak
Magnolia
Pecan
Black walnut
Hickory
Beech
Elm
Willow
Birch
Ash
Sweetgum
Soft maple
Yellow-poplar
Hard maple (Worst)

Offline PatM

  • Member
  • Posts: 6,737
Re: struggle to bend recurves
« Reply #11 on: April 08, 2019, 08:49:18 am »
Nonsense.  Maple bends fine.  Wooden toboggans were made of  Maple.

Offline maitus

  • Member
  • Posts: 310
Re: struggle to bend recurves
« Reply #12 on: April 08, 2019, 08:55:59 am »
I don't know if you did, but I clamp the strap in position before I steam it. Steam them both. I fold the end of the strap over itself 2 or 3 times to form a lip that hooks over the end of the piece.
So do i :). I have piece of metal welded to strap.

Offline goomba

  • Member
  • Posts: 67
Re: struggle to bend recurves
« Reply #13 on: April 08, 2019, 09:16:57 am »
Sorry for conveying bad information.

Offline DC

  • Member
  • Posts: 10,396
Re: struggle to bend recurves
« Reply #14 on: April 08, 2019, 09:28:07 am »
You were just looking at it wrong. ;D ;D Another way says Maple is number 17 of all hardwoods. The list was the best 25. ;)It was just on the bottom of a portion of the top.