www.KitGuitarsForum.com

Learn to Kit Build a Guitar. Learn to Scratch Build a Guitar. Learn EVERYTHING Guitars Here!
It is currently Sun Dec 09, 2018 6:50 pm

All times are UTC - 5 hours [ DST ]




Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2
Author Message
PostPosted: Sun Nov 27, 2011 3:35 pm 
Offline

Joined: Fri Jul 30, 2010 6:44 pm
Posts: 1668
Location: Arkansas
I've seen videos where the waist is bent roughly 80%-90% at the beginning, then the lower bout followed by the upper bout, and finally the waist is tightened that last 10%-20% which pulls everything very tight around the form. This appears to work well in the videos (and in the only side I've bent it worked fine).

Is there any concern about "work" or "case" hardening the waist if it is put through two bend cycles? Seems it's fine most of the time from the reported success so just curious if it is a possibility that might rear it's ugly head once in a while. Is case hardening dependent on the type of wood used?

_________________
Slacker......


Top
 Profile  
 
PostPosted: Sun Nov 27, 2011 4:41 pm 
Offline

Joined: Tue Sep 06, 2011 2:51 pm
Posts: 506
Location: Bothell, WA USA
I've actually thought to do this, although I haven't put any effort into obtaining the materials.

My thought is that with the aluminum on the caul, which eliminates the need for the inside steel slat, you no longer have to worry about damaging your bend when releasing the inside slat.

I need to figure out how thick the aluminum needs to be, and how to fasten it to the form. I was thinking about a combination of some small stainless steel screws and some kind of heat proof adhesive.

Thoughts?

kencierp wrote:
To make your forms more like the high volume producers, you can actually cover/enclose them with aluminum. This traps the heat and eliminates the need for the inside slat --- if you pre-bend the waist curve.

Image

_________________
My poorly maintained "Blog"


Top
 Profile  
 
PostPosted: Sun Nov 27, 2011 9:48 pm 
Offline

Joined: Sat Feb 09, 2008 8:06 pm
Posts: 3001
Location: Visalia, CA
I took Ken Cierps advice and made a reflector plate for inside the bender. Then I decided it would be nice to be able to clamp this down to the bench too, so I took of the end stands, made some cut outs and took care of that issue.
I think I'm ready to go. No dimmer, not sure I'll need it, but I can wire one in later if necessary. I turned it on, put a thermometer on the form at the waist, and it got to 225 in less than 10 minutes and was still rising, so I can see with the side sandwich on there holding some of the heat in, this should get plenty hot.
Ken H, how hot does yours get?
Oh, and I also ran the wires under the ceramic bases through a hole and under the jig where there is about 2" of space, so especially now with the reflector, I can't see that heat will be an issue down there.

Kevin


You do not have the required permissions to view the files attached to this post.


Top
 Profile  
 
PostPosted: Sun Nov 27, 2011 10:00 pm 
Offline

Joined: Fri Mar 03, 2006 7:09 pm
Posts: 5760
Location: Hegins, Pa
the original plans for the bender used them and it will protect your wiring as Ken had pointed out. I used reflective insulation.

_________________
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
Board of Directors of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com


Top
 Profile  
 
PostPosted: Mon Nov 28, 2011 9:54 am 
Offline

Joined: Fri Mar 03, 2006 7:09 pm
Posts: 5760
Location: Hegins, Pa
Ken had good advice. the only thing I can ad is to have a fire extinguisher handy . I have all my bending equipment at one spot , and while I never had to use it the fire extinguisher is handy , one thing you never mind owning and never having to use.

_________________
John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
Board of Directors of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com


Top
 Profile  
 
PostPosted: Mon Nov 28, 2011 10:45 am 
Offline

Joined: Sat Feb 09, 2008 8:06 pm
Posts: 3001
Location: Visalia, CA
Thanks guys, I already have the fire extinguisher in my shop, not sure about a dedicated stand for 360 degree access, but I'll work on it. I can place it on my table saw, but not sure how I'd clamp it, I'll take a looksee there.
I'm excited to try it out............."CRACK".....not, I hope!

Kevin


Top
 Profile  
 
PostPosted: Mon Nov 28, 2011 10:50 am 
Offline

Joined: Mon Mar 13, 2006 12:34 am
Posts: 608
Location: Wilmette, IL
Hi Kev: I am not sure how hot mine gets.....I got a grill thermometer to use with it, and promptly lost it. 2 years later, I just found it. I have lightly scorched some zebra (forgot to spritz a side) even wrapped in foil, so it gets hot. I am using a 300 watt bulb in each bout, and a 150 in the waist. I think I will downgrade to 200 all the way across, the 300's are BIG bulbs. They just didn't have any when I went shopping that day. I'll retrofit the thermometer after I revise the whole thing. Actually, now that I think about it, the thermometer needs to go into each form if I want to measure the temperature near the wood, so all I need to do is drill a hole for the probe, and transfer it to each form I am using.

_________________
Ken Hundley
Nocturnal Guitars
http://www.nocturnalguitars.com

So, my big brother was playing guitar and I figured I'd try it too.
- Stevie Ray Vaughan


Top
 Profile  
 
PostPosted: Mon Nov 28, 2011 10:57 am 
Offline

Joined: Sat Feb 09, 2008 8:06 pm
Posts: 3001
Location: Visalia, CA
Yeah, I got one of these inexpensive oven themometers that will sit on top of the SS slat. I realize it will be a little bit hotter at the wood, so I will have to take that in consideration. My bulbs are pretty close to the inside curves of the mold, probably within 4 inches so I figure the wood should heat up pretty fast. I may find that a thermo with a probe is better to insert into the side sandwich, like John sells.

Kevin


Top
 Profile  
 
PostPosted: Mon Nov 28, 2011 11:08 am 
Offline

Joined: Sat Feb 09, 2008 8:06 pm
Posts: 3001
Location: Visalia, CA
I suppose once you've done this a few times and know how long it takes for the wood to bend with what you're working with, then the thermo is a moot point, and, as you say, it becomes a time formula. I have 500 watts, so I'll see what that does.

Kevin


Top
 Profile  
 
PostPosted: Mon Nov 28, 2011 2:18 pm 
Offline

Joined: Tue Sep 06, 2011 2:51 pm
Posts: 506
Location: Bothell, WA USA
Really nice Kevin!

One thing I learned when I set up my bending machine. You need access to both sides. It might not be a problem if your bench is low enough and you can reach over to get to the springs, or if it's near the end of your bench.

My benches are pretty high because of my back issues (bending over a low bench is not a good recipe for a comfortable evening in the shop). I originally had mine mounted parallel to the edge of the bench like yours, but found I had a hard time reaching around behind it to attach the springs to the bending cauls. I ended up building a platform for it that would allowed me to extend it out off the end of the bench a bit so I can easily reach around it without my arms touching the hot stuff....

Some people but them on dedicated stands with 360 degree access, but I don't have room for such luxuries. :p

_________________
My poorly maintained "Blog"


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 20 posts ]  Go to page Previous  1, 2

All times are UTC - 5 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group