Go-bar rods

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nkforster
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Go-bar rods

Post by nkforster » Sat Dec 15, 2018 9:06 am

Where do you feller s get your fibre glass go-bar rods from?

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kiwigeo
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Re: Go-bar rods

Post by kiwigeo » Sat Dec 15, 2018 9:24 am

I'm a cheap arse...I just buy a bunch of hoop pine dowel from my local Mitre 10 and chop 'em up. A few of them break but you learn to move fast as you dodge the pieces of dowel flying past your ear.
nkforster wrote:
Sat Dec 15, 2018 9:06 am
Where do you feller s get your fibre glass go-bar rods from?
Martin

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peter.coombe
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Re: Go-bar rods

Post by peter.coombe » Sat Dec 15, 2018 9:45 am

Me too. Dowel from Mitre 10, chopped up. They work fine, are cheap and only a couple have snapped. Easily replaced if they do snap.
Peter Coombe - mandolin, mandola and guitar maker
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Paul Henneberry
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Re: Go-bar rods

Post by Paul Henneberry » Sat Dec 15, 2018 10:42 am

Hi Nigel
I found my fibre glass rod by tracking down the kite repair guy in town (Fremantle), he was also the guy that repaired kite surfing gear. I got enough 4mm to make 20 rods and he also had the little rubber feet that slipped on the ends. From memory it cost less than $100. I tested them on a scale and they give a down force of about 2.6kg and it doesn't change much no matter how much they are bent. They don't snap but I found they did like to escape from under the go bar deck ceiling and turn into arrows so I attached some plastic lattice to control them.
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cheers

Paul

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Re: Go-bar rods

Post by kiwigeo » Sat Dec 15, 2018 11:14 am

Great idea with the plastic lattice Paul....consider that idea stolen :mrgreen:
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demonx
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Re: Go-bar rods

Post by demonx » Sat Dec 15, 2018 2:02 pm

All mine came from Blues Creek Guitars in the USA.

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Mark McLean
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Re: Go-bar rods

Post by Mark McLean » Sat Dec 15, 2018 2:36 pm

I use bamboo. I bought some bamboo screening at Bunnings, which is multiple lengths of bamboo laced together with light wire. Cut the wire and I ended up with dozens of usable go bar rods for about $9. I bought little rubber caps to put on each end (also Bunnings). There are white caps and black. The black ones leave black smudges in your work.

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Re: Go-bar rods

Post by mooshalah » Sun Dec 16, 2018 2:29 am

Hi Nigel.

About 10 years ago, I decided to make a kick-arse go-bar deck, and naturally the issue about what might be the most appropriate rods needed to be addressed.

I began with the following criteria in mind (and I've had pause to reconsider these over the years) but overall, I've been very happy with how things turned out:

* "Floor-to-ceiling" distance, i.e height that the rods would need to span - 800 mm. I based this roughly on the go-bar decks being offered commercially by places like StewMac and LMI. I made my deck height adjustable, but I've never bothered to change it; it works just fine. I sometimes dismantle it, because my workshop is very small.

* Based on the way I thought things would work, I decided that the rods I'd need would be 900 mm long. I.e. they'd always be somewhat bent when they went into the 800 mm deck.

* I approached an organisation in Sydney selling fiber / resin (not actually fiberglass) rods used as battens in sail-boats, and quickly discovered that there is an organisation - Permex Products Australia - extruding such rods here in Australia, and distributing them throughout the country. You will thus be able to order them (or maybe they'll even be in stock) at any places that sell sails for dinghies and the like. You can easily find them on the internet. In fact, I bought the rods directly from Permex, and they cut them to length and posted them to me once we'd worked out what I wanted. One can also choose from a range of "tips" that go on the end of the rods (presumably to stop them from eventually poking themselves through the fabric of the sails), but I never bought any; I've just rounded and smoothed the sharp ends off the rods with sandpaper.

* I gave them the criterion that I wanted each rod to exert a force of around 7 kg, when a 900 mm rod was forced into a space of 800 mm. They (understandably) didn't know which rod might be most suitable so they sent me a bunch of samples of varying diameters, and I came to the conclusion that an 7.2 mm diameter rod was what I wanted. I ordered 15 of these. At the time, these cost around $3.00 a meter.

* Once I started using them it became very clear - much to my delight! - that within very wide limits, it made no difference how drastically I bent them, the force they would exert was an extremely reproducible 7.0 kg. By that I mean, whether I was bending a 900 mm long rod into an 800 mm space or a 400 mm space, the force (and I measured this all using a bathroom scale) was always around 7.0 kg. I've been using them for the last 10 years, and they still each exert exactly this same force, and spring back perfectly strait when I take them out of the deck. None have ever snapped.

* In retrospect, I think that I should have bought 20 rods, and over the years I've worried that 7 kg force per rod might be way too much, and that the joints might become starved of glue because too much might squeeze out - but so far, I've not had a problem. If I was to do this again, I'd probably buy the 5 mm or 4 mm rod that they offer. That way the force will probably be more like 3 or 2 kg respectively. (And I see that you, Paul, are using a 4 mm diameter rod, and getting 2.6 kg from them. Permex also make a 4.5 mm diameter rod. Maybe that's optimal - but I'm still happy enough with what I'm getting.)

*One thing to consider is that if you happen to use (be afraid; be very afraid!) 20 go-bars at one time, their combined force on the deck is going to be (in my case of 7 kg per bar), a total of 140 kg! Even though I used pretty thick MDF when making the deck, I can see that it has become very slightly dished over the years. This isn't a problem for the "ceiling" but although I insert a predetermined radiused dish when gluing braces, I no longer have a perfectly flat "floor"surface, should I need one. (And I too really love your solution to preventing rods from slipping on the "ceiling", Paul!)

Kindest regards,

Frank.

kiwinoz62
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Re: Go-bar rods

Post by kiwinoz62 » Sun Dec 16, 2018 8:55 am

From this place in Sydney...

Permex
22 Lincoln Street, Minto, NSW 2566
Australia
Phone: +61 2 9820 1266
Fax: +61 2 9820 3511
Email: Info@permex.com.au
cheers wayne . . .

'keep on strummin'

blackalex1952
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Re: Go-bar rods

Post by blackalex1952 » Mon Dec 17, 2018 5:13 pm

All that remains now is where to get the plastic lattice.
within very wide limits, it made no difference how drastically I bent them, the force they would exert was an extremely reproducible 7.0 kg. By that I mean, whether I was bending a 900 mm long rod into an 800 mm space or a 400 mm space, the force (and I measured this all using a bathroom scale) was always around 7.0 kg.
Yes, springs are linear, including soundboards and braces, within reason...also a very good point re the additive load on a gobar deck. I use a few different pieces of MDF to adjust the height of the deck and then put my radius dish on top of that. I have also glued and repaired braces using a piece of 15mm Kmart neoprene which was sold as a 'yoga mat' as a radius 'dish'. This conforms to compound radius braces, eg Selmeroid builds (Selmer Maccaferri) and archtopbrace repair.
I gave them the criterion that I wanted each rod to exert a force of around 7 kg, when a 900 mm rod was forced into a space of 800 mm I gave them the criterion that I wanted each rod to exert a force of around 7 kg, when a 900 mm rod was forced into a space of 800 mm
I'm wondering where the 7 kg figure originated here? With additive force on the braces, given that for each brace there are multiple rods, is 7 kg overkill?
Cheers Ross
"Everything I say on the topic is based solely upon inexperience and assumption!"

blackalex1952
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Re: Go-bar rods

Post by blackalex1952 » Mon Dec 17, 2018 8:10 pm

I just measured my go bar rods, which aren't rods at all. They are very old straight grained mountain ash floorboards with minimum runout, run through the bandsaw -ie REAL mountain ash! They vary in thickness and length. Some came in at 8kg, some as high as 17kg. The white 10mm rubber ends from Clark Rubber never slip and I wear safety glasses. These "rods" tend to snap anyway and don't tend to fly in your face when they fail. And yes, if I ever rebuild my go bar deck I'll make it from much heavier top and bottom plates to eliminate flex, as I have noticed a little when doing an entire soundboard with lots of go bar rods. That's when the tension on the go bar plates can loosen some of the rods as the bracing continues. I have found with a flexing go bar deck that repositioning or retensioning the rods can be fiddly getting ones hand in between multiple rods with the risk of bumping one as well as knocking it out of position. Doesn't help with HHG glue up's as time is of the essence. Will eventually re build the deck so that it fits the workshop better and doesn't take so much space. At the moment it serves as another flat surface! Actually, two flat surfaces...the top as well.
BTW: There are basically two rules for flat surfaces. One, from the engineering world, is that two surfaces, I think of equal hardness (but not sure,) when rubbed together will eventually form a flat surface with an error of one molecule. (I suspect that the joins between the blocks of the pyramids and other ancient structures were transported in a way which caused the mating surface to become very flat.)
The other rule, from the architecture and interior design world is that "Flat surfaces attract clutter!!!!"
Cheers! Ross
"Everything I say on the topic is based solely upon inexperience and assumption!"

mooshalah
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Re: Go-bar rods

Post by mooshalah » Wed Dec 19, 2018 2:46 pm

"I'm wondering where the 7 kg figure originated here? With additive force on the braces, given that for each brace there are multiple rods, is 7 kg overkill?"

The 7 kg figure was just sucked out of my head! I'd never used a go-bar deck before attempting to build one. At the time, it just seemed like a good number. In retrospect, I think 7 kg is too great a force, and between 3 kg and 5 kg is a better number. Those with "true" knowledge of the matter (like, someone who has bought a commercially available deck and go-bars might wish to chime in here .......

Frank

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kiwigeo
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Re: Go-bar rods

Post by kiwigeo » Wed Dec 19, 2018 2:51 pm

My hoop pine go bars generally exert pressure around the 7Kg mark. Not huge when you consider how much pressure you can exert with a cam clamp.
mooshalah wrote:
Wed Dec 19, 2018 2:46 pm
"I'm wondering where the 7 kg figure originated here? With additive force on the braces, given that for each brace there are multiple rods, is 7 kg overkill?"

The 7 kg figure was just sucked out of my head! I'd never used a go-bar deck before attempting to build one. At the time, it just seemed like a good number. In retrospect, I think 7 kg is too great a force, and between 3 kg and 5 kg is a better number. Those with "true" knowledge of the matter (like, someone who has bought a commercially available deck and go-bars might wish to chime in here .......

Frank
Martin

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WJ Guitars
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Re: Go-bar rods

Post by WJ Guitars » Wed Dec 19, 2018 3:56 pm

When I bought my Go-bar rods I didn't consider trying to reduce costs (probably now more experience than when I initially set up my workshop should have looked around more locally). I just purchased them from LMI. They included plastic end protections covers. They are great.

Wayne
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