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Guys,

I was wondering if my go bars are 24" long and are fiberglass. How close
together should my go bar deck be to apply the right amount of pressure?
Thanks.

Ross

Hi Rossy

Good Question, I asked the same a while ago and got some good information in the thread below

http://www.luthiersforum.com/forum/forum_posts.asp?TID=5045& KW=go+bar+deck#forumTop


Hope this helpsRussellR38813.7908796296

Thanks Russell,

That was really helpful. I'm doing the split level thing so I can do my braces
as well as glue my top and back. Thanks again.

Ross

No Problem Ross

What I did on mine was.

I made the overall deck 27", giving approx 1" of flex on my bodies with my protective packer in place, I made my removable platform 3 1/2" to allow for the thickness of my radius dishes and then give an appox 1" of flex when gluing tops and back.

Ross,

If you want flexibility in go bar pressure and/or height of item youre
gluing up then consider making the base of your go bar deck adjustable. I
just have a "false floor" on my deck which sits on supporting chocks of
varying thicknesses....the chocks are just offcuts of MDF. Not very flash
looking but it works for me.

Cheers Martin

[QUOTE=kiwigeo] Ross,

If you want flexibility in go bar pressure and/or height of item youre
gluing up then consider making the base of your go bar deck adjustable. I
just have a "false floor" on my deck which sits on supporting chocks of
varying thicknesses....the chocks are just offcuts of MDF. Not very flash
looking but it works for me.

Cheers Martin[/QUOTE]

If you're also changing go bar length, you will end up with a change in clamping force. But, just adjusting deck height, and using the same go bars, won't change the force. The force a go bar applies doesn't depend on how much you compress it. (unless it takes a permanent set, or you break it).

This is why you don't need to have a split-level go bar deck to clamp things of different heights.

If this doesn't seem right to you - try it by pressing a go bar down onto a bathroom scale. Change the compression and see what happens to the force.


Phil

mine is made with 3/4" all-thread rods with nuts and washers on both sides of the upper deck. I cand adjust the height from 12" to 30" tall in a matter of a min or two.

I never use it less than 24" but often use more than 24" for attaching back and top

Howdy,

You've probably already seen this but StewMac has good instructions on how to make a 'Go-Bar Clamping system'...I followed it and it works well. I use 24" rods from LMI, but as Phil said in a previous posting, diameter is the key to pressure.

http://www.stewmac.com/shop/Tools/Clamps,_support_tools/1/Go -bar_Clamping_System/Instructions/I-4733.html#details

Thanks guys and gal.

[QUOTE=Phil Marino]

If you're also changing go bar length, you will end up with a change in
clamping force. But, just adjusting deck height, and using the same go
bars, won't change the force. The force a go bar applies doesn't depend
on how much you compress it. (unless it takes a permanent set, or you
break it).

This is why you don't need to have a split-level go bar deck to clamp
things of different heights.

If this doesn't seem right to you - try it by pressing a go bar down onto a
bathroom scale. Change the compression and see what happens to the
force.


Phil[/QUOTE]

I stand corrected...will do the little test on the bathroom sclaes with my
hoop pine go bars anyway just out of interest.

I guess what I really was trying to say was that where youre trying to hold
down a high item on the go bar deck and its taking alot of force to bend
the go bars (and increasing chance of them breaking) to fit between the
top of the deck and the item, its easier adjusting lower deck height than
going to different length go bars.

Cheers Martin

[QUOTE=ToddStock]

I adjust the height to avoid having to deflect the rods more than the
minimum necessary to get full clamping force - purely a safety issue.

Todd[/QUOTE]

This is what I was trying to say.