Pressure when laminating

[mikekeswick]

Get a strip of material and staple on blocks of wood 1 inch in length and about a 1/4 inch apart the length of your intended bow. This makes a great, adjustable for any curve, even pressure 'device'. I use these when using thin backing strips...I learnt the hard way that thin/wide backings and inner tubes leave a 'crowned' back!

[Parnell]

It's been awhile since I did glue ups but I found the inner tubes to be too finicky with pressure and just unpredictable.  I like wrapping them with string/cordage.  It has much better even pressure and the wraps can be easily controlled.  Just my 2 cents.  You've got way more experience than me!!!

[Badger]

Get a strip of material and staple on blocks of wood 1 inch in length and about a 1/4 inch apart the length of your intended bow. This makes a great, adjustable for any curve, even pressure 'device'. I use these when using thin backing strips...I learnt the hard way that thin/wide backings and inner tubes leave a 'crowned' back!

This is what I will probably end up doing

[Don Case]

Get a strip of material and staple on blocks of wood 1 inch in length and about a 1/4 inch apart the length of your intended bow. This makes a great, adjustable for any curve, even pressure 'device'. I use these when using thin backing strips...I learnt the hard way that thin/wide backings and inner tubes leave a 'crowned' back!

Do you use inner tube to clamp this 'devise'?

[zenart]

Get a strip of material and staple on blocks of wood 1 inch in length and about a 1/4 inch apart the length of your intended bow. This makes a great, adjustable for any curve, even pressure 'device'. I use these when using thin backing strips...I learnt the hard way that thin/wide backings and inner tubes leave a 'crowned' back!

Do you use inner tube to clamp this 'devise'?

I think that's what their saying Don. Using inner tube, has good tension. But I would imagine you could use cordage as well. The main idea is to get consistent pressure along the crown and edges.

[bushboy]

Blackhawk pointed out a while back that a slightly narrower backing strip in relation to the belly will go a long way in preventing crown buckling. I use rubber roofing membrane cut in 3/4" strip, then add clothesline style clamps,c clamps and bar clamps.

[Badger]

  Tension on the edges is what gives us good glue lines. The inner tubes are good about this. If we use something to increase the crown we can have better control over spreading out the pressure. Just messing around with some test pieces I am leaning toward a lower crowned center strip, just enough to keep the center flat but still have a little extra on the edges. I am thinking 1/4" high might be enough. Nothing needed where limb is below 1 1/4 wide. Also if backing is just slightly narrower than core I think it helps.

[dragonman]

whats wrong with G-clamps?  ( I think they may be called C-clamps over there!)    I always use them with no problems! controlable pressure just where you want it.....I guess the amount needed 30-40, is expensive to buy all at once.