Keeping lams straight during glue-up?

[Sharp Shooter]

I use a limb press similiar to Bingham's recurve design. The problem that I run into is keeping the stack straight. I'm thinking about trying wrapping sarah wrap around the stack full lenght after glue up, wrapping 2-3 wraps of tape then, putting them in the press with 65 lbs air pressure. Does anyone see a problem with this idea? Thanks Tony

[3point or better]

how about putting some washers along the from to keep everthing in line then you can spin the washers out of the way as you pump  up the air hose.

[Dick in Seattle]

nothing beats the side washers for keeping things straight.   You may find that in the riser area they aren't high enough.  I made some metal fingers to reach up so that the lams and risers are held in place.  Don't forget the tip wedge area if you use them.

Another trick I find helpful is that before the layup, I take the whole stack, including wedges and turn it sideways, held between two rigid boards I use for the purpose and run it through the drum sander to reduce the width to exactly the width of the form top.  Same with the riser.  If everything is exactly the same width it's a lot easier to keep it aligned.

[Sharp Shooter]

I forgot to mention, my limb press is 2" wide and stack width is 1.75". Tony

[Robertfishes]

sounds like you need to use 2" lams for your 2" form and install the washers for good results.

[T Folts]

I think you will have the tape marks on your glass after they are cured. You need either wider lams or find a way to keep them in plase using shims or something on the side and washers.

[Roy from Pa]

My form is 1.5 wide like my lams are and has 1 inch small boards along the side to keep the lams straight. I also wrap the bow with plastic wrap and then wrap high strength tape around the limbs before gule up.

[dcmeckel]

I do like Roy from Pa.,my form is 1.5 inches wide as are my long-bows.Don't deal yourself misery,make a form to match the width of bow you plan on making.

[Pat B]

After adding the dlue to your stack wrap tape every couple of inches along the entire bow before putting it in the press. When I built my one glass bow Bingham sold heat resistant tape for this purpose.

[Sharp Shooter]

Have you ever had a problem with the tape leaving marks after curing? I use the 1 1/2" hose with 60-65 lbs pressure. Tony

[Pat B]

I only did one but tape residue can be removed with a solvent like alcohol or acetone.

[Dick in Seattle]

If I were faced with a situation where my plan involved a narrower layup than my form, I'd make the full width layup, i.e. make it 2", then use the drum sander and grind it back down to the desired width.   Either that or build some side braces that are "step in" to make up the difference.   I made a set of forms... 1 1/2", 1 3/4" and 2".  Don't use anything but the 1 1/2" any more, but I'm ready for whatever comes up.   Course, my builds are easier;  I don't mess with hoses and stuff, just good old fashioned clamps.   Tried the hoses three times and still have nightmares.

[Walt Francis]

Like others, I highly recommend using a form that is the same width as your glass and other materials.  However, if you already have a two-inch form and use 1 ¾” material there at least two options I know of.  First, countersink any screws and/or metal on your form then run it through a planer and then a thickness sander until you reach the desired thickness.  The other method is to add large washers as suggested before but counter sink them ¼” on one side of your form, which keeps your lay up material in line.  I did this with a form once and it worked well; I used a plunge router set at 3/32” to hog-out/countersink the washers to the depth I needed.  Also, use washers on both sides of the form.

[GREG IN MALAD]

Tony,
Laminations sliding can be caused by several things. The first is using WAY too much glue, this is a common problem that I see. Another problem is applying too much pressure, too fast, give the excess glue a chance to squeeze out slowly. Make sure the air hose is centered in the form, if it's off to one side it will push the lams out the other side. And finally, if your form is twisted it will push the lams to the side.

[Sharp Shooter]

Thanks everyone for your comments, I glued up a limb today using plastic wrap and taping every 6" or so, it seemed to work OK? I'll find out tomorrow. Thanks again Tony

[**DONOTDELETE**]

[Sharp Shooter]

Well, the plastic wrap worked, alittle more glue to remove along the limb edges but, lams and wedge stayed lined up. worked good!! Thanks everyone. Tony