First form for first bow

[Susquehannariverarcher]

Last night I made a form out of a 3/4" piece of birch plywood. I was able to snag the board for half of due a small gash in it. Anyways, I cut it down to two 14"x65" pieces and glued them together. Its about 1/16 narrow of 1.5". The edges also aren't perfectly flush, I'm guessing due to not square factory cuts. My plan is to run it on the table saw take off about 1/8" to flush it up.

Is that 1/16" a big deal? I thought about adding a washer to my washer that I will use to hold lams on place.

[Stagmitis]

Hey Suskie for my forms using 3/4 plywood I use a 72" 1.5" Aluminum strip on top to match my lam width.

[Susquehannariverarcher]

Hey Suskie for my forms using 3/4 plywood I use a 72" 1.5" Aluminum strip on top to match my lam width.

I have a 1.5" pressure strip from big jim I plan on using. That goes underneath the fire hose and above the lam, right?

[Stagmitis]

No pressure strips are too thin-  you can get aluminum strips at HD-1.5 wide,1/8" thick by 72" long

[Stagmitis]

And yes thats where the pressure strip goes 

[Stagmitis]

just to be clear the 1/8" aluminum strip goes right on top of the form- youre just creating a base to evenly support your lams

[Mad Max]

just to be clear the 1/8" aluminum strip goes right on top of the form- youre just creating a base to evenly support your lams

do you glue it on?

[Stagmitis]

Max I use a spray contact cement and evenly split the ovehang on both sides. I am going back to LVL`s but will bolster the sides with channel iron since Ive had them warp on me in the past. I like the fact that you can get these dead nuts for the width.

[Kirkll]

Your form should work fine a wee bit narrow… when I built plywood forms like that, the first thing I did was used epoxy and glued an edge band into the shape of the form with a couple 1/8” pieces of  hardwood. Either red oak or maple. I liked to use a heavier edge band on the bottom too, to help keep it straight, or simply screw a piece of angle iron to my one piece forms.

After the form was completed I seal the whole form with shellac or an economical brushing lacquer.(This part is important)

But…. With the quality of 3/4” plywood these days, and expense…. I have replaced most of my forms, and built newer forms with LVL material and did not sand them for thickness at all. I leave the factory sealer on them and keep the thickness at 1.75” , even for my 1.5” longbow forms. I’ve had real good luck with these staying straight, with no twist for years now.

Many years ago I quit using a hot box and prefer a heat strip curing method. This added further longevity to my forms not being cooked again and again, and I don’t have to muscle those heavy one piece forms in and out of a box either. When I found out about the battery charger heat strip method, it required purchasing stainless steel pressure strips that are longer than the form and I can attach the charger clamps too.

Prior to using this system I used aluminum pressure strips, and they seemed to work well until getting a lot of epoxy on them, and needing to sand them smooth again. I found that the aluminum is pretty soft and can easily be deformed by sanding without notice and found slight imperfections in the glass after lay up.

When I upgraded to stainless steel pressure strips / heat strips this eliminated that problem. They are much easier to sand smooth without ant deformation. So even if you are going to use a hot box or no heat at all, I would highly recommended the 303 stainless in an 18 gage over aluminum.

Another little trick that evolved with years of experience, is getting rid of side washers or tabs on the edge of my forms, and using heavy zip ties to hold your lams straight in the form. You just drill 5/16-3/8” holes every 6-8” along the bottom edge of your form about an inch down from the edge. These work really nice on all types of bow designs allowing you to get everything positioned just right before buttoning up your form and applying air to the hose. It also makes cleaning up your pressure strips much easier.     Food for thought.    Kirk

[Mad Max]

Max I use a spray contact cement and evenly split the ovehang on both sides. I am going back to LVL`s but will bolster the sides with channel iron since Ive had them warp on me in the past. I like the fact that you can get these dead nuts for the width.

 

[Susquehannariverarcher]

just to be clear the 1/8" aluminum strip goes right on top of the form- youre just creating a base to evenly support your lams

Ohh ok that makes sense. Thank you.

[BO-R]

Your form should work fine a wee bit narrow… when I built plywood forms like that, the first thing I did was used epoxy and glued an edge band into the shape of the form with a couple 1/8” pieces of  hardwood. Either red oak or maple. I liked to use a heavier edge band on the bottom too, to help keep it straight, or simply screw a piece of angle iron to my one piece forms.

After the form was completed I seal the whole form with shellac or an economical brushing lacquer.(This part is important)

But…. With the quality of 3/4” plywood these days, and expense…. I have replaced most of my forms, and built newer forms with LVL material and did not sand them for thickness at all. I leave the factory sealer on them and keep the thickness at 1.75” , even for my 1.5” longbow forms. I’ve had real good luck with these staying straight, with no twist for years now.

Many years ago I quit using a hot box and prefer a heat strip curing method. This added further longevity to my forms not being cooked again and again, and I don’t have to muscle those heavy one piece forms in and out of a box either. When I found out about the battery charger heat strip method, it required purchasing stainless steel pressure strips that are longer than the form and I can attach the charger clamps too.

Prior to using this system I used aluminum pressure strips, and they seemed to work well until getting a lot of epoxy on them, and needing to sand them smooth again. I found that the aluminum is pretty soft and can easily be deformed by sanding without notice and found slight imperfections in the glass after lay up.

When I upgraded to stainless steel pressure strips / heat strips this eliminated that problem. They are much easier to sand smooth without ant deformation. So even if you are going to use a hot box or no heat at all, I would highly recommended the 303 stainless in an 18 gage over aluminum.

Another little trick that evolved with years of experience, is getting rid of side washers or tabs on the edge of my forms, and using heavy zip ties to hold your lams straight in the form. You just drill 5/16-3/8” holes every 6-8” along the bottom edge of your form about an inch down from the edge. These work really nice on all types of bow designs allowing you to get everything positioned just right before buttoning up your form and applying air to the hose. It also makes cleaning up your pressure strips much easier.     Food for thought.    Kirk

TRUE!

[Susquehannariverarcher]

Your form should work fine a wee bit narrow… when I built plywood forms like that, the first thing I did was used epoxy and glued an edge band into the shape of the form with a couple 1/8” pieces of  hardwood. Either red oak or maple. I liked to use a heavier edge band on the bottom too, to help keep it straight, or simply screw a piece of angle iron to my one piece forms.

After the form was completed I seal the whole form with shellac or an economical brushing lacquer.(This part is important)

But…. With the quality of 3/4” plywood these days, and expense…. I have replaced most of my forms, and built newer forms with LVL material and did not sand them for thickness at all. I leave the factory sealer on them and keep the thickness at 1.75” , even for my 1.5” longbow forms. I’ve had real good luck with these staying straight, with no twist for years now.

Many years ago I quit using a hot box and prefer a heat strip curing method. This added further longevity to my forms not being cooked again and again, and I don’t have to muscle those heavy one piece forms in and out of a box either. When I found out about the battery charger heat strip method, it required purchasing stainless steel pressure strips that are longer than the form and I can attach the charger clamps too.

Prior to using this system I used aluminum pressure strips, and they seemed to work well until getting a lot of epoxy on them, and needing to sand them smooth again. I found that the aluminum is pretty soft and can easily be deformed by sanding without notice and found slight imperfections in the glass after lay up.

When I upgraded to stainless steel pressure strips / heat strips this eliminated that problem. They are much easier to sand smooth without ant deformation. So even if you are going to use a hot box or no heat at all, I would highly recommended the 303 stainless in an 18 gage over aluminum.

Another little trick that evolved with years of experience, is getting rid of side washers or tabs on the edge of my forms, and using heavy zip ties to hold your lams straight in the form. You just drill 5/16-3/8” holes every 6-8” along the bottom edge of your form about an inch down from the edge. These work really nice on all types of bow designs allowing you to get everything positioned just right before buttoning up your form and applying air to the hose. It also makes cleaning up your pressure strips much easier.     Food for thought.    Kirk

Thanks for all the information. I may try this route on my next form. I like the zip ties idea.

[Kirkll]

These are the zip ties you want... You can put a lot of pressure on these without breaking them.

https://www.amazon.com/gp/product/B07B5C5YD5/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&th=1

[Longcruise]

I want mine to be the exact width of the lams.  I get there with a filler.  Usually roofing felt but sometimes thin laminate that I've come across.

[Kirkll]

I just rebuilt a long bow form last year that I use 1.5” glass and lams in. I stayed with the 1.75” LVL. And just took a router and mortised out slots ever 6-8” 1/8” deep on each side where I use my zip ties to center up bow in the form.

The extra mass in these LVL forms help with twist and straightness longevity.

[Mad Max]

I have used "Ram Board" to make it wider

[Kirkll]

I want mine to be the exact width of the lams.  I get there with a filler.  Usually roofing felt but sometimes thin laminate that I've come across.

I’d be checking those laminated forms a lot for twist doing that….Do you edge band them with hardwood?

[Susquehannariverarcher]

I just rebuilt a long bow form last year that I use 1.5” glass and lams in. I stayed with the 1.75” LVL. And just took a router and mortised out slots ever 6-8” 1/8” deep on each side where I use my zip ties to center up bow in the form.

The extra mass in these LVL forms help with twist and straightness longevity.

Wheres the best place to get LVL. I couldn't find any around me. Granted I didn't look that hard.

[Stagmitis]

https://www.homedepot.com/p/1-3-4-in-x-9-1-2-in-x-20-ft-Laminated-Veneer-Lumber-626251/202526239?source=shoppingads&locale=en-US&pla&mtc=SHOPPING-BF-ARM-GGL-Multi-Multi-NA-NA-NA-PLALIA-NA-RKT-NA-NA-NBR-NA-NA-NA-ALL_IN_TEST_THRIFTTRAD&cm_mmc=SHOPPING-BF-ARM-GGL-Multi-Multi-NA-NA-NA-PLALIA-NA-RKT-NA-NA-NBR-NA-NA-NA-ALL_IN_TEST_THRIFTTRAD-71700000110012104-58700008378060418-92700076247482225&gad_source=1&gclid=CjwKCAiAsIGrBhAAEiwAEzMlCwXdvKSymBuzvd7vjVDApWbXh3csGG_yzm1YEWs4lXTj6ef29Yl4EhoClBUQAvD_BwE&gclsrc=aw.ds