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Main Boards => The Bowyer's Bench => Topic started by: Mad Max on September 06, 2019, 05:03:44 PM

Title: What to use for a bow form
Post by: Mad Max on September 06, 2019, 05:03:44 PM

what do you use??????????
I have used 7 ply, 3/4" plywood but I still get some warping.
Do you think 1/4" plywood would be better?

(https://i.imgur.com/u2YUToK.jpg)
See the 1" wide strap left to right on the lower form.
bolted to the form on each end and a push bolt to take out the curve (left to right)

Title: Re: What to use for a bow form
Post by: Forwardhandle on September 06, 2019, 06:22:18 PM

I have never used plywood in a form but use 1" dimensional sugar maple boards laminated together & never hade any movement on them ,I don't know how wide your going but two 1" boards comes out at 1 1/2 " 

Title: Re: What to use for a bow form
Post by: Bob T. on September 06, 2019, 07:43:22 PM

That strap really does not do much. I have always used angle iron from old bed frames bolted threw the bottom of my bow forms.

Title: Re: What to use for a bow form
Post by: Mad Max on September 06, 2019, 08:24:21 PM

Quote from: Bob T. on September 06, 2019, 07:43:22 PM

That strap really does not do much. I have always used angle iron from old bed frames bolted threw the bottom of my bow forms.

Bob the form, using a straight edge has about 1/16" gap in the middle (centerline of the form) , the bolt is pushing on the middle of the form. back into place.
I have used 2" angle iron but it does not do as good as this strap.
(https://i.imgur.com/85GEwqU.jpg)

Title: Re: What to use for a bow form
Post by: Bob T. on September 06, 2019, 09:30:05 PM

max, When I looked at your picture of your form I did not see your adjustment bolt. I though the strap was just bolted to the side, sorry.
Bob

Title: Re: What to use for a bow form
Post by: Shredd on September 06, 2019, 10:44:53 PM

Do you put your forms in an oven??  How many degrees???  Do you ramp up the heat fast or slow and steady??

Title: Re: What to use for a bow form
Post by: monterey on September 06, 2019, 10:54:02 PM

I like the strap.

Title: Re: What to use for a bow form
Post by: Mad Max on September 06, 2019, 11:21:16 PM

Quote from: Shredd on September 06, 2019, 10:44:53 PM

Do you put your forms in an oven??  How many degrees???  Do you ramp up the heat fast or slow and steady??

I don't think I put that one in the oven ever.
My hot box takes 1 hour to come up to temp. with the form in. 180*
Check your forms with a long straight edge.
With the high reflex and static recurves I always check my forms, I have some other ones with straps too.
Plywood warps, some of my pattern sanding templates warp also.

Title: Re: What to use for a bow form
Post by: OkKeith on September 06, 2019, 11:37:23 PM

The one form I built I used three quarter MDF. I glued two pieces together and then used a pattern and patterning router bit to cut the bow shape. I don't use air hose though, just rubber bands and bicycle inner tubes.

That looks like there is a lot of force in that system when it gets all aired up!

Who was it that posted a solid aluminum form? I bet that doesn't warp any.

OkKeith

Title: Re: What to use for a bow form
Post by: hunting badger on September 07, 2019, 01:35:53 AM

I use LVL on all my newer forms, I haven't had a problem to date.

Title: Re: What to use for a bow form
Post by: Walt Francis on September 07, 2019, 12:12:17 PM

I use LVL and bolt a 1 1/2” angle along the full length of the bottom

Title: Re: What to use for a bow form
Post by: bamboo on September 13, 2019, 05:45:38 PM

i've had good luck with laminated spruce scaffold planks--very stiff and true

Title: Re: What to use for a bow form
Post by: Mad Max on September 13, 2019, 06:08:46 PM

Thanks for the info guy's

Title: Re: What to use for a bow form
Post by: Flem on September 14, 2019, 10:26:10 AM

One word, Plastic.
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Title: Re: What to use for a bow form
Post by: Roy from Pa on September 14, 2019, 10:33:54 AM

One word, Clamps..

Title: Re: What to use for a bow form
Post by: Crooked Stic on September 14, 2019, 12:32:27 PM

 :notworthy:

Title: Re: What to use for a bow form
Post by: Flem on September 14, 2019, 05:42:20 PM

That looks like a torture device. And I'm not sure if the Bow is the thing that got tortured :bigsmyl:

Title: Re: What to use for a bow form
Post by: Roy from Pa on September 14, 2019, 06:03:39 PM

Nock it off, Clem..... :)

Title: Re: What to use for a bow form
Post by: Robertfishes on September 14, 2019, 11:01:09 PM

I have only used Cabinet grade plywood myself.. along with a thin "filler piece" of thin wood like a door skin if needed to make thickness. I use tite bond 2 glue and lots of wood screws, if building a 1 3/4 inch wide form i use 1.5" screws put in from both sides. I think glue alone is not enough for a multi piece bow form, I have a bow oven and heat up to 160 degrees.  Bowyers with big wide belt sanders can build forms thick and sand it down to correct thickness.  LVL is used by lots of successful bowyers. 

Title: Re: What to use for a bow form
Post by: Mad Max on September 14, 2019, 11:17:21 PM

Thanks Robert
 :thumbsup: