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Main Boards => The Bowyer's Bench => Topic started by: bsv on March 20, 2019, 11:37:41 AM

Title: bow form material
Post by: bsv on March 20, 2019, 11:37:41 AM

is mdf okay for forms I have access to all thickness at work.. Thanks Burt

Title: Re: bow form material
Post by: Flem on March 20, 2019, 12:03:10 PM

Mdf has real good compressive strength on its flat surface, not so much on the edge. I would guess if you used a stout piece of material on the assembled face, it would be OK. Hopefully somebody who uses a high pressure hose system will chime in.

Title: Re: bow form material
Post by: David Flanrey on March 20, 2019, 12:31:12 PM

I use LVL and run it through a planer or drum sander to get the thickness I want.

Title: Re: bow form material
Post by: bsv on March 20, 2019, 12:46:53 PM

My plan is the topless method I saw on here in a video,Steel plates on the sides with steel pins and mule tape with pressure hose..formica on the top of the form.we have a laser at work to make the plates. Burt

Title: Re: bow form material
Post by: bsv on March 20, 2019, 12:52:07 PM

when I think LVL I think I-beam shape,Can ya get LVL at home stores?

Title: Re: bow form material
Post by: JWheel on March 20, 2019, 02:20:10 PM

I've used 3/4" birch plywood glued n screwed together to make 1.5" thick....I think you may have problems getting formica to glue to the MDF surface.

Title: Re: bow form material
Post by: Crooked Stic on March 20, 2019, 02:57:59 PM

You are better of using LVL or 5 or 7 layer plywood. MDF not good with moisture. And I have seen pics of forms that broke under pressure.

Title: Re: bow form material
Post by: bsv on March 20, 2019, 03:26:52 PM

Thank-you I have found 2x11x8ft LVL for $47 bucks  :goldtooth: :goldtooth:

Title: Re: bow form material
Post by: monterey on March 20, 2019, 03:40:55 PM

Is the  LVL a true 2"?

Title: Re: bow form material
Post by: Crittergetter on March 20, 2019, 09:12:22 PM

I wouldn’t trust mdf.
I use lvl and no complaints. I run it through the wide belt and get it down to desired thickness for both recurve and lb forms.

Title: Re: bow form material
Post by: skeaterbait on March 21, 2019, 06:23:02 AM

What is the difference between LVL and just gluing plywood together? Aside from with LVL the factory gets to worry about straightness

Title: Re: bow form material
Post by: bsv on March 21, 2019, 07:35:38 AM

It is not a true 2 inch but I will bring it down to 1.5 with Kennym"s method on his build-along

Title: Re: bow form material
Post by: Forwardhandle on March 21, 2019, 09:15:42 AM

That LVL sounds interesting I been using deminsional maple for my topless forms 2 peaces plied together perfect 1 1/2 " and face the top with .040 glass I really like the topless form now I got all the bugs worked out !

Title: Re: bow form material
Post by: bsv on March 21, 2019, 10:01:11 AM

this will be my first laminated bow but that style seems to fit me..

Title: Re: bow form material
Post by: jess stuart on March 21, 2019, 11:02:51 AM

I have several MDF forms for takedowns, made a bunch of limbs on them without issue.  I do reinforce the form with 3/8" plywood.  MDF mills very easy but does have some drawbacks, heavy, doesn't do well if wet, soft and can chip easily
 I would not use it for a full length form  too heavy.  I think the LVL is the way to go, especially for a one piece form.

Title: Re: bow form material
Post by: Stagmitis on March 23, 2019, 04:47:40 PM

Every form I have ever made from LVL has twisted/warped whether using heat strips or hot box. String alignment became impossible and I tossed quite a few bows in the garbage before I figured it out. Btw, this twist is difficult to detect.  I only use cabinet grade 3/4 plywood and have had no issues since.