MDF bow form ?

[IAOUTDOORSMAN]

I'm going to try and make my first bow in the next couple of weeks.  I have 3/4 MDF and plan on making the form in the next couple of days using Kenny M's method.

question 1?
what is the best glue to use gluing the form together?  I have titebond III and gorila.
question 2?
Do you use a formica strip on the MDX form?  If so what is the best way to attach it (glue, screws, both)?

[kennym]

Better use titebond and strategically placed screws,gorilla will swell I believe.

The MDF is full 3/4 so will make exactly 1.5" form. Kerry's form was completed with good sized 1/2" ply screwed on where the bolts go thru the form.

I don't even use formica anymore,just sand smooth with a sanding block carefully, and wax or silicone spray it.

All JMO  :cool:

[wihill]

Use Titebond.  I've glued far too many MDF boxes together, and know what NOT to use - gorrilla works, but it'll swell and expand past your edges.  Once it dries up, it's a pain to remove all the bubbles etc.

I'm really interested in how these MDF forms will work out for you guys, my experience with it leads me to believe it might work for a couple bows, but it won't last.   Good maybe for prototyping a new design?  

Also, are you guys using the 3/4 or the 1/2" MDF to make your forms?  Just curious...

Another option could be HDF, but it's not as easy to find, but much more stable.

[Tunames]

What about OSB ( chipboard ) ?

[Robertfishes]

I have no experiance working with MDF. I talked to my neighbor who owns and operates a fair sized cabinet shop about making bow forms. His opinion was that the plywood they use would be better choice than the MDF that they also use.

[Str8Arrow]

MDF may have some advantages. It is very stable and likely to be very flat. You might have to use some re-enforcement to keep it intact. Maybe some laminate on the top of the form. It is very heavy. I'm not sure if that would be an advantage or a disadvantage.

[Jeremy]

My bow forms are MDF.  I just used screws, no glue, but later reinforced it with nuts and bolts.

You'll run into a problem if your shop is very humid (like the garage I was gluing bows up in).  Basically, as the form is sitting in the shop it's soaking up all the moisture in the air and gets to a very high moisture content.  Throw it in your hotbox and it'll dry out quickly, but will distort.  A couple of cycles of this and the screws will be pulled out and the form unusable.  I added the bolts to keep the distortion to a minimum and they're holding up better.

[Robertfishes]

Jeremy thanks, good info, it is very humid here in Florida that is why the cabinet shop guy suggested that I not use the MDF.

[wihill]

Originally posted by Tunames:
What about OSB ( chipboard ) ?

OSB won't work at all - the chips are too varied in size, you'll have voids in the pockets, it's just bad stuff.  

If you're refering to particle board (like MDF but much smaller particles/chips than OSB) you can't get as nice of a cut on in, and it tends to crumble very easily.  

I know it's pricy, but any hardwood plywood would be the best bet - MFD would work for a couple, but MDF's really just compressed cardboard - any humidity/water will just wreak havoc on it.

[bjhaug]

There are certain types of particle board to use.  OSB is a little rugged to use as wihill said, but some of the better particle board is just fine.  I made several forms of this type of wood.  If there were any voids, (we're talkin small) I simply used vinyl spackling to fill them, or just coated the whole surface with epoxy.

[razorsharptokill]

I ran a 6' pc of 1 1/2" angle iron down one edge of the form on the bottom to retain the straightness. I think as long as it stays dry it will be ok.