How to build an airhose form- build along

[bjansen]

I built a new form today and took some pics along the way, so here comes a build along.  Surely there are alternate ways to do this but this is my method:

First, select your design.  Looks like someone has their eye on a hill bow.  



I am building this form with about 3/4" of backset as you can see compared to the straightedge.  I drew out the bow and then created a half template.  I used a scrap piece of birch plywood that I cut on a bandsaw and then sanded it perfectly smooth.  

[bjansen]

Next for form material.  I have tried many different things, but the best I have found is a piece of Laminated Veneer Lumber (LVL).  They are available at some big box stores and you might be able to find a construction buddy to get a piece as well.  This piece cost $32 from a lumber dealer.  It was 1 3/4 wide (exactly) and 74" long, 11 7/8" tall.  I ran it through the planer to arrive at 1.5" in width (although I hear some big box stores carry it in 1.5" widths as well).  

[bjansen]

Lay your template on the form material and scribe out the form line.  



Flip it and then scribe the other side.  I then take a compass and scribe a line 1.25" above the form line.  For a heavy piece of lumber, this will give you plenty of room for a rough cut on the bandsaw to split the form.

[bjansen]

Now take the bottom side of the form and cut about 1/16" from the scribed form line.

 

Back to the workbench, clamp the piece and attach your template. Be sure to sand the template to make it flat and smooth as the router will need to ride on top of this.  

 

[bjansen]

Using a flush cutting bit with a top bearing (which will ride on your template) make a first pass, then a clean up pass.  You should be left with a nice clean surface matched exactly to your template.  Now flip your template over to the other side and repeat.  

 

If your bit is not deep enough to go through the entire form (like mine), use your fresh cut form surface for the bearing to ride on to make the second pass.  You should be left with your form surface.

[bjansen]

Put the two half together again and draw out your riser relief which will then be cut out on the bandsaw.  

 



Now to attach the two halfs.  I cut some scrap pieces of plywood for spacers (to keep the metal directly off the side of the form so the airhose is not constricted), then I went to the hardware store to pick up some bolts, eye bolts and these metal plates (probably a name for them).  I typically bought these connection assemblies from Bingham's but thought I would try it myself from items found at a local hardware store.  

 

[Diamondback59]

hey brad  how are ya? been a while im finnaly back home the lil guy sure is gettin big  keep them pic s a comin im watchin this brock

[bjansen]

Glue on one sides worth of spacers



Then we are ready to drill the holes to mount the metal brackets.  Using 1.5" wide spacers and using your brackets, drill the holes through.  

[bjansen]

Then flip the form over and glue on the remaining spacers over the holes:



Flip it over and then drill through again.  I then take a larger sized bit and re-drill the holes to allow a little play.  

Mount the brackets and then check for allignment prior to tightening them up:

[bjansen]

I then will glue on a strip of hickory, or glass to make the surface smooth.  For this form, I glued on scrap lam, then a piece of glass.  

You can tape back on the riser relief cut out prior to the glue up to avoid having to make a riser.  

 



Also, if you want to attach temporary pieces to the sides to ensure the glass is alligned while inflating the hose, that helps.  



I then cleaned up the excess epoxy and let it cure.  

When removed from the oven clean up any excess epoxy and you have a form.

[GREG IN MALAD]

I'm going to try LVL for my next form, sure beats gluing plywood. Using eyebolts is a great idea, I have several forms without clamps because i'm too cheap to buy anymore.

[hova]

nice form , and nice bench!

[greyhawk39]

Your building along's are always nice to follow!

[Dmaxshawn]

Great job Brad as usual.  Can't hardly wait to see what comes out of the form.  

Shawn.

[jsweka]

Nice!

You just gotta love the simplicity of a Hill style bow and I can just imagine the beauty that will come off that form.

[Jered Shofner]

Great job Brad.  I was looking for some LVL for forms and found out the local lumber yard had several 6-8 ft pieces by the cut-off saw.  I think they charged me $1 / foot for the cut offs.

Your son is getting big!

[H8nonCubs]

Great pics easy to follow. One question though, what kind of setup do you have for the air hose? I'm sure you need some kind of reducer. Just wondering where to find something like that and how big of a compressor do you use? Any pics would be great also! Thanks

[bjansen]

Well the airhose is simply the firehouse and alluminum couplings sold on Bingham's Projects site.  One of the alluminum ends is a solid end, the other is tapped for a one way air fitting (like how you air up your car tire).  I just have a small pankake compressor but you can even do it by hand with a bike hand pump if you wanted.  I shoot for about 60-65 psi when I do my glue ups.

[Robertfishes]

Like bjansen I have had good results using a bike pump, I air up slowly checking hose alignment and for slippage of tapers,glass and riser every couple of pump strokes..once I get to 55 or so psi with the bike pump I use my air compressor to air up to 60-65 psi. I really like using the bike pump cause I can work slowly and keep an eye out for slippage..plus its a great back up if something happens to the compressor during glue up..I have 2 bike pumps and an extra (Binghams)1 1/2 inch firehose ready just in case..

[monterey]

Great illustrations and instructions!

Here is my question;  how do you set up to drill the holes for the clamps?  My drill press is too small to rassle the form onto to drill straight through.  Have never come up with a good alignment system to make the holes straight through at 90 deg to the form.

Any suggestions?