Tips about advanced Woodskills needed

Hi all,
I've modelled a phase plug but I can't figure how to build it....... cnc not availble sorry, just a router, a diy lathe, jigsaw
this is the shape

if you watch in front of it....you'll see this

you could look at cutting the hole out of a piece of ply then another 10mm smaller etc. Down to the opening size. Then using a rasp file it smooth.....

ehmmmmm quite rough..... smiley6

bitzo- would it be possible to obtain a chunk of balsa wood (Real soft), carve it down, then glass it over.
Or, over here we can get like large pieces of heavy styrofoam, Could carve that, then fiberglass

the issue is how to carve it to fit the calculated shape and be reproducibile...
I'm thinking to change the shape to be latheable...

I like Bee's idea. If you cut the pices out of mdf it will be easier to work on, and as long as you cut each piece accurately you will have a built in guide to shave it down to. A belt sander with a 40 grade belt will make it quite quick to remove the surplus. Also drill a hole dead centre in each pice to help glueing the slices together, just stack them up with a rod up the middle.

If your plan works you can then make a mould of the prototype to make the rest from grp.

Kieran

kieran i need to do a quick sketch of what i mean but you kinda got the idea. if for example your horn is 100mm in length and you use 10 pieces of ply at 10mm each. in each corner of the pieces of ply you would drill a hole in the exact same place. Then use a bit of threaded bolt through each hole then add nut on end. all the pieces would line up exactly in line. A sander would be great but may not fit inside if you use this method to make a small horn or any random shapes you can think of. In your case if you use mdf a small random orbit sander will do. If you where to draw to scale the curve of your shape on graph paper, then draw on each piece of ply you get the minimum size cut you can get away with. if you use mdf a good quality rasp wont take too long to file down. smiley20

Yes Bee, I now understand what you mean. Your idea is for a horn, you're thinking of making a horn. I meant to make a plug, same technique really.

Despite trying this method for plugs I never considered it for making the actual horn. You've got me thinking now- I could try this for some wacky shaped horns I'm planning. If I dont glue between the pieces I can bolt them with threaded rod and then easily make quite drastic changes by just swapping some of the layers for new pieces with different shaped holes. This should keep me busy in the spring/summer when it's warm enough to work outside. I don't like using mdf inside, the dust coats everything and takes ages to clear up.

Bitzo- what shape will the horn throat be? if you can get away with a rectangular cross section I know a way of doing it with a router. It will be much easier to calculate the cross sectional area than with an elliptical shape.

Kieran

throat will be rectangular...just a waveguide, the plug make it a proper horn. Now I'm thinking to model a plug in 2 section...the central one conical and latheable, the external the substraction from the one that I post from the conical....not so easy to calc the shape of that.

kieran this method would work for a plug as well just use one bolt dead center then use filler to hide hole when happy with. I have been playing around for a few weeks with this idea and so far had good results. its been the best way i have found so far. Ill try and get a few picks posted up.