How have you guys found to best make the molds adjustable to different sizes without remaking any parts? Is there a way?
Getting much close to having this project getting to construction. The press frame is going to be made this weekend (I hope) and then it's onto the molds.
i'm sure others have a much better method for an adjustable mold but here's a simple method:
1. first make just the camber portion with no tips or tails.
2. make the tip and tail molds separately. these tip and tail portions simply sit on top of the mold and are held in place using any of following methods: double-sided tape, bolts, nails, etc. i found that the strength of attachment doesn't need to be that strong. the force from your bladder will actually hold it place.
3. put a smooth, relatively thick piece of material (i.e. HDPE) covering the entire mold to make the transition from the tip/tail to the camber section smooth.
hope this helps.
note this mold is only adjustable for the ski length and tip/tail curvatures only. it doesn't allow you to adjust the camber, which would be difficult to design if you intend to use a pneumatic press.
thats pretty much what i did
I can get a lot of different thicknesses of HDPE. Would something like .025 be thick enough, or are you talking 1/8-1/4 of an inch?
you might want something a little thicker so it smoothes out the transition and any bumps in your ribs. For our molds, we have a couple of sheets of 1/8" melamine or hardboard (cheap at Home depot) with a 1/8" sheet of hdpe on top.
Why is MDF used? what is it about it that makes it the material to use over anything else?
I'm guessing it is because it doesn't compress or change under the pressure that a press puts on it, but couldn't you just make it out of some plain wood? Just looking for some info. for when I talk with the carpenter(s) who is(are) gonna help me make the molds.
We use mdf because it is:
1. relatively cheap (~$35 for 4'x8')
2. easy to machine
3. stable and very flat
4. strong in compression
the bad thing about mdf is it creates a lot of fine toxic
as alwys, thanks a ton for the info. I picked up (hopefully) the final load of i-beams tonight, and will start building the frame this weekend. I can do one of two things. I have enough i-beams to make a 2 8" wide sections of press with the top and bottom having no space between, OR I can have one 16-20 inch press with no spacing between the beams (16") or small spacing between the beams (>16"). What would you reconmend? is 8" enough to use for a mold?
If you make the adjustable bottom mold would you still need to make a different top mold?
I spent all day trying to make a jig for my router to cut out the tip/tail parts of the bottom mold. I cannot for the life of me figure it out. tigs/suggestions for making it, more specifically the curved section and how to fixture it?
1. First make a template of your tip/tail mold out of some scrap wood.
2. Secure wood template to a big piece of MDF (or whatever wood you plan on using for the tip/tail molds) with countersunk nails, double-sided tape, or hot glue. I use 3/8" thick wood or something similar. Your MDF should be large enough so that when your template is placed on it you can still clamp the MDF to your working table without getting in the way of your router.
3. Use your router with a either a template guide or a straight bit with a ball-bearing to follow the template and cut out the tip mold shape from the MDF.
4. Repeat for ____ number of pieces.
5. Glue pieces together using wood glue and clamp together.
6. Once the glue is cured, take your belt sander and sand away until the tip mold is nice and smooth.
I'm sure there are better ways of making a tip mold.
I made the mold using a turbocad printout of the tip, camber section and tail-> templates-> cut out and sand pieces->bolt together alternating pieces (tip/tail, then camber, then tip/tail again, etc.)
