[morphious69]

interesting. I have considered making molds from aluminum and casting HDPE parts using a high pressure press and vacuum system to draw in the molten HDPE. being the lowest level of friction of all the plastics it makes a lot of sense especially if it can be doped to keep it from having any creep. though I am thinking I should look into some sort of resin and fiber concept for making parts too. then I could use something like HDPE to make the molds from.

[microcarve]

interesting. I have considered making molds from aluminum and casting HDPE parts using a high pressure press and vacuum system to draw in the molten HDPE. being the lowest level of friction of all the plastics it makes a lot of sense especially if it can be doped to keep it from having any creep. though I am thinking I should look into some sort of resin and fiber concept for making parts too. then I could use something like HDPE to make the molds from.

I tried making parts from polyester/polystyrene resins....which I think
is basically the same as a lot of fiberglass resins. The smell was terrible...
and I'm usually OK with that sort of thing....
But the smell takes forever to leave your house if you do it indoors.

I tried epoxies, but a lot of them will actually boil and foam up if
much more than an oz is mixed in a cup.

HDPE can make molds, but getting a good clean mold finish isn't too
easy. It won't polish. Even then, it doesn't last long without a good mold
release.

The alumilite stuff can be used as a mold. Just make sure it's waxed...as
the mold release.....and doesn't have undercuts.

See how I made my e-chain....

http://www.cnczone.com/forums/diy-cn...achine-11.html



John

[ger21]

The 1/8" 2 flute bits from Drillman on Ebay are excellent, and unbeatable for $3.30 each (when you buy 10). You're not going to get very good chip removal with an 1/8" tool in MDF, as the dust and chips quickly pack into the cut. If you want the chips out, cut your 1/4" MDF in 4 passes at 200+ipm.

another issue that MDF has going for it, is it's ability to absorb vibrations with out being deformed by them. another option I am wondering if it would be useful in this is using fiberglass and resin on the parts inbetween the layers. cause the skin of the glue I use to stick layers together make the final wood part way stronger and less flexible than a solid piece of MDF of that thickness. And that glue is no where near as strong as the fiber glass resin mix.

I don't think fiberglass is stronger than glue in this application. Epoxy is much stronger than fiberglass.

One issue you'll run into, is that the resin will soak into the MDF, leaving very little for the actual bond, possible resulting in a weaker joint. If using epoxy, you'll need it to be fairly thick to prevent this.

A less expensive option than epoxy is plastic resin glue, which is a powder that you mix with water. It's one of the most rigid wood glues there is when cured, and will probably give you comparable strength to epoxy, for less money.

only other option I have been able to think of that would still keep costs down for the end buyer on these, is using thin stock aluminum (like close to 1/8th inch thick) and layering that on the outside of something like the MDF or a plastic

Both aluminum and most plastics are very difficult to bond, as most glues don't adhere well to either. There are "primers" for both that can increase bonding strength, though.

Another inexpensive option is to use plastic laminate (Formica) on the outside of your MDF. It will greatly increase rigidity of your panels, and is not too expensive.

[morphious69]

thanks all, those are some brilliant insights. I will look into it all. glad to be able to pose my ideas to people who have so much experience.

that plastic resin glue I will have to look into for sure. with the aluminum and plastic or MDF idea I was planning on relying on the glue for vacuum and screws and nuts for permanency. not sure how that would work. but I have some I can experiment with.

I work with sheet metal a lot and use a lot of different techniques to get rigidity out of it that should not be possible too. hopefully I can use some of those ideas to improve things. I will definitely post on all my tests too, incase it might be helpful to others.

[morphious69]

Drillman1's bits I bought came in today. paid for them Thursday night late so that was pretty good shipping considering the soonest he could have shipped was Friday morning and I got them the following Monday. once I have ran the unit and tested them I will also comment on their quality, but from giving them a much more discriminating eye, I do feel confident that they will perform as I am expecting.

[morphious69]

not entirely sure what it means in the long term but the cuts these bits are doing are far superior to anything else I have had. the extra bits of MDF that normally stick up or the excessive bits that stuck up from those other new bits I got, are almost non-existent with these bits. the cut edges are just incredibly clean and sharp. if these can keep that up for as long as the original bits I got that had only minor stuff sticking up *wholesale tool import 4 flute 1/8th center cut carbide* then I will definitely be in business. if they last even longer due to being made for this sort of work then WHOO HOOOO heh heh.

[morphious69]

things have slowed down a bit but some progress is being made, just not picture worthy really. Lost a source of income so I am having to do the below to make up for it, and that is taking a bit of my time away from the mill project, but it has potential to provide more than the source was, so more money for parts and supplies for the mill project

got a few auctions up but this one might interest some one here.

ebay link
leather mask RED DARE DEVIL elemental spirit demon mardi gras STEAMPUNK RLSH | eBay
a couple of pics for those not wanting to click on links.







also have a black cat mask here:

leather mask BLACK CAT elemental spirit mardi gras STEAM PUNK STEAMPUNK | eBay

some pics:


an Anubis:
leather mask ANUBIS elemental spirit mardi gras JACKAL STEAMPUNK egyptian | eBay

pics:



and a fire mask here:
leather mask fire elemental spirit dragon mardi gras | eBay

pics:




let me know if anyone has any sort of mask they might be looking for too. as I will be making a few more. as well as trying to work on a couple that I have underway for some people.

[xairflyer]

I have found the 2 flute (slot drills) are the only job for cnc work. I am cutting polycarbonate 95% of the time and have yet to wear one out. I use 3mm carbide tipped for most of my work.

Love the idea of laminating the mdf, have you tried aliphatic resin

[morphious69]

good to know. I have not tried the Aliphatic resin, definitely have to check into that. 3mm? so are you outside the US (seems we are the only ones still using the standard system anymore.)

[morphious69]

just some pics of progress made in the last two days.

[morphious69]

new progress pics.







(video)
[ame=http://www.youtube.com/watch?v=iYj0r0LD7Ms]MOV04431 MPG - YouTube[/ame]

[morphious69]

seems work on a personal machine is never really done. constant tweeking and such. so I did some work on the machine I built years ago, that I am using to build the machine I am making now, on, and with.

here are some pics of a solution I found was far better than the typical hose clamps you get at an autoparts store.











let me know what you think and what solutions you have pulled out of the tool box and the scrap bin

materials used were:
*metal banding (used 4 holding metal pipe & channel on a pallet 4 shipping)
*2x 4-40 stainless screws. (usually use those for making goggles)
*2x 4-40 stainless nuts.
*about 1 inch of rubber hose for fuel line on a car. 3/16th ID

Tools used were:
*hole punch to make two 1/8th holes in each strip
*aircraft metal shears to cut the strips
*various pliers for bending the metal both in a round and angle form.
*couple of metal tools that were round to bend it around
*1/4-20 tap (the tube was really tight being 3/16ths on a 1/4 rod & screw)

[PaulRowntree]

Is there any evidence of 'winding up' the flexible tube under load or high accelerations?

[lukewarm]

Congrats on your project coming along! Maybe Im blind but I coul not find a description of that piece you showed a video of two posts down. What is itÉ It looks like a clyinder head to me....

Also keep us posted on how those bits last you. For 4$ if they last thats hard to beat.

[morphious69]

@PaulRowntree, not that I am aware of. though before I used a bit of steel shim over the tube, so if I find any in it, I will go back to that solution to be certain. the whole thing does not really move that fast due to low voltage, and small motors. one of these days I really need to get some proper couplers.

@lukewarm, I am not sure what you mean. 2nd post down does not have anything in it.

[rocketflier]

Very cool!

Somebody talked about epoxy being much stronger than fiberglass which isn't a valid point. Epoxy resin is the stuff that keeps the fiberglass strands from moving forming a strong, lightweight composite.

Strong structures are often made with fiberglass composite on the outside with wood (balsa) on the inside. Even foam can be used (search Rutan).

Wood magazine has performed tests with wood and various glues. If I recall correctly, the epoxy tested very well with other waterproof wood glues. It was more expensive knocking it down a bit.

The rocketry community also did some experimenting:
HPR Strength of Materials - In God we trust, all others bring data

Someone mentioned machining plastics,.. check out:
http://www.smooth-on.com/

Casting resins:
http://www.smooth-on.com/Urethane-Pl...120/index.html