Open Source Interface

Polishing Acrylic - Diamond, Flame or Buff Polishing - Which is Best?

2008-07-18T14:12:13-05:00

I am getting my acrylic sheet ordered and wondering which would be the best way to have the edges polished.

They offer diamond, flame and buff polishing. I am also thinking of getting 10 or 12mm thick as well to get stiffness.
Display is to be FTIR method, though I might have a go at LLP if its proves not to be too expensive and continues to get good reviews.

Shall this acrylic work well?

2008-08-20T03:51:37-05:00

Hi there,

I’m worried about my piece of acrylic when I see some pictures of perfect smooth edges.
I polished it with sand paper, from 40 to 1000, after cuting with a metal saw.
Could you tell me if someone already tried with edges looking like that?

Thanks!

Extremely Cheap Compliant Surface Material!

2008-01-10T01:13:38-05:00

This is my first post and because I have been trailing every possible material here in Australia to use as a compliant surface for my FTIR table- yes I even screened my own silicone sheet! - I have finally found a material which works perfectly in combination with Rosco (or in my case white nylon PVC sheeting..)

And it’s Cheap!!!

It’s called Non-Woven Interfacing 305L1200 White (I think the code is store specific.) And it comes on a roll. I paid AUD$1.50 per meter!!!

(See pic below)

This material can be found at most Fabric stores (In Australia I bought it from Spotlight)
It is sort of see through and has a silicone like layer applied to one side of the material. (This layer is very thin and shiny)

I will post more pics of this material showing both sides soon.

The combination of (from bottom to top) Acrylic/Non-Woven/Non-Woven/Rosco/Laminating Sheet gives very good “Zero Force” results. The table still needs to be calibrated properly and I need to buy a projector for rear projection so it’s a little fiddly to calibrate. Using a test projector the image from the projector difuses very well with the combination of the above layers.

I will add a YouTube Video soon of the test results.

Below is a screenshot from Touchlib showing the “Zero Force” applied to produce an image using my fingers [pic1] . in [pic2], I have placed a roll of tape on top of the surface and you can clearly see some FTIR effect being produced with “Zero Force” when the tape is rolled from one corner to the other.

Has anyone else tried this stuff out???

Tinkerman’s thinned RTV silicone on acrylic

2008-07-07T11:39:11-05:00

I just can’t stop experimenting!!

It’s so easy to thin RTV silicone with zylol that I thought I’d mix some up and spread it over a piece of acrylic to produce a bonded compliant layer.

I masking taped a scrap piece of acrylic to my workbench and then taped the perimeter with about 8 layers of tape as a thickness guide.
I poured the thinned silicone onto the acrilic, spread it out as even as I could with my stir stick and then I used the same technique
that builders use for the sorta-clear 40. I smoothed it out with a metal straight edge. The air bubbles went away and it smoothed out well enough.

You have to work a little quicker with RTV, even when it’s thinned with zylol. The zylol does increase the working time, but it’s stil fairly short. About ten minutes and it starts to get thicker. Plan your work accordingly.

It’s curing now. I’ll take a look later and see how it came out.
I have an LED rail with 5 IR LEDs in it for experimenting. I’ll have to mount it on one side of this small sheet and see what kind of blobs it produces.

If it works, it’s an easy inexpensive alternative material for a compliant surface.

ROLL-ON Silicone Coated Drafting Vellum

2008-07-06T19:53:21-05:00

I’m pleased that my technique for applying textured silicone to vellum is working for the people who have tried it.
Cheers!

In the interest of making this even easier, I’ve improved on the technique to apply the silicone.

I now thin it with Zylol at a 1:1 ratio, mix well, and pour it onto the vellum. Here’s the cool part that makes it easy-peasy.
I roll it out over the surface with a foam rubber paint roller like the ones they have at hardware stores.
The texture produced is micro-bumps on the surface. I applied two coats, and now the silicone layer is about half the thickness of the squeegie/fabric technique!

It produces blobs with a light touch, but it still needs a few more coats to be as sensative as the squeegie style sheet. With this technique of application, it’s even easier to get a good, even coat of silicone onto the vellum so building it up in several layers is not so hard to do. It just takes a little wait time between coats. I waited an hour on the first one. It felt like it was cured up pretty well after 30 minutes, but I gave it another 30 minutes to be sure it wouldn’t lift.

I think I’ll make more and do about 5 or 6 coats.

Here’s a how-to video I made:

[youtube]http://www.youtube.com/watch?v=vvO_lvyDGVo[/youtube]

You can clean the roller pretty easily with the zylol and a rag. Just get the roller wetted out with the zylol, then roll out the excess onto the rag. Dispose of the rag in a fireproof container or hang it to dry. NEVER put solvent soaked rags in the trash. They can self ignite.

Have fun rollin the silicone!

Really need help.

2008-08-17T14:40:46-05:00

I was wondering if putting tissue paper between two sheets of acrylic would work well for FTIR? If not, what do you suggest? Also, how would be the best way to wire 100 leds and wire them to a power source? Thank you.

A little bit confused.

2008-08-17T10:02:06-05:00

I’m really new to all of this and I’m planning on building a FTIR system in my desk but I want to know if my idea in the image will work?

Thanks for the help.

Goo Spray on Rear Projection

2008-07-19T20:19:18-05:00

Rear Projection Screen Goo can be sprayed on glass or acrylic to create a high quality rear projection screen. It’s very expensive at $120 US for the smallest container, but some of the demos are very cool.

First test on DSI but some problem…

2008-08-14T20:05:13-05:00

Hi Guys !

I’m pretty silent on this forum( i read a lot ! )

I started A DSI project with Pocket projector (95mm X 80mm X 45mm).
Pretty cool to reduce the size(i want something pretty portable for my Live set,i’m musician)
this gave me a 17-19 inch display for only 30cm of height(i think i can reduce with multiple mirrors...)

Ok, here the problem:

I use an EndLighten Acrylic with Ir led ribbon, all it’s ok, but the blobs is more strong and fast(to appears)when my fingers is wet…
it’s pressure sensitive. ok. but :
I have to use Compliant surface?
I have read it ,it’s not obligatory…

Oh, and i haven’t Ir filter ( i test on totally dark room) ? any influence?

Thank you all for any helps.

Bye

ps: sorry for my bad english...i’m French and school is so far…

Silicone and DI setup

2008-08-04T13:25:55-05:00

Hi there,
I got a 6mm thick piece of perspex and want to use vellum
as the diffuser. I must ask will silicone help as part of the
blob detection even though I plan to use a Di set up?
Cheers