UPDATED
I started out with fabric for this surface, then switched to drafting vellum several post down the page.
Now you know why I’m using fabric in the first few posts here.
Dino
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Here’s a video of a test between bare acrylic with drafting vellum underneath VS silicone coated cloth.
I squeegied the silicone on myself. Just enough to coat the fibers but still leave some of the cloth texture.
That way, the silicone releases quickly after a touch.

Watch and see what you think.
This was shot with a lot of daytime ambient IR light in the room.

Wow looks great! How does that material look as a diffuser for a rear projection?

Well Gw this was just a test piece. It’s not the best for projection. Kind of dull. It’s just cotton.
I have a piece of fabric on the table now with silicone on it that isn’t too bad, but I know I can find better

There are a few other fabrics at the fabric house that I will try and post results in this thread.
Anyone who has experimented with fabrics as rear projection material knows it’s a lot of trial and error.

It’s like Edison with the light bulb filiment…
( ah! Tungsten! )

Try everything until you find what works.

Wow great work mate.... thanks for the test what type of cloth are you using??
Also when you say “you squeegied the silicone” by this i gather the cloth you are using as has cotton type feel so the silicone fuses with the fibers, how effective do you think this method would be with a vinyl type material such as rosco, which doesnt have a fibrous feel.

Taha

Nice work tinkerman. The results are great, almost like the results of the interfacing fabric thread. The interlacing is essentially very similar in that it has silicone type resudue on the bottom of the fabric. This is better though since you can control what the silicone is. What type of silicone are you using?

The problem with the interfacing fabric, (and what you might discover) is that using fabric isn’t very good as a projection surface. I ended up removing the interfacing on my table since the projection was just not clear enough (too blurry). If you can find a fabric that won’t show any of the threads, then you might have something here

BTW, your video isn’t completely fair though (lol) since one your material is on top and the other is on bottom (with no silicone). When the projection material is on bottom you will definitely have less bright blobs. A true test would be “silicone fabric” vs. silicone directly bonded to the acrylic and projection material on top.

I’ve currently switched to a different technique which i’ll be sharing later. We’ve concluded that silicone that is NOT bonded directly to the acrylic will provide better FTIR (brighter results).

That looks really promising. The blobs are beautiful.

This test was to compare the bare acrylic to the fabric, not so much the vellum. That was to just show how much it diffuses the IR blobs, which isn’t all bad.

I testsd three more types of fabric today with no silicone. Close, but no cigar. The biggest problem is the projector light showing a hot spot through the fabric.

I have one though, that’s OK but not the best. It has a white vinyl coating on one side. I coated the other side with silicone and it works OK. Just not that good of a projection surface. Kind of dim and blurry.
The vinyl side up feels nice though.

The search continues… however, when I’m done, I’ll be able to open a fabric store!

Oh, to answer your question, I’m using GE Silicone 1, clear, in a caulking tube. I use a 10” rubber squeegie to spread it on the cloth.

I just tried another experiment. I coated one side of vellum with a very thin squeegied out layer of silicone, then I laid a piece of nylon fabric over it and squeegied that to the vellum/silicone.
Then I lifted the nylon fabric and it left a nice fabric like textured layer of silicone on the vellum.

I’ll post results when it cures.

I’m getting excellent results with vellum with silicone on it. I’ll post a video later… I have to get some sleep!

We’re currently working on textured silicone. It works really great. I’m interested in your technique and outcome. We’ve tested about 10=20 different textures.

Great results tinkerman!

I am new to the forum so maybe i ask some questions that have been asked before (also i read a lot in the forums already )

1. What thickness has your silicon layer? You said it’s just enough to leave the texture. Did you spray it on or really just squeezed it on?

2. I am not sure, but could silicon spray on fabric work, maybe? Or has this already been tested by someone?

3. Has anyone thought (or maybe tried) to use rosco screen as fabric and put the silicon directly on the rosco?

Best regards,
chris

Has anyone tried to make the silicon bonded to the Rosco and leaving an air gap between these and the acrylic?

It sounds a little hard to engineer but it might be possible if the compound gets tensioned enough on top of a spacer placed at the acrylic borders.

Anyway, it should be easier to do in a vertical setup, because gravity would not play such a big role.

Some people have tried silicone on Rosco. I guess the results were not as good as expected.

Here’s how I put textured silicone on drafting vellum.
After this cured, I flipped it over and gave it three coats of PPG DCU2021 automotive clearcoat on the touchable side.
This should provide a protective layer that can be cleaned and be fluid proof.

Hmm...I’m very interested to see the next steps and final results.

What avoids the silicone coming off onto the nylon when you lift up the nylon? Is it that the silicone is just so thin and you’ll do multiple coats? From my experience, we’ve had to leave the texture on until the silicone cures or else the silicone comes off onto the texture when taking it off. Your technique is VERY similar to what we’re doing (but in about the 1/10 of the time) so I’m very curious to see how this goes.

Part of the trick is the nylon. It works for this kind of stuff. I’ve used it as bleeder cloth in vacuum bagging composite resins. It releases from the silicone and yet it retains a bit. So, I do what you saw here, twice. That builds up a nice layer and it has the texture of teh nylon eben more than the first pass!
The other side with the clear coat is still curing, but in a few hours, I should be able to throw it onto the table and test it!

More videos then…

I tried something a bit like this but using a net curtain which lets the silicone bleed right through the fabric.

How are you removing the tape thats holding the drafting film down?  I found whenever i removed it or even cut it away it would peel some of the silicone around the edge.  The best I could do was remove the tape when it was wet, but usually the silicone had started to dry by then and still peeled away in some places.

I didnt experiment with this too much because the silicone is rather messy and really stinks when it dries.

Great video tutorial. For each coat are you using a new sheet of nylon or are you reusing the original?