i know many of you are looking for a cost alternative way to build a light fusion screen... so here is my suggestion to do so.

you can find the following type heavy duty mirrored mylar...



at this distributor... http://www.mirrorsheeting.com

i recommend the double-sided 3mm-7mm mirrored mylar. (no see-through)

using clear packing tape... adhere the mylar to a rigid board. i prefer the light-weight 3/8 honeycomb durotherm pvc board which menards sells for $30.

to complete the screen 'sandwhich'... you need a 1/8" acrylic clear sheet of the same size on which you'll spray paint your MM topcoat.

hopefully this help you folks looking for a cost effective LF screen.

Hey! great find

7 MIL SILVER (COATED on BOTH SIDES) Very Reflective GREAT FOR MIRRORS

7mil is about 0.17 mm thats thin stuff

10 ft 7 ml x 56" $50.00

56" wide, (1.42 meters wide) and 10ft long (3 meters)

I like it , all you would need is clear plexiglass for the sandwich. I cant see why this would not work.

Just an FYI for people with a Menards near by, they have acrylic plastic on
sale now.

The largest is a 1/8 x 48 x 96 for $62.99
Smaller sizes and thicknesses available.

Since the widest acrylic we're going to be able to find reasonably is going to be 48" wide, if 2 sheets are used side by side will the crease be noticible under the MMUD coating? Will it show as a dark line or something?

Its a shame we cant just spray a MMUD coating onto the mylar sheet and have the same or similar effect. That would be the answer to all our problems

I've been 'out of the loop' for a few weeks, but why can't we spray it directly onto the mylar? What are the downsides?

Thanks.

you would have to adhere the two sheets together using a clear epoxy... so that the crease is filled... being careful not to overlap the two sheets too much. when the epoxy is dry... you'll have to sand the crease smooth before spraying the MM topcoat.

Its mentioned that if the Acrylic Mirror is anything greater than ( 1/8") its not so good, what about less than ( 1/8") ?

"The MMUD SE he formed(when correctly applied) creates a light transparent film like cover. It is transparent enough for the light to go through and reflect off the mirror, and then reabsorbe the reflected light and fuse it in-between the mirror and the MMUD SE to create gain, which is where the thickness of the mirror/acrlyic is important ( 1/8") and not any thicker"

If this would work you could make a simple frame that clamps the sides of the mylar. each side of the frame would be adjustable so you could stretch it out flat. Then there is no need to sandwich it. Just an thought

WWHHOOAA guys!

1.) you will NOT be able to paint directly onto the the mylar mirror... you will not have the 1/8" acrylic gap that is required for a true LF screen. the acrylic gap is extremely important because it absorbs the light that passes through the transparent MM topcoat... which it then uses to 'create' ambient light throughout the 1/8" acrylic sheet.

2.) the measurements you are referring to are entirely different. the 5mm mirror mylar is Micro Meters and no thicker than a ziplock sandwich bag... where as the 1/8" acrylic sheet is .125 millimeters.

I did not have any doubt that would be the case, but we have heard that painting MMud straight on the wall will improve the picture quality, I would really like to see results of a A4 size piece of mylar coated with MMud against a wall or screen for comparison. My point is that its not easier getting the acrylic clear glass for the sandwich at that size than it is getting the acrylic mirror so its good to explore for alternative methods.

the mylar film will be like a flimsy plastic wrapping paper. as long you realize that painting the mylar mirror film would be like getting some shiny silver wrapping paper and painting it. you will have a heck of a time getting it entirely flat... that's why the weight of the rigid acrylic sandwhich (with the mylar between it and a rigid backing) will flatten it out.

i know the MMan goes through painstaking effort to give us exacting details and all the info we need so that we'll get similiar and consistent results. cutting too many corners also ends up in diminished results.

Joining Acryllic/Polycarbonate:

This is possible.

Step 1: Get as smooth and flat an edge as possible. This will require at the very least a tablesaw, and a jointer wouldn't be overkill here. What you need here is an edge that is as smooth and clear as the face of hte material. you will not be able to acheive this with any woodworking cuting tool! If you happen to have access to a waterjet cutter, then great. Otherwise you'll get a slightly cloudy edge.

Run some sandpaper or a file over that edge, making sure to keep the sanding block or file perfectly square. Beware of oversanding which will make the edge less than perfectly straight. This will leave you with a very smooth surface, but not a clear one.

Now for the neat trick... Run a torch rapidly and lightly over the exposed edge of the material. The heat will allow the material to flow, and the result will be a perfectly clear edge. Repeat this for the matching joint on the other piece of material.

Step 2: Use a good quality acryllic (or polycarbonate) cement in order to joint he 2 pieces. Use a small exess amount of glue so that there's a ridge of material at the join.

Step 3: Remove the ridges. Use a fine file to remove the excess glue at the seam.

Step 4: Break out the torch again. Hit the seam with the torch to remove the slightly cloudy surface at the join. Once this step is done, you should have a join that is practically invisible to the naked eye.

I've used this technique to join pieces of acryllic to make odd shapes that would otherwise waste large amounts of material for car audio installations (Or more accurately take pieces larger than what I had!) It's time consuming and finicky, but you can have a literally invisible seam in the middle of your material. Natually getting things absolutely straight is imperative.

It seems to me that a join in the mylar underneath the acryllic or polycarbonate material should be more forgiving, but that'll be up to someone else to test.

wow!!!! that was an absolutely amazing tip for us all.

MM was right, this board is full of folks who want to succeed and are serious about making it better for all of us. the other board (we won't mention names) is full of... well... something else.

...and i agree the mylar seam is not nearly as important as the acrylic seam. in fact, rather than fit a perfect mylar seam, simple overlap it just slightly, the weight of sandwich will make it nearly invisible.

Woah, good call, Supraguy. We may get a viable LF screen soon yet :-D

Guys, joining acrylic is as easy as getting a "Vinyl Floor Seam Kit".

No problemo. Easy to do. Inexpensive to buy.

Be sure to get the "Clear" type though.

Thanks SupraGuy,

Believe me guys I did not like to try and cut corners especially when MMan has dedicated hours and hours to develop and share his knowledge with us. I just did not think we would find acrylic glass that size, but I am wrong. The only concern I would have would be the paint seeping in between the acrylic glass and mylar. It would also be great to see PLOG’s on the LF screen. I have only seen results from MMan but not from any other users on LL or AVS forums but I maybe wrong again.

Looking at the mirrorsheeting.com site I noticed that they had a "dark-dark silver", I know some people have said that a black screen seems to add contrast, and people have also talked about black chrome. I did notice that the dd silver is "Hard to See Thru" so maybe 2 layers would be required I don't know, I'm just throwing ideas out there (that what this whole site is about...well at least I think that hopefully other's do too ). As usual being new to the game I imagine that someone else has already thunk of this and it will be shot down pretty quick, but it never hurts to ask, except when it does.

The best way to join acrylic so that the seams do not show is to use step 1 below to start. I do not recommend the 'torch' method of getting rid of the sanding or cut marks. The best way to get rid of these is to use a Dremel tool with a buffing pad and some buffing compound. If you can afford a torch, you can afford a Dremel.

After you have buffed the edge, which will remain straight using a Dremel tool to buff it, you will need to join the two pieces of acrylic together. Again, I do not agree with Supra (sorry Supra) on using clear glue. Methyl Ethyl Ketone is the compound you should use to join acrylic together. You put a little on both sides of the joint and then clamp really well so that it dries with no bubbles in the seam.

You are still going to have some rarefraction properties even if you use this method, but they shouldn't be so bad. I don't think anyone here has tried to join two pieces of acrylic together using light fusion, so I can't say whether the seam will be noticeable in the resulting picture or not.

I plan on trying SM painted on the back of a piece of acrylic along with MMud on the front. I am also planning on joining two pieces acrylic together as my screen in 4:3 is larger than a 4'x8' piece of acrylic.

I will let everyone know how it goes.

Jerm...

Best of luck with that, I know i'm not the only one waiting excitedly for your results. Pleeeease give us lots of pics of the finished product!

Yes, the Methyl Ethyl Keytone is definitely the right stuff for acrylic. This is sold as "acrylic cement" locally. There is a similar product for polycarbonate, but I don't recall the active ingredient.

I've never managed to get a perfectly clear edge using a polisher, there's always some haze left. Perhaps this isn't noticable in thinner material. I've used my technique to join 1/2" to 3/4" plexiglass for stereo installations. When I'm done, the seam is absolutely invisible.

The "torch" that I use is a $12 butane unit, and the trick to getting a clear edge is light rapid passes over the material. Spending too long on it will result in a rounded corner. The nice thing with the torch is that it does not abrade the material, so unless you do something dumb, the edge remains as straight as it was when you tooled it. With an abrasive polisher, there is the possibility of creating slight variations in the surface, which will be difficult to join. (Not that I've seen it happen, but the possibility exists.)


I've made car stereo amp racks where the seam in the 1/2" material is absolutely invisible. It allowed me to create a window 36" long and 3" wide from a single piece of material 13" square that I had. Well... I knew where the seams were, but the owner of the car couldn't find them. I've also made box corners where it's difficult or impossible to see which corner belongs to which piece.

In any event, I'd suggest using some scrap pieces to practice before going all out and working on your large shets. It took me a while to get it right... My main point is that it's possible to join sheets of plastic together. My way is not the only way, but it's one that works, and I know that it works, because I've used it. I suspect that just like the building of hte projector in the first place, there are many ways to get the results that you want.

Oh, and I've used the torch and glue method to repair broken pieces of plexiglass, too. (3/4" material is expensive, and I didn't want to have to throw out a large piece that got knocked off of a shelf (Destructo-kitty strikes again!) and broken.

I've done some acrylic welding making parts for my aquarium, and the cement many use for aquarium building is Weld-on Acrylic Weld. It comes in varying styles depending on the thickness of the acrylic, but i've used the #4 mainly for 1/4" acrylic welding, and that should be fine for 1/8" as well. I can't find any locally in my hardware stores, but it's fairly cheap online.

http://www.oceanproaquatics.com/shop/produ...roducts_id/2103