Bought an 85mm square gel filter from www.formatt.co.uk for Â£10.50 including post. It's about 3mm thick and completely rigid.
Bought 4 rubber hollow wall fixings from B&Q. Removed the bolts, cut off the ends with the nuts in them, and glued the other ends to each of the four corners of the gel, positioned so that the rubber lightly grips the outer rim of the PJ lens.
What projector have you got? if it is a vw10 or vw11 then check out the smart site of steve smallcombe. I have just got one for my vw 11 and it is real neat and is just like the lens cap with a filter inside it. Like you, i imagine, my set up is in my lounge and needs to be as wife friendly as possible! Sorry I cant remember the website address but a quick search under smart or steve smallcombe should suffice. It has also ben discussed quite a lot on this forum so a search for SMART on the threads will probably throw it up.
I got the 30 because i have a da-lite da -mat grey high contrast screen and they recommend this over the 40. In all other cases though, they advise the 40. I think it was about £50, i cant find the receipt but I paid extra because I wanted it quick! The difference is very noticeable and thats with a muppet like me playing about with the settings. I have booked Gordon to do a proper ISF calibration and this should be done some time in October. Given the cost of the projector , screen, iscan and all the other bits of kit, I think the filter is well worth the money.
I paid 5.81 euro for a filter of 60cm x 60 cm from a stage lighting specialist. I bought 2 one cc15r and one cc30r. I have ended up with cc45r, but still want something better.
To make your filter look professional you need:
Ben & jerry icecream, yes really!!
eat the icecream and use the lid!!
Cut out the inner circle. Paint it black. place your filter inside, Or if you have a non stiff filter place any kind of hard non coloured plastic first, then stick some black filt all around the inside except on the window!! haha. Place it on the lens, fits snugly over it and wow you have a 200 euro looking filter for a few pounds.
You could be right nobber, I made it 8 months or so ago. Its a plastic lid, was not too sure if it was ben en jerrys or hagendas. And yes you have the perfect site there. I do not know why some people try something else as this is the best way to build a filterholder for your vw10/11. However its easier to fit the inside with material (black velvet), easy to fit, and makes the filter sit well.