Split fresnels have the grooves exposed. The split lenses were cleaned with pressurized air prior to shipment but will most definitely retain some traces of plastic dust from the cutting process. It is imperative that you never touch the grooved sides of the lenses with your bare hands, they are next to impossible to clean with a solvent. To remove dust from the grooved sides there are 2 possiblities; either use compressed or canned air, or a NEW CLEAN SOFT paintbrush to gently wipe out the grooves. Before you handle the lenses obtain new unpowdered disposable latex examination gloves from your local drug store and always wear them when handling your lenses. Dispose of gloves frequently to avoid buildup of oils and other contaminates. Finger oils will contaminate the grooves. NEVER use windex to clean fresnels, the ammonia can degrade the acrylic. To clean the smooth sides of your fresnels use lens cleaning solution and lens paper or a very soft clean cloth. The grooved sides of the lenses are also especially vulnerable to scratches and dents, treat them as well as you treat your LCD.

A note to all cut lens customers. Your cut lens order was upgraded to a split lens.. A split lens can be used as a cut lens or a split, and the design specs for the guide are changing to the split lens. We will no longer offer the cut lenses. If you should decide to use keystone adjustment or if your LCD doesn't tolerate both lenses behind the panel you will not have to cut the lens yourself. These lenses are hard to cut without special equipment and many have cracked their lenses trying.

Here's the deal from the people who make them:

Procedure for cleaning microstructures

1. Blow off surfaces with dried, 5 micron filtered air to remove large debris.
2. Dip part in clean isopropyl alcohol / water mixture (roughly 10% alcohol).
3. Using a pre-moistened, nylon bristle (0.003” to 0.005” bristles) brush, wash smooth side in a straight motion.
4. Using the same moistened brush, clean the groove side by following the grooves, without hand pressure.
5. Repeat step #2.
6. Using an air gun, dry the smooth side.
7. Using an air gun, dry the groove side by moving the liquid away from you. Remove as much liquid as possible.
8. Inspect the lens for dirt.
9. Repeat the entire process if necessary.

Special Problems

Stains from fingerprints or oil residue do not always come off with the alcohol mixture. In these cases, use a soapy solution (2% Micro brand cleaner with water) using a soft, moistened brush before repeating the procedure above.

Hello Brainchild,

I have been looking for disposable gloves without powder but can't find any thing other than light powder.

Are these ok to handle the fresnels with?

No way. Try the latex dishwashing gloves from the grocery store. Since you can't throw them away only use them to handle the lenses then put them away in a ziplock to avoid finger oil contamination (of the gloves).

Attention newbies: do not take the above statments lightly. I've just done some prelim tests with a transparency, and I was disgusted at the amount of sawdust visible on my projected image. Admittedly it needs some tweaking as the grooves were projected also, but keep the lenses wrapped until absolutely necessary to unwrap them. Yeah ok, it is cool to take out the lenses and pull silly faces through them, but the amount of pleasure gained from such an endeavour will be dwarfed by the amount of resulting grief when you realise the tiny specs of whatever on your shiny new lenses are actually noticable. Very noticable. Brainchild does a damn good job of packing them, they were immaculate when I first looked at mine (but the novelty of reading the American newspaper they came wrapped in distracted me from putting them back immediately..). The canned air is currently in transit to my house.

If you need the measurements, then search the forums for them, or post here even.

Sorry for the lengthy ramble. I feel better now.

I used my 3M Scotch-Brite lens cleaning cloth with interwoven oil and water absorbing micro-fiber tufts to clean both sides of my fresnel. The tufts fit into the grooves. I used care and moved it in circles along the grooves multiple times.

I haven't tried cleaning the grooves the recommended (complicated) way to compare how much better that might be. Consider this an experimental suggestion until more people agree with me. If you do try it, don't press hard.

-Phayzer

Dudes,

Whatever you do, please, please, please do not use the lens paper that the lenses come wrapped in on the lenses without some kind of lens cleaning solution.

That's right, friends. I was actually thick enough to do this. 100 Grit sandpaper couldn't have been more destructive.

I plan to show pics once I get my projector working.

Thanks,
Zendance

Ouch, I use a chamois and remember never use windex or the like, it will destroy your lenses. Use pure alcohol.

Here's a quick solution. When my lenses arrived I took them out of the wrapping (with gloves on) then set the lenses on a length of glad cling wrap (seran wrap), then i just wrapped them up a few times and rolled the edges over. Keeps them clean and scratch free! And it's a CHEAP solution lol!

I have some sawdust on my lenses. I was thining of trying to vaccum it off with the soft hair brush. Any problems with doing this? Would the brush scratch the grooves?

Scott

Get a can of compressed CO2 as for cleaning computer parts.

I wouldn't recommend it, the bristles would still probably be too hard. I don't think either you would have sufficient suction. Compressed air in a can will solve your blues, it works particularly well with sawdust. Have the vac handy though, turn it on and have it to the side of your lens. Then blast the sawdust off in the direction of the vac, to catch it before it settles elsewhere.

Use alcohol to cleanse any remaining fine spoil. I used a lens cloth and meths.

Brain, could you use PVA (polyvinyl alcohol) to clean the lenses. PVA goes on as a liquid then dries to a film encapsulating dirt, dust etc with it. After it dries, stick a short piece of scotch tape to the film and peel it off. Back in the days of vinyl LP's, it was my method for cleaning records that nothing else could clean. I don't think PVA would attack the acrylic lens. Any chemists out there that can comment?

I haven't got my lens kit yet so I am going to take care not to get the problem in the fist place. Dust is the bane of my existence - well, not really, but it might be in this case.

I cant seem to find caned air. I have found alot of other canned "cleaners" for electronics but it says it will stain some plastics. Where are you guys finding compressed/canned air?

Scott

Any computer store should have it.

Can you give me a brand name? I see lots of stuff that look like canned air but its not. its a cleaner of some kind. A name would really help.

Scott

Go to Yahoo! Shopping and type in "canned air." You'll see lots of different brands from different stores. The link below is to some they sell at Office Depot.

Canned Air

ohh thats just great, i read this post the day after my lenes arrived and after I have had my oily fingers all over them. Do I feel like an idiot or what?

Better go and see what damage I have done :angry:

Brain,

I ordered the pro lens and fresnels. I purchased a 17" monitor and do not plan to upgrade to 19". How do I cut the fresnels down to match the 17" monitor.

You can get a quote on cutting by writing to chuck@lumenlab.com

If you are comfortable cutting them yourself you cut do it with a plex knife. Score the lens multiple times and break it along the score.

If I don't have a plex knife, what else can I use to score the fresnels?

Carpet knife.

I need to give my lenses a bath...

I bought some isopropyl alcohol at the drugstore for like $.59. Is this the correct kind? It's the kind you use to clean a cut on your finger.

Also- do I need to cut the alcohol with water? I read the post about using a 10% solution mixed with water.

Any help is appreciated -

I haven't had any trouble with alcohol full strength.

10% solution of alcohol to water may already be the concentration of the isopropyl alcohol one could get at a drugstore.

Aaron

I need to cut my pro lens fresnels. I have a 15 inch monitor, basically 8 x 12. I'm thinking .25 over LCD size. What is the recommended apperature of the fresnels for this size panel? I have no intention of going with keystoning so that is not a factor.

Thanks
John

.25 is fine.

By the Way I believe canned air can be purchased at Auto stores like the autozone and supposedly it is cheaper. I think that I will do a visit today and see if this is true what I have been told.

What about using an Air Compressor?

Serious... I use them all the time to "blow out" computers....etc.

That's fine but be warned that ACs can have oil in the air.

Canned air can also be purchased at many camera stores.

not to mention most Costco's Stores sell the compressed air in 3 can packs for around $15 can.

my fresnels came so electrostatically charged out-of-the-package, simply unwrapping them made them all cover with dust on both sides

hope these cleaning methods will do just fine

Canned air only for static dusting.

I like to use the refillable CO2 cartridges with the little gun you can get at just about any computer or camera store. They are cheaper in the long run because you can refill them with just about any standard CO2 cartridge from Wal-Mart or similar store.

Linky!

New member, 1st post. Going to start making my PJ in late May after I get my lens from LL (which will just by chance coincide w/ my wife leaving for a week on business ).

Anyways, reading this thread on lens, I work in the biotech field and we use rubber latex gloves daily. The brand we use is MicroFlex. www.microflex.com , phone #1-800-876-6866. Powder free. I would imagine really good gloves for dealing w/ the lens.

I have a feeling a box might disappear from my company when it's time for me to start working on the PJ...

how about an air compressor? just dont fire it at 100 psi as I did!

The canned air sounds like the best solution for removing dust. As Brain mentioned earlier, an air compressor may blow oil onto your lens. It could also blow abrasive particles from the compressor if the air is not filtered.

I use canned air on mine, but I find it nearly impossible to keep the static charge off enough to not attract dust particles minutes after cleaning them. The same thing applies with my lexan .....

Do all OHP fresnels come with condenser/collimator welded together or do some only have one or the other? I can source the fresnels and lens locally (S. Africa) and don't want to buy the wrong thing. Also is a 315 lens ok?

tx

would i use a plex knife to cut lexan?

my lenses are absolutly filthy, dust, hand prints (not even just the fingers!) and a strange gummy substance. if i cleened them in alcohol and then dried it off with compressed air would that work? or should i order replacments

r1

DO NOT USE ALCOHOL!

Alcohol will ruin the transparency of acryllic. Go to Home Depot, You can get cleaners specially forumlated for use on acryllic materials. (Plexiglass is acryllic, so ask for a cleaner for plexiglass, and you'll be fine.)

While you're there, get a soft paintbrush, which you'll use for the grooved side. It may also be an idea to get a jug of distilled water for rinsing the fresnels afterwards (distilled water won't leave mineral spots, which tap water will) Distilled water will also be available in the drug store, or the grocery store. (NOT Spring water, again, make sure!)

The smooth side isnt' that bad to get clean, but the grooved side is a real pain.

Good to know .... Ive yet to attempt an actual cleaning.

which is odd, why would the manufacturer suggest using alcohol. I assume according to Brains opening post of this thread, that they told him the cleaning instructions ....

can u use an exacto knife to cut the lenses?

exacto knife is not strong enough to cut the fresnel, you would need a plex knife or a carpet knife.

When you're cutting the fresnel be sure to cut the fresnel within the center or circle otherwise the fresnel will be skew.

This seems to be the place where people are asking about lens sizes, so i'll do the same

I'm gonna be building a 17" PJ, but i'm still in the researching stage. I'm confused about the sizes of the fresnal lenses required. I read somewhere in a PLOG that the 17" LCD is 360mmx298mm (14.2x11.7" i think??.. sorry i'm from metric land ). Is this the pixel display size or the whole screen?

What would the minimum size of the lenses need to be (including a bit around the edges for mounting)?

Thanks
..
Valid8oR

Easy and quick way to clean fresnels.

Use steam from boiling water and clean the grooves with cotton wool in a circular motion before the steam dries off. This work perfectly for me.

The best gloves to use are the nitrile examination gloves. They are clean, easy to find, and disposible so there is no build up of finger grease. That becomes a real problem when . The best thing to use to blow off the dust is dry nitrogen, if you have access. A lab is the best place to work on your projects.

Simple question - I have LL Pro fresnels. How can I tell them apart?