Projector recommendatoins?

[Finhead]

Hi guys first post, great info by all and awesome your all willing to share.

I'm just in the process of getting parts together for my first SLA based build, I've built a few Deltabots and a CNC router so this was the next on the "to do" list.
Recently replaced my home theater projector and thought I might be able to use my old projector for this project, if not I am open to buying one just not sure exactly which would be best. The one I have is a Optoma HD65
Would this work Ok or would I just be better off getting a better model? I have pretty much everything else kicking around other than the vat coating and resin which I will be ordering this weekend. If anyone has any suggestions or info they can share please feel free.

Thanks
Clinton

[watsonstudios]

Should work. If anything, it may be a question of brightness. It's only a 180W bulb. Anything over 200w is no problem. You may just have longer exposure times but no reason why it shouldn't work. The other factor is how easy is it to modify the lens assembly to be able to focus at a shorter distance and keep your projection within your planned build size. Most of the time, you need to move the lens outward, further away from the source. With my projector, I was able to use a couple shims/washers to mount the lens a couple mm's outward thus giving me a good focus at 4.5 x 6" build size.

Most lens assemblies are bolted to the DMD housing with 4 small screws.

That should be the only mod you need to do on the projector.

Jon

[258cj7]

On my projector (a Mitsubishi, 230w UHP bulb) there was a screw that acted as a stop on the focusing ring. After I removed the screw I was able to adjust the focus untill it was sharp at the size I wanted (4x6). I also left my color wheel intact. Cure times for SubG+ are 5 seconds.

[watsonstudios]

Yes, some projectors have this easy fix for sure, wish mine did. Mine's also a Mitsubishi but the focus ring was not editable.

I also learned, at great cost, that you do not have to remove the color wheel or any other filters to get good exposure results. I ruined a brand new $1000 BenQ HD projector when I removed these filters. I completely burned up the light tunnel and then proceeded to melt the lens mount that is between the light tunnel and DMD chamber.

At first, I was out 1000.00. I decided to order another BenQ 1080ST. Once I recieved the new projector, I chickened out and sent it back for fear of ruining another.

On the bright side... Fedex misplaced the shipment on the way back to Amazon. SO... Fedex then reimbursed me for the shipping screw up (Luckily I had the projector insured for 1000.00) So I got 1000.00 back from Fedex. THEN....Amazon finally got the projector from Fedex. Since it was past the 30 days on the return, I only got 80% refunded back. SO I got 800.00 from Amazon.

So, in the end, I was only out 200.00 and I still have my destroyed BenQ projector. I'm sure I could get back my 200.00 if I sold the lamp on Ebay. They go for about that much.

[johnrpm]

Wow, I think I would cry if that happened to me, my stuff is mainly scrap, so little to loose, I do have a strong reputation for hanging aroud skips though.

[Finhead]

Thanks for the super quick replies.
So I don't have to take out the color wheel? This doesn't impact the print at all? That sounds great to me for sure since it would have needed to be broken out just no room in there to place it elsehwere as far as I can see from the breakdown pics on the web.
I believe there is only one screw holding the lens from moving/rotating at least that is what I think I am seeing at about 2:40 sec into this video.


I'm sure I'll have many more questions on my build, really glad I found this place and such a helpful group.

Thanks
Clinton

[Pie]

I got a Toshiba projector off craigslist. I opened it up and broke off the color wheel and UV filter. Then I couldn't get it to work again (for a long time). It is very cramped projector and has way to many screws and boards to remove to get to the guts. I would say don't get a Toshiba (unless its a great deal).

[watsonstudios]

Moving or breaking the color wheel should not effect the projector's performance. Just DO NOT REMOVE the UV/IR glass filter that's mounted in the lamp housing. You will more than likely burn something up in the projector. That filter is very important in blocking IR heat from getting into the projector. The UV blockage is negligible and won't hinder the exposure time.

I have a correction. I did break off my color wheel because it was too difficult to get to the screws that held the wheel in place.

If you need to break the color wheel, just be careful to make sure none of the small glass particles get in the light path. You will end up with little speckles in your image. I was able to clean mine up pretty good and don't think it's effecting my prints at all.

My Mitsubishi projector was only 150.00 on ebay so I wasn't too worried about messing it up. Not like with the BenQ.

Now with the BenQ, the color wheel was easy to unbolt and move to the other side and tuck away while keeping the connection in tact.

[Finhead]

Ok sounds good, the projector is my old one so it's free. I'll see if I can move the wheel if not I'll break it out. If you move it does it still need to spin or does the projector just need to "see" that it's still connected?

Thanks again guys.
Clinton

[watsonstudios]

Not sure but I'm guessing it needs to spin for proper operation.