The NEW Build Your Own Arcade Controls
Main => Main Forum => Topic started by: TravistyOJ on December 18, 2005, 01:26:54 pm
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I bought a Sega Hologram game for pretty cheap at an auction, unfortuneately, the parabolic mirror did not survive the move. It has a big crack, and it does not reflect properly. You can see the crack on the image, and it creates an annoying refraction effect. The light does not reflect from the cracks. Anyway, all it is is a big quarter-spherical piece of highly reflective black plastic. Heres a pic:
(http://www.freeimagehosting.net/uploads/7eb1c0a277.jpg)
Any ideas on how to bond the plastic so that light still reflects where the crack is?
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Wow, I'm amazed that they are using an uncoated optic in that unit. I wonder how bright the image would be if they used a real optic in that system.
But I have bad news. That problem is pretty unfixable. One would need to find something to fill the crack with, then grind off the excess without destroying the material around it, and then polish a shine back onto it without messing up the curve.. In other words, virtually impossible for the average person to do.
The part was probably half of a "blow molded" piece of acrylic. You might be able to find someone to make a replacement part for it, but it's not going to be cheap.
RandyT
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Dang that sucks, any ideas on how to at least make it better?
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Dang that sucks, any ideas on how to at least make it better?
Yep. ---smurfette----slap the joker who broke it.
Sorry to hear about the break, I always wanted that game and was blown away you got one for that price.
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I didn't know what the thing looked like before seeing the pic, and I was thinking throw some aluminum foil on the thing and smooth it out. Shows what I know :-\
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Did you buy a Holosseum or a Time Traveler. I was under the impression that the mirrors are plastic. Is that true with yours?
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I was under the impression that the mirrors are plastic. Is that true with yours?
As directly stated in the very first post of the thread. :P
Man does that suck. How was it damaged in the move?
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Did you buy a Holosseum or a Time Traveler.
Holosseum
Man does that suck. How as it damaged in the move?
Well, I didnt have an access to a truck and had no way to take it home so i had to spring to pay someone to do it. I found a guy who was willing to do it pretty cheap, turns out he has to charge ppl next to nothing to compensate for his tiny brain. I told him the top and the bottom came apart like 5 times. "Its ok man, I can move both." Well, the top part slipped and landed right on the mirror, i was ------- irate. Thats the way it works out though, i mean i knew it was too good to be true to get a system like this so cheap.
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You think its possible to sand it down, bond the plastic, and recoat with some sort of reflective material? Anyone know what kind of material is on there to begin with?
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wait a second....that looks exactly like the backside of one of those security mirrors from a retail store...you may be just looking at the back of that.....
one of these may be just what you're looking for!!!---
http://www.keysan.com/big/picxsee1955.html
I think looking at your photo...they just used the back of the mirror......I hope this is what you're looking for!!
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This may work, but the problem is that the wrong side is the reflective side, i need the inside to be reflective, I may be able to use one of these if I use some sort of reflective coating on the inside. Thanks for the idea, keep em coming! :)
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This may work, but the problem is that the wrong side is the reflective side, i need the inside to be reflective, I may be able to use one of these if I use some sort of reflective coating on the inside. Thanks for the idea, keep em coming! :)
I think the INSIDE (the "not shiny side") of these mirrors are BLACK and reflective!....call the company. I'll bet you almost anything this is EXACTLY what you're looking for.
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If it's not exactly the same size and shape, though, it will reflect the images someplace other than the playfield.
Very sorry to hear about this, that is one I'd love to have. Gotta take the lessons from it, though.
1) NEVER go to an auction to buy if you don't already have a means to get the stuff home.
2) ALWAYS make sure the people moving something are moving it the way YOU WANT IT MOVED. It is yours, not theirs, and they don't care if it gets broken.
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One other possibility, and it is a stretch, but if all else fails you might give it a shot.
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Could you use that one as a template to create another? Perhaps out of Fiberglass?
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Could you use that one as a template to create another? Perhaps out of Fiberglass?
I dont know you tell me :). I havent done anything like this before, so I really dont know my boundries. How can I create something custom shaped out of fiberglass? Also, I found a local place that does custom mirror stuff, so I will get some measurements together tonight for a quote.
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I dont know you tell me :).
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Well so far here are my options.
1.) I contacted my local Sega distributor to see if Sega still has some of these lying around. Still no word back yet.
2. )I need to take pics and get measurements for possibly pricing a custom made solution.
3.) Make a new one using the existing one as a mold. Any info on how to possibly do this would be appreciated.
4.) Repair the one i have now, by somehow bonding the plastic so no seams exist, and coating with some sort of reflectice coat.
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2. )I need to take pics and get measurements for possibly pricing a custom made solution.
Do you mean out of glass?
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Well so far here are my options.
1.) I contacted my local Sega distributor to see if Sega still has some of these lying around. Still no word back yet.
2. )I need to take pics and get measurements for possibly pricing a custom made solution.
3.) Make a new one using the existing one as a mold. Any info on how to possibly do this would be appreciated.
4.) Repair the one i have now, by somehow bonding the plastic so no seams exist, and coating with some sort of reflectice coat.
um.....are you totally against contacting the security mirror company. Do you even know what is on the reverse of that security mirror?
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um.....are you totally against contacting the security mirror company. Do you even know what is on the reverse of that security mirror?
I have already contacted a local company with lower prices. The reflective part is not on both sides. That would needlessly almost double the cost.
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You would use the existing one TO MAKE A MOLD, not AS A MOLD. I've seen car guys make custom parts for their audio systems this way. IIRC, Stingray has mentioned in the past knowing how to do it. Try asking him.
This is pretty far out of my league. You could probably make one that looks cosmeticly like the old one, but I have no idea if you could really get the shape precise enough for it to actually work. Then there's the question of the reflective coating. I'm not at all sure how you would go about replicating that.
-S
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Who says it has to be a coating? If he actually made the fiberglass black, then put something like an acrylic spray on it, that may work. It at least wouldn't have to cost $500 to find out.
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Yeah i mean i wish i really knew what the stuff was, i mean an acrylic spray could work, but i dont know if it would be reflective enough.
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It wouldn't be the spray that did it, it would be whatever is underneath. The spray would just be for sealing it without affecting reflectivity.
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Is it really a MIRROR? Or is just a glossy black dome? See the thing is, high-gloss surfaces in DARK environments will reflect things just as well as any true mirror will. Judging from the photos, it's BLACK. Does it really have a "mirror" style coating on the other side?
Reason I'm raising these questions is that it LOOKs to me like all it needs is to be repaired and then made very glossy.... (but looks are decieving--especially JPEG images)
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RayB does raise a possibility.
People repair cracks in pinball ramps in minutes with a blowtorch. They heat the plastic just enough that the crack goes away when the plastic reflows. It's the same thing as reflowing a solder joint.
The more I think about it, the more I think this can just be reflowed with a skilled hand on a blowtorch. You may have to repair the surface shine a bit after that, but that shouldn't be too hard with a little sandpaper and a spray can/gun.
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As far as I can tell, its just high gloss black plastic. I think this is logical too, since it would save Sega a lot of money to do it this way. I really like the blowtorch idea, I just have no experience with one, so maybe i will ask around and see if a friend can do this.
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You can practice the blowtorch method all you want, too. Just get some scrap plastic stuff of similar material and thickness, get a blowtorch, and go about cracking/repairing the stuff until you feel comfortable touching your mirror.
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Anyone one out there done this before?
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I so wanna see this work.....g/l with it
Tim
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Just talked to a friend of mine. His Dad owns a metal shop and has many years experience welding, I know this isn't the same, but i think it is fundamentally similiar, so maybe he can help me out.
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That's a terribly lit picture for us to be able to gauge ANYTHING from.
You wanted it moved by someone else. They broke it.
You want someone else to do this work for you.
You're crossing your fingers and hoping everything works out at every turn.
I say this because you even realize, and state, "It's not the same thing, but it seems similar, so maybe it'll work out"
Chad has told you how to teach yourself to fish, now go start. Continuing to rely on people who clearly won't have the same enthusiasm for this as you is just asking for more of the same to KEEP happening.
Your best solution is to keep looking for a replacement and just buy one if you are just gonna rely on others to fix this.
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I hate to be the wet blanket, but trust me, none of these will work. That is unless you are very lucky and the radius of that curve is the same as something a security mirror company already produces.
Everything else will:
A: Make the problem worse than it already is
or
B: Be very expensive.
BTW, a shiny black piece of acrylic comes nowhere near the reflectivity of a true mirror coated optic (typically AlSiO) A mirrored optic will get you 95+ percent reflectivity in the visible spectrum. A highly polished piece of uncoated plastic will get you 3 or 4 percent tops. The image is projected into a lit room, but it is shaded by the construction of the unit. It was made this way to save money.
But this is only relevant in terms of image brightness. The real issue here is distortion. The tiniest deviation is going to result in a very distorted image. If you put heat to that thing, it will distort so badly that you will be lucky to even get an image in that spot.
If you want to know how I know all this stuff, visit www.opd3d.com. My name is on a good chunk of that company's IP base (plus they give me a check once a week :) )
RandyT
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That's a terribly lit picture for us to be able to gauge ANYTHING from.
Sorry
You wanted it moved by someone else. They broke it.
I had no choice, I learned a lesson, I'm sorry
You want someone else to do this work for you.
If it came down to a professional or me using a blowtorch I would pay a professional. Dont worry, I talked to the guy and hes pretty sure it would warp the plastic too much.
Your best solution is to keep looking for a replacement and just buy one if you are just gonna rely on others to fix this.
I will do this, sorry to have wasted anyone's time.
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I'd still look into the security mirror deal. Either they're the right size, and reflective enough on the inside, or they aren't. But it's probably the only possible answer other than waiting for a used replacement part to show up on ebay.
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Your best solution is to keep looking for a replacement and just buy one if you are just gonna rely on others to fix this.
I will do this, sorry to have wasted anyone's time.
Don't get upset about it, these guys just don't want to see you make the problem worse. Just take your time and don't rush it, make sure you get the right type of replacement of something with the same curvature and reflectivity as RandyT and many other suggested. I would be excited to get this going ASAP, but force yourself to be patient.
Tim
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There are a number of plastic polishes and scratch fillers out there - if it's just a shiny surface with no treatment and you can glue it back together without defacing the front any more, it might just be a matter of putting a high gloss polish back on it.
The one that seems to be all over the web is Novus, but I have no experience with it.
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BTW, a shiny black piece of acrylic comes nowhere near the reflectivity of a true mirror coated optic (typically AlSiO)
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I am siding with Avery on this. Here's what I would do. From the appearance of that crack, I wouldn't go messing with any form of heat at all. Glue it back together with a black sandable epoxy. When it glues together, there will be raised portions of epoxy. Get some fine grit sandpaper, and wet sand it slowly back down, being careful not to take material off the surface, but with a fine grit that shouldn't be too much of a problem. Then get yourself some scratch filler, I would think you could use the stuff that fixes scratched CDs, or possibly even some wax, to fill in the small scratches and get the finish back to a high gloss. My $.02 on the matter.
Perhaps something like this - http://www.koalaproducts.net/polish.htm
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I am siding with Avery on this. Here's what I would do. From the appearance of that crack, I wouldn't go messing with any form of heat at all. Glue it back together with a black sandable epoxy. When it glues together, there will be raised portions of epoxy. Get some fine grit sandpaper, and wet sand it slowly back down, being careful not to take material off the surface, but with a fine grit that shouldn't be too much of a problem. Then get yourself some scratch filler, I would think you could use the stuff that fixes scratched CDs, or possibly even some wax, to fill in the small scratches and get the finish back to a high gloss. My $.02 on the matter.
Perhaps something like this - http://www.koalaproducts.net/polish.htm
Optics aren't car bodies. Hand grinding a curve that is accurate enough for optical use is nearly impossible.
Also, transmissive optics are very different from reflective ones. You can get away with murder on the transmissive ones, but not reflective or "imaging" optics.
But hey, if someone is really bored it might make a good waste of a weekend ;)
RandyT
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Yeah maybe, I think it is worth a shot though, as it's already broken. He's not going to make it *worse* by trying to glue and wetsand. And as far as it being optical quality, look at the picture. It's already got a decent amount of scratching, this isn't going into a telescope...
As long as he's careful about sanding into the material too much, there's not going to be crazy distortion from a 1000 grit wetsand. Look at the polish the plexiglass took.
(http://www.koalaproducts.net/images/DSC05083_small.jpg)
(http://www.koalaproducts.net/images/DSC05085.jpg)
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And as far as it being optical quality, look at the picture. It's already got a decent amount of scratching, this isn't going into a telescope...
(http://www.koalaproducts.net/images/DSC05085.jpg)
I guess you didn't see the part where I wrote:
Also, transmissive optics are very different from reflective ones. You can get away with murder on the transmissive ones, but not reflective or "imaging" optics.
It's not going in a "storm door" either. And FYI, optics similar to these are used in telescopes. How do you think they collect the tiny amount of light from stars billions of miles away and focus it on a small receiver? This application is not as critical, for sure, but the function of the optic is very similar.
RandyT
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How do you glue something together that is not physically separated? To get glue in there he would have to find a way to get separation into which he can put the glue... plus, it's not BROKEN, it is a visual reflectivity issue. You aren't going to be able to be visually rid of a crack by gluing it.
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Im sorry I should clarify the problem. There are 2 cracks, one long one, and one short one that intersects into the other, making a small triangular piece that broke off. Right now it is all being held together with tape.
What if used some sort of glue and pressed together to minimize the seam, and then took some novus deep scratch remover on the seams, and then a couple layers of novus polish?
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Erm, yeah, you just took a small issue and turned it into a giant issue.
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Randy is right on. Your best bet is to tape it together from the backside as best as you can, live with it for now, and look for another one. any polishing /glueing /heating /voodoo you perform on it at this point will just render it completely useless.
I also suggest kicking the guy who moved it for you in the nuts. Perhaps you could contract Chad to do it.
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If it is close enough I will do it for free since he would have robbed me the chance to play a Holosseum.
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Also, transmissive optics are very different from reflective ones. You can get away with murder on the transmissive ones, but not reflective or "imaging" optics.
Yes, I must have glossed over that. I guess what I am not understanding is why the relfective properties aren't repaired by a gloss finish compound, that fills the scratches and fixes divergence. I mean you are the expert on optics apparently, Randy so I'll yield if you can help me understand why it is that filling a void with a transparent compound wouldn't help it reflect better.
Obviously it likely won't work anyways if the crack is so bad that it cannot be fashioned/glued back into a perfect shape. It also might be a long shot hand sanding, since you wouldn't be able to bend sandpaper to smoothly sand the inside of a concave shape. You'd have to find some abrasive cloth or somesuch. My main point is, he's going to have to find a replacement anyways, so why not give it a try?
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I also suggest kicking the guy who moved it for you in the nuts. Perhaps you could contract Chad to do it.
You're such a jag. Didn't you read before where I SAID he's gonna have to start learning how to do stuff himself? Farming out a kicking is NOT helping him at all. No soup for you, bad post-fu ;D
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I will give it a try MYSELF, and maybe Ill get lucky and score another one which i will move MYSELF. :) Thanks for all the suggestions and time. One last idea, what if I recoated everything is some sort of reflective sheeting like this...
http://www.growell.co.uk/p/0309/Mylar_Reflective_Sheeting.html
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I also suggest kicking the guy who moved it for you in the nuts. Perhaps you could contract Chad to do it.
You're such a jag. Didn't you read before where I SAID he's gonna have to start learning how to do stuff himself? Farming out a kicking is NOT helping him at all. No soup for you, bad post-fu ;D
I am following the BossX posting methodology... read the last 3 posts and respond. He also allows for simply disregarding all posts by Drew Karee. I'm just learning by example :)
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I am following the BossX posting methodology... read the last 3 posts and respond. He also allows for simply disregarding all posts by Drew Karee. I'm just learning by example :)
Shows what you know. He hangs on my every.......werd. ;)
Oh, and Travisty, that'll never work. Take it from someone who's never done it before ;)
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For gluing the pieces together, what about one of those liquid solvent based glues used for models. You're going to have to be REAL careful not to let it mess up the front. I'd set it on a pair of saw horses and glue from underneath - let capillary action pull the glue into the crack (and I'd test the glue first on the back, away from the crack, where there's no way it's going to effect the front).
The amateur astronomy crowd grinds their own telescope mirrors (and some damn big ones too), but they have special equipment that I don't think you're going to be able to find for something the size your dealing with. I think in this case you just want to polish out the little scractches you can. Reshaping that thing, to any serious extent, is going to be impossible.
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I was thinking along the lines of Avery But I would consider using liquid methylene chloride (available at most glass Shops) instead of the model glue. Its what they use to glue sheet acrylic together and it wicks into the cracks.
If you do it use tape to hold the pieces together in the exact position once you apply the solvent you wont be able to move the pieces. Whatever you do don't put the tape on the front the solvent will wick under it and make a big mess.
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Also, transmissive optics are very different from reflective ones. You can get away with murder on the transmissive ones, but not reflective or "imaging" optics.
Yes, I must have glossed over that. I guess what I am not understanding is why the relfective properties aren't repaired by a gloss finish compound, that fills the scratches and fixes divergence. I mean you are the expert on optics apparently, Randy so I'll yield if you can help me understand why it is that filling a void with a transparent compound wouldn't help it reflect better.
The answer is simple. I'm assuming you have seen a typical "funhouse" mirror. These are usually made out of polished metal, but could be made out of plastic and coated just as well.
In any case. imagine a funhouse mirror and the distorted effects it creates This is accomplished by bending the mirror in one direction or another to achieve the distortion required. If that mirror had its mirror coating stripped away, you could see perfectly through it (not counting refraction) with virtually none of the distortion seen in the reflected image.
Now consider a spherical (or parabolic) surface that has been meticulously calculated to collect light from an object a certan distance (and angle) from the mirror and then to bring the light generated by that object to focus at a very specific point in space. Any deviation in angle/curvature is going to move portions of that light disproportionately to the rest of the image, creating severe distortion. If the deviation is enough (and it doesn't take much) the reflected light will be somehwere else in space entirely and appear as a void, or a very out of focus blob in the image.
This doesn't even take into account whether or not one can polish the plastic to a point approaching the reflectivity of the original.
As for why not? I guess that's a personal choice TravistyOJ is going to have to make for himself. But if he has limited funds for purchasing experimental materials for futile "fix attempts" or values his time in the slightest, I was just trying to save him some heartache.
RandyT
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Yeah, I will try to make the current one i have as best as possible while still looking for a replacement. The only really way I know to improve it without possibly making it worse is to tape it up as close as possible, and apply some novus. From what I've gathered, any solvents, glues, etc will probably make it worse. Please PM if anyone comes across one of these or even a destroyed holo-cabinet with one in it.
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I wasn't grasping what RandyT was saying before, I thought like anyone else that just a high polish woud do it, but the funhouse theory explains it pretty well
Tim
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I understand the funhouse effect. From my experience, when plastic breaks, it's usually not a totally clean fault. So you can put the pieces back together and they almost lock, something like a jigsaw. If that's the case, then the geometry should be almost identical. He could test by putting them back together with the tape like he wanted, and testing it out. If the image coalesces into the right spot, then it has a chance. I am bothered by the smallish triangle piece he says broke off though, instead of just one break there's several. His main hope is to look for a replacement in a busted machine, would be much cheaper than trying to have one made. Sucks in any case, good luck with your endeavor. -JC
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For gluing the pieces together, what about one of those liquid solvent based glues used for models.
I don't know what kind of plastic this is made of, but I use those types of solvent 'glues' pretty often. The two main brands that I use are Tenax & Plastruct. Both work great on styrene (which is what most scale model kits are made of) but won't touch acrylic, which seems to be what most here are assuming this dish is made of.
-S
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Both work great on styrene (which is what most scale model kits are made of) but won't touch acrylic, which seems to be what most here are assuming this dish is made of.
Good to know. Maybe just getting the geometry close and smearing JB weld all over the back of the crack is the right answer then.
Meanwhile, back at the ranch - is this disk just reflecting a flat screen image that has been distorted to allow for the curvature? Is it really parabolic or just a spherical section? Is there a fresnel lense in this setup anywhere?
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Meanwhile, back at the ranch - is this disk just reflecting a flat screen image that has been distorted to allow for the curvature?
Yes, basically if you run "mame holo -flipy" that is the output of the JAMMA board.
Is it really parabolic or just a spherical section?
I think both, are these terms mutually exlcusive? Please excuse me on this, since I dont use these words very often. :)
Is there a fresnel lense in this setup anywhere?
I dont know what that is, but my guess is no. Its just a TV and the plastic mirror.
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Is it really parabolic or just a spherical section?
I think both, are these terms mutually exlcusive? Please excuse me on this, since I dont use these words very often. :)
A parabola has a constantly changing curve, whereas a sphere has a constant one. Based on how this was probably manufactured (blow molding), I'm going to guess that it is a sphere. Parabolas are more difficult to make, thus much more expensive.
Not to mention that fact that a parabolic segment won't work in that configuration.
RandyT
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Is there a fresnel lense in this setup anywhere?
I dont know what that is, but my guess is no. Its just a TV and the plastic mirror.
Hey Travis, The lensing on the top of that thing is fresnel. It is how they give the illusion of bending the image to stand up on the table.