Restoring a Mini 24

[Dan Wilhelm]

Are you Kellie or Steve? Either way, do you sell Epilog spare parts? I think I've determined what I need, but it has been over 11 days since I sent in a list of parts for a quote, and Epilog has yet to get back to me. I shook the tree earlier today, so we'll see if they respond. If not, I guess I might need to look elsewhere.

[Dan Wilhelm]

Well, I finally got my parts order in today. Ended up getting a whole new cutting table, several parts for the X-axis, and one part for the Y-axis. I'm reasonably confident that I can get this up and running, and for what I'll have in it, I will have paid about 10% of the original price for the laser.

I got quotes for the Epilog brand air compressor (air assist) and rotary axis. I decided to not pull the trigger on them since I'm not 100% sure that I can get the laser running. Do you all that own Epilog (or Trotec, Universal, etc.) use the OEM air compressor for air assist, or do you have an alternative? The price I was quoted seemed excessive for a 30 psi air compressor.

[Paul Phillips]

Dan, not all air is created equal, you can find a small cheap compressor that will output the same volume and PSI but it will need to be properly filtered as they typically put out moisture and oil vapor into the air line which you definitely don't want to get onto your lens, the manufacturer supplied units (western ones at least) usually come with the proper filters already installed, thus the increased price.

[Gary Hair]

For the price difference between what the manufacturers want for an air compressor, you can buy a decent compressor and a really good filter/dryer and still be money ahead. There is nothing special about what the mfg's want to sell you, they just mark it up as much as they can.

[Dan Wilhelm]

For the price difference between what the manufacturers want for an air compressor, you can buy a decent compressor and a really good filter/dryer and still be money ahead. There is nothing special about what the mfg's want to sell you, they just mark it up as much as they can.

That's what I figured. Any suggestions on compressor/filter combinations?

[Kevin Gregerson]

Get the machine up and running first then look at the compressor. Also double check the back wall of the machine to see if its straight as most Lasers are pretty much toast once that goes bad. Second piece, the compressor is really only needed as a way to keep the optics clean on epilogue machines and even then it's really only for when you are working with materials that put out a fair bit of smoke. If you are doing a ton of cuts on smoky materials like wood sure. But if you are using it for only anodized aluminium, no machine needs a compressor attached to it. I say wait till you go through a lens or mirror then look at air assist. The price of air assist compressor is usually equal to 5 or ten lenses. So unless you are planning on going through a set of optics annually or more. It's not exactly going to pay for itself especially when you can pretty much add it to your shop compressed air along with a dryer and oil separator for less.

[Gary Hair]

That's what I figured. Any suggestions on compressor/filter combinations?

Get an oil bath compressor if you want a fair amount of volume and relatively quiet. They are a bit more than a typical compressor but a lot quieter. If you can put it in the garage, or away from your work area, then you can get away with anything that is in the 30 gallon tank size range. I have a 60 gallon, 5 hp, electric and it puts out more air than I'll ever need for the laser and still has enough to run my glass sandblasting cabinet, way overkill for any laser usage. The filter I have for my diesel powered rotary screw is made by these folks - http://tsunamiusa.net/ - I think it's this one - 21999-0082.


If you got the same version but lower cfm, it would work really well for separating oil/water for your laser. Here is one for $130 http://www.filters.com/Air-amp-Gas-F...rain-20-Series

It's not rocket science but the manufacturers want you to think it is...

[Mike Null]

My first machine didn't have air assist. I got by just fine but I have built in air assist on my Trotec and wouldn't buy a machine without it. If you're going to cut anything it's a real asset; particularly with acrylics.

You can rig a supplemental unit without a lot of hassle. Get the machine running--then address the compressor question. Gast is the standard for this type compressor so keep your eyes peeled for a used one.

[Doug Griffith]

...Second piece, the compressor is really only needed as a way to keep the optics clean on epilogue machines and even then it's really only for when you are working with materials that put out a fair bit of smoke. If you are doing a ton of cuts on smoky materials like wood sure. But if you are using it for only anodized aluminium, no machine needs a compressor attached to it. I say wait till you go through a lens or mirror then look at air assist. The price of air assist compressor is usually equal to 5 or ten lenses. So unless you are planning on going through a set of optics annually or more. It's not exactly going to pay for itself especially when you can pretty much add it to your shop compressed air along with a dryer and oil separator for less.

Air assist is not only there to keep the optics clean. It prevents flare up and helps remove incinerated material from the kerf. I would not cut wood or acrylic without it.

[Dan Wilhelm]

So you guys just use regular "shop-type" compressors then regulate the air down to 30 psi? I have a pancake compressor for some air tools I have, but that thing is loud as holy hell...and total overkill for air assist on a laser.

I was thinking you could get a much smaller compressor that just put out 30-ish psi. That is what comes with the Chinese lasers. I know they are just aquarium pumps that aren't really rated for continuous use on a laser...but it seems like a more reliable, but still similar, option would be available.

[Kevin Gregerson]

Air assist is not only there to keep the optics clean. It prevents flare up and helps remove incinerated material from the kerf. I would not cut wood or acrylic without it.

Some people swear by it, and if you are doing volume by all means. I've never had flare up issues on acrylic and I've done all the way up to 1/2 inch cast without any flare up(at least on the top) with 50 watts.

Now if you are talking HDPE, Nylon, Delrin, kapton Films, vhb tapes. Air assist is necessary.

[Glen Monaghan]

There are some small "industrial strength" compressors that are generally highly regarded, such as some of the Gaast line. Dee recommended a "salon" compressor and likes hers. I'm on my third one (warranty replacement) because the plastic one-way valve keeps self destructing. They said they wouldn't replace it again... I also have one of the Harbor Fright air brush compressors, which works well but gets scorching hot if I don't put a small fan close by, blowing across it.

[Doug Griffith]

Some people swear by it, and if you are doing volume by all means. I've never had flare up issues on acrylic and I've done all the way up to 1/2 inch cast without any flare up(at least on the top) with 50 watts.

Now if you are talking HDPE, Nylon, Delrin, kapton Films, vhb tapes. Air assist is necessary.

I have had flare up with acrylic more often than once. Most often when nesting parts tight and the area between them is very thin. Also, paper backing exacerbates the issue. My point being, air assist is required in many situations so it should be recommended no matter what. Dan's machine that he's restoring probably caught fire in the first place because there was no air assist. That, and the operator left the machine unattended. HDPE and nylon cut (or should I say melt) bad but air assist helps remove the slag. Delrin cuts great and I doubt it needs air because it does not tend to flare up. I use air anyways because it's there and safer to run with it.

[Dan Wilhelm]

Progress report: I have all of the parts I think I need to restore this thing. I have now re-built the entire X-axis with a new back plate, auto-focus plunger (hey, it was cheap), belt, and air hose. I bought an entirely new cutting table, so it just needs to be bolted in. The most major repair I have left to do is replacing the left X-axis mounting plate on the Y-axis. That is going to require removing one of the Y-axis belts and linear guide rails...not looking forward to it. I also have a new Molex connector for the rotary axis plug in the cutting table. Just need to re-wire the connector and attach it to the cutting table.

I bought a new final mirror and focusing lens assembly. Out of curiosity, I removed the lens and mirror from the old assembly and cleaned them with DNA. The surfaces are clean now, but they are both discolored. There are no scratches or fractures in the lens. There are few minor scratches on the mirror, but I rotated it when I put it back in the frame so that the scratches aren't exposed any more. But the old lens is pretty severely discolored compared to the new one. The old one has some rainbow type discoloration, and is generally darker than the new one. Is this normal for a used lens? Do you guys think it is still serviceable? I plan on keeping the new lens, but if I can get some use out of the old one, it'd be great to have a spare.

[Dan Hintz]

The rainbow discoloration is the AR coating, though it's likely you have a burned lens considering what it has been through.