Smoking Deal To be had.... potentially (Exposure Unit)

[Inkworks]

http://www.ebay.com/itm/NuArc-Fliptop-Platemaker-/300808577853?pt=LH_DefaultDomain_0&hash=item460996a33d

I have no connection to this unit or whomever is selling it, but I have a smaller version of it I converted to a screen exposure unit and it's very fast, reliable, has a built in integrator, instant start 3K MH bulb. The conversion is fairly straight forward and I could talk someone through putting in the neoprene blanket with pictures.

I'd love this one as, once converted, will do screens up to 30 x 38" or a touch bigger. Mine, since it's smaller will only do 20 x 24, but I invested in a wall-mount frame and free standing light source for my bigger screens. The nice thing about these flip-tops is that you can work right beside them while they run as they are all self-contained and the light is completely shielded.

I'm 99% sure this is a single phase unit, not 3-phase, as shown in the specs..
http://www.mrprint.com/en/ProductFeatures.aspx?id=82

[Frog]

Converting a plate vacuum frame to one with enough depth for screen frames is no mean feat for most. Please share your experience and technique as these platemakers crop up often
Ron from M&R may weigh in on this as well.

[Inkworks]

Fair enough, I'm pretty handy and build/modify/maintain/repair almost all of my own equipment, so it seems easy to me.

I have a FT26V3UP flip top I was using as a pad-printing plate maker. When I started bringing in screen jobs I already had the wall mounted vacuum frame, but no light source for it. To get the job done a few times when I didn't have time to drive to a buddies shop and use his exp. unit I actually defeated the flip-tops magnetic safety switch, tipped it on it's side and shone the light on the frame, but due to the distance I was getting exposure times of 8-10 minutes, which sucked. At the time I was only using 20 x 24" screens, which would fit, so I bought a chunk of neoprene and went to work.

It's not that tough actually, what I did was remove(unscrewed) the glass/frame/top hinge assembly to have better access, then unscrewed the metal bezel pieces holding the original plate making vacuum blanket down, and removed the blanket, which is fairly hard rubber. After that I cut out the metal back-plate with a jig saw and metal blade and sanded/ deburred the edges so the neoprene wouldn't chafe on them.. There is a bracing bracket that goes to the back of the flip-top, it had a few spot welds that needed to be carefully drilled out. I used a valve stem from an innertube to make a vacuum fitting for the new blanket. It was cut from the innertube leaving enough rubber to make a flange to glue to the vacuum blanket with contact cement. the new neoprene blanket was cut to size (limp-fit to allow for stretching around the screen frame) and put in with the screw in bezel pieces that held the original blanket in place. Then I used two layers of the neoprene to build a new side gasket around the new blanket and siliconed it in place, including siliconing the edges of the gasket so vacuum couldn't leech out through the fabric on the neoprene. The simply reattached the glass/frame/hinge, set the clearances to the gasket for a nice tight seal and you're done. I think it took me about 3 hours all told.

I'm off to work soon and will get some photo's. The thing works like a champ. It's fast, accurate, and as mentioned completely shielded so you can have unexposed screens out in the same room while you expose. That's great for taping up film on screens, exposing and washing out in one continuous workflow all in the same room.

[Inkworks]

PS: the unit I linked to is double sided(one vacuum frame on each side), made so you can be putting one plate in the top side while the other side is exposing. Mine is single sided. It may be possible to retrofit to have both sides with neoprene blankets so you can really crank through letting the vacuum draw on one side while the other is exposing, flipping and going in a steady stream. At worst you could do the one side. For me I'd love to leave one side stock as it's great for flate plates like pad printing plates, although you can use the neoprene blanket for that by putting the plate on a piece of cardboard or the like.

Those flip-tops also come in a 6K bulb version.....! I believe the distance from the bulb to exp. surface is about 24" so they are very efficient and fast.

[Itsa Little CrOoked]

I use Wetsuit neoprene for my vacuum blankets. It is cheap enough and seems to be more durable than the neoprene blanket material that came with my NuArc. It has fabric on one side, like a mouse pad, and I leave it pretty loose, because it doesn't stretch quite as easily as the real deal.  I buy it from a local fabric store. I also use it for my shirtboards that need a spongy surface, like when printing over seams and collars.

Someone might be able to convince me it doesn't hold a very deep vacuum due to surface porosity, and so I shouldn't use it. But if it's a bad idea, I sure don't see why.....

[RonH]

The comment about this being Single Phase and not Three Phase is correct.  We have manufactured units for Litho and Screen Print for many years.  Quantity wise, there have been many more litho units than screen units made over the history of NuArc.  As for converting a unit from litho to screen, it would all depend on the skill and resourcefulness of the person attempting the conversion.  In many of the Flip Top units sheet metal supports in the center of the vacuum frame would have to be removed or possibly cut down and other support added to give support to the vacuum frame.  Also keep in mind that litho units are loaded by raising the glass and placing the plate and film on top of the vacuum blanket.  Once vacuum is pulled the whole vacuum frame is rotated 180 degrees for exposure.  This is upside down from the typical screen print set up, so would require some change in how the blanket would be mounted as well.

Ron Hopkins
Domestic NuArc Sales Mgr.
M&R Sales and Service Co.

[Action1]

I use Wetsuit neoprene for my vacuum blankets. It is cheap enough and seems to be more durable than the neoprene blanket material that came with my NuArc. It has fabric on one side, like a mouse pad, and I leave it pretty loose, because it doesn't stretch quite as easily as the real deal.  I buy it from a local fabric store. I also use it for my shirtboards that need a spongy surface, like when printing over seams and collars.

Someone might be able to convince me it doesn't hold a very deep vacuum due to surface porosity, and so I shouldn't use it. But if it's a bad idea, I sure don't see why.....

Hello Crooked - We inventory that material in 1/4" thickness exactly as you described. Can this material be used for the blanket? Is there another thickness that is better?

[Itsa Little CrOoked]

@ Action, nope. That would be too thick, I think. I've not mic'd what I have here, but it would be in the 1/8" range.

It comforms nicely over frames in my NuArc, but I leave it pretty saggy. (Sorta like the pie crust Grandma would drape over her favorite tin for the cherries she just picked. then she'd always apologize for the pie 'cause it wasn't perfect.) Oh by the way, I personally let the fabric side contact the mesh, but it might not matter. Probably not, actually.

[Inkworks]

Okay, I forgot my camera yesterday, but have it here today:

Unit:



Gasket (looks like I used 1 layer of the neoprene over the bezel, not two)



Mid-flip:



3K MH light source:



20 x 24" screen in place:



Old plate making blanket removed:



Stock Vacuum fitting, which is essentially a tire valve stem:



metal backing plate and bracing bracket removed to allow for a screen to fit:







How they were stacked up in there:



The Neoprene I used was fabric faced, looks like 1/8". The fabric face is nice to protect against wear and allow the vacuum to travel without the need for a string or rope like some vacuum frames need.

I'd bet I have about $50 into the conversion, and like I said about 3-hours.