Moonboy's First Build

[spamsickle]

Does the Lexan MR10 weld the same as other acrylic? I'd be afraid the coating would prevent the solvent from working.

[univurshul]

Does the Lexan MR10 weld the same as other acrylic? I'd be afraid the coating would prevent the solvent from working.

spam,

Yes. Welds the same, there is another chemical that melts down poly-carb (forgot the name, I'll dig it up);
according to the engineers at SABIC--who now own Lexan--it has very similar welding characteristics as acrylic (I did notice there's some bubbling that occurs when too much methylene chloride is applied. A plastics shop wanted to line-bend a platen made of 0.060" MR10, but he was reluctant to try it on the MR10 or the Acrylite Antiglare because he believed there could be discoloring....I should go back and look into this option.

The future of platens is looking like a fork in the road: Gorilla Glass w/upcoming built-in antiglare VS. high tech plastics capable of solid-platen line-bends (no seam at the V-base).

For portability, the sectional platen is still a goal like we talked about, but I'm trying to figure out how 2 pieces of 1.1mm glass can unify at the V-base of a platen without impacting each other or bowing, thus hindering their functional purpose. Separating 2 pieces of G.G. on glass-standoffs or frames is suggesting that they're actually too thin to use.

I did some testing with MR10 here: http://www.diybookscanner.org/forum/vie ... ?f=1&t=449

[spamsickle]

Hmmm, thanks. You say somebody thought they could get a nice tight bend in it? I'd be willing to try that. Do you remember who it was?

I've asked for a quote on some Makrolon AR, which should be comparable to Lexan MR. It looks like expensive stuff, and I'm not sure it wouldn't be more cost effective simply to replace the uncoated acrylic when it became so scratched that the lights cast shadows or generated glare, but I'll see what they quote me first.

[univurshul]

I spoke with John Sheehan, one of the technicians at Piedmont Plastics in Denver: (303) 794-9823 http://www.piedmontplastics.com

John wanted $90/hr, 1 hour minimum to do the bend(s). I didn't initiate a work order because I wasn't confident of the glare properties of the MR10 at the time, they didn't have the correct gauge in stock (they required I order a full sheet), I didn't have multiple platens to build, and I wasn't sure I could even produce a working 1/16" platen at the time. That said, I think going back down this road could be a reality now.

Looking down the barrel of a 1/16" poly-carb platen:

IMG_0001.jpg (129.21 KiB) Viewed 5642 times

I'm saying any specialty plastics shop that has a fabrication team should mean they have a bender and sheet cutter. I'm going around ebay today hitting-up sheeting resellers asking if they have the capability to line-bend.

Here are the MR10 data & processing FAQs:

[univurshul]

Just received a message from an eBay merchant regarding line-bending: he says you can't line-bend MR10 because it'll burn the coating. 2 steps forward, 2 steps back...

You say somebody thought they could get a nice tight bend in it? I'd be willing to try that. Do you remember who it was?.

I sent John pictures of a welded platen and he said he could do it by bending. If there's curve, forget it. If it's a precise point, yes. I suppose re-checking this is crucial; they need to demonstrate it with a sample piece.

I've asked for a quote on some Makrolon AR, which should be comparable to Lexan MR.

Whatever you use for hard coat, etch the contact surfaces prior to construction. I triple mask-tape the surrounding field and dremmel these contact points. A clean etch helps the poly-carb weld effectively.

[daniel_reetz]

I am certain that we could implement polycarbonate blending without any of the difficulty or cost mentioned here. A simple wire heater coupled with a right angle piece of aluminum should do the trick. I'll see if I can rig something up when I get back to LA.

[univurshul]

Another merchant is claiming that AR polycarb is thermoset, and once formed after its original heating into mold, it's difficult to reheat and work with. He suggested clear epoxy combined with roughing the contact points.