DIY High-Speed Book Scanner from Trash and Cheap Cameras

Step 25 Platen: Overview

The plastics in this part are something you should buy new. Unfortunately, I have found no good way to make a platen from recycled materials. I have made 4 platens in total, and the first two used recycled scrap plastics (there is a surplus shop in town that sells acrylic cutoffs and scrap). The first platen could not be glued because the plastics were slightly warped, and the second one, the paper covering that protects the acrylic had become hardened and almost impossible to remove. A tip: near-boiling water will remove such paper, but it is not fun.

Save yourself the pain and go buy new, clean plastic. You won't regret it.

Materials:
2 11x15" cuts of 1/8" clear acrylic.
2 6x6" squares of 1/4" clear acrylic.
Some methylene chloride.
A syringe or applicator.
Something square.
A tongue hinge.
A chunk of scrap wood (or two).

Comments

[jradi]

I have a few ideas for a glass platen, but first I think I'll make the acrylic one to get my project working. Since you're already on your way to your 3rd scanner, you can consider if these might work. My thought is that the part that touches the book should be made from glass, the 11x15 parts. The ends can still be made from acrylic, even doubled up if necessary. That way you can drill through the ends to attach the handle and the hinge. Alternatively, why do the ends have to be of any clear material at all? They can just be made out of a small block of wood, can't they? Especially if the end pieces are painted flat black or covered with some light absorbing material. There are several adhesives, PC7, JB Weld, which I think can be used to bond glass to wood or acrylic. Plus, the ends of a block of wood would provide more bonding surface area making it a tighter bond, you wouldn't even have to run adhesive along the length of the platen joint. Another thought would be to modify two picture frames, removing the long side of both frames that would ordinarily extend across the spine of the book. This would provide support to the platten across all lengths except the crease portion. Then you just have to use a block of wood or similar material to create the 90 degree joint between the two picture frames. Like I said, I'll experiment with improvements AFTER I have a working model. My main goal is to just start converting my books. If I could have all my books digitized within a year, that would be awesome. Unfortunately, most of what I own are books, maybe a half dozen bookshelves Packed...

[daniel_reetz]

I have toyed with the idea of making "endcaps" from wood that you could slot glass into. Only problem here is that I don't have a router. Another problem, though not too serious, is that you'd want to the back endcap thing to be as close to flush with the glass as possible. The reason for that is that when the platen is lifted, the back of the "V" made by the platen comes close to gouging the book. Alternately, one could just make the platen longer so that the back extends further from the book. Glass is attractive enough that I might give this a try.

[spamsickle]

You shouldn't need a router - just cut the outside of the slots from thin "shim" material (or 1/4 inch plywood, for that matter), and glue it to a larger block. The clearance on the hinge would still be a problem if the length of the glass wasn't sufficiently larger than the height of the book.

[autophile]

Step 25: I tried using 1/4" acrylic for the 11" x 15" pieces, and it wasn't very good. The problem is that some books have margins close to 1/4", so the platen has to be jammed into the book with a lot of force, and even then you get a mirror reflection. I'm going to try again with 3/32" plexi (but still 1/4" 6x6 pieces).

[autophile]

The platen works very well with 3/32" plexi as the 11" x 15" pieces. First I took one 11" x 15" piece, and glued the 6" x 6" pieces onto it with Weld-On #16. I decided not to go with Weld-On 3 or 4 because the smallest amount TAP Plastics sold was one pint, which felt wasteful to me. If I had to do it again, I would have tried TAP Acrylic Cement, which starts at 4 oz. As you can see in one of the close up shots, the glue tended to get pressed out of the joint because I applied a bead of glue on the edge, rather than put the edges together, feed glue into the join, and let the awesome power of capillary action Do the Right Thing. Anyway, after about 1/2 hour, the welds were solid, so I then glued the other 11" x 15" piece to the thing. Again, after 1/2 hour, it was done. I pushed the platen into a few books, and found that the pages were all well clear of the join in the middle.

[daniel_reetz]

It's beautiful. I love how clean and orderly yours looks with the patterned toolbox drawer liner. I suspect 3/32" plexi will be much more rigid than my 1/8", not that I have a problem. My local shop only stocked 1/8 and 1/4", so that's what I had to choose from. Weld-on looks like a really useful thing to have. Regarding methylene chloride, there seems to be no nice way to get it. I had to buy an applicator (pictured in my video and the TAP video) full of it, and the cost was $10. That's outrageous considering many labs throw gallons of it away after using it as a solvent. Not only that, but the applicators tend to evaporate, so I paid almost ten bucks in glue just to make two platens. In the end, I used methylene chloride from a metal can with a syringe, which was the most economical method. Your arms are painted black now! They look positively wicked. This thing is really coming together.

[autophile]

I think you meant less rigid since 3/32" is less than 1/8". Which means you should double check your answers on your stats final!!! :) I got the 3/32" from Home Depot many years ago. It has a few light scratches and dings, so I might be making another platen later.

I just want to reiterate that I used 1/4" for the 6" x 6" side pieces, which greatlly increase the rigidity. I suspect that if you can only get hold of 3/32" or 1/8", you can just stack two or three together for the side pieces instead of having to track down 1/4" plexi.

I found the 3/32" platen to be pretty rigid, although I had my doubts when I just had a floppy sheet of 3/32". Obviously I'm not going to be smashing it against walls, but it seems robust enough.

Also, I feel like a dummy. My VST is a full 4 1/2" away from the column, so I'm going to have to use 3 2x4s for spacing :/

[daniel_reetz]

double check your answers on your stats final!!! :)

Funny thing... after handing in my exam I realized I made two mistakes. Bummer. But the final is next week... still a chance to redeem myself.

ACK on the column spacing...