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  • Author Author: jomoenginer
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[Pi IoT] -  Remote Horse Feeder System Post Challenge : Fun with Acrylic

jomoenginer

Acrylic Case

 

I'm not sure if it is proper to continue the blog after the challenge, so someone could smack me around if not, but I plan to continue working on the project so here be a short post post.

 

At the end of the challenge, the parts of the Feeder System were sprawled out on the table but I do plan to have them tucked away into some sort of enclosure.  I decided to take a stab at creating an enclosure using acrylic sheets, and after 2 days of work using a Radio Shack dremel tool and a drill, I was able to get the Pi Face Display and Control enclosed.  It would have been much easier to tap into the local Hacker Lab or MakerHQ to use their laser cutter or 3D printers, but I'm a glutton for punishment and wanted to see what I could do on my own.  What I did learn is that acrylic is not easy to work with.  Getting 99% done with a part to have it crack or break while trying to drill the final hole can be frustrating.  Also, when gluing ( or rather welding Acrylic ), it would be best to obtain the proper material for doing so. In my case, the local ACE Hardware folks had no idea of what to use to weld acrylic, so I snatched up a bottle of Gorilla Glue (a.k.a. Gorilla Snot); later I discovered there is a Tap Plastics location not far from my home.  What I found with the Gorilla Snot is that it has a strange chemical reaction with plastic and the little dabs of glue that were placed in the cracks of the case kept growing and expanding leaving what certainly looks like Gorilla Snot.  The good thing was that this covered up any gaps in the seams and disguised the flaws in the cuts.

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I found a good video that showed the proper way to drill the holes in acrylic which includes starting with a small size drill bit and working up bit by bit to the size needed.  Otherwise, if you drill a pilot hole and then try to use the larger bit, the acrylic will crack. I found drilling the piece when it was still part of a lager sheet made things a bit easier.

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So, after all the frustration, I ended up with a fairly nice looking case for the PiFace Display and Control which will be part of a larger case to enclose the rest of the devices.  "Baby Steps."

This is what the case looks like with the Display and Control place in it; note the white snotting looking stuff on the edges and in the lower part of the case; this be the dried Gorilla Snot.

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The bottom with button access.

 

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That is all I have for now, and unless someone tells me otherwise, I'll just keep posting the updates to this and work to completing the system.

 

Cheers,

 

Jon

  • Hand drilling acrylic will usually end up with problems uless you use the proper drill bits.

    You have much better luck with a drill stand, but the piece needs to be clamped down, otherwise it climbs the drill and then breaks out.

     

    There are a few other plastics glues on the market.

    I found one that used a pen which added a primer, and then the glue to produce a clean joint.

     

    There is nothing like using the proper acrylic solvent, it is magic and bonds the two pieces together.

     

    Mark

  • in reply to jomoenginer

    The worst acrylic drill "experience" I had was helping a friend to prepare a test system where 0.2 mm pins was to be fitted inside a 1 cm acrylic plastic piece. I have applied a rotation of 1500 rpm if I remember well with the option to the mill machine of "punching" Take in account that I have used the mill machine with a water cooled high precision shaft but for larger holes a dremel on the vertical stand work perfectly. I got very good results but hand with diameters up to 0.8 mmm. The point is that as low you can drill the acrylic tends to break, but "punching" the hole path - I mean, go down about one mm with very low vertical force, extract the tool, wait a second and apply again - you should obtain a good result.

     

    Enrico

  • in reply to balearicdynamics

    Very cool tip Enrico. 

    I'll have to give this a try with the next part of the case.

     

    Cheers,

     

    Jon

  • in reply to peteroakes

    Thanks Peter.  That explains a lot.

     

    I really dig your videos so I especially appreciate the comment.

     

    Cheers,

     

    Jon

  • First of all, it is perfectly ok to keep on blogging about your project until completion. E14 can see when the various posts are made so it should not be an issue and also everyone would be keen to see how it ends, even thought the challenge is done

     

    When cutting acrylic the reason your getting cracks / breakages is because the rake on your drill is wrong. Yur probably using a metal drill (The most common) and it has a relatively steep rake and will "Snatch" the plastic, especially as it breaks through the bottom.

     

    You need to either re-grind the bit to the correct rake or buy a bit specifically for acrylic. An alternative would be to use a STEP drill, they tend to have a shallower rake and may give better results.

     

    I found this, it will help explain how to grind your drill bit if you are able, or at least explain in more detail

    Drilling and Proper Handling and Maintenance of Acrylic Sheet: Plastic Distributor & Fabricator