Main > Woodworking
Working with Plastics
KevinFlynn:
Thanks for this great thread! I have been working with Plexi on my cab for months now. I'm very glad I tried a practice drill in a scrap piece of 1/4" Plexi and you're right, the key is to go very slow and let the bit do the scraping, not cutting. I pushed too hard and the Plexi shattered in my hand. Fortunately, all the finished product pieces have turned out great.
It also helped greatly to have a board, like plywood under the spot you're drilling. It's the end of the drilling as the bit is getting through the Plexi is where you have to be the most gentle. This is where having wood underneath really helps.
Thanks again for all the info everyone (and for starting this post selfie.)
dyldebus:
I've been working with a lot of 1/4 acrylic on my cabinet. I decided to do a test on a sample piece with several types of drill bits from standard metal and wood bits, forstner, hole saw, spade and finally a step down bit. The step down bit was hands down the cleanest cutting bit (even with a hand drill) and never caused me to worry about cracking or chipping. Unfortunately I didn't have a step through with 1/4" layers so started each hole with the step down bit and used an up-cut spiral bit (best purchase ever) on my router table to make absolutely perfect holes on the first pass.
I did use forstners on my MDF and it produced amazing results. My Milwaukee hole saws do not like MDF. They burn the wood immediately.
Here was my upcut spiral bit (used for all buttons and to actually trim the panel from the MDF template
http://www.amazon.com/gp/product/B000HPYOJ6/ref=wms_ohs_product?ie=UTF8&psc=1
This is similar bit to my step down bit
http://www.amazon.com/Irwin-Industrial-Tools-10231CB-13-Steps/dp/B00126KYMU/ref=sr_1_12?s=hi&ie=UTF8&qid=1374264638&sr=1-12&keywords=step+drill+bit
Rick:
--- Quote from: korbitz on March 10, 2013, 03:02:37 pm ---...what would be required to bend around a circle if at all possible, i will do the straight parts using the oven method and onto a mould, can i do the same with the curved sections?
--- End quote ---
--- Quote from: selfie on March 10, 2013, 07:19:40 pm ---I will reply in your build thread...
--- End quote ---
I'm sorry if this is a late request, but would you mind providing information in this thread as well? It's stickied, and pretty much the "go to" for all things plastics. Oh, and maybe consider changing your username to Plastic Man?
;)
thrasherx:
I tried using a spade bit on some Optix acrylic (from Lowe's), and it ended poorly. Luckily I tried on a scrap piece first. It works ok in reverse, but takes forever and is unnerving. I should note that I didn't sandwich the plexi between two layers of wood while I experimented. I ended up using my flush trim router bit with a non-plunge router. If you ease the router into the acrylic, providing a little upward force to the router's own downward (due to gravity) force, it works like a champ. Super clean edges and all the rest. It cuts like butter!
selfie:
--- Quote from: Rick on September 29, 2013, 08:17:25 am ---
--- Quote from: korbitz on March 10, 2013, 03:02:37 pm ---...what would be required to bend around a circle if at all possible, i will do the straight parts using the oven method and onto a mould, can i do the same with the curved sections?
--- End quote ---
--- Quote from: selfie on March 10, 2013, 07:19:40 pm ---I will reply in your build thread...
--- End quote ---
I'm sorry if this is a late request, but would you mind providing information in this thread as well? It's stickied, and pretty much the "go to" for all things plastics.
--- End quote ---
Done ;D
--- Quote from: korbitz on March 10, 2013, 04:38:30 pm ---Hi Selfie,
I got a question for you regarding bending plastic/perspex/acrylic, in my jukebox build i will be attempting to make the outside light tubes, obviously the straight pieces are easy enough :laugh2: , what would be required to bend around a circle if at all possible, i will do the straight parts using the oven method and onto a mould, can i do the same with the curved sections?
Here is a link to my project. http://forum.arcadecontrols.com/index.php/topic,130980.0.html
Cheers
--- End quote ---
I would steer clear of using a drape mould for the straight bits if you can. The easiest way to do the straight bits would be to get acrylic tube and cut it length ways to get your two half round "tubes".
If I were doing this I would blow mould curved parts. Either in one piece or four smaller pieces, dependant on the size of your oven.
Your moulds will be two pieces. The base board is a flat sheet of mdf with a hole in the middle for an air fitting then the board need to be covered in some felt or similar soft material. The top sheet will have a hole the shape where the acrylic meets the box allow at least 100mm around the edge of the "hole". Put a small radius on the edge of the top sheet of the mould, just enough so the edge is not sharp.
You said you have and oven you can use. Heat a piece of acrylic that is the size of the mould boards, when hot, put the acrylic on the bottom mould and clamp (with lots of clamps) the top mould on and turn on the compressed air though the bottom. The amount of air will determine the height of the dome, you will need to vary the air manually to get them all the same height.
Top mould should look like this
Clamped and blown
ignore the crazy dude in the background, and no that is not me...
You should be able to source clear tube in various sizes, then lay a coloured sign writers vinyl on top.
Vacuum forming is a different process all together. It uses a porous mould that the material is formed over.
This is what I mean by blow moulding.
You can do it at home with a jigsaw to make the mould and an air compressor to blow the "dome"
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