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Can Teflon be machined to a very fine finish?

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  • gellfex
    replied
    Originally posted by A.K. Boomer View Post
    That's why i brought up the armor-all

    heard it from a body shop guy it's one of his worst nightmares is when people use it on their cars trim and get some on the paint, years later and even though you scuff and prep the painted surface the new paint will not stick,
    That crap should be illegal. My wife was inspired to take the car for "detailing" and they ArmorAlled the dashboard, so that the sun glares off it now. I'm disgusted.

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  • greystone
    replied
    I donĀ“t *know* the answer .. but very cold has been a common solution in industry.

    Also, I had a client who tapped holes in plastics - clear as glass.
    He used liquid parafin of some type as cutting fluid (liquid candle wax not gas).

    Some plastics are flame polished to be very clear- amateur examples online.
    Maybe try the teflon makers ?

    They usually have experts as applications engineers, are free, and their jobs are to support major contracts but often help anyone who calls with a "real interesting" question.

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  • Beazld
    replied
    I have used some .014" mylar sheet for vacuum bagging fiberglass directly to foam for RC racing airplanes. It is super slick and when a coat of carnuba wax is applied to the sheet it peals right off the cured fiberglass. I still have some around here somewhere. PM me if you would like to try some. You could use your teflon roller to roll your epoxy on the mylar.

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  • Sun God
    replied
    I would try a card scraper.

    I mean, card scrapers have been used for finishing wood to a smooth, burnished, almost polished appearing finish for centuries, I would imagine it would work on teflon quite similarly as teflon has that sort of brittleness that responds to scraping type cutting.

    I would have tried a sheet of silicone before teflon, though. I know 2 part epoxy glue doesn't stick to silicone brushes, and worst case scenario you could always lift up the silicone sheet and peel the epoxy layer off, while maintaining its thickness. You could probably even cut the epoxy to shape directly on the silicone mat.

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  • GadgetBuilder
    replied
    If you're using glass micro-balloons mixed with epoxy to make the putty then cling film (e.g. Saran Wrap) works well. Rather than a roller you might use a credit card to squeegee over the cling film to adjust the thickness of the putty. The cling film can be removed by pulling at a very low angle, i.e. folding right back along the surface - leaves a smooth surface. Depending on the pattern you're going to imprint, the film can be left in place to avoid the putty sticking to the imprinter, then removed after the epoxy sets up somewhat. If you want to leave a surface for later bonding then fine weave Dacron cloth (aka peel-ply) can be used and left in place until the epoxy cures before removal.

    Some epoxies cure leaving a slight film of clear alkaline material on the surface which may provoke contact dermatitis when handled and especially if sanded. Also, paint doesn't adhere well to this film. Washing the surface with a little vinegar in water removes this film if it's present.

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  • Forestgnome
    replied
    Maybe a smaller diameter roller would work. I relate this to using wax paper. If you roll out putty using wax paper, when you peel it you pull at a sharp angle. If you pull at a shallow angle, it wants to lift the putty. Something about directing more force to a smaller surface area.

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  • PStechPaul
    replied
    Can you make the roller from wax? Maybe a large round candle.

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  • v860rich
    replied
    Originally posted by Lee in Texas View Post
    Many of these alternate ideas have merit, but make it kind of a bummer that the Teflon plate was 75 bucks after shipping.
    You should have came hear first!!!

    THANX RICH

    Leave a comment:


  • Lee in Texas
    replied
    Many of these alternate ideas have merit, but make it kind of a bummer that the Teflon plate was 75 bucks after shipping.
    Last edited by Lee in Texas; 10-27-2017, 01:36 PM.

    Leave a comment:


  • BCRider
    replied
    I think you may need a separator sheet. Cling film has been mentioned already. And perhaps try parchment paper. Plus you may find that you need to wait for it to start stiffening up before peeling away one side of the paper then apply it to the part so it conforms to the shape and then roll in the pattern. This all means you're going to need to work fast if it is starting to stiffen up.

    Or you may find that cling film on one side and parchment on the other works well and let's you work the putty earlier.

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  • Machine
    replied
    I hate to be master of the obvious, but considering the very non-critical application, how about an ordinary wooden dough roller wrapped in saran wrap?

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  • KMoffett
    replied
    Since you aren't dealing with heat, would polyethylene or polypropolene be an alternative? Both have surface energies a little higher than PTEF, but might have a better surface finish for your purpose. An theu are pretty cheap.

    Ken

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  • HWooldridge
    replied
    Most plastics can be machined pretty well with razor sharp HSS tools and no lube. We have turned a lot of HDPE using cold air, venturi-type nozzles to keep the chips cool.

    https://www.vortec.com/cold-air-guns

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  • A.K. Boomer
    replied
    Originally posted by Lee in Texas View Post
    I just realized that I forgot to mention that the Teflon bar has a smooth finish. The 1" thick plate could be better.

    I don't want to use oil for lube because the putty that gets rolled into sheets will be used on models and paint might not stick. Talcum powder is what I used yesterday for the experiment.
    That's why i brought up the armor-all

    heard it from a body shop guy it's one of his worst nightmares is when people use it on their cars trim and get some on the paint, years later and even though you scuff and prep the painted surface the new paint will not stick,

    if you coated and then removed the excess with a clean rag it might be the ticket for it not sticking to the plate but maybe not effecting the putty's ability to adhere to other objects...

    Leave a comment:


  • Frank Ford
    replied
    I think I'd try really getting a terrific polished sharp edge on my Stanley #6 plane and have a go a that 1" thick block of Teflon. Years ago I got a 2" thick piece of UHMW polyethylene and made a kitchen cutting board. Every so often, I skive off a bit by hand planing to renew it. Sometimes comes out mighty shiny and flat.
    Last edited by Frank Ford; 10-27-2017, 01:01 PM.

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