Harry P. Posted August 21, 2016 Posted August 21, 2016 As I understand it, Delrin is almost impossible to glue to another surface... sort of like trying to glue something to Teflon.My first instinct was to scuff up the glue area on the Delrin part with some sandpaper, and use CA to give me a physical bond, rather than a chemical bond, as the CA would flow into all the tiny scratches on the Delrin part and physically lock onto it. Or maybe 5-minute epoxy, same theory.Is there a better way? Is there any sort of glue that would work better? I've heard all sorts of stories about Gorilla Glue, but have never used it.Any suggestions?
Ace-Garageguy Posted August 21, 2016 Posted August 21, 2016 Delrin is generally thought of as a self-lubricating plastic, due in part to its "low surface energy", similar to what makes it hard to bond to polyethylene.When I fabricate something from it (like suspension bushings or clutch pilot-shaft bushings) I always design so the part is a press-in or snap-in fit.However, it CAN be bonded to itself and dis-similar materials. Here's how: http://reltekllc.com/adhesivesfordelrin.aspx
Harry P. Posted August 21, 2016 Author Posted August 21, 2016 I had a feeling you would be the first one with an answer... But what about my "scuff the surface and CA" idea? The joint will be under no stress at all... all I need is one part (styrene) to stick to another part (Delrin) without falling off.
Ace-Garageguy Posted August 21, 2016 Posted August 21, 2016 I had a feeling you would be the first one with an answer... But what about my "scuff the surface and CA" idea? The joint will be under no stress at all... all I need is one part (styrene) to stick to another part (Delrin) without falling off. If it really is under "no stress at all", your "scuff and CA" idea ought to work. After all, even very slippery polyethylene bondo-spreaders will get bondo stuck to them...and sometimes it's hard to remove entirely...as the surface becomes more and more scuffed with use. 120-180 is probably a good guesstimate grit to use. All I can suggest is that you test the bond strength somewhere other than on the model first. And I'd be VERY interested to know your results.
Ace-Garageguy Posted August 21, 2016 Posted August 21, 2016 I did a little more digging, and this hardware-store product by Loctite specifically mentions Delrin as one of the plastics it's effective on. As it also bonds a wide array of other materials too, it might be worth at least trying it on your application, as whatever is left over can be used as a conventional medium-strength epoxy. http://www.loctiteproducts.com/p/epxy_plstc_s/overview/Loctite-Epoxy-Plastic-Bonder.htm
Ace-Garageguy Posted August 21, 2016 Posted August 21, 2016 (edited) I also found this on one of the "practical machinist" sites that have people who actually DO stuff, rather than endlessly-repeated but untested opinions." I always use Devcon Plastic Welder[22045?]. It's part epoxy, part meth-methacrylate[dental acrylic]. Seems to work better than most other types of adhesives for non-bondable apps."And this:'"A loctite applications engineer recommended this for delrin to aluminum.Rough up delrin770 Prism PrimerLoctite 401 " Edited August 21, 2016 by Ace-Garageguy
Ace-Garageguy Posted August 21, 2016 Posted August 21, 2016 More thinking, I'd tend to prefer CA over 5-minute epoxy. The 5-minute stuff doesn't stick particularly well to ANYTHING in my experience.
Harry P. Posted August 21, 2016 Author Posted August 21, 2016 The Loctite product you posted specifically lists Delrin. That's what I was looking for... a commercially available glue that I can find at any home center. Thanks... you have solved the problem.
Ace-Garageguy Posted August 21, 2016 Posted August 21, 2016 (edited) The Loctite epoxy product lists a 20-25 minute cure time, which is going to make it a LOT stronger than the 5-minute stuff. Additionally, the label says it's an "acrylic" formula, which is quite possibly in line with the recommendation I found earlier that someone " always use(s) Devcon Plastic Welder [22045]. It's part epoxy, part methyl-methacrylate . Seems to work better than most other types of adhesives for non-bondable apps." The Devcon Plastic Welder 22045 is also available at places like Walmart. Edited August 21, 2016 by Ace-Garageguy
peteski Posted August 22, 2016 Posted August 22, 2016 I have never been successful bonding Delrin to anything. I employ mechanical bonds (drilling and pinning) or heat-welding (melting) parts together.
mod3l Lover Posted August 22, 2016 Posted August 22, 2016 I did a little more digging, and this hardware-store product by Loctite specifically mentions Delrin as one of the plastics it's effective on. As it also bonds a wide array of other materials too, it might be worth at least trying it on your application, as whatever is left over can be used as a conventional medium-strength epoxy. http://www.loctiteproducts.com/p/epxy_plstc_s/overview/Loctite-Epoxy-Plastic-Bonder.htm I have used this product for a great many thing before, and I just love it! If you keep that little cap on, and store it plunger side down, it lasts quite well also. David S.
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