Looking for thick PTFE heatshrink sleeving - Page 1
Forum section: electronics / projects

author: peter-h
author_rank: Super Contributor
timestamp: July 01, 2025, 12:56:08 pm
content: I have some metal rod, 2.4mm diameter, which needs PTFE sleeving on it, to achieve a final diameter of 3.4mm.IOW, it needs to be 0.5mm thick when shrunk.I've bought about a dozen different sleevings on Ebay (all from China it seems) and the most they achieve is 0.2mm. One would think something like 6mm 4:1 would end up thick enough but no...The obvious way (multiple sleeves) can't be done because this forms a sort of bearing and needs to be fairly tough.

author: mtwieg
author_rank: Frequent Contributor
timestamp: July 01, 2025, 02:04:26 pm
content: Quote from: peter-h on July 01, 2025, 12:56:08 pmWhat did they say about a recovered wall thickness?QuoteI don't know why one would expect that. Wall thickness, diameter, and shrink ratio are completely independent parameters AFAIK.QuoteAfter a quick search the closest I could find isthis stuff from techflex. But the smallest size with a 0.5mm wall thickness has a recovered ID of 3.15mm, too large for your 2.4mm rod. Also it's 40 USD per meter! Not surprising I guess.You may have to select another material. There are likely some which have all the qualities you want.

author: HalFoster
author_rank: Frequent Contributor
timestamp: July 01, 2025, 03:49:05 pm
content: Try TE Connectivity:https://www.te.com/en/products/heat-shrink-tubing.htmlProbably want the double walled tubing but the shrunk-wall thickness is given in the details section of each one.There are many more manufactures as well.Hal

author: langwadt
author_rank: Super Contributor
timestamp: July 01, 2025, 03:57:31 pm
content: Quote from: peter-h on July 01, 2025, 12:56:08 pmflip the problem and put a ptfe sleeve in the other part?

author: tooki
author_rank: Super Contributor
timestamp: July 01, 2025, 04:14:11 pm
content: Quote from: peter-h on July 01, 2025, 12:56:08 pmDoes ithave toshrink on? Or could you use a piece of non-shrinking PTFE tubing? Something like this might work:https://ptfetubeshop.com/en/product-details-en/?sku=PTFE%20tube%202,5mm%20x%203,5mm&chosen=23837Is this a repair for something, or a new design? Because Teflon is not really a tough material. It certainly is low-friction, but it readily deforms under compression (unless reinforced or specially treated, as in Teflon gasket materials).Do youknow for a factthat two layers, carefully applied, are too eccentric to use? Do you know for a fact that a single layer won’t suffer from eccentricity problems, especially if it’ll be under a radial load? I’d be worried about long-term deformation.Daburn, as always, carries tubing (both heat shrink and regular) in a huge variety of oddball materials, including this dual-wall PTFE tubing:https://www.daburn.com/sm450dual-wallshrinkableptfeencapsulatingtubingvw-1.aspxIt might work, but might be too thick. (Alas, Daburn shipping to Europe is always $$ and then customs gets added…) I also don’t know whether you’d ever get the desired concentricity with dual-wall heat shrink.

author: peter-h
author_rank: Super Contributor
timestamp: July 01, 2025, 07:04:39 pm
content: It is indeed a repair, and yes it is a crap design to start with. The hinge is exposed to the elements which causes dirt to get in and wear all the parts, especially the aluminium hinges which this pin goes inside.It needs to be shrunk on because it is about 15cm long and you would struggle to push sleeving onto such a length. There is also a bend at the end.Cost is not important.Thank you all for the leads. Some great stuff there. I didn't expect this stuff to exist in a specified form.

author: amyk
author_rank: Super Contributor
timestamp: July 01, 2025, 08:35:42 pm
content: Drill and press on a slightly bigger rod of PTFE, then turn it to final size?

author: peter-h
author_rank: Super Contributor
timestamp: July 17, 2025, 11:17:20 am
content: I've not found anything that will produce the required 0.6mm wall thickness on a 2.2mm rod (to get 3.4mm OD) but have ordered three different sleeves from the Shrinkflex range. The data sheet doesn't actually say what the wall thickness is for different shrunk diameters so I will find outAt some $20 per 4ft it is not cheap but is fine.TE might do something but are not contactable. No response to email, no response to their online chat but after a while one gets an emailed copy of my attempted input, adding that they waited but I didn't responseYet another broken large-corporate website and a load of chimps behind their UIThank you all for your input.

author: moffy
author_rank: Super Contributor
timestamp: July 18, 2025, 05:37:05 am
content: Another technique is to strip the insulation from a wire that has the sizing you need, then slide the insulation over the wire you want to insulate.

author: tooki
author_rank: Super Contributor
timestamp: July 18, 2025, 08:18:24 am
content: Quote from: moffy on July 18, 2025, 05:37:05 amSure, but I wouldn’t do that in this specific situation, where the tube is basically needed as a bushing for a hinge pin. Teflon wire insulation is a lot softer than teflon tubing, so it would wear out super fast.

author: voltsandjolts
author_rank: Unknown
timestamp: July 18, 2025, 08:19:50 am
content: Quote from: peter-h on July 01, 2025, 07:04:39 pmBuy new hinges?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 19, 2025, 10:52:47 am
content: Quote from: peter-h on July 01, 2025, 12:56:08 pm4:1 heat shrink only gets a thick wall when it shrinks fully. The volume of the plastic does not change. So try a 10mm tube, and shrink that to 2.5mm.

author: coppercone2
author_rank: Super Contributor
timestamp: July 19, 2025, 11:05:01 am
content: ptfe heat shrink is weird when its shrunk, it likes to shrink into like a helix. It pissed me off severely when I insulated my high current electrode for resistance brazing testsThey don't seem to just shrink nicely. At least some of them.normal heat shrink behaves kinda like you think, while ptfe is quirkyMine literarly had a discolored helix band show up when it was shrunk too. it must be some remnant of manufacturing and like ridges that you can feel. And it likes to slip off the shaft too. It might have shit performance in a hinge mechanism. It's OK for wire though. But don't expect it to perform the 'product enclosure' role like normal heat shrink does. But once its hot you can kinda roll it around and stuff to 'form' it smoother.

author: tooki
author_rank: Super Contributor
timestamp: July 19, 2025, 11:36:33 am
content: Quote from: coppercone2 on July 19, 2025, 11:05:01 amIndeed it is!! PTFE cannot be extruded*, so PTFE insulation** is normally made by wrapping skived PTFE tape around the wire/cable, then heating it to sinter it together. Perhaps some PTFE heat shrink is made the same way? I know that some PTFE-jacketed cables (for example, RG-196 coax) have very obvious wrapping patterns on them.*PTFE doesn’t melt in the normal sense, in that it only becomes gelatinous, not liquid or syrupy. So it fails in “normal” extrusion processes. But “paste-extruded” PTFE exists and is commonly used for (non shrinking) PTFE tubing, for example. There are apparently a few other ways of extruding PTFE, but it’s always more complex than with normal thermoplastics.**The Teflon trade name is used for both PTFE and FEP, so a lot of Teflon-insulated wire is actually FEP, not PTFE, because FEP can be extruded normally.

author: peter-h
author_rank: Super Contributor
timestamp: July 20, 2025, 10:39:17 am
content: A new hinge is incredibly expensiveYes I've been trying various 4:1 products with a min dia of ~2mm but none of them get anywhere near 0.6mm finished wall thickness. Surprising!You need an oven to shrink this stuff; 350-400C. Can't practically do it with a heat gun because the rod inside it also needs to reach that temp. It is very different from any normal heatshrink. Actually one can do it with a "red hot" heat gun but it takes absolute ages; the rod is about 15cm long (it is a piano type hinge).I am still testing different things. Bought 3 samples of the Shrinkflex stuff from Digikey. The company replied to one email, suggesting a wrong product, but then went silent...

author: coppercone2
author_rank: Super Contributor
timestamp: July 20, 2025, 10:48:57 am
content: you need to use a catalyst heater pen for that. Like the ones that come with a dremel or benzomatic. Its a tip with a catalyst screen. Pen torch is fine for smaller HShttps://www.toolsource.com/soldering-irons-c-1321_408_823/soldering-catalyst-for-ppsk-p-127015.htmlit burns at first, gets hot, then catalyst decomposes butane without fire, limiting temperature. big ones are used for curing paint or that powder coatif you wanna replace the one...https://www.ebay.com/itm/374796024019?chn=ps&var=643847783347&google_free_listing_action=view_item&gQT=1you can cut disks out of that and put them in the tool attachmentits a 'consumable' for small pen torches that wears out way before the torch does, and forces you to buy another one.Don't let them keep you in the open flame ages.Now, if you actually spend $50, i think it will last a long time. The ones in the torches are proboly just a plate job on a stainless screen.god damn broken torch components make me irate. Those little catalyst screens are like the major planned obsolesce for half the benzomatic product line. Dremel uses shitty motor brushes that are about 4x thinner then they need to be, theoretically it might save them a few cents per dremel.https://en.wikipedia.org/wiki/Catalytic_heaterRead that if you want to know about the tech

author: voltsandjolts
author_rank: Unknown
timestamp: July 20, 2025, 11:49:08 am
content: Quote from: peter-h on July 20, 2025, 10:39:17 amreally?

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 20, 2025, 12:32:16 pm
content: I don't really understand the application of this "hinge". Is it possible to just add a plastic rod with no metal inside?Maybe you can drill out the hinge and put in an even thicker rod (for example if 4mm rod size is available)