Hi there, Russell. I have used Holt Melt Adhesive to hold heavy objects with varying=20 degrees of success. The old 'original' holt-melt is not good for long-term use. I'm=20 talking about the glue from 30 or 40 years ago (I still have some=20 ). The problem with this glue is that it is hard and not flexible. The modern cheap Chinese-made hot-melt from from Dollar Stores is=20 actually not bad. It is much softer and more flexible. It also=20 seems to hold better. As has been mentioned by others: applying the glue to something that=20 is warm or hot gives much better adhesion. One interesting use of holt melt for me is to use it as a moldable=20 form for irregularly-shaped objects. I'm mostly talking about large=20 cylindrical electrolytic capacitors. What I do is attach the object=20 with hot-melt glue and ensure the voids are completely filled. Then=20 I break the glue free from both the object and the surface that I'm=20 attaching to. This is most easily done by putting everything into=20 the refrigerator. Then smack the capacitor with a sharp blow, then=20 the block of hot-melt. The block of hot-melt breaks free quite easily. But: now I have a=20 perfect spacer that fits both the surface and the object. Now, I=20 simply glue everything back in place using cyanoacrylate (super=20 glue). This works very well - I'm pretty sure that I still have=20 stuff mounted this way after decades of use. Unfortunately, I don't have any long-term data for the modern=20 (softer) hot-melt glue. But you may want to consider the technique=20 that I mentioned above. dwayne At 03:52 AM 1/31/2019, RussellMc wrote: >Short: Does anyone successfully use hot-melt adhesives to retain larger >components in place mechanically, with no bond failures over lifetimes of >many years? If so, please comment. > >Longer: > >At various times we have had discussions on the PICList re the use of >adhesives to help locate / retain ... heavy components on PCBs. > >Here and in other forums I have resolutely insisted (eg *here >* & *here >)* that using hot-melt >adhesive is an invitation to disaster as it does not retain its bond long >term. While this has been my observation in all cases where I have >encountered its use by others, this is clearly 'selling it short" by using >the term HM for a vast range of products, some of which SHOULD be eminentl= y >suitable for the task. > >A quickish web search turned up dozens of(apparently) good quality >references to HM and a large range of technical literature. > >It seems 'obvious' that SOME hot melt adhesives would do a good job of the >'simple' task of retaining a largish component in place indefinitely, and >not losing bond strength weeks months or even years thereafter. > >So - again: Does anyone successfully use hotmelt adhesives to retain >larger components in place mechanically, with no bond failures over >lifetimes of many years? If so, please comment. >Brand, type, application results, ... . > > > > Russell > >_________________________________________ > >https://www.bond-tech-industries.com/about-us/blog/6-reasons-hot-melt-adhe= sive-isnt-working/ > >https://multimedia.3m.com/mws/media/39803O/used-to-rigidize-large-componen= ts-on-cicuit-board-of-dryer.pdf?fbclid=3DIwAR0KtAAUx9VCbIDyQ7moNGGKMnFmmiAJ= vIIfD5FEBSjxkoQYIHqJf5jAskg > > >https://multimedia.3m.com/mws/media/1245163O/3m-hot-melt-adhesive-3764-374= 8-technical-data-sheet.pdf > >https://www.tandfonline.com/doi/abs/10.1080/00218469708010513https://wiki2= ..org/en/Hot-melt_adhesive > >https://www.intemag.com/images/uploads/Loctite_Hot_Melt_Technology.pdf > >https://intactadhesives.com/products/adhesives/ > >http://www.siegeladhesives.com/heatspek-technology > > >https://www.google.com/search?q=3D3M%E2%84%A2+Scotch-Weld%E2%84%A2+Hot+Mel= t+Adhesive+3748&oq=3D3M%E2%84%A2+Scotch-Weld%E2%84%A2+Hot+Melt+Adhesive+374= 8&aqs=3Dchrome..69i57j0l2.1453j0j8&sourceid=3Dchrome&ie=3DUTF-8 > >http://siegeladhesives.com/industrial-assembly/ > >*A nice 3M adhesive guide- HM & much more* > > >https://multimedia.3m.com/mws/media/372489O/adhesives-and-tapes-design-gui= de.pdf > > >http://multimedia.3m.com/mws/media/44021O/3m-hot-melt-bonding-systems-guid= e.pdf > >https://www.google.co.nz/search?num=3D40&q=3Dhot+melt+adhesive+bond+failur= e&tbm=3Disch&source=3Duniv&sa=3DX&ved=3D2ahUKEwj87eGrppXgAhUxKX0KHSFeDSoQsA= R6BAgDEAE&biw=3D1602&bih=3D899 > >https://www.bostik-industrial.com/consider-automotive-hot-melt-adhesives-c= ar-assembly/ >-- >http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive >View/change your membership options at >http://mailman.mit.edu/mailman/listinfo/piclist --=20 Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA 780-489-3199 voice 780-487-6397 fax 888-489-3199 Toll Free www.trinity-electronics.com Custom Electronics Design and Manufacturing --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .