Jump to content

nylon/CF or nylon/glass for stair bracket?

Recommended Posts

Posted · nylon/CF or nylon/glass for stair bracket?

Good morning everyone.   This morning I am working on some brackets to hold pre-fabricated aluminum stair treads.  The treads are pre-drilled to mount on brackets made from aluminum 'T' extrusions, wall thickess may be 1/8" or 3/16", but the brackets are welded to beams at an angle I can't use, so I have to make my own.


I was about to hire a Tig welder to make up a set of brackets, likely out of 6061 angle, but the price is rapidly spiralling.  These brackets are small enough that I can fit two sides of the triangle on my printer. 


So I wonder - with all of the claims about the strength of materials like NylonX, Nylforce, XStrand, etc, would it actually be safe to print these brackets?  And additional consideration is that these will be used in a wet environment, with the bottom brackets likely underwater for much of the time. (fresh water, not salt).


Thoughts?  Thanks!


  • Link to post
    Share on other sites

    Posted · nylon/CF or nylon/glass for stair bracket?

    Technically, it will probably work well if you design the parts thick and massive enough, if load is distributed well (=no stress points, correct orientation of layers), and if you print them correctly (temp, fill, flow), and regularly test for degradation and replace them.


    But personally, I would not really trust it. I wouldn't trust any plastic parts for such purposes. I have seen too many plastic things crumbling apart or breaking after a couple of years: dustbins, bottles, gardening tools, plastic toys, food boxes, garden tables and chairs, car bumpers, all sorts of composite casts,... And these were injection moulded parts, or cast parts, so they even didn't have the 3D-printing problems like layer-adhesion, stress-inducing entrapped air, uneven cooling stresses, etc.


    The biggest risk will probably UV-light degradation, plus to a lesser degree ozone, chlorine (if in contact with tap water or swimming pools), hydrolysis, drying-out (evaporation of plasticizers), fatigue,...


    I am not sure, but I do believe that here in Belgium weight-carrying plastic connections on ladders and stairs are even forbidden. At least, they are forbidden in our university: all connections have to be welded or rivetted.


    Without photos or drawings it is difficult to give advice, but what about using rivets? Or nuts and self-locking bolts? Maybe with use of copper-grease to prevent corrosion?


    • Thanks 1
    Link to post
    Share on other sites

    Posted · nylon/CF or nylon/glass for stair bracket?

    Thanks @geert_2.  Your response makes perfect sense to me.  My default is metal for the same reasons as you cite.  I just thought, maybe I am being old fashioned.  But given the consequences of a step giving way, I think maybe old fashion is best.


    I will look at rivet options.  The nuts and bolts would probably be strong enough, but I am trying to have one flush surface and would rather not have to thicken the metal for a countersink or counterbore. 


    Much appreciated!


  • Link to post
    Share on other sites

    Posted · nylon/CF or nylon/glass for stair bracket?

    I just took a look at the portable ladder in my lab: it is both riveted and welded. This makes it feel rock solid. If only riveted, each connection could still pivot a bit, causing a wobbly feeling. If only welded, the welds could be superficially glued instead of really melted together. I can't weld myself, but I heard from a professional welder that welding aluminum is difficult due to the very high temperatures required to melt the oxide layer. If not high enough, the connection may slightly stick, but is not welded and will separate under load.


    If yours will be mounted to a wall, pivoting will not be a problem. But if portable, make sure you provide multiple connections per step.


  • Link to post
    Share on other sites

    • 2 weeks later...
    Posted · nylon/CF or nylon/glass for stair bracket?

    Plastic folders crumbling apart after sitting in the daylight for a couple of years. And this was even behind sun-shielding green glass, which should catch most of the UV-light.


    These folders are usually made of PE or PP, but I have seen similar problems with other plastics. Last month I had a dustbin falling apart. A couple of years ago I have seen this in "weatherproof" garden chairs...


    That is why I would not trust plastics too much for load-bearing outdoor use, unless they are specifically tested and approved for it. 3D-printing materials are relatively new, and we don't have a lot of experience with long-term durability in this regard.




  • Link to post
    Share on other sites

    Create an account or sign in to comment

    You need to be a member in order to leave a comment

    Create an account

    Sign up for a new account in our community. It's easy!

    Register a new account

    Sign in

    Already have an account? Sign in here.

    Sign In Now
    • Our picks

      • S-Line Firmware 8.3.0 was released Nov. 20th on the "Latest" firmware branch.
        (Sorry, was out of office when this released)

        This update is for...
        All UltiMaker S series  
        New features
        Temperature status. During print preparation, the temperatures of the print cores and build plate will be shown on the display. This gives a better indication of the progress and remaining wait time. Save log files in paused state. It is now possible to save the printer's log files to USB if the currently active print job is paused. Previously, the Dump logs to USB option was only enabled if the printer was in idle state. Confirm print removal via Digital Factory. If the printer is connected to the Digital Factory, it is now possible to confirm the removal of a previous print job via the Digital Factory interface. This is useful in situations where the build plate is clear, but the operator forgot to select Confirm removal on the printer’s display. Visit this page for more information about this feature.
          • Like
        • 0 replies
      • Ultimaker Cura 5.6 stable released
        Cura now supports Method series printers!
        A year after the merger of Ultimaker and MakerBotQQ, we have unlocked the ability for users of our Method series printers to slice files using UltiMaker Cura. As of this release, users can find profiles for our Method and Method XL printers, as well as material profiles for ABS-R, ABS-CF, and RapidRinse. Meaning it’s now possible to use either Cura or the existing cloud-slicing software CloudPrint when printing with these printers or materials
        • 48 replies
    • Create New...