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I need to fasten pieces of HDPE together but I’ve heard gluing HDPE is difficult.

I've bought sheets and pipes to make a feeder for a tortoise.

I will be using the sheets for covers for the pipes.

The sheets will also be about 8in in diameter and 1/4in thick.

My team and I are thinking of using regular bolts to do this.

So what I'm really asking is if this is a good idea and if not what could I use?

enter image description here

We're trying to fasten the bottom circles top the pipes.

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  • $\begingroup$ Bolts are just fine, other than maybe all the stuff sticking out might not be beautiful. Solvent-bond or epoxy systems for various PE do exist I believe, but exotic and might take more trial and error and surface prep and careful application than is worth it. PEM nuts for plastic could be an option too. You'd prob be limited to press-in, which won't be as strong as thermally staked ones, but the latter is for factory work. $\endgroup$
    – Pete W
    Commented Mar 30 at 22:05
  • $\begingroup$ clarification after update to Q - by "bottom circle" you mean fastening the semicircular portion of tube, to the disc which is at the base of the shown composite-part? $\endgroup$
    – Pete W
    Commented Apr 3 at 0:46

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Gluing HDPE is nigh impossible! Please consider to create a sketch or two to better present the construction of your project. This will make things easier to provide useful advice. Quarter inch thick sheets will hold fasteners better than the thin stuff, so you're on a good track there.

One can use T-nuts with appropriately sized holes drilled in the sheet. The barbs on the nuts will secure the nut to the sheet, especially if a small diameter hole is drilled to provide a destination for the barb. If you use a T-nut, drill the pilot hole, place the nut, then tap it with a hammer to make marks for the small holes. The small holes should be 1/16" to 3/32" diameter, as you want the barb to "push" into the hole with some force, not simply float in a too-large opening.

From Amazon: 3/8" T-nuts

The link and the nuts shown are for 3/8" but one can find the 1/4" size easily enough.

Less secure for fastening is to use rivnuts, but especially with HDPE, they will probably spin in the hole and make fastening or removing a troublesome matter.

I've threaded UHMWPE of sufficient thickness with success and it cuts under a tap quite easily. It can also be easily stripped, which should be taken into consideration.

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  • $\begingroup$ Are those barbed T nuts meant for wood? Will probably work if the thickness is there $\endgroup$
    – Pete W
    Commented Mar 30 at 22:11
  • $\begingroup$ They are made for wood, but I can't think of a reason why they would not work in plastic. $\endgroup$
    – fred_dot_u
    Commented Mar 30 at 23:01

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