Reptile & Amphibian Forums

Hello-
I'm looking for a little bit of insight from anyone who's been through this before. I need to solvent weld polyethylene both to itself and to acrylic or polycarbonate if either is even possible. I've talked to IPS and they apparently don't offer a solvent adhesive for HDPE. Does anyone know of one? Is it possible to home-make one by dissolving pieces of both plastic together? Any info would be greatly appreciated.

That is one of the downfalls to polyethylene and polypropylene -- they can't be solvent welded to themselves or any other plastic.

You could pick up a cheap plastic welder (thermal) but then you won't be able to weld two different plastics together as they will melt at different temperatures. I'm not even sure acrylic or polycarbonate can be thermal welded.

I believe some epoxy glues and caulks will stick to HDPE, but I'm not completely sure about that.

How thick is the material that you are joining? You could try rivets or screws, along with epoxy, but this is hard to do with thin material. In that case use polycarbonate instead of acrylic. You'd also have to lay it out in a way that the screws or rivets always went through the thickness of the polycarbonate.
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Currently keeping a small collection of various Gonyosoma. Both G. janseni and G. oxycephala.

Thanks for the info chris. One other question... When solvent welding XPVC to XPVC can you accomplish this over a large surface area? What I mean is can two 1/4" thick sheets be solvent welded together to form one 1/2" thick sheet? I've read that evaporation of the adhesive is important to it's curing, so I wasn't sure if something like this is possible. Thanks again for the info!

Solvent welding pvc to pvc over a large surface area would be a problem. Depending on how big of an area you're talking about, you'd be better off using contact cement and pressing two pieces together, preferably with a vacuum bag.
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Currently keeping a small collection of various Gonyosoma. Both G. janseni and G. oxycephala.

How well would the contact cement hold up to the stresses of being cut, drilled, screwed into etc.? Also would it be able to hole up against the constant heating ie. flexwatt?

It's what they use to attach laminate countertops to particle board so it's very durable.

Why do you need to bond two sheets?
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Currently keeping a small collection of various Gonyosoma. Both G. janseni and G. oxycephala.

I'd like to route out recess in both sheets for a piece of 11" flexwatt. Then adhere the two 1/4" sheets together to make a 1/2" shelf with a slot for the flexwatt to slide right into.

Makes sense. So these are rack shelves? How big?

If these are more or less regular sized rack levels then I have a couple of other ideas for you to consider.

First, instead of using two entire 1/4" pieces consider using just one full sized 1/4" piece, or even 3/8", and then use strips of 1/8" material to create runners for the boxes to slide on. These can either go over the flexwatt or just on the outside of it. The latter would be easier and preferable, but it depends on how big each shelf will be.

Take a look at this rack, specifically at the white shelf, second from the bottom.

The two brown strips are 1/8" hardboard that I placed over the melamine shelf for the box to run on. In your case you could use 1/8" PVCX scrap for the runners and solvent weld it right to each shelf.

Another idea is to build the entire rack out of 1/4" material but instead of having the boxes slide on the shelves, like a typical rack, have the lip of the box slide on PVC angle solvent welded to the sides of the rack. The nice thing about this design is that you have room underneath each box for heat tape and don't have to worry about the tight tolerances normally required by a rack. And it also transfers the weight of the boxes to the sides of the rack rather than each shelf, which makes the potential for the PVCX to sag less of an issue.

But this design requires a box that can hang from the lip around the top.
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Currently keeping a small collection of various Gonyosoma. Both G. janseni and G. oxycephala.

I toyed with the idea of using runners somewhat like what you described but the trouble is the size of the rack. The tubs are 44"x 28" so the shelves are pretty substantial. In addition I need two feet of 11" flexwatt to sufficiently heat each level run side by side rather than end to end. I've actually already built a rack for these tubs but It was from 7/16" polyethylene and the shelves/ walls sag a bit. That's why the new one will be PVC. I may even need to make the shelves thicker to keep them rigid but I'm hoping 1/2" will be enough. AP makes a rack for the Iris VE175 tubs that actually covers a little bit more of a distance than what I'm using and 1/2 CDPVC works for them without sagging... so I'm hoping it will work on mine too. I just think that a 1/2" shelf with the flexwatt right in the middle of it would be nice and clean looking... if it will be strong enough that is.

What box do you have that is 44x28?

I would think through this carefully and I would strongly consider having the tubs slide on rails rather than on the shelves. Just have the shelves as a place to hold the heat tape and to keep the occupants in the box.
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Currently keeping a small collection of various Gonyosoma. Both G. janseni and G. oxycephala.

Truth be told I hadn't even considered using rails to lighten the load off the shelves... that's a fantastic idea.

I've also had this very idea (two 1/4" sheets with routed middle for heat) in my head for a couple of years now, but never really did anything with it. I always thought it would be perfect for smaller - midsized rack setups. Good luck and let me know how it works out.
Scott

I would use PVC angle then. Prices are all over the place so it's worth shopping around.

And I'd still like to know what box that is you're using at 44" x 28". Thanks.
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Currently keeping a small collection of various Gonyosoma. Both G. janseni and G. oxycephala.

I doubt you will find one for HDPE. I have used epoxy, and it holds for very light loads. Silicon works for light loads as well. Screws or bolts work better.
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Mark