Welding HDPE?

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Ok, so I want to weld HDPE and haven't been able to find much info about the process. I want to make some reptile cages out of high density polyethylene. What kind of equipment will I need? The material I'm looking at is 3/16" thick.I found a couple of sites that say you can use an 80 watt airless welder, which is what I got for Christmas. And then I found other sites that say you need a much more powerful hot air welder. Any opinions for the way I want to use it?Also, I've been looking for HDPE welding rod 1/8" natural. I've found prices ranging all over the place! Anywhere from $9/lb to $80/lb!! What's with the price difference? Is it all the same material or are there higher and lower grades?Here is a rough picture of what I want to make. 12" wide x 24" deep x 24" tall. Everything is going to be HDPE except for the door.Any and all info is appreciated, thank you!!
Reply:why don't you use some 1/4" rod or 3/16 instead
Reply:http://slate.wvu.edu/r/download/26534
Reply:Hey BoaGal,We've had a few inquiries regarding "welding" poly/plastic/HDPE & since you indicate you want to "weld" your project, that means you need a process like steel welding that "fuses" your joints with filler. The most economical unit I have seen used is this unit from HF that works quite well, has a nice heat adjustment range, & they also have filler material available. I'm sure others will chime in with their suggestions.Dennyhttp://www.harborfreight.com/welding...ent-96712.htmlAddendum: Here is a really interesting YouTube Vid that will show you how similar steel & plastic welding are with the associated equipment & the application of filler material.Last edited by yorkiepap; 01-10-2012 at 02:14 PM.Complete Welding/Machine/Fab. ShopMobile UnitFinally retired*Moderator*"A man's word is his honor...without honor there is nothing.""Words are like bullets.... Once they leave your muzzle, you cannot get them back."
Reply:i've used the machine that "welds " hdpe(gas) pipe..it uses a rotating knife to square the ends of the pipe, an electric heater to soften the ends of the pipe, and pressure to force the gooey ends together. you need to duplicate those to get your project to work..good fit up.. heat till soft , and ram it together..and they use no welding rod or filler...as for the right heater, trial and error..
Reply:Originally Posted by weldbeadi've used the machine that "welds " hdpe(gas) pipe..it uses a rotating knife to square the ends of the pipe, an electric heater to soften the ends of the pipe, and pressure to force the gooey ends together. you need to duplicate those to get your project to work..good fit up.. heat till soft , and ram it together..and they use no welding rod or filler...as for the right heater, trial and error..
Reply:Originally Posted by jackalopeI have "welded" various plastics and the results are dependant upon your skill, the machine, and material.
Reply:Thanks for the replies so far. It looks like I may need to upgrade to a different welder that uses hot air...As far as the material for the reptile cage, I wanted to go with a white material instead of clear, because it makes the animals feel more secure and "hidden". I did think about acrylic though.I already have one cage that I bought from a company that makes plastic cages. It's made out of 3/16" HDPE and it's pretty big (4'x2'x1'). I thought I would try making my own cheaper, but I wanted to start small first.Anyone have opinions on the extreme difference in price for the welding rod? I was going with 1/8" because that's what fits the welder I got, but I may be able to use bigger if I get a different welder.
Reply:Originally Posted by BoaGalThanks for the replies so far. It looks like I may need to upgrade to a different welder that uses hot air...As far as the material for the reptile cage, I wanted to go with a white material instead of clear, because it makes the animals feel more secure and "hidden". I did think about acrylic though.I already have one cage that I bought from a company that makes plastic cages. It's made out of 3/16" HDPE and it's pretty big (4'x2'x1'). I thought I would try making my own cheaper, but I wanted to start small first.Anyone have opinions on the extreme difference in price for the welding rod? I was going with 1/8" because that's what fits the welder I got, but I may be able to use bigger if I get a different welder.
Reply:Originally Posted by wireheadAcrylic can be "welded" with acetone but fit up has to be excellent, i.e. no "gaps"
Reply:JACKPLOPE is wrong in regards to hdpe.One of the main features of HDPE is that it is designed to be impervious to most chemicals thus it cannot be glued like acrilic or other plastics.   It needs to be welded.  You need heat, pressure and filler to weld it. The pressure comes in pushing the rod into the weld.   The $69 unit from harbor freight work fine,  I have one, a variable temp heat gun with a narrow adapter works well to.  I mail order my rod from US Plastics.  Its about $15 a lb.   Which is a lot of rod.   One recommendation I got from a pro was to use ldpe when welding old hdpe such as fixing my 70's era amphibious ATV body's.   Says it holds better..A spade tip solderong iron is useful tooLast edited by soutthpaw; 01-11-2012 at 12:37 PM.Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:Originally Posted by soutthpawJACKPLOPE is wrong in regards to hdpe.One of the main features of HDPE is that it is designed to be impervious to most chemicals thus it cannot be glued like acrilic or other plastics.   It needs to be welded.  You need heat, pressure and filler to weld it. The pressure comes in pushing the rod into the weld.   The $69 unit from harbor freight work fine,  I have one, a variable temp heat gun with a narrow adapter works well to.  I mail order my rod from US Plastics.  Its about $15 a lb.   Which is a lot of rod.   One recommendation I got from a pro was to use ldpe when welding old hdpe such as fixing my 70's era amphibious ATV body's.   Says it holds better..A spade tip solderong iron is useful too
Reply:Originally Posted by jackalopeWe're getting into semantics here, but this is more of a chemical process taking place. It would be similar to saying that 2 part epoxy is welding. Not really, rather cheimcal process here as well.
Reply:Too late to edit, but I'd add that unlike polyethylene welding with heat or acrylic welding with solvent, where no foreign material remains in the bond once formed, epoxy bonding works much like "brazing" or "soldering". There's no fusion.XMT304 (school)SP125+ (home)HF 4x6 BandsawGood judgement comes from experience and much of that comes from bad judgement.
Reply:Originally Posted by wireheadToo late to edit, but I'd add that unlike polyethylene welding with heat or acrylic welding with solvent, where no foreign material remains in the bond once formed, epoxy bonding works much like "brazing" or "soldering". There's no fusion.
Reply:Originally Posted by BoaGalOk, so I want to weld HDPE and haven't been able to find much info about the process. I want to make some reptile cages out of high density polyethylene. What kind of equipment will I need? The material I'm looking at is 3/16" thick.I found a couple of sites that say you can use an 80 watt airless welder, which is what I got for Christmas. And then I found other sites that say you need a much more powerful hot air welder. Any opinions for the way I want to use it?Also, I've been looking for HDPE welding rod 1/8" natural. I've found prices ranging all over the place! Anywhere from $9/lb to $80/lb!! What's with the price difference? Is it all the same material or are there higher and lower grades?Here is a rough picture of what I want to make. 12" wide x 24" deep x 24" tall. Everything is going to be HDPE except for the door.Any and all info is appreciated, thank you!!
Reply:I have some huge sheets of thick LDPE that came from some closed companies in Silicon Valley, and also some (probably, I forget for sure) HDPE that I cut from an 'old' wafer processing chamber. The second appeared to use standard 'high bead' welds, but I think that was the material extruded when the edges were heated and forced to together. I think the walls were 3'4" thick there.  Anyway, they must have been good enough to contain HF gas and other such toxic chemicals!  At least some polyethylene will harden and crack over time, particularly if exposed to UV light at elevated temperatures; it starts near the surface and is due to over-polymerization.  Also over time, large pieces, at least for the LD, can sag under their own weight. Microscopic surface cuts can harbor bacteria, whereas wood surfaces seem to kill bacteria rather than contain them. Have you considered using good plywood instead? Decades ago, my friends even built gator tanks from it but in those days we coated it with an old product called Hemicure (probably an early polyurethane) which soon became unavailable (illegal to sell due to the solvent, Benzene IIRC); I am currently treating the edges of some plywood for a shed with a thin epoxy to prevent lamination if water somehow gets past the seam sealer, and it would probably be just as good for your purpose.The biggest cage I built was 6' x 6' x 4'deep with double levels, doors at both ends and both levels, a 4' x 6' piece of glass cantered in front...all for "horney toads", whiptails, side blotches, Leopard Lizards, Great Basin rattlers, and what ever else we had during that time.'Course, they weren't all together at the same time.BTW, I never had trouble with mites, but know Boas tend to be bothered by them if any get in. Plastic theoretically would be easier to keep free of them, but in practice I'm not so sure.
Reply:Originally Posted by Oldiron2BTW, I never had trouble with mites, but know Boas tend to be bothered by them if any get in. Plastic theoretically would be easier to keep free of them, but in practice I'm not so sure.
Reply:Go to www.plasticsmag.com , www.laramyplasticwelders.com , www.leister.com , www.seelyeinc-orl.com., for statrers.  There is a whole plethora of websites dedicated to welding plastics. As for fabricating box shapes you can use a router to cut the corners into the sheet by holding off from severing the sheet and heating it lightly to make your bend and then backweld the inside corner. I've seen this technique used to make PVC duct & it makes clean bends & hides the weld inside the box shape. We used to use a shave hook scraper for finishing the exposed joints and another way is to use a router with straight tip with a bearing mounted on the end ( saves time & effort ) . I believe it is used for trimming laminates but a long one can be found.            I machined, welded & fused various plastic sheets & pipe for 10 years & there a lot of variables depending on what kind of plastic you intend to use. HDPE is a good choice for your application. Manufacturers recommendations should be followed for the best results. I own a Laramy but have used a leister for field work.                       Hope This Helps, G. BudziakMiller Mig 130 & Bobcat 225GOx / LP Gas Hatchet9" x 20"  LatheShp Tsk Mill / Drill / Lathe5/8" Bench top Drill PressPlastic WelderMisc. Mech, Machinist, & Metalworking ToolsLongevity FC 500 Plasma Cutter