|
Post by knave on Dec 9, 2019 14:49:54 GMT -5
jamesp what is the melt temp and pourability of HDPE, would there be any way to melt scraps and make a barrel? Haven’t thought it through at all. I suppose one could pour onto a flat surface for sheet material to butt weld over the end of a pipe...
|
|
whyofquartz
spending too much on rocks
So, Africa is smaller than I expected...
Member since December 2019
Posts: 316
|
Post by whyofquartz on Dec 9, 2019 15:05:46 GMT -5
jamesp what is the melt temp and pourability of HDPE, would there be any way to melt scraps and make a barrel? Haven’t thought it through at all. I suppose one could pour onto a flat surface for sheet material to butt weld over the end of a pipe... if i recall correctly it will not pour well, it cools too quick, but you can cast it by melting it in the mold. i suppose you would have to try to shred it(you should be able to feed milk caps into an office shredder that can destroy CDs. your office shredder not mine though) or purchase it in a pelletized form. stand by while i change platforms and I will share a Video
|
|
whyofquartz
spending too much on rocks
So, Africa is smaller than I expected...
Member since December 2019
Posts: 316
|
Post by whyofquartz on Dec 9, 2019 15:07:50 GMT -5
jamesp what is the melt temp and pourability of HDPE, would there be any way to melt scraps and make a barrel? Haven’t thought it through at all. I suppose one could pour onto a flat surface for sheet material to butt weld over the end of a pipe... if i recall correctly it will not pour well, it cools too quick, but you can cast it by melting it in the mold. i suppose you would have to try to shred it(you should be able to feed milk caps into an office shredder that can destroy CDs. your office shredder not mine though) or purchase it in a pelletized form. stand by while i change platforms and I will share a Video Here is a young british fellow explaining it it is around the 12 minute mark in this video
|
|
|
Post by knave on Dec 9, 2019 15:10:12 GMT -5
I used to install geothermal loop fields using socket fusion HDPE, I’m somewhat familiar with it.
|
|
whyofquartz
spending too much on rocks
So, Africa is smaller than I expected...
Member since December 2019
Posts: 316
|
Post by whyofquartz on Dec 9, 2019 15:19:54 GMT -5
i only knew it was milk caps cause this kid said it. I am trying to noodle out how you could get a complex shape, like a ribbed barrel, to come out without any voids. I wonder if you could't have them printed relatively cheaply compared to the 4 to 6 part mold I am designing in my head
|
|
whyofquartz
spending too much on rocks
So, Africa is smaller than I expected...
Member since December 2019
Posts: 316
|
Post by whyofquartz on Dec 9, 2019 15:36:37 GMT -5
well Shapeways can't do it. I have tried nothing and I am out of ideas actually, with a piece of pipe(goes by inside diameter) , 2 pieces of tubing(goes by outside diameter), 2 pieces of plate steel, and a degree of welding and grinding i am not capable of. you could make a relatively simple mold for a drum with a wide waist and thinner neck and make it any size you wanted and as many as you wanted
|
|
|
Post by knave on Dec 9, 2019 16:38:30 GMT -5
I haven’t had time to check out the video because I’m still at work, but it looks very interesting and I want to check it out
|
|
|
Post by knave on Dec 10, 2019 0:58:15 GMT -5
I haven’t had time to check out the video because I’m still at work, but it looks very interesting and I want to check it out Wow! Great find on the videos... Here is another one where he is making sheet HDPE, at the very end he shows how he welds layers together using only a heat gun!
|
|
|
Post by knave on Dec 10, 2019 0:59:09 GMT -5
This has jamesp written all over it
|
|
|
Post by knave on Dec 10, 2019 1:03:17 GMT -5
Wow. If I had a perfect sheet of it, warmed to pliable temp, could you not wrap it around a 6” od piece of steel pipe, then carefully weld the seam... Hmmm.
|
|
|
Post by knave on Dec 10, 2019 1:06:04 GMT -5
I will contact my old employer, I know we used to throw great big chunks of scrap HDPE into the dumpster. Mostly 1 1/4” pipe, up to 10’ chunks of it.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Dec 10, 2019 4:53:14 GMT -5
You guys are talking my language. Melting is a concern. I have shaped and more recently welded HDPE over the years. My first project was cutting an HDPE 55 gallon drum down and used a heat gun to fold a 10" wide pour spout. This leak proof rugged container was mounted in a fish pond waterfall to serve as a fish pond filter. Pond water was pumped in from bottom that rose thru filter media and then poured out the spout and down the little decorative waterfall. I sold them successfully to landscapers and individuals building their own garden pond. These were common HDPE 55 gallon drums and were sold for $6 at a local barrel recycling plant(my neighbor owns the recycling plant). ***The tops of these drums were welded on, so they must be made of a weldable HDPE. So they may be a great source of weldable(and meltable ?) HDPE. On the subject of welding, I tried welding Walmart butcher block to HDPE black pipe and found that some HDPE's do not weld together near as well as "pipe grade" HDPE. And re-welding a messed up weld presented problems at times. (virgin HDPE vs non-virgin ?)For this reason I feel nervous about melting just any HDPE. I know the prison dudes can make shanks out of melted HDPE lol. So I concluded that used HDPE pipe was the best way to go because it is the perfect shape for a tumbler barrel, tough as a 10 cent steak, it welds very well, and it can be had so cheap at $8 to $15 per foot purchased new, much less cheaper or free when used. The trash dumps hate HDPE pipe, like tires. Since the HDPE fittings are expensive I think welding HDPE(pipe grade) flat plate to the ends of pipe sections is the way to go. But you would have to have a lathe or a circle cutter on a band saw to cut the circles out of the plate. The plate was not cheap though, but much cheaper than the fittings. If I were to make HDPE tumbler barrels I would go this route because tumbler barrels are very hard duty and I know for fact that the welds on pipe/pipe plate can handle the duty: Dogs getting ready to rumble, note cardboard neck tie:
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Dec 10, 2019 5:14:41 GMT -5
knave whyofquartzIf you want to do a hands-on intro to welding HDPE simply grab a teflon frying pan and heat it to 325 -350F and weld some bottle caps or smaller diameter black pipe together. Right there in the kitchen. Put 2 bottle caps or 2 short sections of black pipe on the heated teflon surface till you see it slightly melting at contact point and simply stick them together. See the 'bead' before grinding it off. Looks like a weld done on a $100,000 pipe welder in wife's frying pan when she was out shopping(important point). When I do these welds I let the pipe sit on the teflon pans at 200 to 250F for say 10 minutes to heat the weld faces slow and deep. Then raise the temp to the ~350F melt point and wait for the 'bead' to start to form at the pan, even pushing down on them occasionally to see if the plastic is getting soft. These 'slow' welds are probably better than the faster field welds that pipe welding machines make because of the deep pre-heat. I push down on the pipe and raise it up and check that the full 360 degrees of surface has softened. The softened areas are easy to spot, or the cold areas are easy to spot. You MUST have a full circumference weld or you will have leaks ! Bead before grinding off : If you melt HDPE I believe you must have a precision way of knowing the correct temp. If over heated I think things go south in a hurry.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Dec 10, 2019 5:39:30 GMT -5
Wow. If I had a perfect sheet of it, warmed to pliable temp, could you not wrap it around a 6” od piece of steel pipe, then carefully weld the seam... Hmmm. I did try heating sections of pipe and making flat plates out of it. I obviously did not get it hot enough because it had a memory and bowed after cooling. After watching this young man's video I need to take it up to his suggested 175C/350F in the oven to make a flat plate from sections of the pipe. The pipe would be a cheap source of thick plate for the ends of a tumbling barrel since it can be had used for little money. Weld the plate to one end of the pipe to save money for the barrel end cap, and weld a purchased reducer fitting on the other end of the pipe.
|
|
|
Post by knave on Dec 15, 2019 20:48:14 GMT -5
Yay, some grocery bags are HDPE.
|
|
|
Post by knave on Dec 15, 2019 22:30:13 GMT -5
|
|
|
Post by knave on Dec 15, 2019 22:32:10 GMT -5
jamesp, note how he filled in voids using scrap shavings of plastic, then reshaping. One could definitely turn a barrel on a lathe.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Dec 16, 2019 5:40:05 GMT -5
jamesp, note how he filled in voids using scrap shavings of plastic, then reshaping. One could definitely turn a barrel on a lathe. I would love to have a tumbling barrel with that design texture. Hell I would love to tinker with melting all those patterns and shaping them on a lathe. I have been sourcing various HDPE plate (welded to pipe) to make barrels for resale as rock tumbling barrels and ball mill barrels. I am working with a wholesale plastics distributor/machining operation and getting some great quantity pricing. The pipe is about free, plumbing operations all over Atlanta can't get rid of the remnants and are happy having me haul it off(one man's trash.....). Funny thing, I just came up on your thread whilst wife is asleep when her teflon pans are not being policed. Am doing a test HDPE test weld, 1/2 inch tank stock to 10mm pipe stock. Yes, large HDPE tanks are made of thick HDPE sheet. Weld complete, teflon pan put back exactly as found ! Check it out. Will give you $137.42 if you can break the weld with bare hands. Strong weld but how strong ? Ready for standard 8 pound sledge hammer test. Test complete, the tank material has a lower melting point(not good) and the weld failed. Not a surprise. If it were pipe stock to pipe stock I could have beat on it all day. Or the red to the red.... Do you have a rotary rock tumbler ?
|
|
|
Post by knave on Dec 16, 2019 5:47:12 GMT -5
Hmmm. So there are different grades melt points and “Mohs” of HDPE. I wondered about that. Great info, thx.
|
|
jamesp
Cave Dweller
Member since October 2012
Posts: 36,154
|
Post by jamesp on Dec 16, 2019 6:24:48 GMT -5
Hmmm. So there are different grades melt points and “Mohs” of HDPE. I wondered about that. Great info, thx. Yep. That is why I mentioned the used/cheap 55 gallon HDPE barrels. They are made of a very castable/workable/softer/ lower temp HDPE. They are high quailty and UV stabilized for long heavy duty life. Apparently the welding temp increases with the density. The pipe is scary dense tough material, welds are evil strong if not over/under heated. Do you have a rotary tumbler ?
|
|