Anyone familiar with plastic welding/soldering? - Page 1
Forum section: electronics / general

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 05, 2021, 01:49:05 am
content: I need to figure out how to connect a IBC tote to regular plumbing as it will be used as water supply for an offgrid cabin. I managed to find a Polypropylene Cam lock adapter that fits the IBC tote but the opening is a 2" NPT. Hardware stores don't sell anything in 2" for water pipe fittings and I have not found anything online either. I found a NPS to 3/4" hose adapter and chanced that it would still fit, but it does not. It becomes harder and harder to thread until you can't anymore.So I think I need to take a different approach, something more custom. I will start collecting anything with recycle code 5 (PP) and once I have enough, melt it into a sheet. Then I will cut it and weld it to the end of the camlock adapter so I end up with basically just a cap. From there, I should be able to drill a 3/4" hole and then caulk a normal pipe fitting in the hole, like a pex crimp barb or something.My question is, can I mix different colour plastics together when welding? Whatever plastic I recycle will have different colours. Will this work? I'm finding most medicine bottles seem to use PP so I will probably be using mostly white plastic.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 05, 2021, 01:58:36 am
content: You have pretty good odds of having whatever you melt together leaking.Just use a series of reducing bushings. You can get a 2 to 1-1/2 plastic bushing from Grainger for around $5. Then get a 1-1/2 to 1 and a 1 to 3/4 and you're good to go.

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 05, 2021, 02:05:13 am
content: Have a link to those? Have not been able to find anything like that anywhere. Maybe I'm not searching the right thing.

author: JohnMc
author_rank: Contributor
timestamp: August 05, 2021, 12:36:15 pm
content: So you are trying to go from 2" NPT on the tote to 3/4" hose barb? You should have no problem doing that with off the shelf fittings. You might have to look more to a pluming supply house then Home hardware. What part of Canada are you in I might have some ideas.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 05, 2021, 12:53:08 pm
content: Look up 6MV72 on the grainger site. That will get you from 2" to 1". Look up pvc reducing bushing and you'll get all the hits.You could use galvanized but PVC will be cheaper. In the listingings MNPT -> male NPT.Unless you go to a plumbing supply house, finding anything over 1 inch is a problem. Homeowners rarely see anything over 1 inch so the big box stores and most hardware stores don't stock it.

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 05, 2021, 12:53:41 pm
content: I'm in northern Ontario. Even online, can't seem to find any place that sells a big variety of fittings of that size at least not the ones I want. Found Global Industrial that's where I got the parts from, but some parts come in NPT and some in NPS so it's hard to find stuff that's compatible with each other. Did findthis, but at $94 a pop (need at least 2, more in future)... I'm hoping to find something cheaper. Paid $150 for the totes... starting to step into territory where the fittings cost me more than the actual totes.Tried a local plumbing supply store but they only sell to companies. Most of those places are like that unfortunately. I wonder what kind of fittings cities use for municipal water supply.So yeah at this point, just looking into options to make my own fittings. I heard of people just putting a hole directly into the tote and caulking a hose faucet but I don't like the idea of that. I feel plastic welding will probably create a much stronger bond and since I already ordered the parts I may as well make use of them. The shipping was like $40 so not worth returning them since I'm still going to be out at least $40, more if I have to pay to ship it back.

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 05, 2021, 01:04:31 pm
content: Quote from: PaulAm on August 05, 2021, 12:53:08 pmSeems their search sucks, I never would have found that just from searching but it does look like it's what I need. Can't find the others. We actually have a Grainger here maybe it will be easier if I just go over to the location. Not sure if they sell to general public though... seems a lot of these places don't. But the site shows prices and has a way to order so that's a good sign.

author: Ian.M
author_rank: Super Contributor
timestamp: August 05, 2021, 01:13:58 pm
content: This is not rocket science. Follow the Amazon link from this page:https://preparednessadvice.com/fixtures-emptying-icb-totes-large-water-storage-containers/

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 05, 2021, 05:00:10 pm
content: Grainger will sell to individuals, no problem. Order it online and arrange for pickup at your nearest branch. They won't even ask you who you are if your credit card clearsYou're better off ordering online. Their stores are not set up for browsing and a lot of the stock gets shipped in from their warehouse. You could have it shipped to your residence, but pickup doesn't cost anything and, for common items, it's next day.I just bought a 1-1/4 -> 3/4 NPT steel bushing from them because I couldn't find it anywhere else .Grainger isn't the cheapest option but sometimes it's the easiest.

author: themadhippy
author_rank: Super Contributor
timestamp: August 05, 2021, 05:27:27 pm
content: uk based,but will ship anywerehttps://www.intricoproducts.com/cat/ibc-fittings

author: IDEngineer
author_rank: Super Contributor
timestamp: August 07, 2021, 05:15:28 pm
content: On a lark I did a quick search and Amazon seems packed with all sorts of options. I'm not an Amazon guy (I normally prefer dealing with industrial suppliers) but this just doesn't seem that difficult.For example, $19 gets you this:https://www.amazon.com/Adapter-Connector-Replacement-Courtyard-Irrigation/dp/B095P6LXSR...which claims to attach directly to your IBC Tote and even includes a brass valve.If you don't need the valve, $12 will get youtwoof these:https://www.amazon.com/Fittings-Connector-Fitting-Adapter-Connection/dp/B095JJKRKP...which again claim to connect to an IBC 275/330 Tote and have 3/4 male output threads.If neither of those does what you want, there are cross-referenced links on those pages to dozens of related products including hose barb outputs, GHT (garden hose thread), NPT, etc. Basically use these links as a starting point and you should be able to find almost anything you want.Good luck, report back!

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 07, 2021, 05:35:18 pm
content: I don't really trust Amazon for something that will be used for potable water, but most of those probably won't fit anyway. The Camlock one I got from Global Industrial fits but the 2" to hose adapter won't fit on the camlock, the 2" threads are not quite the same. I can't find one that uses NPT threads only NPS, I think the threads on the camlock are NPT. The problem with buying stuff like this online is it's a gamble, as the sites are not always descriptive enough or the pictures are not even of what you're actually buying. I THINK this might fit but not 100% sure.https://www.grainger.ca/en/product/REDUCER-BUSHING%2C2-X-3-4IN%2CMPTXFPT%2CP/p/WWG6MV71?The ones on Grainger MIGHT work, but it's hard to tell from description if the 2" side is male or female. It says male but not sure if that means it mates to male or if it is male.I can keep ordering stuff until the cows come home but it will get expensive. I'm at a point where I just need to cut my losses and fabricate something.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 07, 2021, 06:48:29 pm
content: If it is a reducing bushing, the large size is male and the smaller size is female. That's what a reducing bushing is, full stop. Also, the picture in your link shows it clearly.NPT threads are tapered, NPS are straight so NPT threads are normally used in a pressure situation as the interference fit seals better. Still, they will leak unless a sealant is used. NPS absolutely will leak without additional sealing methods.If you make something you will probably pay more for the pipe tap than you would for the bushing. Unless you cut them with a lathe with a taper attachment (or CNC).Really, this is not that complicated.Steel, galvanized or PVC usually are not a problem with potable water. Brass may or may not be allowed depending on the composition. Grainger, at least, will tell you if brass components are legal for potable water systems. Don't use any cheap no-name brass fittings in potable systems.

author: rdl
author_rank: Super Contributor
timestamp: August 07, 2021, 08:00:33 pm
content: Any attempt to "weld" dissimilar plastics seems almost guaranteed to end in failure.I did a quick search for "IBC tank cap with outlet" and found just about every variety I could imagine. Maybe that will help.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 07, 2021, 08:19:42 pm
content: Agreed on the NPS threads. They are NOT a sealing connection, always used with an o-ring or other sealing element. Don't rely on thread sealant either. History is littered with failures like that.You can use something like 3M 5200 adhesive but it will be a permanent connection. Emphasis on permanent. And even then I wouldn't rely on NPS threads.Fittings are everywhere. Heck, I'd never heard of these water containers before this thread and part of my actual job is managing water through pipes, hoses, and fittings in all sorts of materials. Trust me, what you want is already made by someone and they've already figured out how to do it properly. A few minutes of searching should reveal tons of options.

author: LaserSteve
author_rank: Super Contributor
timestamp: August 07, 2021, 08:20:35 pm
content: Mcmaster.com Everything you want. Has a great search engine.Steve

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 07, 2021, 08:59:24 pm
content: Quote from: LaserSteve on August 07, 2021, 08:20:35 pmThat's American unfortunately. I WISH we had something like that here.I would make sure all plastics are similar. Both pieces I want to weld together are polypropylene which is recycle code 5. I just don't know if colour makes a difference as I probably won't find anything black. Though I could melt down the adapters i bought that did not fit, I only need to melt down the part with the threads, that should give me enough material to glue the hose part to the camlock.I don't decide what kind of threads there are, they come in whatever they come in. If it was my choice it would just be camlock straight to a hose fitting. I did find one on amazon but it's like $90 and I don't really trust Amazon for something like that anyway.Another option might be to try to cut some of the threads but it will be tricky trying to get a very straight cut, it needs to be straight so it can seal with the O ring. I can't screw it in far enough for it to get to the O ring since one set of threads is NPS and other is NPT. Could not find both in same thread format.This looks promissing but not sure if the threads will match.https://www.grainger.ca/en/product/REDUCER%20BUSHING,2%20X%203/4IN,MPTXFPT,P/p/WWG6MV71Also not sure what they mean by "Fitting Connection Type MNPT x FNPT". Does it mean it *IS* a male to female or that it mates to a male and other end mates to a female? I need it to have a female thread since the camlock adapter (the one that does fit) is male.I think the pic is also generic as the size does not look right but it's the same pic for lot of fittings.This is what I have so far:IBC tap:The two fittings I attempted to use:The camlock (one with metal locking mechanism) fits fine, but the other one can't thread all the way, it's NPS (can't find it in NPT) and I think the camlock is NPT (can't find in NPS).So I'm thinking I will just find a way to weld a flat piece of plastic to end of camlock, then weld the hose connector part to the flat piece after drilling it out.

author: PaulAm
author_rank: Frequent Contributor
timestamp: August 07, 2021, 09:26:37 pm
content: Well you really want to do it your way, so go ahead.15 seconds of searching got this page of camlock to male NPT adaptershttps://www.cutandcouple.com/product/aluminum-female-camlock-x-male-npt/Put female npt camlock in the search box, pick one of those, a reducing bushing, your hose fitting and you're done.

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 07, 2021, 09:43:47 pm
content: That too is American. Also I already have that part, it's adapting that thread to 3/4" or 1/2" I need. That's the challenge, 99% of what I find online is not in Canada. By the time you account for exchange rate, customs, taxes etc it ends up prohibitively expensive. I've been hit with $600+ custom bills for a $100 items before, it's a gamble. It's a real pain trying to find specific stuff like this here.Trust me I did lot of searching and the closest thing I found (what I already bought) is not working. So it's time for plan B.

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 16, 2021, 10:01:08 pm
content: So I think I got this, it seems the trick is really the pipe dope, and just pure brute force to try to force them together and manage to turn it enough so that I can force it into the seal. it may not be ideal but so far so good. The second one I did, I put the pipe dope on the female threads (should have done that from the get go, just cleaner) then clamped that part down to a 2x4 that I can step on, then I used a screwdriver on the other part as it has a small area I can stick in it. This gave me more leverage to turn it. I was able to force the incompatible threads all the way to make the seal.If I had many of these to do, I would probably look at building some kind of jig and just do it this way as it seems to work and these are the closest parts I can find in Canada that are at least semi compatible with each other. Time will tell if the connection stays and the seal continues to hold though.The pics are of the first one where I was able to get it pretty far with pipe dope which kind of acted as a lubricant to get it to spin a bit more, but it leaks very slightly. (can see a little drop, that stayed that way for over a day without falling) but the 2nd set I did I was able to get it to hit the seal using the 2x4 and screwdriver for more leverage. It was a bit medieval but it worked.

author: Ian.M
author_rank: Super Contributor
timestamp: August 16, 2021, 11:20:30 pm
content: Anyone care to bet on how long that will hold up before the locked in stress + thermal cycling splits the reducer cap?

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 17, 2021, 04:39:15 pm
content: Yeah could be an issue, time will tell. I am a bit worried that any residual water inside freezes if I leave the fitting outside in winter, but I'll see what happens. This will eventually be in a climate controlled building so I will take them inside for this winter.If this fails, then I will probably go back to the welding route. These are the closest fittings I can find in Canada that fit. There is a few on Amazon that would work but not sure I trust that for potable water (China seems to like adding lead to everything), and they are very expensive. These were not that cheap either though, the full order came up to around $100 as the site I got it from charges like $40 for shipping.But yeah, time will tell I guess.

author: IDEngineer
author_rank: Super Contributor
timestamp: August 17, 2021, 06:15:26 pm
content: Do you have a proper way to simply seal off the existing port? Like a cap that came with it, intended for that purpose?If so, you could just seal off that port and cut your own, in the (smaller) size you apparently want anyway. Most larger hardware stores carry fittings meant for this purpose. They have a "normal" end in whatever size/thread you want, and a "bulkhead" end that typically has a flange, 1-2 o-rings, and a backing nut. These are meant for installation on metal, plastic, etc. nominally flat surfaces to give you a liquid port. If you drilled the new hole near the existing port you might be able to reach through the port to install and hold the backing nut. Or perhaps there's another opening somewhere.Just letting my brain run wild with ideas. Might not be practical if you can't reach the inside surface to hold the nut while you turn the fitting to secure things. But if you can, this would give you total control over everything: Choice of size, choice of thread, choice of fitting material, choice of adhesive/sealant if you wish, etc.EDIT: Here's a photo of what I'm talking about. A quick Google search revealed lots of options in brass, stainless, PVC, you name it. Some with integrated valves, some without.

author: Red Squirrel
author_rank: Super Contributor
timestamp: August 18, 2021, 12:09:41 am
content: Yeah there is a cap that came with it, but I don't think it's rated to work at pressure. It will leak if I open the valve. It's meant to be a dust cap only. I suppose if I found an O ring to fit inside it would MAYBE work though, but it does not have a lot of threads. But yeah I had thought of that too with the bulkhead fitting. Glad I know what it's called now, I had that in mind but was not sure what to search for.I do want to try to find a source to buy fittings and even pipe in larger sizes though, as eventually it would be nice to actually do 2" service at least within the main water treatment building, and then do 1" service to the buildings.