Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
(OP)
I am forming a 1 inch hollow pipe with a 90 degree bend in the middle. The total length is about 20 inches. The diameter is about 1 inch. Wall thickness is about 1/8" but could be as small as 1/16". In addition to the bend there are also 3 tees in the pipe. My first thought was to make rotational moldings, but that is too costly. Then I decided to have abs, pp, or pe extruded to the diameters that I need and then cut the pieces to spec and hot plate weld them together. This is still a viable means as far as cost and time go, but the extrusions are custom and are still a little on the expensive side. Instead of welding I have contemplated gluing but I cant find any suitable glues. Another option that I came up with is to build my own vacuum form, trim the edges and weld or glue the two pieces together. What materails and glue would I use for this? One last hitch! The material and glue need to be suitable for consumable liquid to flow through. Production numbers will start out at about 100 units. However, this could change to thousands. What are some opinions on this topic? Anything will be helpful.






RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
Have you tried PE irrigation pipe.
PE pipe systems for beer and beverage.
Nylon 11 or 12 gas or air lines
The PE pipes will need compression or grabber fittings, but I am sure thatsystems exist.
The nylon can be glued with a proprietory glue, but I am not sure about food contact with the glue, or it can be glued with methacrylate glues, but joint strength will be marginal, or you can use formic acid as a glue, but it can be messy and dangerous to handle
Regards
pat
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RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
PP and PE are very difficult to glue.
ABS is very easy to glue with solvents, but the food contact might be an issue with the solvents
Regards
pat
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
Also with a large complex part, it will be hard to accurately align the entire joining surface, so leaks and mismatch will be a real challenge.
Thermoforming plastic sheet is not a very precise process.
Buying pipe is by far, my prefered method, possibly with nice neat compact glue together fittings. The socket and spiggot connection with glue together fittings makes for a strong joint. The nylon gas pipe system is that design.
You can also weld PP and PE with a hot air gun and plastic welding rod. This way you get a strong joint and some reinforcement by the build up of weding rod at the joint.
Regards
pat
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
Not knowing what the flow rate needed for this apparent "manifold", but seeing that there might be some volume for the future, you might want to explore 'gas assist' injection molding. This can make a hollow part in virtually any configuration and material. Think of the handles on a chainsaw or weed wacker for example. Start with a low cost aluminum tool. Still expensive, but accurate and no muss or fuss. Hope this helps.
Mike Glynn
763-428-6180
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
Welding of PP or PE sounds the most promising.
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
Take care when machining it as it will easily pick up in the machine and break. Use sharp, woodworking tools with plenty of back clearance and set so as not to generate to much heat, and use low rake angles so it does not want to self feed and grab.
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.
Using solvents on acrylics is difficult when stress is involved. The solvent induces stress cracking (minutes to weeks after joining). Be carefull not to create tight interference fits, as these are especially prone to it.
Anneal the finished product in an attempt to relieve stress, as this should protect the part from solvent attack, and future cracking.
Trick for solvented joints: Add a small quantity of acetic acid (vinegar) to methylene chloride (usual solvent to use), as this stops the joint having the unsightly bubbles that usually occur in large joints.
hope this helps
Craig
RE: Best Method, glue? weld? What material, pp? pe? abs? Opinions needed.