Plastic Verses Plastic

HooYah Deep Sea

Thank you both. I tried and semi-succeeded in attaching PVC pipe to the styrene with CA, but as said, in the test fix, it doesnt stand up to much side-load / shear. I'll try the epoxy next, then go with what holds best. The big question is whether ABS piping might fare better than PVC, or maybe an acrylic tubing? 

CA/Superglue is good in compression, but poor in shear strength.  Witness the old Superglue TV commercial with the guy hanging by his hard hat from a cross beam. 

A trick I've used is to laminate styrene sheet to PVC pipe or sheet plexiglas.   Use superglue/epoxy.   Now you can use your favorite solvent styrene glue to attach other structural or details

Another connection process you may take from wood working would be to make a mortice and tenon joint to attach the parts

HooYah Deep Sea

Thank you both. I tried and semi-succeeded in attaching PVC pipe to the styrene with CA, but as said, in the test fix, it doesnt stand up to much side-load / shear. I'll try the epoxy next, then go with what holds best. The big question is whether ABS piping might fare better than PVC, or maybe an acrylic tubing? 

 

This might be stupid but have you tried pvc glue? I have no idea if it is effective for anything other than pvc. I even glued some pvc together once (in a pinch)with pvc cleaner. It wasnt for pressure use though it was just a simple structure I was making. But it did hold.

Aha!

      I have found in doing Models for Law firms these work great. C.A. and any commercial glue for Plexis. I will use the regular glues for Styrene.The glue made by Plastruct, Mixed, with Revell tube glue and or Pipe cement has always worked. Now ,that said I can't speak to shear.

     I have found though that most straight C.A. glue will do okay if you use the Gel medium and let it set for a day or two under pressure by itself. Do Not use the Zip Kicker.That makes the join brittle.

      When mixing , don't mix before application. Do so in layers one over the other. By the way,I don't know what kind of plastic LEGO products are made from but Bob Smith Products Medium C.A. melts the plastic much like styrene glue does for styrene.

I should add that if possible, I would pin the join, too, if possible, to add strength.

I think too many scale modelers overlook wood as a material.  I find it just the thing for structures that need compound curves.  They are easily carved in a fine-grain wood like basswood (actually, basswood carves more easily than balsa.  I glue the wood pieces to plastic with gel CA- works fine.

You do have to learn to carve, but then if we like to try latest trends, we have learned to work with resin, photo etch, metalizer paints, etc. It is just a new skill we can aquire.

The IPMS long ago did away with their materials rules for contests, so I can't see a reason to only use plastic.  BTW, I also use a lot of metal in my scratchbuilding.

Thank you both. I tried and semi-succeeded in attaching PVC pipe to the styrene with CA, but as said, in the test fix, it doesnt stand up to much side-load / shear. I'll try the epoxy next, then go with what holds best. The big question is whether ABS piping might fare better than PVC, or maybe an acrylic tubing? 

I'll second GM.  For attaching other things to styrene, I use CA or a 2-part epoxy.  I also use those on resin-to-resin, or white metal-to-white metal.

I like a 5-minute 2-part epoxy, because it gives me some wiggle room to make adjustments as necessary.  Also, I think it makes a stronger bond, able to stand up to shear better than CA.  But CA is fine for attaching small bits, like the railings on a 1/700 ship, or PE cockpit details, and so on.  White glue can work in that particular case, too.

My CA and epoxy glues are from Bob Smith Industries in California, though the bottles have the logos of the stores that sell them (eg, HobbyTown).  I think BSI supplies a large portion of the market.

Solvent glues are hard to use with dissimilar plastics, although I suppose MEK would work. I wouldn't limit what plastics you use, for instance I have used plastic ball point pen barrels.

Try CA or epoxy.