aluminum rod inside styrene tube

[fiatboy]

I'm wondering if this method will work for A.scratch making exhaust systems, and B. scratch making a roll cage.  It seems some table of data should exist for matching small alum. rod with the appropriate inside diameter of a styrene tube.  Solder isn't the answer; it sags.  Right now, I'm buying all the 'fine' alum. rod I can find.  Thanks.

[DJMar]

The short answer is yes, that method works. The catch is finding the right size aluminum rod to fit the tube you want to use. Personally, I use coated florist's wire, which I find much easier to work with, as it bends without kinking and holds its shape. 

Plastruct offers an array of butyrate tubing and fittings that can be used to build roll cages, but it can get pricey.

 

[sidcharles]

1 hour ago, fiatboy said:

I'm wondering if this method will work for A.scratch making exhaust systems, and B. scratch making a roll cage.  It seems some table of data should exist for matching small alum. rod with the appropriate inside diameter of a styrene tube.  Solder isn't the answer; it sags.  Right now, I'm buying all the 'fine' alum. rod I can find.  Thanks.

no wonder the market is dropping . . .

but back to the solder trick. why would it sag? i would think the runs short enough [under 4" real?] that a slide/ loose fit piece of solid would work out fine. whaddimiss?

[johnyrotten]

I've found SOME aluminum tube and rod will fit in certain sizes of styrene after a bit of clean out with a drill bit. Hobby styrene tube most likely doesn't have a consistent wall thickness like metals will. Most likely because the way its manufactured.  I can't begin to image the cost of drawn-over-mandrel super small diameter plastic tube. The plastruct butyrate or floral wire mentioned above is probably your best bet. 

[NOBLNG]

I bent up some 3/32” plastruct tubing for a roll cage with some soft wire shoved inside. It bends beautifully, but the moment I touched the bend with some Tamiya quick set, the styrene split. I eventually used CA for my cage which does not cause a problem. But then I tried another test. After bending I just quickly passed it over the flame of a butane lighter. The flame took all the tension out of the styrene. The middle bend has also had the quickset applied…but no cracking at all. I imagine it would work for solid rod also if it is prone to cracking.

Edited 14 hours ago by NOBLNG

[DJMar]

37 minutes ago, NOBLNG said:

I bent up some 3/32” plastruct tubing for a roll cage with some soft wire shoved inside. It bends beautifully, but the moment I touched the bend with some Tamiya quick set, the styrene split. I eventually used CA for my cage which does not cause a problem. But then I tried another test. After bending I just quickly passed it over the flame of a butane lighter. The flame took all the tension out of the styrene. The middle bend has also had the quickset applied…but no cracking at all. I imagine it would work for solid rod also if it is prone to cracking.

One of the reasons I use CA in these situations, and I should have mentioned it. I've had some beautifully made bends crack apart with liquid glue, but I never thought to heat temper the plastic like that. Great tip, good to know! 

[Straightliner59]

I would use brass rod, rather than aluminum, due to its rigidity. Also, Plastruct (non-styrene--ABS, maybe?) can be slowly bent, using the warmth of your fingers, and gentle pressure. That's how I do most of my cages, now. The rod I've been using was purchased in a lot, on Ebay.

Edited 7 hours ago by Straightliner59

[Bugatti Fan]

The reason that styrene with a metal core splits on a bend when styrene cement is used is because although the metal core prevents the tube from kinking, it will not prevent the plastic tubing from stretching (and therefore thinning) where it is bent. As the wall of the plastic tube becomes much thinner as a result the application of styrene cement will go straight through it causing the plastic to split.

An earlier poster mentioned that the inside diameter of plastic tube can vary. I disagree with that as the tube is made by the extrusion process through very high precision tooling.

Daniel mentioned using Plastruct's non polystyrene tubing that  he thought to be ABS. it is. Incidentslly, normal polystyrene cement does not work well with ABS. Plastruct's own Plastic Weld liquid cement works better on this stuff. In fact it works on a variety of different plastics and I tend to use it as an all rounder on my models.

Edited 5 hours ago by Bugatti Fan

[bobss396]

I have a bunch of floral wire I use in Evergreen 3/32" tubing. The I.D. is 3/64" if it helps anyone. I pin sections and the cage to the floor using 3/64" brass rod for strength. I use plastic rod as well.

I think it was Plastruct that had one with wire inside of it. I used that up a while ago. I should revisit their product line.

[64SS350]

As an alternative....I use solid styrene rod from a guy on eBay that sells it in lots. I have about a 97-98% positive outcome with his materials. I use a wire bender from my slot car days to do most of the work.

 

Edited 2 hours ago by 64SS350

[Beans]

21 minutes ago, 64SS350 said:

As an alternative....I use solid styrene rod from a guy on eBay that sells it in lots. I have about a 97-98% positive outcome with his materials. I use a wire bender from my slot car days to do most of the work.

This right here ^^^^^^^^^^^

I tried tubing over and over and never got a good result.  Then I read on forums that a lot were using the solid and it bent well and held and that has been working for me ever since.

[Zen]

What does this wire bender look like?

[NOBLNG]

41 minutes ago, 64SS350 said:

As an alternative....I use solid styrene rod from a guy on eBay that sells it in lots. I have about a 97-98% positive outcome with his materials. I use a wire bender from my slot car days to do most of the work.

 

What wire bender are you using? Can you post a picture of it? Thanks.🙂