oval/elliptical tube supplier

[kenking-King Design]

Does anyone know of a supplier of thin(nish) walled tube, in oval or elliptical section, M.S. or L.A., and a variety of sizes?

Failing that, any tips for flattening round tubes but avoiding kinking-in on the centreline?

I need reasonably aerodynamic section tubes for struts, landing gear etc. Any assistance gratefully received,

Ken

[PatMc]

Any retailer that sell K&S metals might stock their streamline tubing.

[alan p]

As PatMc says K&S streamline tubing used the aluminium version for gladiator struts sourced from Modelshop Leeds.

[kenking-King Design]

Thanks Pat and Alan, but the section I am after is symmetrical oval or elliptical, and whilst the 'streamline' tubing is admirable, for my scale application the sharp rear edge will not do.

I guess some experimentation is called for,

Ken

[Malcolm Fisher]

If you can access an old fashioned mangle of the type which used to be for wringing clothes, preferably with rubber rollers, it could be possible gently to squash round tube to an oval section. It would mean passing through the rollers several times with gradually increasing pressure and might even need an annealing process at some stage.

Malcolm

[Don Fry]

You don't do easy. I hope your pay rate is good, or it's for a passion.

You don't say how long, but is suspect this might do you.

Make a blank, wood or whatever. A bandsaw blade thicker than your eventual dream. Wax it.

Now make a pair of heavy blocks with a groove in them, depth, half your blank, plus half a bandsaw blade. Width a bit wider than your blank. ( this is not science).

Now HobbyKing do a thermomolding material wot melts at a right low temperature, giving time, and minimising skin grafting.

Put your melted plastic in a groove, experiment with warming the block first, 40 centigrade ?. lay your blank in, prewarmed, bit more molten plastic on top, with your top block last, preheated, pre wetted with plastic, which is still plastic, but not runny. (Sorry about the non scientific terms).

Clamp quick, and go away. Whisky helps. Not on the job, but yer fingers got hot.

When cold slide the two halves apart with a band saw, carefully set up for square. Take out the waxed blank halves.

Lay a piece of Ali tube, annealed to soft, soap, flame, soap, black etc, in the half grove, size as maths demands, and put the top half on, a few "washers" of wax steadies the gap. Bit of solid steel bar, or T bar, ,or heavy square tube, on top, and hit it with a sledge hammer, ONCE.

You will either have what you want, or not. Adjust as necessary.

The Ali tube needs to be extruded tube, but in our sizes, it's all extruded I think.

I hope the model is exquisite. Because that is a skill murdered by Thatcher and Co when she deindustrialised the West Midlands. And I have not done it in over 50 years, and I was a kid being educated by my dad. And it was much hotter then because low temperature melts didn't exist. And it needs judgement.

Good luck.

[Don Fry]

Edit to post, consider the strike with a 4 to 6 lb lump hammer.

[Martin Harris - Moderator]

I haven't tried it but a simpler method might be to get two lengths of planed 2 x 1, glue a couple of sticks to one, of marginally smaller depth than the desired thickness of the finished tube (to allow for spring back) to form a channel and amply far apart to accommodate the finished "squashed" tube. Put the annealed tubing in the channel and then either clamp the second 2 x 1 on top or place several screws either side of the channel and tighten progressively.