Early Radiator construction

[Ian Williams]

Not all hexagonal radiators are tube construction, some were made from pressed films which I suggest is what was used on early sevens. They are currently manufactured here on pre war tooling and available from a local company for a decent price Marcus.....not to be confused by the highly priced replica cores, or the Serk A film.

[Marcus Ling]

Hi Ian,

Yes you are absolutely correct that later, they all had film radiators. However according to Wyatt and The Source Book, Austin manufactured radiators were not fitted until May 1929 which presumably was when they were starting to be made in-house, rather than as bought in components. The film of Austin radiator production is film type radiators.

Both The Source Book and Rinsey Mills state that early cars had tube radiators, so I am trying to find any other, preferably contemporary evidence, that this is correct and for how long, if it was the case.

The locally manufactured cores are indeed very good and reasonably priced, but may not be correct for early cars if the above 2 books are correct. Hence the search for more information.

[Ian Williams]

What I am saying Marcus is that not all hexagonal cores are buildup from tubes, some are from film, hence the confusion which appears to reign with some. There are enough contemporary pictures of early cars with hexagonal cores to prove use, however I am not sure anyone can state for certain they were constructed from film or tube. The point is that a Hexagonal core looks correct on an early car, and a dam sight better on a later car than a modern i.e 50's 60's pattern film type. The correct mid/late 20's Serk A film is still available but at one hell of a price, the localy made, on pre war tooling, hexagonal film types are very reasonably priced.

[Marcus Ling]

Yes film cores can be hexagonal form.

The Source Book  has a drawing showing tube construction, and Rinsey Mills says; At first the radiator cores were of true honeycomb construction but for reasons of economy these were soon substituted for hexagonal film block  then, by the mid to late 1920s, interleaf diamond film block.
This would tend to agree with Wyatt who says Austin started fitting their own radiators in mid 1929, this is the style of diamond core which Austin are making in the film.

I am hoping we can find some contemporary literature which confirms the above.

[Bob Culver]

The Big Seven radiator, along with other makes, has separating strips of steel.
I am familiar with the true honeycomb and the later zig zag Seven film and the straight film styles of late, rbut how is hexagon film arranged?

[Lance Sheldrick]

Hi Marcus, there is no "inside tube" on my rad pattern, it is just like the photo posted by Mike Costigan and the inside measurement of the hexagagons is 9/32".

[Tony Griffiths]

Why not have a go at building your own? Here’s a paraphrase of what an enterprising and skilled Scott owner reported in the Magazine "Yowl" after building one for his bike. Although their engine capacities are not too far apart, the Scott radiator is, of course, less than half the size of that on a Seven so material and time costs would be considerably greater.
Obtained 1500 pieces of 7mm brass tubing from a Chinese supplier on Alibaba.com All cut to length and polished for £110  
Annealed the end of each tube with a blow torch and dropped in water – about 20 hours’ work.
Swaged the tubes using a 7-position, home-made jig held in a machine vice on the table of a drill press. A hexagon punch in the drill chuck was wound down to swage the ends. About 12 hours’ work.
Made a frame with sides complete with screw fitting used to hold all the tubes firmly in place.
Thought about making a soldering tank.
Thought about buying enough solder and flux to cover the bottom of the tank to a depth of 6mm. Price £250
Instead, bought two big rolls of solder (£80) and hand-soldered each tube in place. About 12 hours’ work.
A pressure test, followed by 2 hours of soldering up all the invisible pin-hole leaks.
Made top and bottom tanks, turned up and threaded a filler neck and made a cap.
Soldered everything together.
Send for plating.
Pressure tested again and a bit more soldering.
Easy, eh!

[Chris KC]

The Autocar:
Hex film?

[Marcus Ling]

Hi Lance,

Thank you very much for measuring the hexagon.

Sorry I didn't explain very well what I meant by "inside tube" what I should have said is the inside diameter of the round portion of the tube inside the hexagon where the tube hasn't been flared on the ends. The section where I have put the red arrow on the drawing below if possible please.



Tony Betts has put the description of the method the guy used to build a radiator for his Brough, he used Brass tubes although most of the honeycomb radiators I have seen use copper tubes, do you happen to know whether your tubes are brass or copper ?

---

Hi Tony,

Thanks for posting the information on the guy building the Brough radiator. While there was a lot of effort building the core, I suspect there may have been the same or more building the header tanks and fittings. I'm certain he takes, and so he should, a lot of pride in the finished product.

I'm not suggesting I want to build a honeycomb core, I'm just trying to see if there is any confirmation of the books that say the early cars had tube honeycomb radiators and if so how long did that continue before it changed to film radiators.

However, for me, the enjoyment of old cars is learning new skills even if they were once commonplace. I had the chance to buy a set of whitemetal pouring moulds and a conrod boring machine. We have had a few false starts but we now are confident in the pouring of whitemetal bearings helped by a local forum member who spent a lot of his working life doing this type of work. I hope its a skill which can be spread to a number of other people in the A7 movement locally to keep the skill going and a service for members who need it for their cars.

[Steve Hainsworth]

Hi Marcus
I assisted Len Southward to make the Radiator tube pressing machine that Replicore (George Mihaljevich ) in Auckland use to Make Tubular Radiators in Hexagon and Round profiles among others.
The tube was imported from Ireland? in long boxes back then I remember  and was definitely extruded Brass in an annealed condition. That was back in the late 1970s.
I think the reasoning was Brass was lighter and more durable.
I remember we cut up a few damaged radiators at the time to get samples. The machine cut and champhered  the tube ,collated and magazined the matrix very quickly.
The National Radiators Hexagon film machine came from the Dunedin plant. Uses Brass strip fed thru crimping rollers.
I hope this helps.
Steve