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Race car construction details

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bigjones

bigjones

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Racer2.jpg


Racer1.jpg


No, I'm not getting any ideas!

At the last car show, I was looking under the hood of our local resident MG Midget racer and was very impressed with how things were made from sheets of aluminum (I think). For example, the air filter housing, or more correctly called, I suppose, the "air box", as it extended to the front of the car for a ram effect. This was obviously home made but very neatly done - sort of like an aircraft wing but with Allen bolts, I think, instead of rivets.

Where do you get this aluminum from and what thickness? How do they cut this aluminum - surely not with a hack saw. Band saw wouldn't give a straight line, if I was using it, ha! Prolly a table saw with special blade, right? What is the recommended hardware used that bolts it all together?

Cheers!
(still waiting on head gasket)
 
The best way to cut large pieces of sheet metal or aluminum is with a sheet metal sheer. Cuts straight and quick. You then need a brake or finger brake for bending/folding your material. Having a tig welder would be handy.
Free advise; buy a race that is already built and has a current log book. Go to the track and see if you like it.
The street prepared classes (IT) in SCCA offer a cheaper way to race and is alot of fun.
It gets expensive and right now there are alot of race cars for sale and parked because of the economy.
Best of Luck, Bill Close, Mesa, Az.
 
alfa33047 said:
Free advise; buy a race that is already built and has a current log book. Go to the track and see if you like it.
The street prepared classes (IT) in SCCA offer a cheaper way to race and is alot of fun.
Click to expand...

Huge fun, nothing else like it, but the bills can rack up very quickly.

alfa33047 said:
It gets expensive and right now there are alot of race cars for sale and parked because of the economy.
Best of Luck, Bill Close, Mesa, Az.
Click to expand...

Good advice Bill, thanks!
 
I made these using stock picked up at Lowes. The brushed effect is done with a sanding block with 80 grit sandpaper. The thinner aluminum can be cut with aviation shears.

1975Spitfire215.jpg
 
alfa33047 said:
...You then need a brake or finger brake for bending/folding your material...
Click to expand...
Yeah, bending it in the vice little by little doesn't work too good, does it.

Rhody, so then you go ahead and rivet the pieces? Nice work.

Bill, I wasn't thinking of racing just trying to tidy up the engine bay, etc, but thanks for the tips!
 
For small fab pieces there's a "nibbler" that works well for cutting contours an' such. Great tool to have. We use B&D ones, good service and "replaceable".

Unless you're doing production work a shear is kinda pricey. Hard wood and C-clamps coupled with some imagination can produce "one-off" pieces of reasonably craftsman-like quality.

As for the threading job instead of pop-rivets, Marson (others as well) have a 'system' for setting threaded inserts into sheetmetal, works like a pop-rivet. The inserts can be had in steel, aluminum or stainless, too. VERY clever option.
 
bigjones said:
Uh, oh.
Posted this in the wrong forum - should have been over in the Spridgets. Ah well, never mind.
Click to expand...

Want me to move it for you?
 
That's it. I did the interior trim panel attachments with 10-32 stainless. NO more sheet metal screws to fight and strip out. :wink:
 
To get the stuff, try your local Amish sheetmetal shop or here:

https://www.aircraftspruce.com/menus/me/aluminum.html

Riveting aluminum isn't very difficult to learn although to do the job right you need a rivet gun, most people not in the aircraft biz try to get away with using an air chisel and that is a very different tool.

A rivet gun has a much slower and heavier hammer in it.

Here at work we do 1 1/16 hot steel rivets and heat the rivets with electricity. great fun.
 
Doc,
Thanks for the info on suitable fastener size.

Steve,
Cool link - all you wanted to know about aluminum!

Mickey,
Yes please.

Cheers!
 
You can cut aluminum on a table saw or miter saw with a carbide blade. Spray the blade with WD-40 as you cut. You can pick up a good carbide blade with a descent tooth count at Harbor Freight for about $20.
 
I got the aircraft aluminum I used to make things for the TR3 racecar from Charlie Vogelsong at Dillsburg Aeroplane Works in Pennsylvania. Aircraft Spruce gets their stock from Dillsburg. I used 2024-T3 .025 thick and some 6061-T6 .125 plate. Also I have gotten channel, tubing, hardware, etc. etc. etc.

I don't know if he has a website. We used to order by telephone.
 
As a footnote to the information given thus far, not all grades of aluminum are suitable for bending. 2024, 6061 and 7075 are great for machined parts but will generally crack if bent. 5000 series as used in marine applications and 1100 series (often at the home centers) is easily bent.

The draw back of those softer grades is that they don't cut as cleanly. The carbide blade method mentioned above works well. However, for thin sheets be sure to support the aluminum with a piece of sacrificial wood or plywood so the metal isn't badly distorted. There are different types of nibblers available. I have two different types of hand powered nibblers (slow but accurate). I also have a set of metal cutting electric shears. They work well on thin gauge material but they take a very wide 1/4" kerf.
 
Followed this from Triumph with interest. Good comment here on aluminum alloys, as properties can be vastly different. I too cut aluminum with table saw and with geared down wood working bandsaw. I cut steel with the bandsaw also but if you are just working with aluminum, you don't even need to slow it down. Lubricate with Lenox Lube Tube (very helpful but not necessary). Backup with 1/4 luan ply for both (another good point from Doug L).
I also cut up to 18 gauge with aviation snips and can do 16 in a pinch but that is pushing it. I also make decent bends without a brake by clamping the wokpiece between two pieces of angle iron in the vice and folding with a hammer. Work back and forth along the fold and tap (planish) it smooth.
For anyone interested, if you can tack weld steel sheet, you can tack weld most aluminum alloys with an oxy-acetylene torch. Clean the areas thoroughly with a stainless brush and acetone, apply flux (available at welding supply)and use a strip of the same material you are welding as filler.
Problem is that you can get so involved with metal working that the car gets neglected.
Tom
 
Isopropyl alcohol works well as a drilling lube too. Use the good stuff from the hardware store, not the watered down stuff from the grocery store.

2024T3 is bendable if you go perpendicular to the grain. It will crack with the grain at 1 to 1 1/2 x the thickness on the radius. I can tell you exactly if I go dig out my A&P books. Stack a couple of prebent pieces in your brake to make your radius longer.

clear silicon adhesive also works really well on CLEAN aluminum. The Grumman Cheeta's and Tigers were glued together, with a really goopy epoxy. too long ago to remember exactly what it was, I just remember once you got it on you, it finally wore off a few weeks later.
 
EPOXO-88!!! :laugh:
 
All good stuff, thanks.

Doug, on the electric shears, to cut a straight line, do you use a fence (straight length of hardwood clamped on the work) or can you do free hand?

Cheers!
 
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