What Mick was trying to do earlier was to post some pictures of the latest Southern GT chassis being panelled out for a customer, and to keep a running update of pictures as the build continues, BUT as most of us know, posting pictures is a lot harder than building a GT40, so I am putting an earlier picture up to get him started, and hopefully one of us can update you more regularly. If there any particular aspects of this new car you would like to see, please ask and we will make sure you can see it. Frank
I really feel duty bound to make a damn good effort with this build. I am not going to cut corners. I may not be fitting a vessel bursting lump or the latest Carlos Fandango box (can do that later, if necessary) but I must continue the existing engineering standards to do the car justice. And once it is built learn how to drive it proper like. Shouldn't really prophesize like this but goals are goals.
I am glad that they show all the panels that are required for a properly panelled car. I have been working on panelling mine for the longest time. I don't have access to a professional brake, but have managed to build a shop version which has done a very good job for me. I will be posting the panelling and the device here soon under my build thread. Working with stainless is particularly hard in that it isn't as forgiving as aluminum, not to mention the scratches and marks that come with putting the panel on and off 10 or 15 times to check fit. Even finely detailed templates will only get you so far and then its crunch time for the bend. 1/16" off makes a big difference in mating surfaces. My hat is off to the guys that do that work. They must go through a lot of sheet to finally get the experience to get it right on the first go. I have gone through 3 4x8 sheets of stainless just doing the amount I am doing.
I agree, stainless can be a pest to work with but once it's done it's done for good! Aluminium can be a pain if you don't treat it with care. I am a tin basher by trade but do not have the necessary specialist tools at home to make a proper neat job as Mick has done with this set for the Southern GT. I will be painting mine satin black or as close to the colour of the chassis as pos.
Thanks for the correction Frank. I am calling in tomorrow to see Mick and check out Chassis #006. Camera is on charge, paint swatches at the ready!
This might sound a bit daft but has any one used coloured rivets during the panel build up? I remember seeing a sidecar outfit at Thruxton which had black panels and dark green rivets and it looked quite, dare I say it, sexy! I am not a purist, just want to give it my own twist in certain areas.
Interesting about the rivets. I assume you could have normal blind rivets anodized before installation. I used Cherry Q rivets and found that I had to use a file to clean each one up, otherwise they would snag any shop towell or rag that came near them.
For this application the shear stress of the rivet is not that important because the steel chassis is doing all the work. To be honest an ordinary pop rivet would do the trick as they are plenty strong enough in tension and shear. There are blind rivets that are sealed at the tail end hence stopping moisture getting into the chassis.
There are a variety of coloured (anodised) rivets available. I have seen a variety of colours on various web sites, red, green, black etc. I reckon a large diameter head would be more beneficial also to spread the load to reduce that "puckered" affect.
Your problem is in the choice of rivets. The "Q" rivets are self sealing in that the mandrel is pulled into the shart of the rivet and breaks off in the shaft of the rivet sealing the rivet from water entry. You will have pieces of the mandrel sticking out almost every time. To avoid this, and assuming you don't want a water tight seal is to use the "N" type rivets. You won't have a water tight seal, but the mandrel will break off at its base rather than in the middle
I beg to differ. the frame will have some flex or movement in it, as it is not a solid structure. The true issue with rivets is the grip lenght being correct(the shaft is longer than the two pieces being joined) and the purpose of the rivet. There are an endless number of types of rivets out there. Ones for irregular holes or surfaces, plastic to metal, plastic to plastic etc. With metal to metal, the rivet should be the same material as the pieces joined if they are similar. Otherwise you could use aluminum rivets on stainless etc. and it would not hold very long, and there are also oxidizing issues. The shear strenghts of the rivets are a lot higher than most would think. The 1/8" stainless size in the 2000 lb area. The real problem is the constant changing of the forces on the rivet over time that cause them to give up their hold and start rattling. Remember, airplanes use solid rivets, we are using hollow. The other problem is the rivet isn't set correctly and the grip is less than what is expected. With the number of rivets that go into todays cars, you can bet that one or more rivets won't set correctly and will work loose and start to rattle. One trick is to add ordinary window caulking(dries clear) under the head. this way the rivet won't rattle when and if it does work loose. There are tricks to getting the load correct especially if the materials are dissimilar, such as fiberglass to metal. While installing my paneling to the rear of the engine bay window, it was impossible to pull the rivet from the fiberglass side as the roll cage blocked all access to the fiberglass at the top, which meant I had to pull from the stainless side. The mandrel would have just pushed the fiberglass aside and would not have held for 10 minutes. The solution was to add a stainless washer to the back side of the rivet and let the mandrel set against the washer, spreading the load and giving a rivet head on both sides.
The only reason I know these things is I just finished researching an article on panelling for the GTD club mag. I got a real education in the process.
Another point worth noting is: When joining two metals of differing specification, as with aluminium sheet onto steel, the rivet spec should be the same (ish) as the softer metal. This is the main reason for rattling rivets, the harder spec of rivet eats into the aluminium over a period of time due to vibration. I have set literally millions of rivets whilst carrying out major airframe repairs around the Globe during my Naval carreer. Cherrymax are the best blind type of rivet, they set flush (no mandrel protruding from rivet head) and have a shear stress not far short of a hiduminium solid. One snag, they are expensive. Grip length is quite critical with these along with accurate rivet clearance (3.25mm for 1/8" and 4.1mm for 5/32").
A good rivet to use is the all aluminium MBC rivet made by Avdel (I think). They have a very forgiving grip length i.e. as long as they are over length they will grip. We used these for battle damage repair because they are fast to install!! One shortfall is that you cannot use a standard type of rivet pliers because they have a special locking collar around the stem. Rivet clearance for these is 3.2 and 4.0 respectively.
Wet assembling is also important as you say Bill. For this application, in my opinion, a polyurethane body sealant is best. A little dab around the rivet is not a bad move in my experience. It helps to prevent the rivet spinning when it all goes horribly wrong and you have to drill the b*gger out!
Popped into Southern GT's yesterday to check out a few bits and pieces with Mick. All is well and looking good.