Ian Vincent Posted September 12, 2014 Report Share Posted September 12, 2014 The centre flat panel on my TR3a bonnet is very floppy. When polishing it for example, you have to be careful not to press too hard or it will push in - it springs back but I'm worried that it might not. Is there anything simple that can be done to stiffen it up - like sticking heat insulation on the underside? Any suggestions gratefully received - short of welding something to it - Yes, I have seen a TR3a bonnet with stiffener welded to the underside, presumably it was suffering from the same problem. Rgds Ian Quote Link to post Share on other sites
Rodbr Posted September 12, 2014 Report Share Posted September 12, 2014 hi ian, Got the same issue,and considering fitting sound deadening sheet in the centre section. Short of putting a duvet or somesuch under it when polishing or train as a midwife and get the delicate touch it may even be a slight vibration issue when driving but with so many other noises I barely notice. eBay item number:220839326815 looks enough to do the centre and may be sufficuient. rgds Rod Quote Link to post Share on other sites
AlanT Posted September 12, 2014 Report Share Posted September 12, 2014 Sticking the sound-deadener on is easy. You warm it with a heat-gun a bit and it will sag into the right shape. You can develop, quite complex, curvy shapes this way. Keeping it stuck on with engine-bay heat may not be so easy. Quote Link to post Share on other sites
Graham Harris Posted September 12, 2014 Report Share Posted September 12, 2014 I don,t think sound deadening sheets will do it, it sounds like it has been bashed up in the past. The only way to fix it is hammer and dolly and heat shrink refinish and paint or just be gentle with the polishing cloth. Graham Quote Link to post Share on other sites
vic Posted September 12, 2014 Report Share Posted September 12, 2014 Alternatively, as I had to, you could bond some reinforcing bars to offer additional support Quote Link to post Share on other sites
Fireman049 Posted September 12, 2014 Report Share Posted September 12, 2014 It's quite possible that you have a replacement bonnet constructed with much thinner metal? My original bonnet is solid as a rock in the centre panel. Tom. Quote Link to post Share on other sites
BrianC Posted September 12, 2014 Report Share Posted September 12, 2014 I'm pretty sure that both the bonnet and bootlid on my 1958 TR3A were stiffer and possibly thicker than on my current 1960 car. Quote Link to post Share on other sites
Ian Vincent Posted September 12, 2014 Author Report Share Posted September 12, 2014 Alternatively, as I had to, you could bond some reinforcing bars to offer additional support Hi Vic, What sort of reinforcing bars did you use? Lateral aluminium strip - say 50mm x 3mm? Rgds Ian Quote Link to post Share on other sites
vic Posted September 13, 2014 Report Share Posted September 13, 2014 Hi Ian I used 15mm x 4mm steel bar (the sort widely available in DIY stores) and because I was preparing for re spray, I was able to tack weld mine into place. However, I know that with careful and appropriate surface prep, they can be glassed or bonded into place. I fixed two going across the 'troublesome' area and spaced accordingly with great results; if aesthetics come into play, you can always fix sound deadening material over the bars when in place and either cold or cured. I simply finished mine as part of the re spray. Regards Vic Quote Link to post Share on other sites
AlanT Posted September 13, 2014 Report Share Posted September 13, 2014 (edited) Welding on to a flatish flexible surface is risky. You could easily end up with a lot of troublsome ripples. Now you will be adding filler. This may crack later on. Its the heat thats the problem. If this pings into an alternative position with only light hand-pressure then it will spring back as it was. I'd live with this. Anything else introduces its own problems. Edited September 13, 2014 by AlanT Quote Link to post Share on other sites
boggie Posted September 14, 2014 Report Share Posted September 14, 2014 Dad and I had three bonnets to chose from. One needed too much work and the second we rejected due to the 'oil canning' you are experiencing. I think Brian might be onto something re thickness of steel as there is no reinforcing on either bonnet but the current one is pretty solid. Incidentally it was an earlier bonnet (pre-TS60000) as we had to create and silver solder on a couple of raised hinge plinths. Quote Link to post Share on other sites
GoGuy Posted September 25, 2014 Report Share Posted September 25, 2014 I have just sucessfully sorted out this problem on my TR3. I bonded a sheet of 1mm thick aluminium to the whole centre section using Tiger seal adhesive. Ensure that the underside of the bonnet is de-greased and clean metal. Fix the aluminium with the shiniest side visible, so that engine heat is reflected back - looks good too! GoGuy Quote Link to post Share on other sites
Ian Vincent Posted September 26, 2014 Author Report Share Posted September 26, 2014 Thks for this Guy. I was pleased to find I wasn't alone with this problem and it's not a bonnet that has been bashed. I will try and live with but if I find it too annoying, this sounds like the best solution. Rgds Ian Quote Link to post Share on other sites
stuart Posted September 26, 2014 Report Share Posted September 26, 2014 A run over the centre panel with this will tighten it up no end http://www.ebay.co.uk/itm/Shrinking-Disc-Sheetmetal-Panel-Smoothing-Tool-/380995452547?pt=Motors_Automotive_Tools&hash=item58b5193e83 Stuart. Quote Link to post Share on other sites
Ian Vincent Posted September 26, 2014 Author Report Share Posted September 26, 2014 A run over the centre panel with this will tighten it up no end http://www.ebay.co.uk/itm/Shrinking-Disc-Sheetmetal-Panel-Smoothing-Tool-/380995452547?pt=Motors_Automotive_Tools&hash=item58b5193e83 Stuart. Looks good Stuart, but then I would have to have the bonnet re sprayed. Rgds Ian Quote Link to post Share on other sites
stuart Posted September 26, 2014 Report Share Posted September 26, 2014 Looks good Stuart, but then I would have to have the bonnet re sprayed. Rgds Ian True but a better fix and would look far more original once done. Stuart. Quote Link to post Share on other sites
AlanT Posted September 26, 2014 Report Share Posted September 26, 2014 Do you use this on the inside, outside or both? Does it really work by heat or is something else happening? What's the difference between heat generated by this and using a torch? Quote Link to post Share on other sites
McMuttley Posted September 26, 2014 Report Share Posted September 26, 2014 hi ian, Got the same issue,and considering fitting sound deadening sheet in the centre section. Short of putting a duvet or somesuch under it when polishing or train as a midwife and get the delicate touch it may even be a slight vibration issue when driving but with so many other noises I barely notice. eBay item number:220839326815 looks enough to do the centre and may be sufficuient. rgds Rod Ho Rod This appears to be the same material as the Woolies sheets I have been having issues with inside my hardtop. The material is fine, but the applied adhesive may not be strong enough to hold, especially in an engine bay. It is heavy. Quote Link to post Share on other sites
stuart Posted September 26, 2014 Report Share Posted September 26, 2014 Do you use this on the inside, outside or both? Does it really work by heat or is something else happening? What's the difference between heat generated by this and using a torch? It depends on how far it will go out of true but in this instance probably underneath. It works by the friction it generates between the disc and the panel. If you have ever used a gas torch or Oxy to try and shrink a panel you will understand that the heat from them isnt just on the high spot and very quickly spreads out from the spot that you hit first which can often make it worse to start and isnt controllable enough. With this the heat is only generated in the high spots that you are trying to get rid of. Its not particularly easy to get the hang of but if you are used to panel beating then you will have some understanding of moving metal around. Stuart. Quote Link to post Share on other sites
AlanT Posted September 26, 2014 Report Share Posted September 26, 2014 How hard do you have to push on this to get enough heat? Quote Link to post Share on other sites
AlanT Posted September 26, 2014 Report Share Posted September 26, 2014 How hard do you have to push on this to get enough heat? Quote Link to post Share on other sites
Ian Vincent Posted September 26, 2014 Author Report Share Posted September 26, 2014 There are a couple of videos on u tube - you seem to have to push quite hard as there are sparks generated. If the video is to be believed it certainly works. Rgds Ian Quote Link to post Share on other sites
AlanT Posted September 26, 2014 Report Share Posted September 26, 2014 So the aim is to shrink, and therefore flatten, the centre of the bonnet by pushing hard enough, on the inside, to generate heat and sparks. Maybe, in the hands of an expert! Find something to practice on first, I would think. Quote Link to post Share on other sites
AlanT Posted September 26, 2014 Report Share Posted September 26, 2014 So the aim is to shrink, and therefore flatten, the centre of the bonnet by pushing hard enough, on the inside, to generate heat and sparks. Maybe, in the hands of an expert! Find something to practice on first, I would think. Quote Link to post Share on other sites
stuart Posted September 27, 2014 Report Share Posted September 27, 2014 You dont need to push hard at all, the weight of the machine and the metal to metal action of the disc on the panel will easily generate enough heat. If your leaning on it then you are defeating the object as the panel will be going away from you. Stuart. Quote Link to post Share on other sites
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