Still following this thread with interest. I'm sure all of the hard work will pay off and you'll have a great product at the end of it!
Ok, finally something to share! Thanks Pete, and thanks to everyone for bearing with us. Things are moving along again. We've made more adjustments to the bonnet.. you didn't expect anything less did you? We needed more rigidity and a consistent finish on the back edge, so we've added some more flanges. The new core material is a bit easier to work with and should help reduce weight further. The picture below shows the vacuum bag process, it's an extremely effective way of applying massive pressure equally over the bonnet. This makes sure that the layers stick together properly. That particular bonnet will post cure overnight at 40 deg, helping to give the finish that we require. It'll then need another layer of weave on the back before we finalise the fixing pods, and then we'll make another jig to ensure consistent fixing point fitment.
Suddenly much more interested in this thread now as my carbonfibre bonnet has just failed a "speed movement test" Gonna need a "bigger boat" so to speak,so i'm subscribed on this progress
This is what we've been making today. They're the hinge fixing points, the rough shape is there but they need finishing off before we make the final molds More to come tomorrow
Today was a good day, as we made the jig for accurate placement of the fixings (hinges and latch) This makes sure that the 99th bonnet we make fits like the 1st. The fixing pods in the photos from the previous post are now just about finished, and we will have molds from them by the weekend. On Saturday, we'll be assembling the bonnet that we started the other day as it's now had time to cure. This means that we'll have a chance to use our new jig. Monday will see speed testing of our own.
I've had the bonnet on for a couple of days now and all is looking well. The issues we had with imprinting seem to be a thing of the past and it still behaves itself at speed. The latest resin combined with the new core seem to be coping with the heat but we'll probably recommend use of silver reflective tape above engine hot spots. We'll be ordering a batch of our chosen core material tomorrow, then fannying about with finishing touches until it arrives some time next week
Having recently done a little fibreglassing myself, I take my hat off to you for the finish you`ve achieved on that `prototype` ! These are looking very high quality items indeed. What`s the finished weight expected to be ?
Thanks Nige, I've just been admiring one of your latest projects. I would be making a rod for my own back if I were to start naming weights at the moment as every change seems to add or subtract as much as a fifth of its own weight! Just as a bit of interest, I recently lifted a carbon bonnet with inner frame and oem fixings. That felt as heavy as a steel bonnet in comparison to this.
Feels like you're getting close to production ready now! Looking forward to getting my hands on one soon
Ditto! I get all excited when I see a new post in this thread! Not exactly essential for getting my car on the road but I waaaaant one non the less
Hi, we're due a massive update on this thread. I also need to adjust the title of the thread and add the word "Epic" somewhere. We always knew that heat would be an issue, especially with turbo cars. We didn't see the point in making a bonnet that needed a kilo of insulation on the back to stop it melting, so we've been busy... I'll update this properly with pics later but the short and sweet of it is that we're just about there. Thank you for your continued interest
Hey Nige As I was saying before, we were aware that heat would be an issue so we've been testing different materials and techniques. We already own a heated curing cabinet but it only achieves about 50 deg c before topping out and we needed 120 deg c !! Below is a picture of how we would not have done it as it would have been far too dangerous... As you can see, this is obviously a snap shot from the Health & Safety Executive archive. If this experiment had happened, there would have been a wall off baffles (bricks) in the box to stop the intense heat of the space heater setting fire to the mold and the part within. (space heaters can achieve around 800 deg c at the grill on the exit!) The bricks that you can see laid on the pipe are probably there because the wall of the oven probably exploded... If we had done this experiment we would have had a vent at the other end to draw the heat through and control the temp a bit. In the experiment we carried out, we needed to achieve 80 deg c for 5 hours and the 3 hours at 120 deg c (I'm sure that's Gas MK 4?) to make sure that it was properly cured. That's 8hrs in an oven! The result of our experiment (not the one above) yielded a bonnet skin thinner and lighter than anything we've made before yet a diamond cutting wheel had to be muscled along to trim it. We're aiming for a product that will not require any insulation other than reflective tape above major heat sources. We were beginning to think that we had bitten off more than we could chew, and patience was wearing very thin indeed when we hit on a series of breaks with materials, processes and techniques. The latest spec bonnet will be going on the car tomorrow for testing but pictures such as the one below should be a thing of the past! It's a bit like VPL lol
I`m still amazed at the bonnet vents. If I were doing it, they`d be the first thing to go lol The weave showing through must be very frustrating. Is it because you are trying to keep the gelcoat layers as thin as possible to keep the weight down ? I`m assuming (wrongly ?) that you could fix those problems by just adding more layers, but as you are aiming for a super light / strong bonnet, you are making it much harder for yourself. From the photos, I think it`ll be worth the effort. With what you`ve learned, future panels should be a piece of cake
Diolen may help with impacts? Much cheaper than Kevlar too! I have a roll here, although I have never used it, and I am not very experienced. Enjoying the thread.
Blondie has been in this business for over 25 years but has learn't a lot recently through our experiments. A lot of what we've learn't would be useless to the DIY'er as it relates to finish, but that's what is important to someone handing over their hard earned! You're right about the gel coat, it's about as thin as we can get it now which makes imprinting worse. We've been hovering around a certain weight for months now but every time we made a change, it threw the weight up or down by as much as a kilo! Super light and super strong don't usually go hand in hand unless you're talking Titanium (imagine the cost of a Titanium bonnet!!) We were thinking about using diolen on the back but we're unsure as yet. We have some laying around so we'll have a play Cheers Mathew
