Hi Simon,
Thanks for your post and sorry for the delay in getting back to you. I should have been notified of your post but for some reason didn't see it.
Answers to your questions as follows:
Would you build up the sides of the mould tomake the shape a complete ‘bowl’ and trim after, or using clay, construct anedge/flange following the contours of the shape..
Well, essentially, providing that the flanges were build so that they extend the surface of the part 'flat' out beyond where the trim line currently is then either of the above would amount to the same result in the finished part. You'll need to 'extend' the part all the way around (including at the base) too so I think I would be tempted to get the part raised up slightly and mounted properly to a board and at the same time fill in those missing peices all the way (with some flexible plastic or thin chip board). You might want to use some body filler to smooth the step - when you've got a lot of building up to do you might find that clay/plasticine/yellow wax is a little vulnerable to dropping out.
I had planned in the first instance to followthe wet lay technique shown on the video. What would be the most pleasing tothe eye to lay the fabric.. i planned to use two pieces of fabric due to theshape, firstly cap the top of the cowing using a circular-ish piece and use aseparate piece of cloth to cover the sides. Are there any issues with overlapping the cloth ..any special considerations in doing this,, will it look nasty.
Yes, I think that's a good idea. Make the cap and place that in first then the 'band' that will go all the way round. Make sure there is plenty of overlap when you put the band in. You might want to stiffen the carbon that you use to make the 'cap' using a little hairspray (or use our specially made 'ProFinish' carbon) otherwise you won't be able to cut this disc without it fraying and spoiling the appearance of this join-line.
How many layers of fabric would typically beused to achieve the same thickness at the sample in the photos. this will besubject to vibration and heat
I can't see exactly how thick the laminate is in the part in the photo but here's how to work out what thickness any given laminate would be:
1 layer 200g carbon cloth (or 195-205g really) = approx 0.25mm thickness in a finished laminate.
1 layer 450g carbon cloth = approx 0.57mm thickness in a finished laminate.
1 layer 660g carbon cloth (or 650g really) = approx 0.78mm thickness in a finished laminate.
Kevlar is lower density so will be slightly thicker for a given weight and carbon/kevlar will follow suit slightly, according to its kevlar content.
This means that if the part is 2mm thick you would need 8 layers of 200g carbon or 2 layers of 200g and 2 layers of 660g (=2.06mm)
this will besubject to vibration and heat
The heat tollerence of the part is more down to the resin system you use. The High Temp Laminating Kit you've chosen has an HDT of 180C so you should have no problem there.
Can i let each layer cure fully before addingthe next or should it all be laid in one sitting
You can do this but it's not good practice. You'll have far more strength if you put down everything in one go. If you do want to do it in multiple sessions then ideally you would add additional layers onto the back of 'partially cured' resin underneith. If you do this then you will get some cross linking and the laminate will be that much stronger for it. If you can't do this then you'll need to 'key up' the layer beneith using coarse abrasive paper.
Can something of this deep bowl shape be doneusing a Vacuum bagging. Is there anything on the web showing this type of shapebeing made this way.. all i have found is flat or shallow panels.
Yes, definately. We don't have any videos at the moment which show it but it could certainly be done. Either vacuum bagging (use SLOW hardener to give yourself time) or resin infusion would be possible. Warren (on this forum) has done some awkward shapes with infusion (a centre console part for a car) which was not too dissimilar. Just try to position the vacuum lines and resin feed lines as far from eachother as possible - the infusion process
should take care of the rest.
I hope this helps!
matt
Matt StathamEasy Composites / Carbon Mods - Technical Sales