PRF Material test and self supporting seat for a customers race bike.

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PRF Material test and self supporting seat for a customers race bike.

Author	Message
morepower	morepower posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 242, Visits: 1.2K	It is not 25 layers thick... It has some core in between the mounts and has been built up with about 30-40 small strips wrapped round the inserts and then off along the sides with a full layer along the structural section after several layers have been built up round those inserts. It was more about getting enough direction changes in the weave to spread the load through the seat unit. It is more than strong enough with around 10 to 12 layers which fully encapsulate the seating area. The area behind the seat is only 2 layers thick in the open areas and 3 to 4 layers along the seams and a reinforced T section over the hump. I got advice from a guy who has been doing this for 30 years and even at 900grams he said it was heavier than he would have made but it is better to be heavier than weak.. lol..
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Shaneer22	Shaneer22 posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 156, Visits: 14K	You should look at durbahn.de you will appreciate his work,I did over compensate at mounting points just for security I've just calculated that I could have achieved 700 grams give or take a little would have been possible.enjoy the weather.
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morepower	morepower posted 12 Years Ago HOT Post Details
Group: Forum Members Posts: 242, Visits: 1.2K	Shaneer22 (13/07/2013) You should look at durbahn.de you will appreciate his work,I did over compensate at mounting points just for security I've just calculated that I could have achieved 700 grams give or take a little would have been possible.enjoy the weather. I have had a Durbahn seat unit.... It was carbon but it had a black gel coat surface and was wet lay... I thought it was light at the time... My monocoque seat and complete fuel tank (not cover) weighs less than just his seat unit did..... It is safer to go with overkill and not worry... I went with advice from someone with experience as I would possibly have done the same as you.... Edited 12 Years Ago by morepower
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20_rc51_00	20_rc51_00 posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 95, Visits: 548	Morepower, I'm a big fan, well done. I have a few questions, I'm hoping you would entertain them. You say that you baked up to 85C in the oven. I'm assuming the Tg of the resin is going to be in this range then, maybe as high as 100C but the HDT would be perhaps in the 85C range if not lower(just my loose estimations). I know on my bike 2000 Honda VTR SP-1 the subframe and mount locations get SUPER hot due to the heat the motor gives off. My concern would be that the HDT of the resin would be surpassed at the mount locations, on my bike in particular. Is this a concern on your particular bike? What would be your estimations for this as an issue in general? Do you do anything as far as galvanic corrosion is concerned? Kevlar or glass at mount areas where aluminum/magnesium/steel come in contact with carbon to insulate it from the carbon? Looks like you had a multi-piece mold. Do you put anything between the flange halves to seal them together? Is there a concern of getting air leaks in these areas and negatively impacting the prepreg bake process? With a few pin holes here and there do you just lay the clearcoat on extra thick? Do you sand back on the epoxy or after some layers of clear to eliminate them, before placing the final clear coat? Trying to put things into perspective and get a good big picture of techniques and things that may or may not be overkill/necessary. Thanks.
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morepower	morepower posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 242, Visits: 1.2K	20_rc51_00 (26/01/2014) Morepower, I'm a big fan, well done. I have a few questions, I'm hoping you would entertain them. You say that you baked up to 85C in the oven. I'm assuming the Tg of the resin is going to be in this range then, maybe as high as 100C but the HDT would be perhaps in the 85C range if not lower(just my loose estimations). I know on my bike 2000 Honda VTR SP-1 the subframe and mount locations get SUPER hot due to the heat the motor gives off. My concern would be that the HDT of the resin would be surpassed at the mount locations, on my bike in particular. Is this a concern on your particular bike? What would be your estimations for this as an issue in general? Do you do anything as far as galvanic corrosion is concerned? Kevlar or glass at mount areas where aluminum/magnesium/steel come in contact with carbon to insulate it from the carbon? Looks like you had a multi-piece mold. Do you put anything between the flange halves to seal them together? Is there a concern of getting air leaks in these areas and negatively impacting the prepreg bake process? With a few pin holes here and there do you just lay the clearcoat on extra thick? Do you sand back on the epoxy or after some layers of clear to eliminate them, before placing the final clear coat? Trying to put things into perspective and get a good big picture of techniques and things that may or may not be overkill/necessary. Thanks. http://www.prfcomposites.com/materials/prepreg/ Have a look here. I used the RP464.. Also have a look at this material... http://www.shdcomposites.com/pdf/LTC250-2XLPDS.pdf Both work out of autoclave. You will need to have a play with lay up and curing to get the results you want. Which may not give you the TG you want without doing a post cure too... But like all OOA pre-pregs it is a compromise. Galvanic corrosion... I tend to use an essembly paste anyway like a Ti Prep or copperslip. yes it is a multiple section mould. No I dont put anything between the sections to seal them.. I have never had a problem and all you need to do is clean up the flashing where the excess resin has gone between the sections. Since this part I have been using the SHD material more and more so I have had less problems with pinholes. I have to be honest done nothing about the few I have had and customers have been happy with the parts as they come out of the moulds with a simple polish. A cosmetically perfect part is amazing and is the goal for us all.. But it comes down to time and cost. Perfect is expensive to produce and then sell.. If you have to drop your price to get the sale just because people see the price as too high then it may be better to make the same amount of profit with less effort and expense by selling parts that most would be happy with.. To be honest 95%+ of customers dont know the difference between wet lay carbon with glass filler between the surface layers and pre-preg.. To them is just carbon and it is all the same..
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morepower	morepower posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 242, Visits: 1.2K	Sorry... I missed a bit... I know there could be more heat in some areas and I do put a metalic heat reflective material on the side facing the exhausts. As it is not usually structural I dont worry too much as air will be flowing over the part when you are riding anyway.
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20_rc51_00	20_rc51_00 posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 95, Visits: 548	Thanks for the replies!
	Reply Like 3