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Hanaldo
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Group: Forum Members
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If you use a phenol novolac epoxy to coat the insides of the tank then you won't have any problems with petrol or ethanol attacking the resin.
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Asurada
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Hi buddy，I am from China, I like Honda motorcycle, Indonesian the latest new Honda CBR250RR, I plan to refit the motorcycle, especially part of the tank, for epoxy resin corrosion problem of petrol I have been online to find the problem, how did you handle it? Corrosion protection has been handled? There are layers in the tank, I expected placement 5 layer, a layer of the surface layer and four-layer volume level. For moulding process of carbon fiber and resin flow forming technology I am more skilled, I myself had a hand trolley, use the diversion process, produced, taking into account the wear problem, I spray a matte color car paint.  |
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morepower
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Fasta (07/03/2016)
It could be the moulds cooling as someone said? I have done lots of pre preg parts from wet laid moulds and not had this problem. Have a done a bunch of 11ft?3.3m boat hulls where I unbolt part/end of the moulds to allow the hulls to self release as the moulds cool. Seems to work really well. When cooled/released the hull would stick out mould about 3-4mm. When I have tried to release the parts while hot it works but I always feel the parts seem difficult to pull and release. Letting them self release with the cooling/shrinking works well. The problem is when you have a multi section mould that has zero draft or has sections that are on 3 or 4 faces so if the mould shrinks it actually gets tighter round the part and it cannot self release.. The dive bottle cover is one part where there is zero draft and it locks in so tight that the best way is to actually ramp UP the temperature 10 degrees just before you remove the part! The fuel tank moulds also get clamped down upon when the mould cools and as it is 4 or 5 sections the time it takes to remove all the sections is too long to remove it all before it starts to shrink. In both cases the moulds crack. I have done a few parts from one piece moulds that will self release when they cool. Great when it happens but almost all of mine will not self release so wet lay tooling shrinking is my worst nightmare.
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Fasta
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Group: Forum Members
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It could be the moulds cooling as someone said? I have done lots of pre preg parts from wet laid moulds and not had this problem. Have a done a bunch of 11ft?3.3m boat hulls where I unbolt part/end of the moulds to allow the hulls to self release as the moulds cool. Seems to work really well. When cooled/released the hull would stick out mould about 3-4mm. When I have tried to release the parts while hot it works but I always feel the parts seem difficult to pull and release. Letting them self release with the cooling/shrinking works well.
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morepower
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Another mould that cracked so I had to make a new mould. I have had enough of the wet lay moulds I had made cracking up so it looks like ALL of them will be remade in Pre-preg tooling.  There is some release agent residue on the master and the mould here but a quick polish and it will be as good as ever. I had to remake a fuel tank side after I made a mistake and missed an issue left on the tank I used to remake the mould. It came out great too.. Both moulds were made over two days and that was not a rush as I wanted to let the surface debulk overnight. 
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morepower
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Done... Just going through post curing now and then loads of sealer and release...   The weight is in Kilos... 
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morepower
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Exactly..... If he felt bad and was doing a new mould at a good price especially as he had not fixed the initial problem, I would have expected he would do the next mould with materials that he knows would work better than the materials that had a problem and do it to see what could be used for future moulds. If not for free but at cost. I had always said I would never haggle a price if I am getting good moulds and I would stick with him. But when things go wrong you expect the same respect to be returned. This area had been repaired once and started to crack again.   The blame by him was the mould cooling with the part still in the mould and I had not de-moulded hot. By Marbocote.. The gelcoat was not suited to pre-preg use or the main body resin had not fully cured correctly and was not hard enough. By Nord, Scott Bader etc.. The resins used were not suited to pre-preg use.
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Hanaldo
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Yeh fair enough, I do try to support my customers when something goes wrong. You would hope that everyone is the same, but I guess that's not always the case.
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morepower
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Hanaldo (19/01/2016)
Speaking from a business point of view though, I never charge my customers cost price for the material, I add 30%. I provide a break down of prices, one section being material costs. These costs are what I am charging the customer for the materials, not what I pay for the materials. Theres numerous reasons for that, one is storage. I use my own space to store materials, and that space is worth something. I also use my time to source my materials. I also factor in a small amount for wastage. All these things add up. I get that.. I have a price for materials too.. But the price I had been quoted for the last mould was "A good price" as he had made such a mess of the mould and to see a £100 extra for carbon over glass tooling just didnt add up when the part is less than 0.25 Sq/m. There is a reasonable profit and then there is taking the piss.. Especially when you have spent £2500 on a mould that started to crack after 4 pulls and you know others who have had a similar problem and they have had their mould tested telling them the gelcoat is not suitable and the problem should have been sorted out..
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Hanaldo
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Group: Forum Members
Posts: 2.5K,
Visits: 28K
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Speaking from a business point of view though, I never charge my customers cost price for the material, I add 30%. I provide a break down of prices, one section being material costs. These costs are what I am charging the customer for the materials, not what I pay for the materials. Theres numerous reasons for that, one is storage. I use my own space to store materials, and that space is worth something. I also use my time to source my materials. I also factor in a small amount for wastage. All these things add up.
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