Process for fibreglass mould

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Process for fibreglass mould

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Undercover	Undercover posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 9, Visits: 46	ive tried this again on the same part along with another one. The other being much easier to work with but although they are currently curing, i feel its not going to go so well. The fabric lifted in the corners etc no matter how much i rolled and pressed the air out. Let alone all the mess. Is it alot easier to to vacuum to make a mould?
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Hanaldo	Hanaldo posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Undercover (17/04/2016) Changing the shape of the plug is not something i can do. I shall give it a go with a 2 peice mould and see how i get on. I do understand about it distorting when i remove the plug but before the backing/reinforcing layers are added, the plug will be placed bacl into the mould. It would simply removed to ensure that it will fit again correct, if its a tight fit, anything i make from the mould wont be a good fit when i come to use it Placing the plug back in the mould prior to laminating the backing layers won't prevent distortion. Once it has been released, the mould is free to move around as it will. Your issue isn't shrinkage, it's draft angle. You need to change the angle of release, and you can only do that by either modifying the shape of those mounting points or by dividing up the mould into sections that provide you with a positive draft. Truth be told, you are likely to still struggle with doing it as a split mould, because the difficult area is in those mounting points. There's no way to split those recesses that will allow you to pull the mould off on a different angle, they are a complete 360 degree lock. Why can't you change the angle of the sidewalls on the recesses? Just a tiny bit of filleting wax is all it would take. If you really can't do that, then I would suggest building a very strong mould and bonding nuts to the back of the mould where those recesses are. This will allow you to wind a bolt in and use mechanical force to push the mould up and out of those recesses. It is much easier to push a plug out than it is to pull it out.
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Undercover	Undercover posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 9, Visits: 46	Changing the shape of the plug is not something i can do. I shall give it a go with a 2 peice mould and see how i get on. I do understand about it distorting when i remove the plug but before the backing/reinforcing layers are added, the plug will be placed bacl into the mould. It would simply removed to ensure that it will fit again correct, if its a tight fit, anything i make from the mould wont be a good fit when i come to use it
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Hanaldo	Hanaldo posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	You definitely don't want to remove the part from the mould prior to having all the backing layers in place, as once the part has been released you will be very prone to distortion. Also yes, adding too much hardener and applying too much heat (by working in the sun in your case) will have a big effect on shrinkage. I do remember your post though, and I'm sceptical that your demoulding issue was due to shrinkage. Your part is simply not designed to come out of a one piece mould, and the reason it is so tight to get in and out of the mould is because you have opposing angles in there that are too tight. You need to either change those angles to give yourself a bit of draft, or you need to make the tool in more than one piece.
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Undercover	Undercover posted 9 Years Ago HOT Topic Details
Group: Forum Members Posts: 9, Visits: 46	ive posted a topic before i had where shrinkage so bad that i couldnt remove the part without breaking the mould. And even then, the part wouldnt fit in the mould because the mould was too small/tight I now plan on not just using csm but using a lighter woven fibreglass in 1 or 2 layers so i can safely remove part from mould then check there is no/little shrinkage by refitting the part back into the mould. Once i am happy, apply multiple layers of csm to build the thickness of the mould. I hoping this should cure my previous issues. I have read online that too many layers straight away can cause shrinkage. Also, on my first attempt, i could of added too much hardner (i was working in the sun, but everything seemed to cure pretty quick), would that affect shrinkage? -undercover
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