How to go about this. First time making a mold

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How to go about this. First time making a mold

How to go about this. First time making a mold

Author	Message
ants87ss	a ants87ss posted 6 Years Ago HOT Topic Details
a Group: Forum Members Posts: 4, Visits: 50	First Id like to say Hello from The US. I have gained a bunch of knowledge from this forum as well as the EasyComposites YouTube videos. Thank You! I am going to mold my first part, a trim panel off a Ford Mustang. As you see below, there is a few burrs around the holes where an emblem once mounted. My question is, do i sand the area around the holes smooth, leave the area dull, add clay and proceed with gel coat? Or do I just fill with clay, lay out gelcoat and sand the gelcoat smooth after cure? This panel is plastic, and I do not believe it is painted. I am concerned that I will not be able to buff the area if it is sanded. I was wondering what would be easier, sand the mold afterwards or just sand before. Thanks a ton in advance
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Hanaldo	Hanaldo posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	I wouldn't sand it at all if its plastic. Just use a blade to deburr the hole and then fill with wax. Just a side note - be aware that if you are using a polyester or vinyl ester gelcoat to make the mould, then these will very often attack uncoated plastics, ruining both your original and your mould! So I would advise doing a test in an unseen area, and if in any doubt about compatibility then using PVA release agent to protect it, and later refinishing your mould to a high standard. You may also want to support your original so that any heat from the mould curing won't cause the original to warp and leave you with a distorted mould and parts that don't fit. Edited 6 Years Ago by Hanaldo
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ants87ss	a ants87ss posted 6 Years Ago HOT Post Details
a Group: Forum Members Posts: 4, Visits: 50	+x Hanaldo - 7/1/2018 2:05:11 AM I wouldn't sand it at all if its plastic. Just use a blade to deburr the hole and then fill with wax. Just a side note - be aware that if you are using a polyester or vinyl ester gelcoat to make the mould, then these will very often attack uncoated plastics, ruining both your original and your mould! So I would advise doing a test in an unseen area, and if in any doubt about compatibility then using PVA release agent to protect it, and later refinishing your mould to a high standard. You may also want to support your original so that any heat from the mould curing won't cause the original to warp and leave you with a distorted mould and parts that don't fit. Thanks Hanaldo. I was going to use a polyester tooling gelcoat, along with pva and partall wax.
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Hanaldo	Hanaldo posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	In my opinion, lose the wax. It isn't necessary and just creates an opportunity for difficulties with the PVA. If you can spray the PVA then this is ideal as you will get the best possible finish meaning less work later on refinishing your mould. If you don't have spray equipment, just get a Preval sprayer, these work great for PVA.
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drippy	drippy posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 32, Visits: 388	+x Hanaldo - 7/1/2018 2:05:11 AM I wouldn't sand it at all if its plastic. Just use a blade to deburr the hole and then fill with wax. Just a side note - be aware that if you are using a polyester or vinyl ester gelcoat to make the mould, then these will very often attack uncoated plastics, ruining both your original and your mould! So I would advise doing a test in an unseen area, and if in any doubt about compatibility then using PVA release agent to protect it, and later refinishing your mould to a high standard. You may also want to support your original so that any heat from the mould curing won't cause the original to warp and leave you with a distorted mould and parts that don't fit. What would you suggest using for support? I have a project pretty close to this and it is ABS plastic and very flimsy. I have seen people use tubing or wood to add support and also seen people adding a couple layers of fiberglass to the back of it to make it sturdy. Is that a good option or am I still gonna have warping due to adding fiberglass on the back?
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Hanaldo	Hanaldo posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Fibreglassing the back wont do much if it cant bond well, and ABS is difficult to bond to. So I would avoid that one. Really the best thing to do, which is also the hardest, is to make a jig replicating the original mounting position. For something like a kick panel it may be as easy as a piece of steel or ali square tube with holes drilled in the correct positions. But that assumes the original floor plan is dead straight. In the past I've taken a fibreglass splash mould of the mounting panel, then used that to make a fibreglass jig. Round-about way of doing things, but for intricate and critical applications its often the best.
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Fasta	Fasta posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	You could fill the backside of your abs part with an expanding foam to add support?? Fastacraft Facebook page
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drippy	drippy posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 32, Visits: 388	+x Fasta - 7/26/2018 8:21:13 AM You could fill the backside of your abs part with an expanding foam to add support?? That's not a bad idea at all
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Hanaldo	Hanaldo posted 6 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	You still need to hold it in the correct position initially. The expansion of the foam will want to twist it if it can.
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