|
macgtech
|
|
|
Group: Forum Members
Posts: 20,
Visits: 102
|
Great, thanks for the replies. Spraying the polyester gelcoat with PVA was too obvious - not sure why I didn't think of it!
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
I have on a few occasions when getting a car ready for competition been forced to turn around a part from producing the plug/mould/carbon part in less than 48 hours. I've layed up the mould, demoulded a couple hours later, applied the release system and infused the part and demoulded that, all in one day. No post curing, all done with polyester tooling. No issues at all with sticking. Certainly not recommending people try that! Just saying I don't have any issues at all using polyester tooling with Frekote 700NC, green mould or not. Of course I would always recommend anyone does any testing with their own products first, I can't speak for all tooling systems.
|
|
|
|
|
wozza
|
|
|
Group: Forum Members
Posts: 688,
Visits: 5.4K
|
Hanaldo (04/11/2014)
I don't have any issues with using epoxy in polyester moulds. 8 coats of Frekote, nothing will stick to it. A bit too risky for me having had a couple of stickers in the past.  Often with prototyping time (or lack of) means the moulds are still new/green and still full of styrene.
Carbon Copies Ltd
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
I don't have any issues with using epoxy in polyester moulds. 8 coats of Frekote, nothing will stick to it.
|
|
|
|
|
wozza
|
|
|
Group: Forum Members
Posts: 688,
Visits: 5.4K
|
macgtech (04/11/2014)
There's always ways to make the mould cheaper if it's just a one off. For custom parts that I make for customers that are unlikely to fit anyone elses car, I use a standard polyester gelcoat rather than a tooling gel. Cheap as chips, and is even strong enough to last 10 or so pulls. This is interesting - what do you do to ensure that it pulls freely if you use polyester - what do you do about a release agent? I often do the same for one offs/prototypes. Either use PVA or an epoxy compatible in mould clear gelcoat like GC50, then you can use a semi perm as the epoxy isn't in contact with the poly gelcoat of the mould.
Carbon Copies Ltd
|
|
|
|
|
macgtech
|
|
|
Group: Forum Members
Posts: 20,
Visits: 102
|
There's always ways to make the mould cheaper if it's just a one off. For custom parts that I make for customers that are unlikely to fit anyone elses car, I use a standard polyester gelcoat rather than a tooling gel. Cheap as chips, and is even strong enough to last 10 or so pulls. This is interesting - what do you do to ensure that it pulls freely if you use polyester - what do you do about a release agent?
MacG Racing Ltd., UK based Motorsport Racing Team - follow us on Twitter and on Facebook
|
|
|
|
|
Alibro
|
|
|
Group: Forum Members
Posts: 44,
Visits: 384
|
There's always ways to make the mould cheaper if it's just a one off. For custom parts that I make for customers that are unlikely to fit anyone elses car, I use a standard polyester gelcoat rather than a tooling gel. Cheap as chips, and is even strong enough to last 10 or so pulls. If I wanted to go even cheaper, I'd just fill some polyester laminating resin with microballoons or similar until it's thick enough, then use that as the gelcoat. Won't polish up as nicely, but can always clear the final part. A mould like that on a part this size wouldn't cost you more than 5 bucks in materials. Time sure, but you get out what you put into it.
Ok You win, [bows down in submission] 
Loving your photos and explanation.
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
Alibro (03/07/2014)
Wrapping is just unnecessary weight and often doesn't work well on plastic trims like this. This is such an easy part to mould and produce, it just takes a bit of practice to know where you need to put things.
Fair point but unless you intend making multiple items, making a mould is a lot of work and money. For some people who just want the carbon look then wrapping is easier and cheaper.
There's always ways to make the mould cheaper if it's just a one off. For custom parts that I make for customers that are unlikely to fit anyone elses car, I use a standard polyester gelcoat rather than a tooling gel. Cheap as chips, and is even strong enough to last 10 or so pulls. If I wanted to go even cheaper, I'd just fill some polyester laminating resin with microballoons or similar until it's thick enough, then use that as the gelcoat. Won't polish up as nicely, but can always clear the final part. A mould like that on a part this size wouldn't cost you more than 5 bucks in materials. Time sure, but you get out what you put into it. whitecel (03/07/2014)
Ok so I tried a somewhat similar method to hanaldo except I used cardboard. It worked well until I was trying to attach the cardboard sections to the base board using fillet wax. Cardboard just flexes to much that I could press the two together using the wax. Guess I gotta get thicker material It's always better if you make it solid, rather than rely on soft substances like wax to hold it on. I hot glue mine, and build supports underneath areas that need it. Here's a few photo's of a part I'm currently in the process of flanging. Not the part I was going to show you as this one isn't as closely related to your part, but you can see the technique I'm using. I use tape to get the general shape, and decide where I want to cut:  Stick that on my coreflute, and draw up my flange around it:  Cut on the line:  Attach the first section:  Get the shape to fill the gap:  Leave a bit of a gap so that you can fillet nicely:  Then fillet your gaps and radius any 90 degree corners that are created:  Repeat the process as many times as needed:  Just remember to watch your draft angles and adjust your flanges accordingly:  Do that every time the pattern changes shape. I find it easiest to do the easy, flat sections first. Then think about how to fill the gaps in between them.
|
|
|
|
|
whitecel
|
|
|
Group: Forum Members
Posts: 19,
Visits: 39
|
Ok so I tried a somewhat similar method to hanaldo except I used cardboard. It worked well until I was trying to attach the cardboard sections to the base board using fillet wax. Cardboard just flexes to much that I could press the two together using the wax. Guess I gotta get thicker material
|
|
|
|
|
Alibro
|
|
|
Group: Forum Members
Posts: 44,
Visits: 384
|
Wrapping is just unnecessary weight and often doesn't work well on plastic trims like this. This is such an easy part to mould and produce, it just takes a bit of practice to know where you need to put things.
Fair point but unless you intend making multiple items, making a mould is a lot of work and money. For some people who just want the carbon look then wrapping is easier and cheaper.
|
|
|
|