|
Shinobiwan
|
|
|
Group: Forum Members
Posts: 14,
Visits: 97
|
Hi guys, I've got my plugs to a stage I'm happy with and I'm about to start on the mould making. I've chosen the unimould system from easy composites. This will be my first time. I'm worried about the release and sticking of casts though since there's a lot of 90 degree angles and sharp edges involved - this is unavoidable since its just the nature of the parts I'm making. The part is two sided and will be done as split mould, the parting line is easy since there's a natural edge. So far I've attached the plug to a sheet of glass and used filleting wax to seal stick it to this. Afterwards I've applied 5 coats of easy lease agents but also have both wax and pva on hand if needed. My question is what will be the safest option for a clean release. Nervous about ruining the plugs since there has been a considerable amount of time and money spent CNC'ing as well as finishing them. Many thanks for any advice Anthony
|
|
|
|
|
wozza
|
|
|
Group: Forum Members
Posts: 688,
Visits: 5.4K
|
First question. What are the plugs finished in, looks like high build but is it 2K?
The middle one looks like a tricky lay-up. Have you done this before?
Warren
Carbon Copies Ltd
|
|
|
|
|
Shinobiwan
|
|
|
Group: Forum Members
Posts: 14,
Visits: 97
|
Hey Warren and thanks for the help. Its high build primer but cellulose and not 2k. I don't have the equipment to safely spray 2k and I'm asthmatic so have pretty sensitive airway/lungs and wouldn't fancy chancing it. I'm guessing this is a problem and the gelcoat will react with it? I have never done this before but definitely want to learn. For the middle one, I was going to cut up the 100g CSM into short strands and pack them into the tricky parts then take small patches and lay them down in the coupling coat before the main reinforcement. Any advice you could share would be invaluable.
|
|
|
|
|
wozza
|
|
|
Group: Forum Members
Posts: 688,
Visits: 5.4K
|
Shinobiwan (08/04/2014)
Hey Warren and thanks for the help. Its high build primer but cellulose and not 2k. I don't have the equipment to safely spray 2k and I'm asthmatic so have pretty sensitive airway/lungs and wouldn't fancy chancing it. I'm guessing this is a problem and the gelcoat will react with it? I have never done this before but definitely want to learn. For the middle one, I was going to cut up the 100g CSM into short strands and pack them into the tricky parts then take small patches and lay them down in the coupling coat before the main reinforcement. Any advice you could share would be invaluable. Hi, the cellulose is going to be a problem. The tooling coat is going to stick to it because of the styrene it contains. You may get away with PVA for the release agent if you spray it on thick enough. The downside to PVA is that you will have to do some work on the mould to bring it up to a gloss. The lay up of the mould won't be a problem, CSM will conform to the shape ok. I was meaning the lay-up of the actual part assuming your going for CF. Warren
Carbon Copies Ltd
|
|
|
|
|
Shinobiwan
|
|
|
Group: Forum Members
Posts: 14,
Visits: 97
|
I should have mentioned that these won't be CF but just just poured with fast cast PU. Hmm, that's a shame about the paint since I spent a bunch of time buffing them but definitely don't want things sticking so that'll have to be addressed before anything else can happen. Would it be possible to use pattern coat over the celly? If not then I'll have to go with the PVA release, how many coats would you suggests is thick enough?
|
|
|
|
|
Hanaldo
|
|
|
Group: Forum Members
Posts: 2.5K,
Visits: 28K
|
Not sure if it depends on brands of PVA, but the stuff I use has excellent self-leveling properties. So when it's sprayed on, it leaves a very smooth, high gloss finish. I just give my moulds a quick flat with 2000 grit, then polish them up; but I do that regardless of whether I use PVA or not. I am in a similar boat to you Shinobiwan, I can't spray 2K. I use 1K stuff to paint all my plugs, and they come out fine using PVA. I have destroyed a couple unfortunately, but that was before I started spraying the PVA. I don't necessarily count coats, but what I normally do is spray a few (2 or 3) very fine mist coats, then I go over it with heavier coats as if I were spraying a paint. So by the time I' done, I will probably have done 2-3 mist coats, and then 2-3 heavier coats. If your PVA is anything like mine, it won't look perfectly flat at first, it will have some tiny air bubbles in it. But these all disappear after 5-10 minutes, and leave a very smooth surface. Spraying it on this heavy will make it pool in tight corners and radius' though, so have some paper towel handy and just stick a corner into the pools and let it soak up. Or use it more sparingly in the corners. It will also take a little longer to dry, which you can speed up with a hair dryer or a heat gun, but just be careful not to cause bubbling with the heat as that will come out in your mould. Personally I think that approach is easy enough to not bother with setting up for 2K, especially given the costs of 2K.
|
|
|
|
|
wozza
|
|
|
Group: Forum Members
Posts: 688,
Visits: 5.4K
|
Applying most things by spraying makes it more hazardous to your health even PVA. If that was my main concern I would be getting my local body shop to 2k it for me or finding an alternative coating media. 2k can be applied by brush reducing the health risks.
Warren
Carbon Copies Ltd
|
|
|
|
|
Warren (Staff)
|
|
|
Group: Administrators
Posts: 2.5K,
Visits: 8.5K
|
if you're not in a hurry you could leave the plugs to season in a warm place for as long as possible, ideally a few months!!! That would get most the styrene out then you can pay someone to 2k coat over the top which should seal it ok and youll get away with it.
Worst case you could oven bake it to drive out the solvents but its not garunteed.
With hindsight, 2k is the better option in the future.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
|
|
|
|
|
Shinobiwan
|
|
|
Group: Forum Members
Posts: 14,
Visits: 97
|
Big thanks guys! After reading all the advice and chatting with Warren I'm going to spray a good PVA release layer and then fix any imperfections in the tooling gel afterwards. Shame that I hadn't realised celly paint is incompatible but mega relieved all is not lost! For future plugs I'll be using pattern coat primer to avoid this issue. I had a question asking how I'd made my plugs and the answer is I CNC machined them out of easy composites high density modelling board. Here's a video I did at the time:
|
|
|
|
|
Atomant
|
|
|
Group: Forum Members
Posts: 7,
Visits: 694
|
|
|
|
|