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dcfoster
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so again, covering it up means that I am completely sealing it from air? do I smooth the plastic wrap onto the gel coat or just lay it over and will it stick to the gel coat once it cures? Im assuming the wax-in-styrene is a product.... can I just fill the imperfections clay/wax and make sure to use mold release on the clay? thanks again
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Hanaldo
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Sorry mate, thought I had replied. You won't need to cover the spots where you have sanded through the gelcoat, they will release fine. If you are using a polyester or vinyl ester gelcoat then you will need to cover it up or add wax-in-styrene, otherwise it won't cure to a stage where you can sand it without it clogging your paper. Or it might eventually, but it will take ages. If you are using epoxy gelcoat, then you don't need to do anything, you can just mix up a small amount and apply it and let it cure hard.
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dcfoster
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ChrisR, Hanaldo? My 2nd to last post I asked about clarification on covering the gelcoat after I reapply it to fix the mould. Also is that for all gelcoats or only certain types? Im fairly certain the gelcoat I am using gets to a tack free state and thats only with 1 side not exposed to air. Though maybe not... I cant remember now.
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dcfoster
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Here are a few pics of the mold so you can see the dips. Like I said I wet sanded, 320 grit>400 grit>1000 grit and got most of the low spots out, just need to fill now I guess. |
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dcfoster
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Flow media? is that the cloth or the mesh? also you mean cling film like the stuff you use in the kitchen to seal food containers? do i smooth it on the gelcoat or just lay it over. tape?...odd ive been sanding down the gelcoat alittle and that has helped smooth out the surface alot. there are a few spots where I went into the resin underneath. im hoping release agent will work the same or do I need to layer gel coat on that as well? Hanaldo (13/05/2015)
Apologies, should have looked up the resin. You may be able to get away with it. I have infused with regular laminating resin before, but it's usually only on very small parts where surface quality isn't a big deal and I just don't want to waste good infusion resin on it. You may have to accept that it isn't going to be a perfect result though. A couple of things I might suggest changing: double up your flow media. This will waste a lot of resin, but it does help flow speed. Do as Chris suggested with heating up your resin, but be aware that this will shorten your pot life, so it may not be viable. Warm up your mould a bit too. At least make sure everything is at 25 degrees C minimum. You might want to set up a second feed line about half way across the part, in case your resin starts to gel before it finishes. Have a second batch of resin ready to mix up and go before you start so you don't have to mess around with that half way through. Again be aware that this might give you a less than perfect surface finish, but if you're in a pinch... Regarding your tooling gelcoat, that is generally the best way to repair a mould. You will just want to scrape out any chipped or loose gelcoat with a scalpel, and again make sure you clean it well with a solvent, especially if you have already applied release agent to the surface. Acetone may be a bit harsh on the gelcoat, isopropyl alcohol would be better. Furthermore, if you are using polyester or vinyl ester tooling gelcoat, then it won't cure hard unless you add 5% wax-in-styrene, or place a piece of clear packing tape or cling film on top of it then leave it to cure.
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dcfoster
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Hanaldo and ChrisR. Thank you very much for the help. I wont have much chance to try out these new suggestions till Friday. But I will update this thread with my results.
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Hanaldo
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Just go over it quickly, you can see the bubbles pop. You don't want to create any bubbles, that means you're boiling the resin.
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dcfoster
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It doesnt have to be absolutely perfect. I just need these blasted bubbles to go away, as well the shallow spots where there is barely any resin in the carbon. My 1st attempt at this approx a month ago I had to skuff the surface of the part and brush on a thin layer of resin atop the part to give it that gloss. Though I suppose a high gloss clear coat of paint will work as well. These are interior pieces so a flat look might suit me better, not sure till I can get an acceptable finished part and then trim and install.
Oh yeah, how long do you hit the resin with a heat gun to get the bubbles out when you brush resin. A few seconds? just leave it on there forever? or is it until you dont see it bubbling anymore? Or is there really no clear answer
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Hanaldo
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Group: Forum Members
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Apologies, should have looked up the resin. You may be able to get away with it. I have infused with regular laminating resin before, but it's usually only on very small parts where surface quality isn't a big deal and I just don't want to waste good infusion resin on it. You may have to accept that it isn't going to be a perfect result though. A couple of things I might suggest changing: double up your flow media. This will waste a lot of resin, but it does help flow speed. Do as Chris suggested with heating up your resin, but be aware that this will shorten your pot life, so it may not be viable. Warm up your mould a bit too. At least make sure everything is at 25 degrees C minimum. You might want to set up a second feed line about half way across the part, in case your resin starts to gel before it finishes. Have a second batch of resin ready to mix up and go before you start so you don't have to mess around with that half way through. Again be aware that this might give you a less than perfect surface finish, but if you're in a pinch... Regarding your tooling gelcoat, that is generally the best way to repair a mould. You will just want to scrape out any chipped or loose gelcoat with a scalpel, and again make sure you clean it well with a solvent, especially if you have already applied release agent to the surface. Acetone may be a bit harsh on the gelcoat, isopropyl alcohol would be better. Furthermore, if you are using polyester or vinyl ester tooling gelcoat, then it won't cure hard unless you add 5% wax-in-styrene, or place a piece of clear packing tape or cling film on top of it then leave it to cure.
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dcfoster
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so yeah...I watched a vacuum bagging video.. forget that noise. Thats more materials I need to buy and theres more to learn, maybe when im not on a time crunch. Im gonna do what Hanaldo said regarding the in/out points on the mold and keep my fingers crossed, maybe my toes and eyes too... just for good measure
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