Strange tooling gelcoat delamination

Talk Composites - The Forum for Advanced Composites

Back

Strange tooling gelcoat delamination

Author	Message
Massimiliano	M Massimiliano posted 4 Years Ago HOT Topic Details
M Group: Forum Members Posts: 167, Visits: 1.1K	Hi, Please see pics below of the mould and the part after infusion. The mould has been applied 6 passes of easylease, 1 pass of wax and 1 mist of pva before laying fabrics. All the timing between passes has been respected, and pva was left overnight to dry. Composite spray glue from ec has been used to keep the fabric in place. When it came to extract the part, some small areas detached as they should fine but the majority had the gelcoat stuck on it, as visible in the pic. I was afraid of a long sanding job but tried first with a chisel and small strokes and with much relief chips by chips all the stuck gelcoat came away with leaving a glossy part surface. My questions is: - what could be the reasons why the gelcoat was so adhered (I use adhered and not bonded because with some mechanical force the gelcoat separated) to the part?
	Reply Like 3
Replies
Hanaldo	Hanaldo posted 4 Years Ago HOT Post Details
Group: Forum Members Posts: 2.5K, Visits: 28K	Yeh 100% agree with Oakmont. I very highly doubt this issue was caused by the use of silicone, its a very typical case of the epoxy gelcoat being outside its overcoat window. Silicone has a bit of a reputation, which I find somewhat over-hyped. I use a lot of silicone, I've never had any issues. I even use it in my spray booth. In fact I keep two bottles of silicone oil in the same cabinet as my paints and adhesives. I dont have problems with paint fish eyeing or structurally bonded joints failing or moulds delaminating. Thats not to say it couldn't happen, but I always have to wonder when I hear these horror stories how meticulous the prep work was. Were the parts even cleaned properly, or did the apprentice go straight from spraying the coffee machine with silicone to handling the parts about to be bonded? It should not matter if there was silicone overspray nearby, any work you are doing should be properly cleaned and prepped just before you spray/bond/laminate it. I always assume that my parts are contaminated just as a matter of course, and I treat them appropriately. It is far from impossible to clean, your run of the mill Prepsol/wax-and-grease remover will remove silicone residue very efficiently. Edited 4 Years Ago by Hanaldo
	Reply Like 3
Massimiliano	M Massimiliano posted 4 Years Ago HOT Post Details
M Group: Forum Members Posts: 167, Visits: 1.1K	+x Hanaldo - 1/22/2021 5:14:13 AM Yeh 100% agree with Oakmont. I very highly doubt this issue was caused by the use of silicone, its a very typical case of the epoxy gelcoat being outside its overcoat window. Silicone has a bit of a reputation, which I find somewhat over-hyped. I use a lot of silicone, I've never had any issues. I even use it in my spray booth. In fact I keep two bottles of silicone oil in the same cabinet as my paints and adhesives. I dont have problems with paint fish eyeing or structurally bonded joints failing or moulds delaminating. Thats not to say it couldn't happen, but I always have to wonder when I hear these horror stories how meticulous the prep work was. Were the parts even cleaned properly, or did the apprentice go straight from spraying the coffee machine with silicone to handling the parts about to be bonded? It should not matter if there was silicone overspray nearby, any work you are doing should be properly cleaned and prepped just before you spray/bond/laminate it. I always assume that my parts are contaminated just as a matter of course, and I treat them appropriately. It is far from impossible to clean, your run of the mill Prepsol/wax-and-grease remover will remove silicone residue very efficiently. Thank you everyone for contributing to this topic. I have to say that a previous mold, made with the green EC epoxy tooling gelcoat and another brand of silicone has had no issue at all. So I will make two additional tests on small molds: - red epoxy gelcoat with the first silicone - EC green epoxy gelcoat with the second silicone. Maybe the second silicone has some additive in it which interferes with the full curing of the gelcoat, or the red gelcoat is crap. I will on purpose overlook the overcoat window not to introduce another variable. I will update this post as soon as I will have results.
	Reply Like 4
Lester Populaire	L Lester Populaire posted 4 Years Ago HOT Post Details
L Group: Forum Members Posts: 311, Visits: 13K	+x Hanaldo - 1/22/2021 5:14:13 AM Yeh 100% agree with Oakmont. I very highly doubt this issue was caused by the use of silicone, its a very typical case of the epoxy gelcoat being outside its overcoat window. Silicone has a bit of a reputation, which I find somewhat over-hyped. I use a lot of silicone, I've never had any issues. I even use it in my spray booth. In fact I keep two bottles of silicone oil in the same cabinet as my paints and adhesives. I dont have problems with paint fish eyeing or structurally bonded joints failing or moulds delaminating. Thats not to say it couldn't happen, but I always have to wonder when I hear these horror stories how meticulous the prep work was. Were the parts even cleaned properly, or did the apprentice go straight from spraying the coffee machine with silicone to handling the parts about to be bonded? It should not matter if there was silicone overspray nearby, any work you are doing should be properly cleaned and prepped just before you spray/bond/laminate it. I always assume that my parts are contaminated just as a matter of course, and I treat them appropriately. It is far from impossible to clean, your run of the mill Prepsol/wax-and-grease remover will remove silicone residue very efficiently. This is actually really useful information for me, thanks. We never had any problems with silicone contamination but i am a bit paranoid whenever someone works with silicone in the workshop. And i was lucky to participate on some seminars where speakers and participants had these kind of horror stories to tell.
	Reply Like 4