Newbie Question About Epoxy "Beading" in Mold

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Newbie Question About Epoxy "Beading" in Mold

Newbie Question About Epoxy "Beading" in Mold

Author	Message
Zebra	Zebra posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 14, Visits: 32	You could try not adding the clear coat to the mold and spraying it on the part later.
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Tango	Tango posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 5, Visits: 14	Thanks for the reply. I'll make sure I stick to the correct ratios for the epoxy harder then. I thought about high temp clear gel coat, but I don't think EC do one? I think some more experimentation is required. Cheers
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Dravis	Dravis posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 592, Visits: 1.9K	You can not change the ratio of hardener to resin without affecting the properties of the resulting epoxy matrix in your part .. It is a chemical reaction that takes place between to reagents - they need to be in precise proportion to create the chemical bonds between the correct number on molecules to achieve the properties that you want .. Epoxy hardener is not an "accelerant" or "catalyst" like the MEKP in polyesters. Stick to to correct ratios as closely as at all possible .. To be able to brush in a gelcoat, use some fumed silica in the "top layer" or a specific Gelcoat . With the High temp Epoxy from EC, I have always used vacuum bagging with no attempt at "gelcoating", then added several layers of either 2k clearcoat or High temp Epoxy to the part, after having very lightly keyed the surface, and cleaned it with acetone. I've had very nice cosmetic results with this tech- For parts that must live out in the sunlight, I've always used high temp clear coat .. I have made exhaust end cans /covers that have lasted years without any UV damage or yellowing. "Sapere Aude"... Dare to KNOW! The written word is the only truly efficient vehicle for transmitting a complex concept from mind to mind... 103% of all people do not understand statistics... Do not adjust our mind, theres a fault in reality :-)
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Tango	Tango posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 5, Visits: 14	Many thanks for the advice guys. I've just received my next batch of materials, so the experimentation will continue! I feel that I'm close to a solution. With the High Temp epoxy I'm mixing the hardener at 35%, but would increasing this slightly hurt the finished product?
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Fasta	Fasta posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	You can also add enough of a thixotropic powder like cabosil to make the resin thicker (honey like) so that it can still be still brushed on. Fastacraft Facebook page
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petereng	petereng posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2, Visits: 4	Hi - for this approach you can try using glass tissue or glass veil. This is like tissue paper and will hold your epoxy "together" so won't bead. Your cloth supplier should have some. This is std approach for first layer off moulds and chemical resistant parts so the first layer is thick and consistant. Peter tissue is usually 25 or 30g per sqm.
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mrlindeman	mrlindeman posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 10, Visits: 61	Hi Tango. Sorry to hear about the drawing of resin you are going through. I had the same issue but fixed it by maintaining brush strokes and applying a little warmth from a heat gun to accelerate the working time of the resin. Basically keep using soft even strokes with the brush for your first beauty coat of resin. If the resin you use has a longer working time then use some heat gun action on a low setting keeping at least 12 inches from the mold in sweeping motions for 10 second intervals at a time. This will help the tack occur faster, but also kill those pesky air bubbles that love to live in our first layer of resin. Between these heat gun cycles make sure to use a brush to lightly smooth the resin out until it starts to gel. Once it gels it will hold and wont separate; creating those thin and dry areas. Also what I have done is to let that first coat cure to a tackiness then do one more very thin coat on top of it to make sure that the beauty coat is uniform and bubble free. let this second thin coat tack up until it is sticky but does not leave goo on your finger if you lightly touch it with a rubber glove on. Once this has occurred start to layup the carbon fabric. If this does not work let me know and we will work on it together with other members here Im still learning but have found alot of info from trial and error, but I do know how much of a pain cosmetic pieces can be. Air Bubbles, Pin Holes, & Voids are my worst enemy. I am committed to their permanent prevention at all costs.
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Tango	Tango posted 9 Years Ago HOT Topic Details
Group: Forum Members Posts: 5, Visits: 14	Hi guys, sorry for the Newbie Question, but this is really giving me some grief. I made a mould with the Easy Composites mould kit, which came out really well, and I'm using wet lay to make parts from it. I've coated the mould with easylease, but when I put a coating of epoxy into it as a kind of gel coat the epoxy beads like water on a waxed car panel. I've tried using release wax and PVA release agent, but they all do the same thing. I did try a gel coat, which was slightly better as it was a bit thicker, but I had to keep brushing it until it had virtually cured to stop it leaving gaps. The part is going to be used near a motorbike engine, so I was using high temp epoxy, which has a longer cure time, so it's harder to keep brushing it to maintain the even coverage. So, I'm at a loss to know what I'm doing wrong? The mould was thoroughly cleaned before applying the release agents. The part is cosmetic, so the finish is really important. Any ideas please? Cheers.
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