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Old 10-06-2016, 10:25 AM   #51
Ron118

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I've tryed the Duratec clear top coat, turns yellow can't handle the 275 degrees.
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Old 10-13-2016, 01:14 AM   #52
morepower

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This is straight out of the mould. No pinholes here. Its also not an alloy mould this is just a high temp polyester based tooling from Nord Composites.

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Old 10-17-2016, 04:32 AM   #53
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Nice. What carbon fixation glue do you prefer ?
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Old 10-17-2016, 06:42 AM   #54
Hanaldo

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That will be a pre-preg tank I'm sure.
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Old 10-18-2016, 05:50 AM   #55
morepower

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Quote:
Originally Posted by spaggiari View Post
Nice. What carbon fixation glue do you prefer ?
Quote:
Originally Posted by Hanaldo View Post
That will be a pre-preg tank I'm sure.
It is a pre-preg tank yes.. If Spaggiari is asking about bonding the sections together though. I use a Phenol Novolac base resin with several additives and thickeners to use it both as an ethanol sealer and an adhesive when I bond the base into the tank shell. As I make up the adhesive myself I am keeping the exact ingredients to myself..
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Old 10-25-2016, 04:29 PM   #56
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I know this is not 100% answer to your pinholes, that being said always wipe your mold surface with a tack cloth to remove fine dust particles. Also you probably need a more resin rich prepreg for your first layer in the mold.
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Old 10-27-2016, 04:39 AM   #57
morepower

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Quote:
Originally Posted by Fastrr View Post
I know this is not 100% answer to your pinholes, that being said always wipe your mold surface with a tack cloth to remove fine dust particles. Also you probably need a more resin rich prepreg for your first layer in the mold.
This does make sense.. BUT there are also some materials that do have a higher resin content that will still have pinholes. You may find that one material that does not work perfectly can be made to work perfectly if you change the cure schedule a little too.. Either several steps with 1,2 or 3 increases in temperature with a dwell time between each step. A lower/higher final cure temperature or a change of ramp rate too.

It can be a bit of work getting a material to work perfectly but once you have it cracked use a decent ramp and dwell controller so you automate the curing process.

The material I use is 41% resin weight. I have tried 48% and it was worse as it is all down to the chemistry of the resins used and how it works in the oven. I am sure the 48% material could have been made to work but I got the other material to work first and have stuck with it..
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Old 04-16-2017, 01:28 PM   #58
KLComposites

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Does anyone have experience with APCM DA4090 MX? It is a 250F cure single side coated prepreg. Here is my experience:

This is my best result - a 10 ply laminate cured with a one hour debulk at 100F, then a 2.5 degree/minute ramp to 250 with a 1 hour hold. Presumably the additional voids that appear on the surface in the thinner parts below are trapped somewhere in the middle of the part:



The two parts below are 4 ply laminates and were cured as follows: on the left - a 1 hour debulk at 100, followed by several 2.5 degree per hour ramps and 1 hour holds at 150, 200, and 250, with a 2.5 degree per hour ramp down. On the right - a 12 hour room temperature debulk with a 1 degree per hour ramp to 250 and 1 hour hold. Slow ramp down as before, of course.



All parts are laid up with the tacky side down and a layer of peel ply between the first layer and the tool surface. I have not tried a lower temperature cure yet. I have a call scheduled with APCM on Monday to talk things over, but also an inquiry submitted to Cytec for more info on the VTF261 - I have heard great things about it. Most of the advice I've heard about APCM has been from guys on their shop floor laying up flat panels for testing purposes. I would love to use a material that has some additional pedigree.

I will update as I gather additional information.

Thanks and Happy Easter.

Nick
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