Dry Spots on Fabric After Infusion

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Dry Spots on Fabric After Infusion

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whitecel	whitecel posted 11 Years Ago HOT Topic Details
Group: Forum Members Posts: 19, Visits: 39	Hello, I have been infusing my parts lately and each time I pulled the part, I have dry areas on the surface. Seems like the fabric is not fully wetting out. Or is it due to the super 77 adhesive I'm using to hold the carbon fiber in place? I mist it a few passes on the carbon fiber and press it into the mold.
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brainfart	brainfart posted 11 Years Ago HOT Post Details
Group: Forum Members Posts: 198, Visits: 1.4K	using polyester surfboard laminating resin (unknown viscosity). Wrong material. I assume its viscosity is too high and pot life too short, especially at elevated temperatures. At least use the catalyst at the lower recommended ratio, not the full two pecent (or whatever the manufacturer says). Try 1.6 or 1.7%, or adjust accordingly. But it's still not a suitable material. Polyester contains a lot of styrene, which is pretty volatile. It will start to evaporate at full vacuum and is sucked through your pump. In the long run you will contaminate your vacuum pump's oil, and it won't reach its full vacuum anymore, so consider changing the oil eventually. Since the styrene has considerable vapour pressure the whole infusion takes place at a higher pressure than you think. Also used systemthree mirrorcoat epoxy (700 cps) but had almost the same result, but slightly better (still had a lot of dry spots). Better choice, but viscosity still somewhat high. I assume it has a longer pot life? Buy real infusion resin. As far as how fast was the infusion, since it is a small part, it infuses through in no more than 2-3 minutes. That's why you had at least some success, a bigger part would have been a total failure with these resins. Temperature out here in hawaii is roughly low to mid 80s*F when infusing. Too warm. Start early in the morning when temperatures are lower. You might want to consider a different infusion strategy. Introduce the resin in the middle, directly onto the part, and have the vacuum line on the mould flange. This way enough resin is sucked into the part and there should be less problems at the edges and corners. Peel ply break zone will slow down the resin enough so it stays in the part.
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Dry Spots on Fabric After Infusion

whitecel - 11 Years Ago

can you post a picture? Do the dry spots match the areas you used the adhesive? What is the layup?...

ChrisR - 11 Years Ago

[quote][b]ChrisR (15/05/2014)[/b][hr]can you post a picture? Do the dry spots match the areas you...

whitecel - 11 Years Ago

Are you referring to the circles or the bridging on the corners?

ajb100 - 11 Years Ago

Neither. Those circles were there to be drilled out after I made the part. Don't mind the bridging...

whitecel - 11 Years Ago

Are you sure it's actually dry? Or is it just matte? Can you take a photo closer up, so we can see...

Hanaldo - 11 Years Ago

You'll probably just find that the laminating resin just isn't a low enough viscosity, infusion...

ChrisR - 11 Years Ago

Hi guys i'm having the same similar issues but i dont have any voids nor pin holes, see pics on the...

tha_pop - 11 Years Ago

In the picture of the infusion are you stopping the resin feed at that point? Some of the cloth...

wozza - 11 Years Ago

[quote][b]wozza (19/05/2014)[/b][hr]In the picture of the infusion are you stopping the resin feed...

tha_pop - 11 Years Ago

[quote]using polyester surfboard laminating resin (unknown viscosity).[/quote] Wrong material. I...

brainfart - 11 Years Ago

Are you degassing your resin? I've found a similar 'dry' appearance on some infusion trials I did. I...

FLD - 11 Years Ago

[quote][b]FLD (20/05/2014)[/b][hr]Are you degassing your resin? I've found a similar 'dry'...

tha_pop - 11 Years Ago

Who are you guys referring to with the questions? I'm not sure if I'm supposed to answe those...

whitecel - 11 Years Ago

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