Resin infusion, help evaluating the result.


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Ronny
Ronny
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Hi
The more i read the more i get confused about the proper way to infuse.
EC tutorial says as soon as resin has reached the catchpot you should shut off the resin feed and 10 seconds later shut off the resin exit.

After doing this i noticed lots of airbubbles in the mould, and both resin inlet and exit hose was "bubbling" with air.
I had full vacuum -30 when i shut the lines, and the morning after the gauge read -28, so there was a tiny leak somewhere.
(maybe because of changes in the room temperature?)

Anyways the results are seen here:
http://imgur.com/Q3HyxCr
http://imgur.com/aUaG0MA

Looks to me as its resin starved, and the bubbles i observed in the mould during cure has probably caused alot of problems.
Should i leave the resinfeed on for a longer time? til i only observe pure resin and no air in the resin exit?
Any other advice?

Layers were 4x220g, peel-ply and infusion mesh.

Also after peeling of the peel-ply it leaves a really "dry" surface, is this surface strong or should i coat it with a layer of resin?
Strengt is the primary concern on this part, not looks.
http://imgur.com/1hlbns1
MarkMK
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To help ensure that your part is fully infused with resin, it's helpful to leave the resin feed open for a short while after closing the vacuum feed, not the other way around, as this may have had some bearing on your part been starved of resin

Of course, if you haven't achieved full vacuum and your bag has a leak, however tiny, the end result is likely to be air bubbles affecting the finish of your part. With practice and neat bagging-up you'll be getting perfect vacuum nearly all the time without having to chase down leaks.

Using a resin break (a deliberate gap in the infusion mesh just before the vacuum exit) will also help to ensure that your part isn't infusing too quickly for the resin to reach and wet-out the part completely

If you're confident that all areas have infused by the time the resin starts to climb the exit tube, then you are safe to clamp off, followed by the resin feed. Don't worry too much about bubbles in the resin, as you have to realise that it is subject to the highest vacuum near the exit and the bubbles are greatly expanded because of this. A short while after clamping off, the negative pressure will begin to equalise across the part and these bubbles will likely shrink to almost invisible.

The key is to make sure that you get a fully tested vacuum prior to infusing, however, as it's surprising sometimes just what little errors in infusing you can get away with when this is the case

The peel-ply texture is quite normal and there's no need to coat the 'b' side, unless you're really looking for a cosmetic finish on this side 

Allowing your resin to de-gas a little prior to infusion will also help is going for perfect cosmetics, but I suspect that it was a leak somewhere that was introducing air into things. The resin inlet/exit points can be prone to leaking, if you've not sealed them carefully and haven't avoided excessively creasing the bag
Edited 9 Years Ago by MarkMK
Hanaldo
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The resin will always bubble in the vacuum line, that's normal. The resin inlet hose, should not. You may notice small bubbles from the mixing process if you haven't degassed, but they are normal. Anything else is not normal. 

A 2in/Hg drop won't be due to a change in room temp, that's a leak for sure. You can see it in the infusion mesh in that first picture, that's a heap of air in there. A leak was definitely the issue. 

The peel ply finish is as it should be. 
Ronny
Ronny
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Thanks guys, ill try these advices on my next attempt.

To be continued
ChrisR
ChrisR
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It's not just a leak thats the problem there, you have an inordinate amount of bridging going on there. Work more on your layup technique to ensure no bridging in either the surface or internal layers.

Where you have a bridge the resin will take the path of least resistance and flow down the void rather than flowing through the fabric which has a higher resistance to flow.  
davro
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I have started using a resin break in the gap just before the outlet line/s (gap in the infusion mesh) and this helps a lot.

I'm going to experiment putting a small piece of breather cloth in the resin break next time, as some times I find having a complete break slow things down to much anyone experimented with something like this ?



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Hanaldo
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davro (07/03/2016)
I have started using a resin break in the gap just before the outlet line/s (gap in the infusion mesh) and this helps a lot.

I'm going to experiment putting a small piece of breather cloth in the resin break next time, as some times I find having a complete break slow things down to much anyone experimented with something like this ?


Probably won't work the way you are expecting. I often use breather to really choke the resin, as the breather will want to be completely wet out before the resin enters the vac line. 

Peel ply break is the norm and works well. 
GO

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