Air in my finished product

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fallguy1000
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Re: Air in my finished product

Post by fallguy1000 » Thu Oct 19, 2017 9:52 am

I had to get past the notion that pulling resin from the part is bad. Believe it or not; that is counterintuitive. You go through a lot of trouble to add the resin to the part; then at the end you try to subtract it.

Someone on another forum told me that the veil would probably work if I hot coated it first. But I'd rather just fill the 0 strand valleys with fairing filler.


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fallguy1000
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Re: Air in my finished product

Post by fallguy1000 » Tue Oct 24, 2017 1:16 pm

We built another large panel yesterday and it came out very nice with very few laminating defects. There were just a few air bubbles and I think the cause of those is easy to understand. It has to do with variation in different core panel thickness and perforation variations and not a workmanship issue.

We ran the vac at max on this part. Had it under vac in 70 minutes against a 120 minute gel time (100g mass). I added a strip of breather along the top of the part which did saturate. Not sure if I like doing that or not. Next time I think I might try without the extra breather.

My friend was threatening to cut the bag so he was grinning one.
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Jeff
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Re: Air in my finished product

Post by Jeff » Tue Oct 24, 2017 2:29 pm

Nice work fallguy1000!! Jeff

DAYTRIP
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Re: Air in my finished product

Post by DAYTRIP » Tue Oct 24, 2017 5:42 pm

Hi fallguy, just found this. It looks like you are just vacuume bagging not infusing? I have done several large parts both ways. I go to 27" hg. Everything I have read is max vacuum is best. Other thing I am doing is pulling vacuum all the way around the part using spiral wrap tubing. Found that was important as well. Over saturation is not a bad thing as the excess resin flows out of the composite stack. I hate breather on top personally. The cores drink a ton of resin in my experience. I have used that polyumac foam several times and it drinks a ton! I like airex as it doesn't suck it up much.

If you are infusing there are other lessons learned but I don't want to confuse the issue

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Re: Air in my finished product

Post by fallguy1000 » Thu Oct 26, 2017 9:59 pm

Yup, wet bagging.

Can you expound on hate breather on top for me? If you don't use breather on top, do you run the spiral right next to the part?

I have had a ton of trouble. I am putting a 2.5mm rebate in every panel. When we started, I did not use enough resin on the core. Once I found out the right amounts; it was so excessive, I tried to use slow resin on top v xslow on bottom and the slow kicked and locked in the air bubbles introduced on panel flip. Think tons of runs running down the core and locking all the air created by the drips.

Getting the core wetout right is probably still a bit off. I think I ran at 300g/m^2 last time and probably need to take it down 50.

The entire experience has me curious about infusion, and I plan to try it, but my panels are perforated 2" oc, so might need to tweak, and my resin would need warming which is also tricky, so infusion resin might be easier.
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fallguy1000
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Re: Air in my finished product

Post by fallguy1000 » Thu Oct 26, 2017 10:14 pm

Using Gurit Corecell M80 for entire job; except M200 where hd spec'd.
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Tungsten
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Re: Air in my finished product

Post by Tungsten » Fri Oct 27, 2017 9:04 am

2' center on holes should be fine,your resin will not work.you need the viscosity below 300.You could do a small test to get your feet wet with the resin you have but as you've said you will have to really heat it.You'll also need a thick flow media to help the thick resin flow.You can buy cheap Ve resin, its thin enough to get your feet wet ,but the smell :oops:

My first kick at infusion was just a small test,3 pieces of biax tape say 24" long vac at one end resin at the other.Before you know it you'll be a pro at it.You just need to screw up a bunch of small pieces first. :D

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Re: Air in my finished product

Post by DAYTRIP » Fri Oct 27, 2017 2:26 pm

I have found the breather an unnecessary pain. On my last hardtop I did the breather drew in resign and actually dried parts of the top. The spiral tubing is of the part by 4-6 inches. Run the peel ply over to it and it make a path for air. I think you are trying to be to precise on measuring the resin out. The core is a big variable as far as how much it sucks up. I wet out the bottom stack, paint the core at least twice over a 20 minute time frame then put it together. The excess will be drawn out. Were are you pulling vacuum from, one point or along the whole part? If you are trying to pull from points I would bet your vacuum is high at the suction point and drops a lot as you move away.

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Re: Air in my finished product

Post by Tungsten » Fri Oct 27, 2017 4:46 pm

The corecell foam is HD ,resin absorbtion is very consistent threw out.its actually the little peeks and valleys on the surface that fill with resin. the core itself doesn't absorb resin.

I think daytrip is talking about not using breather when infusing. I've done wet bagging without breather just plastic over top. The idea was to keep all the resin in worked ok but ill stick too infusing.

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Re: Air in my finished product

Post by DAYTRIP » Fri Oct 27, 2017 5:41 pm

In both cases I don’t use breather actually.

Here is the setup for the vacuum bagging I typically use. You can see on this one the breather and how it looks whiter in areas. This is the top that had some dry areas.


Image

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