After 3 fails its time to ask where i go wrong..


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jeffrey bres
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As mentioned..   3x not a charm here.

I have this isseu every time.
Clearcoating without gelcoat would be an option. But allso that isnt easy with small holes like this.

Now i used gelcoat. Hoping it would help.

Gel had cured at 25 degrees for 5 hours was dry to touch.

I used 3m high tack clear spray adheasive to hold the fibers in place. (AS LITTLE AS POSSIBLE)


on the vacuum catch pot the dail says my vacuum is 100%
I leace the pump running over night.  In the morning when the resin is hardned the vacuum line form the ez composite starter kit to the pot is flat from the vac. 

(I dont have an official cacuum pump.  I use a 35l/m fridge pump. Whitch seems to work fine.   I can add an extra pump if i need more cfm...)
If my vac is to strong.. i can make a bleedvalve to reduce vacuum.   

But idialy i would love to have a perfect finish.

I use easy lease release agent..  denoulding is a breeze..




Hanaldo
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Yeh its a lot of air, so you definitely have a leak. Gelcoat can't fix that, and in fact makes it worse because the air gets trapped behind the gelcoat so you can't even salvage the part by clear coating.

You can't trust the analogue gauges, they are extremely inaccurate and their reading will even change with the weather. All they are good for is indicating a leak over time, so after pulling a vacuum clamp the part off and leave it clamped off for 5-6 hours or ideally overnight. When you come back and unclamp it, watch the gauge closely - it should not even flicker when you unclamp. If it moves at all, even a touch, you have a leak. 

Normally I actually say forget the gauge, they are misleading. You can often tell instantly if you have a leak just by listening to your pump, their tone is much more sensitive than the gauge. When you clamp off your part, the pump should not change tone at all (and you have to listen closely, minute leaks make minute changes to the tone). Keep looking for leaks until your pump doesn't change tone at all, then do one final drop test by clamping the bag off and leaving it for 30 minutes to an hour. The longer you can leave it, the easier it will be to detect a small leak. When you come back and unclamp, listen to the tone of your pump again. Again it should not sound any different at all the moment you unclamp the bag, and there should be no vapour coming from the exhaust. This is genuinely one of the most reliable ways to check your vacuum integrity, these days I have fancy digital vacuum gauges and obscenely expensive ultrasonic leak detectors - the tone of the pump is 99% of the time the first indication I still have a leak.

You dont need a fancy vacuum pump either, the only critical thing is that it can pull 99.995% vacuum. The CFM does not matter at all, you can connect 20 individual 15CFM vacuum pumps together, but if none of them are capable of pulling 99.995% vacuum then they arent good enough. CFM determines how fast the pump can pull the air out of the bag, it doesn't determine the ultimate vacuum level you can achieve. So just check the specs on your vac pump and make sure it can pull very high ultimate vacuum levels.
jeffrey bres
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Hanaldo - 4/11/2021 1:10:57 AM
Yeh its a lot of air, so you definitely have a leak. Gelcoat can't fix that, and in fact makes it worse because the air gets trapped behind the gelcoat so you can't even salvage the part by clear coating.

You can't trust the analogue gauges, they are extremely inaccurate and their reading will even change with the weather. All they are good for is indicating a leak over time, so after pulling a vacuum clamp the part off and leave it clamped off for 5-6 hours or ideally overnight. When you come back and unclamp it, watch the gauge closely - it should not even flicker when you unclamp. If it moves at all, even a touch, you have a leak. 

Normally I actually say forget the gauge, they are misleading. You can often tell instantly if you have a leak just by listening to your pump, their tone is much more sensitive than the gauge. When you clamp off your part, the pump should not change tone at all (and you have to listen closely, minute leaks make minute changes to the tone). Keep looking for leaks until your pump doesn't change tone at all, then do one final drop test by clamping the bag off and leaving it for 30 minutes to an hour. The longer you can leave it, the easier it will be to detect a small leak. When you come back and unclamp, listen to the tone of your pump again. Again it should not sound any different at all the moment you unclamp the bag, and there should be no vapour coming from the exhaust. This is genuinely one of the most reliable ways to check your vacuum integrity, these days I have fancy digital vacuum gauges and obscenely expensive ultrasonic leak detectors - the tone of the pump is 99% of the time the first indication I still have a leak.

You dont need a fancy vacuum pump either, the only critical thing is that it can pull 99.995% vacuum. The CFM does not matter at all, you can connect 20 individual 15CFM vacuum pumps together, but if none of them are capable of pulling 99.995% vacuum then they arent good enough. CFM determines how fast the pump can pull the air out of the bag, it doesn't determine the ultimate vacuum level you can achieve. So just check the specs on your vac pump and make sure it can pull very high ultimate vacuum levels.

I did a test.. and no hissing sounds on the part. I did a drop test.   Nothing.  After about 2 hours. I had it leak free i thought. Clamping and unclaping without the gouch moving.. at all.     The pro of these motors is that they are super quiet. So listening for leaks is more easy.

While infusing it all starts perfect. Its all nice and uniform collor. The problem starts after a while.. then the mesh starts to show air inside... and you see the bubbles move through the mesh towards the pump.

It starts at random.    Halfway inside the part allso without a trace of leakage.

Could it be gassing of the resin?   Or do i need to let more resin in?       (This part will get painted. So it doesnt matter its not perfectly infused. But that is offcourse my goal here.)     Allso.   I enveloped a part allso..   same result.
My gauch says full vac. (Needle goes over the furthest point on the clock.) (Funny. That reminds me of a car i had. Lol going faster thenbthe speedometer could)
Anyway. .  I have made 4 parts now.  All 4 show the same isseu.   With el2 and in2 resins. With and without gelcoat

Reason i used gel now is i have a smooth surface anyway. And bridging is easy to fix by injecting resin.

Il try t make a flat carbon pannel and see if i have the same isseu.   

Does it matter i leave the pump running the whole time?

Edited 6 Months Ago by jeffrey bres
Chris Rogers
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I am not sure from the picture what is going on but it sounds frustrating!  Infusion is the worst!  There are a few things:

If you don't have leaks and can confirm with a drop test as Hanaldo describes then that is good!   Leaks are almost always the issue though and they are subtle sometimes.  It really doesn't take much!  Is the defect uniform or consistent across the multiple parts and part surfaces? Do you have any pictures of the infusion plumbing setup?

Other problems that can cause this are too fast an infusion over-running air or air bursts during or after the resin is infusing.  Even a little glug of air in the feed tube will mess stuff up in almost un-fixable ways.  This part should take maybe 10-30 minutes with epoxy.  

It is possible that without a vacuum break detail you are sucking out too much of the resin with full vacuum during cure.  Especially with an envelope bag, you need to have a very minimal path from the part to the vacuum side.  You want air to pass but not much - or any - resin.   I am not as convinced as Hanaldo that you need 100% full vacuum for infusion.  You need good vacuum, but often it is just fine to infuse at 25inHg or so and it has several benefits.  I also really like the idea of reducing vacuum during or after the infusion to keep things less vapor-pressure sensitive. I doubt moisture is the issue but it's possible if you have old hardener... 

Do you have more pictures?  This should be figure-out-able!




jeffrey bres
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I dont realy have pictures.   I have my cachpot level with the part.   35cm of line to pot.   U use +-1m of silicon line to the pump

Resin line is 35 to 40cm.
 10 to 30 min...    i think its faster.    I was thinking i was to quick then.

Il make pictures of my setup when i do the bottom

On the part shown. I infused front to back.   And bubbles getting more severe at the back.  At the front/nose its perfect.
And it basicly starts at the reinforcement coremat.. you see a bubble band there...

So next i will try this...

Droptest again.. then infuse.. close vac line. Give it a few minutes to soak more resin..close the resin and pull vac again. And continue with lower vac after infusion..
(Sinds im new i need to built some cobfidence i can close both lines...)   il try that later on a flat pannel..

Im 100% sure my pump is pulling a good vacuum.   
When my clock is touching the needle. I pull it to max or even over max the clock got on the scale..   temp is 20 to 23° C.  

ive tryed a smaller pump allso.  This one doing a little less.
All i found after further inspection was a little glass hair in the seal of the catchpot.
(Could that be the problem)


jeffrey bres
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Here are pictures of my setup.. (yes. I know my wife lets me work in house. Nice and warm.  Love it!!

Anyway.   Pump didnt want to go further then this.
Left it pumping 30 min. Closed the line pot to the pump.
15 min in now. Needle didnt move yet.
Il wait for an hour or 2 then infuse.

Any commands? (I will listen to you if you have better advise.)
Edited 6 Months Ago by jeffrey bres
jeffrey bres
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Ok the clock doesnt move a hair.  Its reading 28hg. Pump doesnt pull out more.

All materials are room temperature.
20 degrees.   I infused it fully. Vlosed the vac line.
Let the resin flow 45sec to 1 min longer. Abd closed that off allso.

Now im about 20 to 30 minutes into a closed vac mould 
And again bubbles appear.    They appear fulley random.
I opened the vacuum. Needle doesnt go down resin starts flowing in the catch pot.   And even more bubbles apear.

I stirred verry slowley and let it stand for 10 min before infusing.   

I dont know what to do no more lol.
Edited 6 Months Ago by jeffrey bres
Hanaldo
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The bubbles in those last 2 pictures are not a problem. They will be due to what appears to be a slight amount of bridging, which is where trapped air liked to collect. What is an issue is when you get air leaking in that creates pattern in the flow mesh that look sort of like trees. This indicates a big leak.

Re. glass strand in seal of catchpot, yes this is enough to be a leak. Same with strands of carbon or glass or peel ply caught under the vacuum bagging tape. Sealing surfaces need to be very very clean.

The types of leaks that will cause you dramas are not audible, you can't hear them. The ones you can hear hissing are massive leaks, and are very obvious and easy to find. Generally you can't even hear the small ones with ultrasonic leak detectors, they are absolutely minute - and yet enough to ruin your infusion.

Again, ignore the gauge - it isn't accurate enough to pay any attention to what it says. If the bubbles you are getting in those last 2 photos are your only concern this time, then they are nothing to worry about. If you dont get any more air than that before the resin cures, the part should turn out well. If it does not, then it is likely to be another issue which, as Chris suggested, could be infusion speed, resin viscosity etc. But my first impression of looking at your first photos is you had a big leak. So hopefully this one turns out better.
jeffrey bres
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Hanaldo - 4/13/2021 9:38:44 AM
The bubbles in those last 2 pictures are not a problem. They will be due to what appears to be a slight amount of bridging, which is where trapped air liked to collect. What is an issue is when you get air leaking in that creates pattern in the flow mesh that look sort of like trees. This indicates a big leak.

Re. glass strand in seal of catchpot, yes this is enough to be a leak. Same with strands of carbon or glass or peel ply caught under the vacuum bagging tape. Sealing surfaces need to be very very clean.

The types of leaks that will cause you dramas are not audible, you can't hear them. The ones you can hear hissing are massive leaks, and are very obvious and easy to find. Generally you can't even hear the small ones with ultrasonic leak detectors, they are absolutely minute - and yet enough to ruin your infusion.

Again, ignore the gauge - it isn't accurate enough to pay any attention to what it says. If the bubbles you are getting in those last 2 photos are your only concern this time, then they are nothing to worry about. If you dont get any more air than that before the resin cures, the part should turn out well. If it does not, then it is likely to be another issue which, as Chris suggested, could be infusion speed, resin viscosity etc. But my first impression of looking at your first photos is you had a big leak. So hopefully this one turns out better.

Learning can only be done by doing.   I pay a lot of attention to detail and work the bag larger oversized. And try to make sure i dont have any leaks.    The last infusion i gave it more resin. And vacuumed it back again a little with a few vacuum pauses to give it plenty time to soak..   its only 1x 210 carbon 1x 280 glass and 1x 200 glass.
Nothing special i would think.

Hand layup is working out superb for ne but takes a lot more time to do..   so i thought il try infusion.

In my oppinion. A boat looks simple. But its (again in my opinion) quite a complex shape with all the small corners...
Usualy i would fill the sharp edges first with carbon roving and thick paste.  But now im trying to infuse it directly.

I might be better off putting some roving in the corners first. To give less sharp edges to the fabric

Edited 6 Months Ago by jeffrey bres
jeffrey bres
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Hanaldo - 4/13/2021 9:38:44 AM
The bubbles in those last 2 pictures are not a problem. They will be due to what appears to be a slight amount of bridging, which is where trapped air liked to collect.

100 point sir.


It was indeed bridging.  Beween gel and the first layer.

A few points that was.   And unfortunantly they didnt fill up. And there it cracked unrepairible (to sell).
Is it helping to place the miuld vertical? And feed at the bottom? I dont know.   Just thinking out loud...



So. I learned again.

Any tips on getting bridging out of my picture?
Or at least avoiding the air trap?     Must i slow down on the resin feed or do i have to put something in the corner or both.    I am sertainly going down to a 6mm resin line instaid of 10. To slow down the resin imput. And make sure it takes longer to infuse. 

Idealy i dont want anything to be visible in the shaper corners exept carbon.. Now im trying it but it would be nice to acutaly doing it.

How can i avoid the faults i created.  I had a perfect vacuum. Im sure. No leaks.    No white bubble finish this time. 

Edited 6 Months Ago by jeffrey bres
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