Deck laminate and vacuum infusion, final episode.

I got help from a young colleague and he was able to close enough leaks to get some pressure so I could find the rest of the leaks with the ultrasonic leak detector. It took me the whole Saturday to finish with an absolute pressure of 260mbar and a 100mbar pressure drop per minute. Very disappointing and it brought me to the end of my rope. Time for a good night rest and thinking about a plan of attack for the next day (Sunday) My goal remained to finish this infusion at the end of the weekend, it has to happen.

Inside leaks

Inside leaks

After a good night rest we went to the workshop together with my wife and son who will help me with their good ears to at first resolve the still remaining leaks and second to assist me with the infusion.



There are two suspicious spots. At first the bottom of the deck hatch, it looks like it is sort of porous. I cannot find the leak but can hear the flow of air. Now this is in the direct vicinity of the vacuum port and I decide to accept it this way. Second is the beam flange at the port side. It is the same area where I had problems with air leakage during the infusion of the hull bottom, despite my precautions I’ve taken in this area. It seems to be not enough so I decided to open the bag and to try to make some repairs with tacky tape. The air leakage is coming from inside but there it is not possible to locate where it comes from. After the bag has been closed – not an easy job – it appears that the repairs are not of much help and it seems like the air leak has moved. In a last attempt I opened the bag for the second time to paste a piece of vacuum film onto the beam flange. It is the last attempt, the vacuum bag would not survive a third time. Now there is a little improvement, but it is still leaking somewhere. I decided to accept it and inserted an infusion needle in a strategic position through the bag and into the peelply. I connected a vacuum tube to the syringe with the intention that this by-pass sucks the unwanted air directly so that this air cannot pass through the laminate.

Repairs and by-pass infusion needle on beam flange port side

Repairs and by-pass infusion needle on beam flange port side

With these two spots of air leakage a high vacuum level is not possible anymore. Normally in my infusions this is an absolute pressure of around 25 mbar. For the rest of the bag I am pretty sure I did all the possible things to get an airtight bag. However, there is still a 100mbar pressure drop and we cannot find the source of it. Very frustrating.

Vacuum pump and resin traps set up

Vacuum pump and resin traps set up

I decided to start the infusion and to use the the resin flow to detect the leakage. Well, after opening the valve, that was not necessary anymore. Immediately I saw a lot of air coming through the ballvalve into the resin tube. Thus the valve and/or the connection between valve and tube was the malefactor. A little bit of tacky tape around the valve and tube and the whole problem was resolved. Wow, what a stupid detection. This leakage was to big to be detected by the leak detector and I had forgotten to ask my wife to hear for leakage around the ballvalve.

Air leakage ballvalve repaired

Air leakage ballvalve repaired

From now on the rest of the infusion went flawlessly without any air and with an absolute pressure of only 115 mbar due to the other two harmless leaks. Quite a relief.

While the auxiliaries went home I kept control over the cure of the resin till it was sufficient gelled to leave it alone.

Succesfull vacuum infusion

Succesfull vacuum infusion

All in all, despite the bad start, and a small incident with a collapsing resin trap, it was again a successful infusion.

Collapsed resin trap (my own fault)

Collapsed resin trap (my own fault)

And I made a youtube film of this succesfull event. Enjoy 🙂


10 Responses to Deck laminate and vacuum infusion, final episode.

  1. Cliff Walker says:

    Hi Henny,

    Sounds like some nerve wracking moments, but I am pleased the end result was fine!

    You were lucky with that plastic resin trap though, as I have known of plastic resin traps to melt completely, resulting in a complete implosion. The end result has been total loss of vacuum on the part and instant destruction of the vacuum pump. Plastic resin traps are OK, but only if the collected resin volume is small, or if they are emptied before the exotherm starts.

    Just a small word of caution to your many followers!

    All the best with the remainder of the project …

  2. Fram says:

    … And this is exactly the reason why I installed multiple resin traps, being able to change over to another one in case there is too much waste resin and an exotherm reaction is to be expected. In this case I was sitting near the boat, waiting for the resin cure, but worked on my laptop and forgot all about the resin trap. I waked up from work by the toppling pvc pipe and a quickly loss of vacuum, but was able to restore the vacuum within seconds. Pfff.

    • Fram says:

      Oh and forgot, dear Cliff, keeping your Vacuum Equipment and resin trap in new condition 😉

      • Cliff Walker says:

        You are forgiven Henny!!!

        Yes, vacuum leaks can be extremely frustrating, even after 25 years trying to find them. If really, really desperate, try opening the bag and putting sugar inside – then watch where the ants crawl in. Not a true story, of course, but sometimes it seems like the best solution ….

      • Not so much ants in NL. But what we can do is toss some money under the bag, then see where the politicians crawl in…:)

      • Cliff Walker says:

        Well there you are then, in temperate/hot climates, use sugar and ants. In both hot and cold climates use money and politicians …

  3. Herman says:

    Also for the followers: I once had a leak in the vacuum gauge used for pressure drop testing. Try finding that leak!

  4. Fram says:

    When I started this project I was very worried about getting an airtight vacuumbag on just a foam hull(part), in the expectation that this was the hardest part of the infusion adventure. I made six of them without any problem and was still in the expectation that infusing an external laminate on a hull(part) with an existing internal laminate would be much easier due to the airtight internal laminate (it’s not). OK, both external float laminates went also flawlessly but for the mainhull I’ve experienced the opposite and have had a headache of the two latest big hull infusions (bottom and deck) Anyhow, it’s done now and with a superb result. I’m happy 🙂

    Anyone who may think I’ve become a specialist in leak finding I must dissapoint. I’m not, I’m really not, I’m not patient enough, much too restless and therefore depending on help from others, preferable someone with patience, perseverence and a good hearing.

  5. Grindys says:

    Well, you did an extremely hard work, amazing!

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