How To Find, Fix, and Avoid Leaks in Vacuum Bags
Project page for further info ►www.easycomposites.co.uk/lear...
Vacuum bagging is an integral part of many composites manufacturing processes, including prepreg, resin infusion and conventional vacuum consolidated hand-layup but getting vacuum bags to seal properly and reliably can be difficult and frustrating, especially for those relatively new to the process.
In this video tutorial we use our many years of experience of vacuum bagging to go through all the possible causes of leaks in vacuum bags, how to avoid them in the first place, how to test for them, how to locate them and how to fix them. We will also discuss when to give up and make the decision to re-bag a part.
Most of the tools and equipment used in the tutorial are available from Easy Composites and are listed on the video's Project Page in our Learning Area:
UK and World ► www.easycomposites.co.uk/lear...
EU ► www.easycomposites.eu/learnin...
These videos are like having a dad or granddad learning you all the smart hacks in the trade. This is one of the most important films you have made. Kudos for not only creating fancy videos for chasing views, but genuinely useful ones as well.
We aim to make our videos informative as well as show casing products, so sometimes it is better to have an instructive video rather than one specifically focused on a product or process.
must have been hard creating those mistakes on purpose to make this video while being experienced sealing bags :D thanks for the great video!
Haha, thanks Matt. Well, even the best of us still make a few mistakes so it wasn’t too hard!
This video won’t get the views, but it’s probably the most important/useful video yet of this incredibly educational channel. Thank you EC!
Glad you like it. We are well aware it may not have the universal appeal of some of our other videos, but the very specific topic will be highly appealing to many people doing vacuum bagging based processes. Although not high in numbers in youtube viewing terms, this video has a high value to those needing this very specific advise.
An important thing to add while using a digital gauge is that moist in your lay up might cause a 'vacuum leak' as water is boiling under vacuum causing the digital gauge to raise over time. you might think you have a small leak, but everything is fine
Hi Matthieu, that’s a very good point and is indeed something that forgot to mention in the video. Depending on the reinforcement, the effect can be quite pronounced so yes, that’s a good point.
Very goog point 👍
what kind humidity would cause that sort of problem?
@@millerchassis6119 The digital guage is very sensitive and when you consolidates your reinforcements the humidity in the air can get soaked into some materials like flax and wood if you lets say use balsa as a core material. so in these cases you need to have the vaccum pump on for a much longer time to make sure the digital guage is stable before going on to infuse your resin.
@@NiclasGudmundsson cheers thanks for the tip.
The only one channel that I'm waiting for videos. Thanks for your work and WE NEED MORE VIDEOS ON CHANNEL!!! At least 2 on month.
We would love to produce more videos, however we produce the videos alongside the other parts of the business and they take a long time in terms of research, filming and editing which is what becomes the limiting factor in many cases.
The stethoscope trick is genius. I bought a cheap one and I'm letting other people in the shop use it. It was taking me forever to find any leak whatsoever. It's a great teaching tool because you can look at that area and figure out why it didn't seal. It's hard to hear very small leaks if it's not quiet in the room, but larger leaks that make the vacuum drop within a few seconds are clearly audible. Don't be fooled by what sounds like a vacuum leak near the port as if air is getting into the bag, that port is sucking it out which won't be silent.
This definitely is the best composites channel on KZhead , great job guys
Glad you enjoy it!
Thank you very much for passing on your knowledge! I was looking for a channel like yours for years. I hope your effort is rewarded with lots of happy customers.
Thanks Anton. I like to think it is but we really do enjoy making this content and sharing our love of composites 😀.
Paul making a bad bag like a 4 year old cracked me up 🤣
you guys are really doing such a good job with these videos.
I know Ill be watching this again down the track. Awesome work!
You guys made an excellent job again. I can't said enough how grateful i am for the information what you gives us (for free). Soo thank you so much Easy Composites.
It really is our pleasure to make them so thank you for watching them :-)
Man this is a super duper awesome video tutorial thankyou for sharing your knowledge with the world for free
Another great and thorough presentation……I’m closing in on the time to try this out !
Great tip about pulling and stretching the tape to get rid of creases!
Excellent video and fantastic information provided with very clear do and do not examples. Your explanation on pleats is the best I’ve seen. Thank you!!!
Glad it was helpful!
As usual good, comprehensive and right explanation! Thanks!
Thanks Abror, appreciated.
@@easycompositestv Pleasure is mine!😉
This was TRULY THE BEST VB Video I have seen ... have waited for this for like ages. THANK YOU 💗💗💗💗
And thank you for watching and giving us such great feedback Neville - this genuinely makes us want to keep making more :-)
Another superbly informative video as we have come to expect. Great job.
Thanks a lot 😀
Thankyou Paul, very interesting. I'm still very much in the learning stage and find your videos to be brilliant!
Glad you found the video useful Tony!
Thank you so much for all of your awesome instructional videos!
Thanks for watching!
Great topic and info as I have found leaks to be one of the most frustrating things.
Hopefully the video will assist in limiting leaks, they certainly are frustrating!
You are so right, for my small hobby (RC) projects, I always find it to be very very difficult to get my vacuum-sealing anything close to perfect. Totally perfect has not been achieved by me yet 🙂
For small parts you can use roll bag as a vacuum bag. Just cut long enough piece, fold one end and use iron to seal it (through baking paper).. Finally seal other end similarly
As always 10/10. What a great company.
Appreciate the really kind comment!
Would be great to see a tips and tricks video like this about bonding composite parts, adding studs or nut plates, etc.
This may be a subject we cover in the future either on its own or as part of a project.
thanks for these advices.
Great stuff mate.
A lesson I´ve learned from working with composites as a Formula Student engineer the past two years: Don´t use old sealant tape that has lost its tack. We had some sponsored tape, which had expired over a year ago when I started - now that we had to buy new rolls I don´t ever want to go back. But don´t be mistaken - new sealant tape can also be too tacky and make it difficult to fix any missalignment with the bags perimeter. When using such tape I would advise to use it in a climate controlled room as warm weather can make it nearly impossible to work with it.
Indeed. I got a box of 20 “discounted” tape rolls from eBay, and it would absolutely not work, too old.
Some freeze spray can be used in warm/humid envirments to get BST to release very easily to fix a misalignment
One more tip: In case you´re using a vaccum hose for your drop test - don´t clamp it right next to the bag. Place it at least 10cm away from it. This way you can clamp the line a bit closer towards the bag after you´ve performed your drop test. Clamping (cheap) polyurethane vaccum lines damages them - this can cause a leak, which you would include in your system otherwise. I wouldn´t recommend clamping down on the same spot more than once as it will damage your line even more - making the leak worse.
Thank you for what you do we need you in the USA
much appreciated guys. great video!
Glad you enjoyed Michal!
I did a wet layup just yesterday, on a small part of a larger mold. It was extremely difficult to make it leak tight, and in retrospect i should have simply watched this! Thanks for the information, i will definitely use it in the future
Don't worry so much about leak proof an a wet layup. As long as you can maintain compaction pressure through b staging of the epoxy system you will be gtg. The only time it is a problem is if the leak is coming through your mold inside of eop and pulling air through your part
Paul, I should have sent you the bloopers clips as I think I’ve made all those mistakes. Great job
Haha, well, at some point I've made all of them myself. Just maybe didn't get them on video thankfully!
Very Nice video to solve problems i hope you will also make one special for release agents because they make a lot off damage to your mould Greatings Danny
Wonderful clear presentation. You do a fabulous job of being clear and succinct. I certainly should have taken your advice to not chase phantom leaks and just re-bag it more often! I would add I'm curious to see your take on ultrasonic leak detectors. I've had mixed experience with them; especially lower cost ones. I couldn't identify the one you used.
The one used in the video was a prototype being tested. We also have mixed results with the detectors so generally do not use them that often.
Thank you very much for this informative video.
Appreciate the kind feedback!
@@easycompositestv hi, is it possible to order vaccum bag equipments from India? Is there any supplier here in India?
@@AkashDeep-st6ms I'm afraid we don't have any distributors or dealers in India sorry.
#1 Always order by the roll - I'd say that an easy 95% of all the leaks that I've ever had have been from folded stock.
I used to do composites as my day job. The parts we were manufacturing were quite large (somewhere around 4 meters long), so the bag had to be folded at least a little for staging and transport between the cutting and layup areas, but we were always very careful about how we folded the bags and scrap very rarely got used for bagging anything.
@@reaganharder1480 yeah its unavoidable between processes sometimes - I do a lot of enveloped bags too, so you have to fold. The problem is when people fold for storage; even under it's own weight most bagging film will distort/press the folded edge... I once had a supplier send 7mx2m precut bag folded down to an A2 size stack. I spent half of that night chasing leaks 🤦🏻♂️ that was the last time
Iv just spent the last 4 years learning all this with trial and error and error again! And now you make the video 😂
Ahhh, sorry about that! If it’s any consolation, we had to learn all this the hard way too, just more like 20 years ago. From the results you’re getting on your channel though, looks like you’ve really got a good handle on it now though. We enjoy watching your content 😀.
@@easycompositestv Thank you 😎
Thanks for that, I have even gone to double bagging to overcome a leak on a tricky part, works well. Would have liked you to explore issues on split moulds too. I struggle with seals on bolted up moulds.
Envelope bagging is a good solution where split moulds are concerned.
@@easycompositestv true but the bolts and edges cause possible bursts. I have found the best thing to do is countersink the bolt holes on the inner faces and line the holes with baging tape, rather like o rings. I also tape the perimeter. Usually gets me to 90% and that is fine with quick resin.
Great video as always! A ultrasound bat detector also makes a handy leak detector.. 😉
Indeed. We might do a bit more on options for Ultrasound devices in a future video.
J'adore ce genre de vidéos avec des explications de base qui nous pause des problèmes. Merci à l'équipe easy composites et bonne vacances.
Content que vous ayez apprécié la vidéo Jean!
Very cool video thank you !! 🎉
Glad you enjoyed!
Thank you
I wish you guys could do a video on making an EPS core
I love all these Easy Composites videos and I'd really like to try some of these techniques. I'm in the US. Do you have any suggestions on suppliers for this side of the Atlantic? Thanks for another really interesting video. I feel like these videos are more entertaining than the subject matter would suggest. I always enjoy your videos.
Hi Duane, glad you enjoyed the video! We unfortunately don't have any suggestions in the US, although we are able to ship to the US and do so on a daily basis.
We do not have any suppliers in the US.
Thank you for sharing 🎶 😀 🌸
Thanks for watching!
I've done a few infused tubes using envelop bags, maybe it's not ideal, but if the back of the mold is nicely treated (sand smooth and demoulding wax), there is only a few "resin creases" that will easily come off, and gotta remember to put some plasticine on the bolts that secure the two halves together, on the threads and on the head.
I have a "walker game ear" its headphones that amplify ambient noise can hear the leaks with it. Also I heat up the butyl rubber as it sticks and is more pliable ductile as opposed to being cold.
Love the video as always! Any update on when the clear-coating carbon fiber video is coming out? I need to fix some handmade parts on my car and I want the clear-coat to last this time around.
Hi Bryce, not quite sure when the video will be uploaded but it's certainly in the pipeline!
Absolutely chuffed to see there's a supplier of your products in my country, I'll be working on making various forged carbon bits for a BMW E36.
Great news, where are you based?
I’m making a e36 gtr , full body , front clamshell , roof and rear 1/4 etc , rear diffuser . I used these guys for carbon and resin etc . I would regard myself as knowledgeable and experienced but still find these videos useful . What’s so nice to see is the comments posted. If only the majority of the world appreciated the actual difficulty processes like this are hard to do . What a lovely company to deal with . Merry Xmas 🇬🇧
@@newagetemplar6100 Thank you! Have a Merry Christmas too!
Hi, I wonder if you could make a KZhead video of how to repair a hockey golie stick? I don't know if this is the correct forum to ask this but I give it a try
Can you share the the best way to seal a two part mould for vacuum infusion (it’s for a wheel guard)
Envelope bagging is the most reliable method as it rules out sealing issues on the mould.
Can you do a video making a track spoiler?
We hope to over this in a video in the near future.
Hi there, couldn't find the Vac Checker product spotlight you talked about at 24:11 on your channel. Could you post a link to it? Thanks!
Sure, its here: www.easycomposites.co.uk/vac-checker-digital-vacuum-gauge
Can you make a video discussing silicone vacuum bags? I am making tooling for silicone bags, but I'm mostly guessing and hoping it works! My tests so far have worked great, so now I'm working out how to design production tools to use silicone bags. But there is almost no info available. I mean, I found 1 video by Smooth-On....
It might be a topic we look at in the future.
Can you guys do a video on an easy way to make lightweight race car or airplane carbon wing elements
We are hoping to cover something similar in the future.
Can you a video how can you make a freediving fins?
Hi Mohammed, thanks for the suggestion. As it happens, we are working with a customer at the moment to add a technical article about free diving fins to our website. At first it won’t be a video tutorial but it sounds like you would find it interesting. Keep an eye on our website and social media for more info on it when we publish it.
@@easycompositestv thank you so much for you work.
Amazing video! I feel ready to take the plunge and try my hand at vacuum bagging. Do you sell to United States customers? I peeked at the site and did not find a vacuum pump for US electrical outlets.
The vacuum pumps are 220V only.
Would it be best to store vacuum film in a cupboard of some sort so it doesn't degrade from light?
In general use, storage indoors is not a problem in terms of light degradation so a specific cupboard would not be necessary.
With resin infusion i have found that if you have a very tiny leak you can go ahead with the infusion and as the resin passes the area of the bag that is punctured you can see it sucking in the air as you get bubbles. Simply apply some tape to the area and problem fixed. I would only recommend this method if needle on the gauge has only moved a slight bit after around 30 mins.
You still risk air in the laminate with that method but it is a good fix to avoid completely ruining an infusion that is in process. Ideally always fix leaks before the infusion.
@@easycompositestv if the leak is small and you catch it fast enough, the air may not make it past your flow media (assuming you've used a flow media in your layup. I've never done an infusion without, but I also have only done infusions at work and most of that was very large parts).
excellent video as always. guilty as charged, yes i just go ahead and make the part when there is a small leak, i find the leaks impossible to find at times and makes me angry and impatient.
Hopefully this video will help you make bags with less leaks.
@@easycompositestv i'm sure it will help. i'd like to try pre-preg next seems less stressful than resin infusion
I am not an expert but when you were mentioning about the bolts and nuts as a part of the mold. What would you say, if we use some amount of seal tape to smoothen out the edges + breather cloth to give a better surface and avoide tearing of bag.
Anything that helps smooth edges is generally fine as long as it doesn't impinge on the basic composite process.
hello, I would like to know in percentage terms how much the largest bag of the mold must be. thanks
There is no percentage term. It needs to be physically big enough to cover all the surfaces with no bridging. That will vary with shape and depth of mould so you must decide each time.
Can you make a video showing how to make a carbon fiber sandwich structure with a honeycomb core, both with prepreg, hand layup, and resin infusion
Sandwich structure construction is a topic we are hoping to include in a future video.
Where can I find a tube clamp like yours?
We have both our regular line clamps and the fancy DDI Compound ones on our website, just search “line clamp” on our site 👍
Sometimes it can also be easier to put the sealant tape on the bag first. I'm doing this on my mold that isnt flat for most of the parts. When I have put my bag on the mold i gently push the tape towards the mold to get a seal, but after drawing vaccum I think it's better for me to go around and pushing and rubbing my thumb in a 90 degree angle towards the tape to see if the inside part of the film lifts up from the mold, if it's doing that you got a leak close by. Air will always take the easiest way, so if you have a bridging just inside the sealant tape and the mold, you will have a leak in the vicinity.
Thanks for the suggestions Niclas; it’s always interesting to hear different people’s techniques.
Depending on the size of the part this can be really good. I did composites as a day job for a year and as I recall one or two of our smaller parts we put the tape in the bag first. Granted, our big parts were like 4 meters long, so what counts as small in my mind is a bit different than the average hobbyist, but yeah... a bag for a 4 M part is far too unwieldy to put the tape on the bag first.
@@reaganharder1480 Yes a part that big is a bit hard to work with. But I normally use vaccumbags around 1 square meter and on those I always put the sealant tape on the bag first. It is very easy to seal the bag then because the pleats dont need to be added becasue you already got them on the bag.
@@NiclasGudmundsson Having pleats be as simple as "fold the bag and press it down" really is a big win when the part size allows it. Almost all the issues with creases disappear when you do it that way.
Question/Thought. In your example 2 part mold with the fasteners, would it be reasonable create a filler block made of foam or similar to fill out the depression? (Possible on a mold that's small enough?) Great video as always. I look forward to all of them! Product Thought/Suggestion: As I've only seen it on Alibaba out of China: Foam filled Nomex Honeycomb "Hexcel / Haxcore" (presumably something that would create less resin weight than CoreMat 3DCore Soric etc. Always wondered if it would allow for an infusion with layup on both sides at the same time & minimal need for perforation to bridge the skins with epoxy.....
You certainly could fill the recesses as long as it is a closed cell foam and can with stand the compression and any temperature of a cure cycle if appropriate. Infusion requires a path to the other side of the core otherwise the laminate on the bottom ends up dry. So the design would need to have some holes through it and preferably grooving to help resin distribution.
Im looking to be a composites technician, is there a certain degree/certifications/education I should be working towards?
Very much industry specific and you are best looking at the requirements that these employers are asking for. A general engineering background and composites understanding is useful but many will want specific experience.
A video on how to spray clear coat would be very helpful…
It is something we'll look to cover in detail in a future video but there is a section about spraying and good practices in our Sled-Making video guide.
Do you have a reseller in USA? It is very expensive to buy from uk
We do not have any US resellers or distributors at present.
When we were trying to do a vacuum bag we noticed pumps are leaking a little bit (1 unit in 30 min i guess). Do you think would that be a problem?
The check valve in most pumps is not designed to be 100% leak tight. It is designed to stop air back flowing through the pump quickly taking oil into the vacuum line and bag. For a leak tight seal between the pump and bag, we always recommend the use of a clamp or in line valve for that purpose.
What ultrasonic detector was that?? Cheap ones don't do anything unfortunately.....
The one seen in the video was a prototype one we were testing at the time.
@@easycompositestv oh brilliant! Is that's something your looking at adding to the site?
@@dannoke7393 Not at the minute, it's just a prototype
I have made 3 vacumed parts(yes thats not much), And I have had vacum problems with all three. Besides 2 times when mold itself had leak. I have unknown leaks from somwhere else. Like vacum goes away with 5 minutes. So I made that way- Vacum line is full perimeter of part. Reisin line is in the center of part. So even if there is a vacum leak at the edge, reisin never reaches there and air will never ruin the part. It still holds -0,9 atm or vacum and its all thats needed.
OK, well, if you're managing to get away with 90% vacuum then it sounds like you've found a compromise that works for you. For quite a few process, including out-of-autoclave prepreg and - in a lot of cases - infusion, working with only 90% vacuum will result in either pin holes (for OOA prepreg) or could result in voids (for infusion). It should be possible to achieve that 100% seal, which is why we made this video, be we do understand it can be difficult at first.
Dude you are the best! I hope to see your goods in Ukraine in the future.
Where to buy vacuum valve connector ?
We sell the metal through bag connector here: www.easycomposites.co.uk/tbc2-through-bag-connector
on infused applications another consideration is temp of outside air and humidity of carbon or fiberglass when bagged will cause different cure times and vacuum inconsistences . also found that a bottle of water misted on the outside of bag will help relax the bag so it conforms into the corners of tight areas so the bag will reduce bridging in certain areas, just be sure to dry off the outside a few minutes after spraying and the bag relaxes, if water left on bag it will continue to relax .. on very large car parts i found it useful to do a double bag system where you pulling the resin thru the first layer at full vacuum (always add optional resin in ports every 18inches max) while low pressure on the second bag and as the resin is pulled thru increasing the second vacuum as your part starts to off gas you'll lose your vacuum bag pressure in the areas where your resin is full making for a low compressed part not good. second vacuum makes it recompressed again saving your huge expensive dry layup ... my work can be seen on the first prototype 4 solar charged electric aptera cars hand built by myself. the best car is the ( aptera sol ) with the SOLAR CELLS INFUSEED INTO THE PANELS kzhead.info/sun/iZVwncmPfH2JnKM/bejne.html
I want to make a steering wheel and I was wondering how you would go about that
Would you have to buy a core type thing in that?
There are many different methods. Some are basically skinning over a core structure, some are fabricated from scratch using moulds, others rely on the stripped down core of an existing OEM wheel.
7:05 yep, the first trys of my wife start like this 😁
A timely video for me. Yesterday I made up a vacuum bag and I noticed that I was getting lots of bubbles between the butyl tape and vacuum film - much more than I ever had before. I then realised I had accidentally used butyl tape that I had bought to fit some windows - bought from a reputable glazing company, and having the look and feel of that supplied by Easy Composites. This was an accident but it reminded me of a comment Paul made in an earlier video that it was vital to only use products for vacuum bagging/ infusion. Another thing it’s worth bearing in mind is that fittings (for line from pump to bag) although sold as suitable for vacuum or pneumatic lines might not be fully airtight . I suspect some of my quick connect fittings fall in that category. Anyway great video as usual. Thank you.
Since you have great videos, I will reveal 2 secrets: 1. An ultrasonic bat detector is much cheaper and often more sensitive than overpriced "professional" vacuum leak detectors working on the same principle. DIY construction takes only a few dollars. 2. For vacuum infusion, especially for the production of very complicated parts, it is often advantageous and faster to pack the mold in two bags rather than solving leakage problems 🤫🙂
Good tip on the bat detector!
One thing worth mentioning is that if you get any resin between the tape and the bag, they don't stick so if you do a wet layup and then try to make the bag with the same pair of gloves on, it makes a huge mess
Yes the key is cleanliness during the bag making process to avoid this happening.
Where have you guys been? Keep the content coming please!
We’re producing as much content as we can but we’d always like it to be more!
If you have a dog, train them to detect the leak. After you've bagged your project, just let your dog have a listen. What could go wrong?
when showing those mistakes while bagging, it's me_irl lol
Haha, we’ll, we’ve all done it!
I'm in the first portion of the video (right after you mentioned the reasons for leaks). Can I ask something that I THOUGHT was common sense (thought this BEFORE spending $150 on three different brands of crappy bags): WHY are all of the PRE-MANUFACTURED / retail versions of this product made of SUCH FLIMSY MATERIALS??? No matter how GINGERLY & CAREFULLY I pack/seal/vacuum/store the bags - They inevitably end up losing suction SOMEWHERE... not bc of user error, but bc they're made of plastics that apparently break down, crack, tear, etc. much more easily than they should. Are these...like so many other products these days..."made to fail" so that consumers are forced to buy more?
Certainly not the case. The bagging materials when used correctly are more than capable of holding vacuum, so i would look for any areas of your process that could damage the bag or cause leaks. We very rarely see issues with the bag itself unless poorly stored.
@@easycompositestv Thank you ... but they aren't poorly stored. 😩
Thanks for the tips! Also, avoid long nails, or wear gloves. And don’t wear a watch or a wristband, they can be aggressive.
Thanks Jean-Luc, yes, good tips also!
How can I get blue carbon like what is used on the Pagani Hyatt’s R in this video at 22:55 kzhead.info/sun/naZteayCkHmdgIk/bejne.html or more importantly, how can I get green?
I was going to complaint for that you post new episodes not often enough. Please post more.
We are aiming for one a month. They take well over a week to make so this is about as much time as we can spare for more content but - of course - we’d like it to be more too!
@@easycompositestv I bet it doesn't take the whole week to just film it. It should be possible to film another one while waiting for this stuff to cure. And something simple that doesn't take too too much time to make would also be very nice to see. Something like "look, this is resin and this is colour pigment, you mix em together like this and boom: colourful resin!". I believe an episode per week would pay for itself really well. I'd voulonteer to help you with this stuff, but I live too far away.
Please provide in language Indonesian 🙏
Not so pro tip... keep cats away from your vacuum bag rolls 🤦♂️ Turns out, they really enjoy sinking their claws into fresh rolls. I asked them to stop, and they just pooped on the floor. There's no middle ground with these animals 🤷♂️
if you were hiring a person with no experience but very basic understanding to train and become part of the team what are some specific key things youd want or expect from the potential team member? @Easy Composites Ltd
Hi Michael. Generally we would be looking for people with existing experience or at the very least demonstrable interest in practical engineering or technical subjects. Pretty much everyone on our team here was already interested in technical subjects and generally spend their free time making things, 3D printing, designing, doing electronics, fabricating, etc.., working on cars, boats, DIY... that kind of thing. Our customers are all practical people who get like to get 'hands on', it makes sense that we need the same type of people to build the best team here to support them.