Hello, can anybody let me know if there is another way to close the bag when using the vacuum bagging mode?
I usually use the butilic sealant, the black one, but I’m looking for another way to seal the bag.
Thanks for your help.
Alessandro
I’m looking for the same thing, and I’ve came up with a number of ways to try this, although disclosure: I haven’t tried them yet.
1: Vac table. When looking at vac tables, they have the bag suspended in a frame that is then lowered over the part, and a gasket creates a seal between it and the table. Most use a bolt ever few inches to ensure a complete seal, which would be time consuming for replacing. I have been looking to make a modified frame that would be the same principle as a window screen. Lay the bag over, push in the spline, and throw it over the part. That way, you’d only need to bolt/clamp it down in a couple places.
2: Heat seal the bag. Lots of issues with this, especially if you’re doing diy without the proper equipment. Big risk of not sealing completely in areas, especially with larger bags. Plus, it’s time consuming and awkward to seal the final end. Still looking at it though, because if I can make a heat sealer for cheap that will do it effectivelly, it may be the fastest method.
3: HH-66 glue. Takes 24 hours for poly bags and needs the edges cleaned, abraded, and clamped, but works well. problem is, you probably don’t have that long to wait to seal the final edge. what you can do is premake some bags on three sides, leave the 4th side open, slip the part in, and then use the standard butyl tape or a quick-lock seal (check out ACP for this one) for the final edge. Never used the quick-lock seal, so don’t know how it works if there’s creases in the bag.
- Smooth-on or similar silicone bag. They’re reusable, convenient, and durable. Problem is, unless you’re making several of the same part, it’s pointless.
If anyone else has ideas, I’d love to hear too.
Thank you for your suggestions.
I will try to seal the bag heating it (it was the 1st alternative way in my mind to the butilic tape), in the meanwhile I got again the butilic sealant, the grey one
I’ve been using quick lock seals from ACP for years. When envelope bagging with poly bags, it’s the fastest, cleanest, cheapest, easiest thing I’ve ever used to seal my bags. Keep in mind, the bag cannot have creases though. They will also custom make the lengths for you if you need anything longer than 70".
Thanks for the info 
A few days ago I also had a look at a Leroy Merlin commercial centre (they are common in many european countries) where I saw a profile like that, but I was not sure if it was good enough to “follow” the bag when air is sucked from the bag itself.
Do you know if ACP can ship worldwide?
Alessandro
If it is just for vacuum bagging you can use acrylic sealant from a hardware store or just duct tape.
When you say “duct tape”, do you mean the one used by electricians?
I have this, and it also has a butilic base
When you say acrylic sealant, I looked it up, and it shows either spray or a caulk tube. I’ve never tried it, but it seems as though it would be too thin to use with good results.
Also, while I can’t speak for everyone (and I know I’ve seen some crazy methods for composites before), I don’t see how duct tape would create a good seal, although I’ve never tried it myself other than to seal a small hole.
Any particular method or insight to using these effectively, and any truth to my concerns from your experience?
Duct tape wouldn’t give a great seal, that’s why you would only ever use it in a process like vacuum bagging where you generally don’t want to pull full vacuum and you can leave the pump running to maintain it.
So, is the butilic sealant the only way to have the better seal?
Both are only for wet layup and vacuum bagging! For prepreg and infusion only use a good butylic tape for composites!
I work using vacuum bagging, so I will try to use both.
Thanks
For wet layup and vac bagging duct tape is fine. It does not has to be perfect tight for bagging. The Acrylic works quite good, here in Germany it is in a caulk tube like silicone and has a good consistence.
I know some people that also use it for infusion, but I would not do that.
I always use a butyl tape for infusion, but take care, there are good and really bad ones you can buy. My favorite is the AT200 from Aitech, but it is only good if you have above 20C°.
Thanks for the info. Here in Sicily the temperature is more than 20°, so it would not be a problem 