Vacuum Molding With Kitchen Materials

Vacuum pumps are powerful tools because the atmospheric pressure on our planet’s surface is strong. That pressure is enough to crush evacuated vessels with impressive implosive force. At less extreme pressure differences, [hopsenrobsen] shows us how to cleverly use kitchen materials for vacuum molding fiberglass parts in a video can be seen after the break. The same technique will also work for carbon fiber molding.

We’ve seen these techniques used with commercially available vacuum bags and a wet/dry vac but in the video, we see how to make an ordinary trash bag into a container capable of forming a professional looking longboard battery cover. If the garbage bag isn’t enough of a hack, a ball of steel wool is used to keep the bag from interfering with the air hose. Some of us keep these common kitchen materials in the same cabinet so gathering them should ’t be a problem.

Epoxy should be mixed according to the directions and even though it wasn’t shown in the video, some epoxies necessitate a respirator. If you’re not sure, wear one. Lungs are important.

Fiberglass parts are not just functional, they can be beautiful. If plastic is your jam, vacuums form those parts as well. If you came simply for vacuums, how about MATLAB on a Roomba?

Thank you [Jim] who gave us this tip in the comments section about an electric longboard.

14 thoughts on “Vacuum Molding With Kitchen Materials

  1. Acutally you can decrease the effort of applying the resin by hand, using an infusion technique[1,2(is also applicable to fibre glas)].

    Therefore, you need a resin reservoir attached to the form on the far side of the suction port(s) (multiple ports = better air travel), that reservoir can be open to the atmosphere, but needs to be filled with enough resin or clamped[3] so the vacum doesn’t suck in bubbles.

    The suction pump must not be attached directly to the suction port, you need a trap for the resin. Which is basically a seal tight bucket with an inlet and an outlet port. Air can be sucked and resin gets trapped not getting into the vacuum pump. I haven’t noticed that in the video above.


  2. 1) You laid the fabric’s in the wrong order. Coarse fabrics go on the inside, and fine threaded layers go on the outside.
    2) The fabrics should all be cut to shape first, (if possible) to save time.
    3) Use epoxy that cures in one hour, not less to allow for the unexpected, and the suction won’t work on epoxy that is hardening, you want the epoxy to flow around the part.
    4) Paper towels don’t provide enough of a proper air gap around the part, use a thick felt material a that allows for reliable conforming around the corners and insert edges.

  3. No room for hate in this forum. Yes there were mistakes made with the materials, and yes at times it was hard to hear what he was saying due to a few different factors. This is how we all learn, by making some minor mistakes. I agree with comments about how the materials are layed out but it could have been delivered a bit differently. I say, well done sir. Your video was fun, informational, and your demeanor and delivery were perfect. Your video was entertaining and also educational. Don’t worry about some haters they lurk in every corner of the internet. Keep up the good work. If I had any constructive criticism it would be to speed up the repetitive parts a bit more and slow down the detailed parts of your future videos. Again, thank you for posting.

    1. There’s a huge difference between hate and that sort of indifferent ‘racism’ (for want of a better word). Not that it matters to a cause fascist, any excuse will do for them.

  4. I like the video and don’t mean to sound unappreciative that he shared it with us but this is a great example of one reason I miss the days when people used “written” webpages to share information rather than videos.

    He did a great job of showing us all the steps involved but… it’s still going to take a lot of Googling to do this myself. Why? Because what the hell is “pill pack”? (the stuff he put between the outer glass mat and the paper towels) I can’t tell what he is saying!

    No, I’m not saying anything about the way he talks or the quality of his audio. New words are hard to learn by voice. The sounds of many vowels just aren’t that different. When we know the words our brains just fill in the gaps and we don’t even notice it but when we try to listen to a word we have never heard before it is very hard. Most new words spoken without any written context just sound like a mishmash of random vowel sounds all blended together. It might as well all be Marklar.

    With construction videos this matters because.. if you want to do whatever you are watching yourself what tools and materials do you buy? If you want to buy it online what do you type in the search box? If you want to buy it in a store then what do you ask for?

    The fact that today we can just go to YouTube and actually watch somebody do the thing that we want to learn is awesome. Video is a great medium for use as a supplement but it really sucks as a primary method of instruction. Unfortunately it seems like the trend continues. I haven’t actually counted them but it seems like more “articles” here on HaD are really just summaries of videos with little to no actual written article. No, I don’t blame HaD, I suspect that is just a reflection of what people are producing.

    1. I usually just click on the “CC” on the bottom of the Youtube video. This enables “Closed Captioning”. It should help you with underdstanding “the mishmash of random vowel sounds all blended together” that you are hearing :-)

      1. Hmmm.. I probably should have tried that for this specific video. IF someone who knows the words happened to volunteer their time captioning this video that might have answered the question. For many Youtube videos this never happens though and a computer algorithm interprets the sounds even worse than I do!

    2. Old ears, I’ve got them too☺️
      I love his attitude and really appreciate his sharing the video. Board is looking nice and he’s testing and looking for ways to improve.
      Great job! It makes me more likely to try the vacuum bag/ trash bag approach. I’ve stayed away from fiberglass because of the air bubble problems. Maybe I just wasn’t putting as much creativity in the process as I was trying to put into the result.

  5. This is a free video made by a person who put in the effort to learn English as a second language well enough to produce content. He has also answered a question about the vacuum motor on the video comments which makes it very plausible he would answer your question as well. If you just said what is the material he uses at 6:30 there would be people happy to answer the question.

    Me unhappily answering your question.
    Peel Ply

    Also a website entirely devoted to written tutorials.

    1. I assume you were replying to me although you missed that thread.

      “This is a free video”
      Yup! That’s why I wrote this: “I like the video and don’t mean to sound unappreciative”. I would never say there is anything wrong with someone sharing things via video. After all, nobody is obligated to share anything at all! My issue is with the overall community trend.

      “put in the effort to learn English as a second language”
      Awesome! He did a good job of it. I could hear that he was from a different area than myself but I still thought English was his first language.

      Criticizing his diction wasn’t really my point though. His speech was plenty clear. I went out of my way to describe the fact that is is specifically hard to learn NEW words from audio only. This is true regardless if speak and listener are close family that grew up together or people from different continents speaking second languages. Human languages have many sounds that are hard to differentiate. The process of interpreting sounds as speech always involves a lot of filling in of blanks using context even if it only happens unconsciously in the brain. When a word is new there is no context.

      My point was not to complain about one video by one person. Like I said, I liked the video. My point is the trend in the maker & open source software/hardware communities to share information via video instead of writing sucks. I only pointed it out here because I saw it as an example of one of the reasons why.

      Further reasons.. text is indexable but video is not. One can skim text if they aren’t sure whether they are interested in the subject or not. Text is easy to reference, especially if it has an index. If you already watched the video once but aren’t clear on one point it is a lot harder to go back and find that point than it is to just hit Ctrl-S and search a piece of text. You can also take notes by highlighting and copying.

      Yes, I know about instructables. I usually find the content more interesting on HaD, even if I do prefer text articles which are still more common over there. Besides, even instructables is starting to be invaded with Youtube links. Also, I don’t doubt that I can ask a video author a question. That’s still not as good as the “old days” when I would have just been able to read it from the original article.

      10 years ago one would have seen something interesting in HaD, clicked it and the words would be right there. Now one watches a video but if you actually want to do it you still end up having to find and read a written article to get these kinds of details.

      I fear that one day written articles will be rare. Learning something new off the internet will involve watching a video over and over and over again because it is too hard to find the part where that one detail is mentioned. Learning things like the name “Peel Ply” will require posting on a forum somewhere and waiting for an answer.

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