CHEAP/ Easy Vacuum Bagging

I was looking for wax paper and accidentally stumbled across Ziploc Brand vacuum bags. I found a "starter kit" for $3.47 IIRC and there were additional boxes of one quart bags for sale. I picked up the starter kit to try vacuum bagging fiberglass onto 3 rocket fins.

I know you need a non-stick release paper, and an absorbing layer on top of that so here's what I came up with:
I folded wax paper in half and poked LOTS of holes into it with a needle

I then folded paper towels into 4 layers thick and used freezer tape to hold the them in place, with one sheet on top of the wax paper and one sheet under the wax paper

I got three of these wax paper/paper towel sets prepared to go with the three vacuum bags that came in the "starter kit". I then cut the six pieces of fiberglass a little bit larger than the fins, with on piece of cloth on top of the fin and one piece on bottom of the fin. I then mixed up the resin and brushed it onto the rocket fins and layed the precut cloth on the top and bottom of the fins. I layed the fins inside the wax paper/paper towel set and placed that into the vacuum bags. I used the handy vacuum pump to suck out the air leaving a pretty tight bag around the part

I let the fins sit for about an hour and pulled them out. The finish had some tiny air bubbles, but this is by far the best, flattest, lightest glassing job I have ever done. The glass weave is crooked, but I wasn't after looks with this set, it was a proof of concept test.


For reference, the fins are 4.5" at root, 4.5" tall and 2.25" at tip. Double layers of 3mm plywood glued together with Elmers glue prior to glassing. Next step will be to sand the airfoil profiles into the fins and I will probably re-bag them to add fiberglass over the sanded portions. I should have sanded them first, but I was so excited to try the bagging process I got ahead of myself.

SO, if you have ever wanted to try vacuum bagging your fiberglass parts to save weight and maximize strength, this might be your ticket!

I will be happy to answer any questions.

Is that the vaccuum pump you used in picture #1?

Yep. You push the plunger down, hold it over the circle shown on the bag and pull up on the lever. Repeat 5 or 6 times and the suction will be pretty good. Very simple little setup but it works well.

So where did you find this Ziploc kit?

etoyoc said:

So where did you find this Ziploc kit?

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I found this kit at Walmart.


Project Update:

Last night I sanded the airfoil shape into one of the three fins. I put pencil marks at 1/4 of the root length and 1/4 of the tip length and connected these marks with pencil lines. I then the marked the centerline along perimeter with pencil lines. I then sanded with a belt sander from the 1/4 pencil lines down to almost the centerline of thickness. I left the fins about 1/16 thick along the edges and will lay another layer of glass over the whole fins. I will take pics and update.

I've never done vacuum bagging, but I definitely want to learn the technique. This solution is just so cheap that I think I'm going to give it a try. Thanks for posting this, and I look forward to seeing your future pictures.

Nice find!

That`s pretty cool and very clever ,I`m going to try that.


Thankyou !


Paul t

Thanks for the idea...wish I had thought of it...

Great idea! More pics?

Thanks for the kind words, guys. I appreciate the feedback. I sanded the aerofoil shape into the fins and added a second layer of fiberglass using the same three ziploc bags and pump. IMO two uses is all they can handle, but they are so cheap it is still a very economical solution.

As a tip, I found I could pull a better vacumm by pulling the plunger up and holding the pump in that position for about two seconds. The bag would slowly shrink around the fin. Repeat the pull/hold pumping until you hear air leaking around the rubber seal on the hand pump. You will have a very nice, tight seal and vacuum at that point.

BTW, the rocket fins are now mounted on the tube, epoxied into place and strengthened with tip to tip fiberglass. As soon as humidity drops a bit here in Louisiana I will prepare next batch of KNSU bates grains and hopefully launch before Christmas.

JohnCoker said:

Nice find!

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Thanks for the compliment. I decided to make these "Nike" fins after watching your Nike Fins video.