|Cicka house, Christmas Day, 2017|
- Stretchlon 200 Bagging Film
- Low Temperature Release Film
- Breather and Bleeder - 4oz
- Econostitch Peel Ply
- Gray Sealant Tape
- Vacuum Connector
I also purchased a vacuum pump from Amazon and got a bunch of needed fitting at my local hardware store.
There are a lot of videos on the Fibreglast site on how to vacuum bag, but basically you use the Release Film or Peel Ply right against the layup. Then you put Breather and Bleeder material above that to absorb the extra epoxy and allow the air to bleed out of the bag. Then use the Stretchlon bagging film and the gray sealant tape to create the bag. The vacuum connector goes through a hole in the Stretchlon.
My plan was to experiment with the window switch holders for the back doors because I print these out on my 3D printer and if I mess one up, I can easily print another. My plan was to use a table surface for one side of the vacuum bag and attach the stretch bagging material to the table with the gray tape. I wanted the part to be elevated off the table so that the carbon fiber would hang below the printed item, so I planned to use two 3/8" sockets of the same height to elevate it.
I put together my bag materials before I started the layup. I put the tape down on the table, put a piece of masking paper down, with the bleeder breather on top of that, then put the sockets down with the part on top. I then cut the Low Temperature Release film, the breather bleeder that would go on top of the part and the Stretchlon for the outside bag. I fitted the vacuum fitting into the Stretchlon and was ready to go.
My layup consisted of one layer of 3K 2 x 2 Twill Weave carbon fiber, which was the same as I used on the rest of the car. I covered the part with a mix of West Marine 105 Epoxy resin with 206 Hardener then laid the carbon fiber on top. I coated it with more epoxy to make sure that it was well impregnated then moved over to the vacuum bagging area.
I placed the part on the sockets, put the bagging materials on, sealed the bag to the table and then started the vacuum pump. And sure enough, the bug pulled the material down and created a great fit, until I turned the pump off and the air leaked back in! I found it very difficult to create a permanent seal! My guess is that you can't really get a permanent seal with this process. There is always going to be some leaking.
The other challenge I found was that, because I had the part elevated so much, the bagging material would stretch under the part until it popped! I went through three bags before I finally got it to hold. Lesson learned there.
Because the bag would not hold a vacuum, and I got tired of waiting for the epoxy to set, I cheated a little and tied a zip strip along the bottom to hold the bag tight, and put a piece of foam into the switch opening with a weight on top to keep the material pressed in. I would go back occasionally and re-vacuum the bag, just to keep everything as tight as possible. The part turned out okay, but I learned a few lessons that I applied on the next one.
Round two incorporated the things I learned from round one, namely:
- Don't raise the part so far off the table. This time I used nuts instead of sockets.
- There is no need to use breather bleeder on top of the Stretchlon. The Stretchlon is not permeable and there was no problem forming a vacuum on this part
- Check for air bubbles. If any air bubbles form between the layup and the Stretchlon, work them out. Otherwise you end up with holes in the layup that need to be filled later.
Here are pictures of my second attempt as well as my vacuum rig.
|Materials: Peel Ply (top), Breather/Bleeder (middle), Streatchlon bagging material (bottom)|
|Vacuum pump with fittings|
|Valve to control flow|
|Bagging setup pre-vacuum application|
|With vacuum applied|
As with the first one, air still leaked and I needed to use zip ties and weighted insert to help the bag keep the shape, however this one sealed much better and with what I learned, I got a much better part. Here are pictures of the two parts right out of the bag. The first one is on the right, the second is on the left.
|Results of vacuum bagging. First attempt on right, second attempt on the left|
|Same picture with flash. Shows wrinkles prominently.|
You can see wrinkles in both, but the first one on the right has far more and deeper, as well as a few air pockets. I think this is because I had the Breather/bleeder material covering the top and could not see how it was wrinkling, or the air pockets. The second one did not have the breather/bleeder material and came out far better.
I also started working on other fiber glass work. I glassed one of the armrests that I had formed out of foam a few weeks ago. I was planning on vacuum bagging this also, but I ended up just doing the layup by hand. I did use the Econostitch Peel Ply and the Stretchlon bagging film, but this time I just pulled the material around and used blue tape to hold it. When I did this the first time several years ago, I used saran wrap without the Peel Ply, which worked okay but required a lot of finish sanding to and the saran wrap was very difficult to remove. Using the Peel Ply and Stretchlon bagging film was much easier and I was able to remove the bagging film in one piece so I can use it again. Here are pictures of the arm rest while wrapped and afterwords.
|Right Armrest still in bagging material.|
|Right Armrest, back side, still in bagging material|
|Right armrest, bagging material removed|
|Right armrest, bagging material removed, back side. Note: still have the glass the inside of the handle|
|Right Armrest with switch holder.|
Until then, Happy New Year and welcome 2018!