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Nice!... Glad you're making a vac-bagging effort.
This process makes so much sense even for the DIY'r. I look forward to see how you make out with the rest of the core project.

Crawl, looks like you are doing a nice job with the right materials. I did a similar job with a friend on a Switzer Shooting Star years ago. It was a lot of work but worth it.

How about instead of tee nuts, screwing a piece of 1/4” aluminum flat bar to the underside of the plywood. It’s easy to drill and tap and provides a much larger area.

You could improve your vacuum by coating the area you are applying the tape to with resin and let it cure. Ground fibre glass could leak a lot of air. Quilt batting from fabric land works pretty well as a bleeder.

One other thing I learned rather late in my composite career, was to use methyl hydrate for cleaning up. It’s much cheaper and less smelly than laquer thinner or acetone.

Thanks for the cudos and response. Arltralite, I like the ideas. The aluminum on the underside has a few definite pros like distrubuting load, more pull-through strength, more placement options, ease of use. The only neg might be weight (over 1/4" stainless tnuts), bonding/glueing the aluminum to the ply, and maybe aluminum corrosion issues. Ive never seen, or noticed that in glass work yet. I plan to put a layer of cloth on the 1/2 ply on top and maybe bottom. Ill do some searching for examples, and tech.

The surface is pretty rough for taping. I didnt do a "fill" coat on the two layers of glass(2 oz 0-90 and a layer of 12oz biax over the original ground down surface) in the bottom since its not the last layer. I like the tooth of the grain for the next bond. The cord weather strip stuff is good but i got lazy with it. The wide carpet tape did ok where i did a good job pleating, and proper bag-to-part spacing. Ive read that 6 lbs vacuum is about right. I couldnt turn off the pump. Should i go for more psi? The way I poked through for the gauge sucked bad. My next go will be better.

I try the Meth for cleanup. Ive been using actone. I tried a bit of white Vinegar that seems to work alright.

Heres a shot of the bag fitting i made out of stuff laying around.

See if you can get some tremco 440 tape from a window place. 1/8x3/8 works great 1/16x3/8 works well if you are careful.
I was just suggesting to put a layer of epoxy where you plan to run the bag tape. Not on the entire part.
I have never used one of the frogs for the hose. I always wrapped some bleeder around the last two inches of hose and wrapped that with the tape and stuck it in the edge of the bag.
I try for 29inHg on my vacuum bags. That would be somewhere around +14psi.
If you are concerned about the aluminum corroding you could use anodized stuff from home Depot

I will be helping a friend build a carbon fibre foam core 125cc hydroplane this winter. Will try to start a thread on that.

Arltralite , thanks for the details and i will implement the changes. Much appreciated. I have zero experience.
Screw the stupid expensive stainless t-nuts. Im going with aluminum strips. Ill just seal it all up with the finnish coat and hope for the best. The only open-air would be in the thread. Now im thinking aluminum hardware....

I have been getting more core in, and the advise has helped. I pulled 9-10 lbs on the next core install. I went big on last weekends and only pulled 2-3 lbs, but i think because of the size of the area my pump couldnt pull hard enough. I dont know, but its down really solid and conforms well to the contours.





All i got now is one more bag on the piece in the bow then on to sanding off the backer cloth, filleting, and glassing over.
One problem i have realized is when coating the balsa with epoxy in the tape areas is its hard to clean for amine blush without getting the bare wood wet. Trying my best to clean the amine up between layers/stages.
I have discovered that using adhesive tape can tell you a bit. If the tape doesnt stick you have some blushing/amine blush on the surface. I can kinda feel it by hand, and cant see it at all. I have been using a toilet brush, scotch bright pads, distilled water, and lots of paper towels to dab it up. It sucks that i cant do it all in one process, so dealing with the blush is what comes with epoxy. The peel ply is awesome for epoxy since it "peels" away the top layer with all the blush leaving a perfect paint, or next layer surface. I need to use it more then i remember too.

Last update for 2017. All the core is bagged in, and the backer cloth sanded off. Some hours were spent blending/sanding down the core at the floor registers for a good fit of the floor board.




All wetted out and filled gaps




Biaxal cloth over all of it. I will be capping the stringer tops when the floor goes down. I planned on doing the floor, but just glassing the core ran me till 5:30am last night. This will all need a wash down and lite sanding now before moving on. It will atleast give me the opportunity to fix some small beginner flaws.

I like it.
good work!

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That's looks great! Good work.