Peel ply is one place you can save if you need less than 100 yards. Small quantities of peel ply sell for over $8/yd. Nylon taffeta "flag bunting" works fine for peel ply and is generally on sale for under $3/yd at the fabric stores just after the high school proms are over.  You just have to settle for local school colors.  If you need more, it is probably cheaper to buy a full bolt of real peel ply from a composite distributor. I bought a 350 yd bolt for $800.

Breather/bleeder is one place you don't want to skimp. It is essential that the pressure be even throughout the bag. We used professional 1/4" poly breather and maintained pressure to within 1" Hg over the entire 700 sq.ft. bag with 6 vacuum ports.  See the Vacuum System in Special Tools

One time saving trick that John Fox suggested is to precut the breather and peel ply and use 3M spray adheasive to stick them together.  Near the end of a lay up the adreninin level is up, energy is down and the epoxy is about ready to kick.  Placing the peel ply and breather in one operation is a real time saver.

The bag itself was just contractors 6 mil polyethylene sheet. A real professional single use vacuum film is made of Nylon. It has one advantage in that it stretches so you can avoid folds and pleats. Its disadvantage is that it is expensive and hard to find. We rolled our poly sheet out and laid it on top.  Starting at the center of the stern, we removed the masking tape and stuck the poly to the sealing tape. The bag was worked forward concentrating the slack into 3 large pleats on each side.  The pleats were then sealed with short lengths of vacuum tape. 

A small X was cut about the middle of one side, a vacuum cup applied and the bag partially pulled down.  While the bag was fairly loose we straightened out most of the wrinkles and concentrated the loose bag is a few big folds. Then we cut 5 more places around the hull and applied rest of the vacuum cups.

Everyone was assigned a section of hull to look for leaks. Once the bag was tight, 3 more Xs were cut and cups with vacuum gauges applied.

The bag reached 15"Hg in about 20 minutes and the pump kept it there over night.

You could spend $20 to $40 each for professional vacuum ports OR you could go to K-Mart and pay $2 for a pack of 3 suction cups that are normally used to stick bird feeders to a window.  Drill out the hub with an 11/32 brad point and cram a short length of 3/8 copper pipe in the hole.  Then stick the pipe into the vacuum tube. Now lick it once (being careful not to let your tongue get sucked up the tube) and stick it on. Works great!

Next came the Roll Over

Site last modified:04/12/04