Poly vinyl or "saran wrap"

Can I use this as a release agent with west systems epoxy? I understand a release agent to be something that won't stick to the epoxy as it cures...I want to use it as a kind of "form" to press the curing epoxy into place.

Thanks for any help

 

wax paper

 

I have been told polyethylene also works.

 

I don't like waxed paper, the exothermic during cure has melted wax on me and I'll never use the stuff again, just to risk the chance. Polyethylene works well as does packaging tape (clear, tan, etc.) which is usually also polyethylene, so is the clear plastic painters drop cloth they sell in hardware stores.

Mylar and other polyester sheets also work very well, but are expensive. I've got limited use from polypropylene, cellulose acetate and PVC too.

I cover molds and small stuff with packaging tape and use rolled polyethylene sheeting for larger jobs.

 

I have been testing neoprene rubber with a very light coating of wax. It has a very smooth finish.

Only playing around at this stage but I am intending to buy a roll of 0.8mm thick rubber to give it a serious test. In a single sheet it will have enough stretch to neatly cover a faired shape that has some complex curvature.

Has anyone else tried neoprene sheet?

I have tried polyethylene sheet but cannot get it to stretch without creasing near the attachment points. It would be OK for a developable shape or maybe if it was heated.

I have also been looking for plastic that will heat shrink.

Rick W.

 

Rick,

Any virgin plastic will heat shrink, you can buy rolls of the stuff from packaging suppliers, a hot gun will pull it down to size.

Electrical heat shrink aslo works on tubular parts and things like wound bearingshafts, but there is a proprietary heat shrink designed specifically for the carbon fibre fellas, any good supplier should be able to follow it up.

 

I need to get a heat gun or pinch my wife's hair dryer for the afternoon.

Any suggestions on packaging suppliers. Name a supplier up your way that might operate nation wide. I have tried folded stuff from Bunnings and it has crease lines. They might pull out with heat but I would prefer to get a roll. I only need stuff that is 700mm wide.

Do you think the heatshrink technique would also work as an alternative to vacuum bagging?

Rick

 

That technique is used all the time on carbon fiber & basalt sleeves to make model rockets. Soller Composites sells the sleeving and the heat shrink tubes specifically for that purpose. They have a paper on their site describing the process.

http://www.solarcomposites.com/MakingShafts.html

I've done one test with these materials using infusion to make a shaft log but it was a failure. Still working out the kinks on that one.

 

Par.,,,or whoever hehehe,,,,does that mean epoxy gets hotter then poly or vinyl ?,,,like ive always said,,,i dont know much bout epoxy,,,other then "Mac" telling me...."use epoxy on that piece",,hehehe

 

Get off the West System bug.

Use Mas or System Three.
Loads of working time with the slow hardener, no amine blush, easy volume mixing in pots (2 to 1 ratio), less chance of allergic sensitivity to hardener, longer re-recoat time on green epoxy, better viscosity for laminating work.

Ok- rant over.

I use saran wrap all the time as well as just about any poly film I have on hand- trash bags, bags from stores, etc

They all work fine and do not stick to epoxy. If you want to do nice mold work you will eventually get into release products. Poly films are a bit of a PITA in molds.

 

My cheap solution was plastic painters drop cloths for on top of the mould. Dirt cheap, $1 for a 12x16 ft piece, and a little thicker than the saran wrap I used around the outside of the hull

 

If you use trash can bags, which have printing on, use the inside. The printed side will stick to epoxy...

 

I use freezer paper. The one with plastic film on one side of the paper.

Wax paper caused a problem with epoxy for me as well.

 

i've used painter's drop cloths. as mentioned, CHEAP! i use them mostly in vacuum bagging situations. i find that smooth finish shelf paper works excellent. easier to get the creases out of since the back is adhesive. works great on simple curves or for flat surfaces.

i switched from west to u.s. composites epoxy (epon) and find it very workable.

 

what do you guys use for hatches and areas with corners and such? to me it would seem impossible to use sheets and films in these areas