SACS

I was wondering if anyone knows of a 'wetting-agent' that you can put on fiberglass to help promote the application of epoxy to fiberglass. I am trying to control the amount of epoxy that I am using in my aircraft and as such have found it very hard to use the correct amount of epoxy for a given weight of glass.

Mike James

If you're using laminating resin, and your cloth is "normal", it shouldn't be an issue.

With a typical hand layup, you want to achieve a 50/50 ratio... i.e., if you have 1 yard of .75 oz cloth, you should use .75 oz of resin. (same proportions, by weight, for any weight of cloth)

What resin and cloth are you using?

SACS

DLR-3400 & DH-9215 is the resin and harder I am using. It is from De-Comp. I am also using the 3oz glass from them as well.

This being said, is there any secert to getting the epoxy started on the cloth, so that you can use the correct 50/50 ratio?

Lightzpro

One method that can be used to control resin content, is to wet your fabric on a flat surface and squeegee out the excess resin. A piece of plastic film is used under the fabric and can be used to transfer the wet fabric to the mold. Resin content by weight can be calculated if you know the fabric weight and the weight of the quantity of resin used, though, obviously a small quantity of resin will be adhere to the film. This method produces great contact layups and can be used to control bleed-off in vacuum bagged laminates.

winship

You might Email DE Comp and see if you can get a viscosity of the resin below. The resin hardener listed below is the same as the HTR-212 and hardener 386 sold by Resin Services I believe. If it is the same resin the viscosity should be in the 800 or so range. The resin you are referring to is stated at 2500 which is a little to thick for an easy wet out. The formulator at Resin Services is now at DE-COMP therefore you will find similar products with similar numbers.

I cannot speak with experience of the resin you are using but I do have experience with the resin below provided it is the match for the Resin Services product. Try this one and you will get what you are looking for I believe.

Another thing worth mentioning is the technique of working the resin into the fabric. Don't be afraid to squeegee the resin. The resin listed below has a faster pot life also. (something to consider in your application)


LAMINATING RESIN
TOUGHENED SYSTEM


DLRH-3212
HARDENER: DH-9386
RATIO: 100 pbw to 33 pbw


GENERAL DESCRIPTION: DLRH-3212 is an unfilled, clear epoxy room temperature curing laminating system used in high temperature and room temperature applications. DLRH-3212 is a tough, strong resin with good heat distortion, chemical resistance and excellent adhesive and wetting quality on Kevlar®, Carbon Graphite and Fiberglass Cloth.

A5fly

Does the 50/50 ratio hold if a balsa core is used?

davidfee

Does the 50/50 ratio hold if a balsa core is used?

Well, yeah... if the balsa is sealed first. Sealing the balsa is not so easy if it's end-grain. Sometimes you'll need to adjust your resin content to compensate for absorption. BTW, you can get by with less than the 50/50 ratio... but it gets harder to ensure a complete wet-out, and you may start to see pin-holes in the surface.

-David

gjs

Blow Dryer to heat resin (after it is spread out on the glass not in the mix container) if it is a slow cure really makes it spreadable but you have to Wet the glass thoroughly. Waist some resin isn't a mistake, not saturating is. Then try to squeegee most out, Light/strong.

shupack

oops, wanted to start a new thread, please delete

SACS

Thank you all for the help. With a bit of practice I was indeed able to get down to 50/50. After getting to this ratio, I can hardly believe the amount of EXTRA resign that I had in my last wing. I should now be able to lose all most 1/3 lpbs out of the wing alone.



Thnks again for the help