Glass / Resin Ratio's

Published 'typical' glass/resin ratio's vary from as low as 35% to as high as 60%.
From your experience, what would an experienced operator expect to get in a 0/90 or +/-45 hand lay-up, using epoxy with no vac-bagging?

 

Eh Will,

As far as I know the glass to resin ratio is about 1 : 1.5 for chopstrand and 1 : 1.2 for waven mat to the nearest lamp pole. depends a lot how you work with it. Someone else may confirm this.

 

I have yet to have the luxury of experienced layup workers....
The last set of big wet-layup parts I did (moulds for a solarcar, so hi-temp epoxy resin, epoxy-foam core, hand laid 200-300 gsm cloth with a bit of CSM, no bagging) probably turned out about 40% glass with the inexperienced crew (although I think there were a couple of spots that were closer to 25%). I think we got that up to about 50% by the end of it, when the few who continued to come out had figured out how to do it properly. Getting higher than 50-55% with hand layup strikes me as somewhat unlikely unless your labour is absolutely perfect.

 

1:1 for that.

 

Will, resin:glass(by weight) the 1:1 is what we use for stitched fabrics, 2.5:1 for chop strand mat, also allowance is made for core priming(plain foam about 125 gram per M2- uncoated balsa will be more) & if using contour cut core some more & allow for core adhesive if used & also a little for peelply(weight comes back off when peely is ripped off) & also allow some quantity for wastage. Also in the stitched fabrics the size & shape of fiber bundles has some bearing on ease of wetout, the triax(1120GSM) we used 15 years ago was awful - big fat round bundles, the stuff we use now(mosly colan I think) has nice flattish bundles & wets up quicker & lays nicer, I also use some 880 GSM uni, usually for tapes but we wet it on a separate table to spend some time taking up the resin before setting it into the job. Best thing for you to do is get some core, fabric & resin & do a couple of 600x600 test panels to see whats acheived with the actual materials planned but also bear in mind that on test panels of small size they are easy to get excellent results & full size panels are harder to get same weights/quality simply by the manpower to square meter thing.All the best from Jeff

 

Thanks Guys, as laways some useful stuff in there.