XPS and Epoxy, good enough for an airplane...

Awhile back, I was watching a show about home-built aircraft where this guy is cutting pink XPS to laminate for an AIRCRAFT WING. A real plane, not a model… I have just started to explore the various home-built sites and have yet to find any mention of delam issues in such construction. I’ll keep digging for an explanation, but doesn’t it seem funny that the technique is good enough for planes, yet people have had problems using it for surf-craft? Any ideas?

http:\www.members.eaa.org/home/homebuilders/building/composite/articles.html

for starters

7/10

Yeah, in 7 months, he’ll find some delams in this wing, by the appearance of a big bubble, and if he ignores it, the wing will break and he will die.

If he’s smart, he’ll figure it out, make a new wing, and be good again.

Even remote control planes have problems with XTR foams, and use EPS only for short term, then replacement.

All the airplane builders that I know have switched from XPS. They generally core with EPS and then sandwich with PVC or Rohacel.

I followed the “technical counselors” link from the EAA site, chose the “composites” link and pulled a list of composites experts in my geographic area. The list included phone numbers so I placed a call to a local fella who was VERY informative and very willing to share his knowledge. Commercial aviation field by day, avid homebuilder by night… Uses quite a bit of XPS/epoxy as well as other core materials. According to this individual, outgassing is not the issue, but stated that the “fabrication billet” XPS that is used in aircraft construction has a larger cell structure than the XPS used for insulation purposes. He suggested that the finer cell structure of insulation quality XPS may be contributing to the “de-bonding” issues that many here have reported. He also suggested that a light coating of epoxy/micro-spheres applied to the blank before laminating may help alleviate the problem. Interesting if nothing else.

7/10

How many of the people on Swaylocks have vac bagged vs hand layup when trying XPS?

It seems that alot of the composite guys pretty much always vac bag but I got the impression quite a few of the XPS surfboards were hand layups.

Kind Regards,

Matt.

Seven is right. There is an XPS used called “floatation billet” that has very large cells that is being used in aircraft. In surfboards it leaks like crazy… I’ve always wondered why they called it floatation billet when it wicks water like a sponge. It comes in much larger billet size than the general XPS and the cells look like that foam you get at craft stores for making Christmas ornaments. I also think that the fact that it’s quite open celled allows the blowing agent gasses to escape after manufacter.