West 105/209

[TDubs74]

I have a supplier locally that I can get the West system from. The pricing beats out any of the other choices at ACS. I know West is approved by the designers, but is not a popular choice. Any reasons why West is not worth the savings?

[Kent Ashton]

See "Gary Hunter's Epoxy Comparision table" here   http://www.cozybuilders.org/ref_info/

People have built structure with West but I believe the lower tensile strength is why it's not an "approved" epoxy.  To me it seems to be a softer epoxy.  Fine for finishing though.  Buy the West Microlight filler in the big box from a boat supply.

[Jon Matcho]

West sands much more easily and is generally used for finishing. However, that does not mean it cannot be used for structural parts. Personally I would not, as the amount of money you would save is not worth the peace of mind. Epoxy costs will be a minor fraction of the total costs for the plane.

Here's a worthwhile discussion on West 105 and choosing an epoxy system in general. 

I recall MGS (or was it ProSet) was not an approved epoxy when it was clearly capable. At the end of Nat's personal involvement with supporting Cozy builders, Nat was just keeping up with the basics. Since Aircraft Spruce purchased the plans we still don't have an "approved" list of epoxy systems that is actively maintained.

[Kent Ashton]

2 hours ago, Kent Ashton said:

People have built structure with West but I believe the lower tensile strength is why it's not an "approved" epoxy. 

Sorry, for bad info.   The 209 is approved

[Jon Matcho]

I vaguely recalled Nat approving it in one of his latter newsletters, but could find no evidence of that.

[Kent Ashton]

41 minutes ago, Jon Matcho said:

I vaguely recalled Nat approving it in one of his latter newsletters, but could find no evidence of that.

I am going by the Hunter list maintained by Marc, linked above.  

[TDubs74]

2 hours ago, Kent Ashton said:

I am going by the Hunter list maintained by Marc, linked above.  

So, I'm looking at that list and they have N/A for RT cure times for Aeropoxy and MGS.  Does that mean that those need a post cure?

[Kent Ashton]

https://www.ptm-w.com/aeropoxy/aeropoxy-faq.html#14

[Jon Matcho]

18 hours ago, Kent Ashton said:

Sorry, for bad info.   The 209 is approved

Ah, I found this note in the Gary Hunter slide:  "Resins Shown in Shaded Rows are NOT approved for construction of Vari-Eze, Long-EZ’s or Cozy’s" 

Still, there’s not a citation for the source of this, but I trust what Gary and Marc have to say on the matter.

15 hours ago, TDubs74 said:

So, I'm looking at that list and they have N/A for RT cure times for Aeropoxy and MGS.  Does that mean that those need a post cure?

No, MGS and Aeropoxy (and others) are fine with room-temperature cures (some folks have post-cured some parts by putting in a hot attic, etc., but that's very uncommon. There's really no need.

[TDubs74]

I'll probably go with Aeropoxy, but am still contemplating MGS, as I hear you use less of it, but not sure how true that is.  Not a huge deal.  I just figured it was a way to save on shipping and pay less for the product at the same time.  

Thank you everyone for the input.

[Mike B]

West cannot be used except for finishing. It simply cures too fast. I can feel the mixing cup warming as I'm stirring. 

Something else to consider is the viscosity. A low viscosity epoxy is much, much preferable to a higher one. This is one of the reasons people use mgs.

[A Bruce Hughes]

West epoxy is available in the local boat supply.

THERE ARE TWO VERSIONS OF WEST EPOXY so don't mistake statements that someone thinks

"West" is structural; The 105 epoxy IS NOT.

Also there is a slow hardener and a fast hardener so you have to use the correct hardener for finishing depending on the temperature.    Fast hardener gives a vicious exotherm and will melt your cup.

Luckily practical all of the airframe was finished when I bought the project so I had little structural work to do. 

I used Aeropoxy but two times I had to arrange a way to keep the area of work at the right temperature (once when I had only shade to work in, once when I was in a hanger that was only 3-5 degrees more than the outside temp so I built a 8'x8'x8' box of styrofoam)   

BE CAREFUL of the temperature that you will have for 24 hours.

 

[Marc Zeitlin]

3 hours ago, A Bruce Hughes said:

THERE ARE TWO VERSIONS OF WEST EPOXY so don't mistake statements that someone thinks

"West" is structural; The 105 epoxy IS NOT.

This is an incorrect interpretation of reality. "WEST Systems" is a brand name. The 105 is the resin, and 205 / 206 / 207 / 209 are the hardeners. Only the 209 hardener, in concert with the 105 resin, is approved for structural layups - the 205/206 hardeners are great for micro/finishing.

[TDubs74]

5 hours ago, Marc Zeitlin said:

This is an incorrect interpretation of reality. "WEST Systems" is a brand name. The 105 is the resin, and 205 / 206 / 207 / 209 are the hardeners. Only the 209 hardener, in concert with the 105 resin, is approved for structural layups - the 205/206 hardeners are great for micro/finishing.

What is your stance on the the West 105/209 Marc?  Strong enough or not recommended?  

[A Bruce Hughes]

Marc: Thank you for giving the correct information.   105 resin with 209 hardener.   

I have Aeropoxy on hand and it works very well so I will continue using it.   At least everyone should now be using structural material.

[Marc Zeitlin]

14 hours ago, TDubs74 said:

What is your stance on the the West 105/209 Marc?  Strong enough or not recommended?  

Any of the approved epoxies are by definition "strong enough" and "recommended". I do not know anyone who USED the 105/209 combination to build a plane, but it is an approved combination. Personally, I'd use the MGS or Pro-Set (and have used them both on projects), with the EZ10-87 for anything that touches fuel. But they all work.