Fiberglass resin not setting up on cowl

[Webb]

Mixed the Aeropoxy up and cut it with acetone, brushed it on, and it still feels tacky and looks greasy. Won't come off on the hand but it's sure feels sticky. Kinda like paint that is almost dry.

Time 48 hours - shop temp ~ 65 - 70F. And I know the proportions were correct because I mix by scaled weight to the gram.

One thought - because layer is so thin, it hasn't catalyzed yet because it couldn't develop the heat that a thicker layer could. Should I put a space heater in the room and run the temp up to about 90 overnight?

Got my lower lip stuck out because of the huge time invested in fitting the cowl.

What's up????

[painless]

I think you are on the right track to apply more heat. Use the space heater idea, or even a shop light positioned close to the surface in question. No need to crank the whole room up to 90. Just get a heat source close to the surface.

My money is on it setting over night.

Regards,

[Mark Burns]

I see this sometimes also.

From the West Systems website:

PROBLEM: Waxy film appears on surface of cured epoxy.

POSSIBLE CAUSES & SOLUTIONS:

Amine blush forms as a result of the curing process.

Blush formation is typical. Remove with water. See Special Preparation--Cured Epoxy in the User Manual.

Mark

[szicree]

A thin layer definitely cures slower. The easy way to get some heat on it is to simply set it in the sun for a few hours. It gets a lot hotter this way than in a heated garage.

[N916K]

Make sure you have both parts. I know this sounds silly but Spruce sent me a large and small container of part A. It wasn't until I mixed them and applied it to my cowling that I realized what had happened.

[Ramendala]

Aeropoxy was (is?) notorious for amine blush. My cozy is built primarily with Aero but when the blush would not stop, I switched to MGS ($$$) You can wash the blush it off with soap and water. The blush is usually not very thick but I have never cut epoxy with acetone either. You should be able to feel the epoxy hardened beneath the blush with the tip of your fingernail. High humidity makes it worse. Most of my work was done in Colorado and I still had blush issues with multiple batches of aero.

Ryan

[Webb]

As they say on the PGA Tour - "These guys are good". I went to the West Systems website and read about amine blush. It is the waxy like substance that forms on top of cured expoy. It is water soluable and according to one PDF file, the author felt it best removed by wet sanding because of eliminating the dust. He also stated that cured epoxy is just under the hardness of formica and can be felt under the amine blush. It is cured enough to cut with sandpaper after 24 hours and fully hardened after 48 hours.

Is it legit to say between the cowl and fitting the baffles that the front end of building an RV is such a pain in the fanny that is why it is saved for one of the very last things. If we had to do it first, there would be a lot less RV's flying and laying in parts in garages.

Webb
RV7A
N32WW

[mike109g6]

Originally Posted by Webb

As they say on the PGA Tour - "These guys are good". I went to the West Systems website and read about amine blush. It is the waxy like substance that forms on top of cured expoy. It is water soluable and according to one PDF file, the author felt it best removed by wet sanding because of eliminating the dust. He also stated that cured epoxy is just under the hardness of formica and can be felt under the amine blush. It is cured enough to cut with sandpaper after 24 hours and fully hardened after 48 hours.

Is it legit to say between the cowl and fitting the baffles that the front end of building an RV is such a pain in the fanny that is why it is saved for one of the very last things. If we had to do it first, there would be a lot less RV's flying and laying in parts in garages.

Webb
RV7A
N32WW

Say it ain't so Miss Scarlet, but you may be on to something there. If not familiar with fiberglass it can be a real pain in the potankas. Wet sand the blush after allowing to fully cure for 24hrs. Use some 320 or 400 W/D and plenty of water. Try washing it down afterwards with some mild soapy warm water(dish soap without amonia in it) and then just rinse it off with clean warm water. Should be warm enough in MS to take it outside and hose it off. A really good fiberglass site is http://www.fibreglast.com/, great products and excellent FAQ section. Are you trying to eleminate pinholes? Look as some of their products designed for this, also high build high solid primers will take care of the little stuff if fiberglass preped properly. Carefull with sitting fiberglass in sunlight. UV can damage most raw fiberglass and products. Read the warning labels.
Good luck,
Mike H 9A/8A

[Dean Pichon]

I just used Aeropoxy (PR2032) laminating resin to make some reinforcements as I replace the hinges on my -4 cowl. I switched from West as I am too tired of dealing with amine blush. To date, I have seen no signs of blush with Aeropoxy. I agree with previous posters that heat and time cures most everything. Although I have not checked with Aeropoxy, most resin manufacturers recommend against thinning their resins. Aeropoxy has good tech help and may be able to help you with this issue.

[Sticky1]

For what its worth.........aircraft spruce sold a vinal ester resin back in august of 07....since then they changed and the stuff they are sending now is mixed differently. Do you think they said something...NOT.