Amine Blush

keelbolts · Post by **keelbolts** » Tue Oct 16, 2007 1:52 pm

I have a quick question concerning the removal of the waxy blush from cured epoxy. We know we have to remove the blush from an epoxy coated surface if we want anything else to stick to it reliably. (West Sys says it's not necessary when using the special hardener for applications that are to be clear coated.) You must remove the blush before you sand the surface or you will spread the blush around with your sander. It seems like we are constantly applying epoxy-based fairing & filling compunds to our boats. I don't see references to cleaning the blush off of these fillers before moving on. Why not or have we just been getting away with this? Are we just cleaning it off with mineral spirits/acetone as we prep for the next step?

Post by **Tim** » Tue Oct 16, 2007 3:49 pm

I always wash cured fairing compound with water and a Scotch-Brite pad before moving on to sanding or recoating. I try to note this in all my descriptions of such work. I use a simple spray bottle of water normally.

I see a clear difference in appearance before and after washing, convincing me that this basic step is worth the effort with fairing compounds (and all applications using blushing epoxy like West System).

Check out this earlier post about blush and the cleaning process. Link: Stop...I'm Blushing

Cleaning with solvents does not remove blush; it's a water soluble compound and therefore requires plain water and light scrubbing to take care of it easily. Wipe off the washed area before it dries to remove contamination.

keelbolts · Post by **keelbolts** » Wed Oct 17, 2007 9:47 am

I'm helping a friend fix up an old Cat 22 and was reviewing info on deck work on your Glissando site & on Dasein688's site. I must have skimmed over the wash after fairing step. I think we'll go with a single laminate of 10 oz cloth on the Catalina.
I always washed after sealing w/ epoxy, but I used to do a lot of topside fairing w/ 410 and I didn't wash the surface afterwards. I guess I just got away with it.

I just went to the thread you linked and I have read it before. I forgot all about the part dealing with washing the microballons application. I guess I was lucky in the past (perhaps I got away with sanding the blush off)- I'll wash my fairing compound applications from now on.

margitchris · Post by **margitchris** » Wed Oct 17, 2007 10:34 am

I remeber reading somewhere, maybe in the West System manual, that 410 should not be used in deck fairing because of its sensitivity to heat. I have a very small amount on my deck right now that I used before I knew this. I plan to leave it there. Let's hope we both "get away with it."
Chris Miller
Lloyd, florida

keelbolts · Post by **keelbolts** » Wed Oct 17, 2007 10:52 am

I didn't use it on the decks, just the topsides. I figured that, on a white, vertical surface, temps wouldn't get high enough to damage the 410 . I have had no problem with it over a period of almost 20 years (in spite of not washing the blush off properly). I hope you'll do as well.

Post by **Tim** » Wed Oct 17, 2007 3:13 pm

keelbolts wrote:...was reviewing info on deck work on your Glissando site & on Dasein688's site. I must have skimmed over the wash after fairing step...

This is something I've made more of an effort to specifically note in more recent writeups because of confusion on the issue. I'm not sure my ancient Glissando project writeups necessarily note the specifics of washing the epoxy every time.

Hirilondë · Post by **Hirilondë** » Wed Oct 17, 2007 8:56 pm

410 is also quite soft compared to 407. But it is the easiest of the West fillers for sanding. I like it with a little 406 and some 407 for fillets that will be sanded. I wouldn't use it exclusively anywhere that gets impacted.