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        3M Super 77

#1 Captain Carlton Jun 14, 2002 02:21 AM

3M Super 77
 
I was digging though matt's web site and saw the info on the formula change on the super 77. Bad news. :(

I need to snatch up a couple big cans of the old stuff. That should last me while.

Any suggestions where to look????

- Rick

#2 Flying Low Jun 14, 2002 05:48 AM

Not sure where to find the old formula, but I think I remember reading something at the LHS that said there's something like the old 3-77 called 3-78. I'm going by there this afternoon and if I see it again, I'll repost later tonight. Then again, I'm sure SOMEONE here will no something about it.

Adam

#3 mkirsch1 Jun 14, 2002 08:08 AM

The old 77 is getting harder and harder to find. Finding it is based on dumb luck; you might find some old cans hidden on the shelves behind the new cans. 77 is sold pretty much everywhere, but your best bet is large home improvement superstores.

#4 Dan H. Jun 14, 2002 10:05 AM

Remember that in a pinch, you can still use the new acetone-based formula on foam if you don't spray it on the foam, but into a cup and then stir it to evaporate the acetone. Test on scrap first. (Doesn't work too well for tape prep though)

#5 KevinM Jun 14, 2002 03:59 PM

Here is the reason for the change:

----Thank you for inquiring about 3M tapes, adhesives and
packaging products.

3M has made a formula change in the Super 77 to meet the new California Air Quality Management District Rule 1168.

Unfortunately, we were required to replace one of the solvents with acetone. This solvent will cavitate EPS and beadboard. The only other aerosol we have that will not cavitate the beadboard in 3M Insualtion 78 Spray Adhesive.-------

This is an email that I got from 3M today.


KevinM

#6 Dan H. Jun 14, 2002 04:10 PM

You can tell if you have the old formula by the first ingredient listed in the fine print. The foam-friendly version reads "cyclohexane". The new formula, "acetone".

#7 Captain Carlton Jun 14, 2002 06:21 PM

Found some Old Super 77
 
FYI: Home Depot in Fairfield, CA has probably 10 large spray cans of the stuff left. (After I bought 6).

I can build 3 to 4 wings with a single can, so I am in business for a while.

Hopefully, by the time I run out, someone will have figured out something else to use.

- Rick

#8 SiRacer Jun 14, 2002 10:17 PM

I also found some at the local Tall Mouse Craft store. It is the small cans but it will do.

#9 Sal C Jun 14, 2002 10:26 PM

I found some at Home Depot too. They had a bunch of it.

#10 sbledl Jun 15, 2002 11:05 AM

I have used the new formula to build some balsa sheeted foam (regular white foam) wings recently. Did some tests on pieces of scrap first. If it drips or puddles the stuff will eat right through the foam. When sprayed at the recommended distance and done carefully, there were no problems. The sprayed surface looked good and had no etching (I sprayed several light, quick coats). I made sure to let it dry long enough before assembly and my wings came out great. I definitely believe if it needs to be put on thick, put it in a container first.

#11 ramair Jun 20, 2002 09:41 PM

old //new????
 
hey guy how do i know if its old or new,,i just built a wing and never knew any better,,first i heard of this!!
is it only a problem in the usa???i know where there is a ton of that stuff,,,worked fine on my wing,,,may be the old stuff though???? please advise ramair

#12 Dan H. Jun 20, 2002 09:48 PM

Read the "ingredients" (contents); if the first one is "cyclohexane", you have the foam-safe formula, and if "acetone", that's the foam-nasty. But if you'd cavitated (melted) your foam you probably would have realized it already. Notice any strange flat spots or dents in the wing while you were taping? It's not a strength/adhesion issue, so I wouldn't worry about it.

I believe the formula was changed for all US markets just to meet the requirements of a California clean-air law, so I doubt 3M would keep the old formula just for N. American exports, though they probably could have.

#13 ramair Jun 21, 2002 05:30 AM

old stock
 
hello dan,i am wondering if they are getting rid of there old stock in canada??i walk into 3 differant stores and found the old stuff without the acetone,,,real pricey stuff though!! thanks again ramair


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