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Old Oct 20, 2004, 06:38 PM
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United States, IN, Indianapolis
Joined May 2004
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Windtrader, I visited my local Grainger branch and they were able to find it in there system. Another way to find some is to contact 3M through their website. When I contacted them they gave me a list of their customers which sell the original formula and the part number that I needed to look for when I purchased the prooduct. The part number that I posted came from a can that is sitting on me work table. Unfortunatly I lost the hard drive in my computer about a month ago and lost the info that they sent me. You might try calling 3M at 1-800-364-3577.
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Old Oct 20, 2004, 07:53 PM
Will fly for food
Maryland
Joined Sep 2004
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Again, you can use 3M 90. I have heard it is available at Home Depot.

But you can buy single cans from Hillas (www.hillas.com).

EDIT: DO NOT use 3M 90 on EPS foam. It works great on EPP though.

I have ordred some 3M 78 which is DESIGNED for polystyrene foam use.
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Last edited by Pinecone; Nov 24, 2004 at 08:36 PM.
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Old Oct 21, 2004, 12:11 AM
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Rochester, MN
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Pinecone:

Sure, you could use 3M 90, but the question was for acetone-free alternatives to 3M 77.

3M 90 has acetone just like the new 3M 77.

Mike
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Old Oct 21, 2004, 01:12 AM
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Bay Area, Ca
Joined Jul 2004
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Definitive facts on 3M spray adhesives

Ok. I dug up the current MSDS sheets for the 3M sprays in question: 3M Spray 78, 90, Super 77 classic (original) and Super 77.

As you can see 78, 90, and 77 classic contain no or low amounts of acetone (the foam eater) and only the new Super formulation has plenty of acetone to eat foam.

Stay away from the current Super 77 and you'll be free of foam eating problems.
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Old Oct 21, 2004, 07:59 AM
Will fly for food
Maryland
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Quote:
Originally Posted by mike50
Pinecone:

Sure, you could use 3M 90, but the question was for acetone-free alternatives to 3M 77.

3M 90 has acetone just like the new 3M 77.

Mike
As you can see from the MSDSs posted, 3M 90 does NOT contain any acetone.
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Old Oct 21, 2004, 08:00 AM
Will fly for food
Maryland
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Quote:
Originally Posted by mike50
Pinecone:

Sure, you could use 3M 90, but the question was for acetone-free alternatives to 3M 77.

3M 90 has acetone just like the new 3M 77.

Mike
As you can see from the MSDSs posted, 3M 90 does NOT contain any acetone. Like classic 3M 77.

And unlike 3M 78 and the new 77
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Old Oct 21, 2004, 08:08 AM
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Grand Rapids Kent Cty, Michigan, United States
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We are using 3M 90 in a model building class that I am doing at my high school. It was obtained by my teaching partner whose wife is a 3M distributor. It definately does not eat the foam.

My only concern with the 90 is that it goes on kind of like silly string, not the smooth almost invisible coating that you get with the original 77. Is this somthing that is a weight issue? We don't have any planes completed yet, but I am just wondering.
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Old Oct 21, 2004, 02:22 PM
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Bay Area, Ca
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Quote:
Is this somthing that is a weight issue?
Good question. I found another technical doc that clears this up. 90 is meant to be applied to both surfaces, 77 can be applied to one surface.

The figures show that the formulation of 90 has half the solids as 77 and half the coverage. If 90 is applied as recommended (spary both sides) then you end up with the same weight per sqft. If you were to apply to only one side ( not recommended) then it would be lighter.

It seems 77 is the better product to use for our purposes. 90 is stronger (230psi vs 77's 160psi) but it is irrelevant when taping cellophane to foam.
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Old Oct 21, 2004, 03:00 PM
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According to the specs, 3M90 uses a a "non misting spray". I think that means it comes out of the can as a fan shaped stream, which would make it very difficult to apply a thin, even light coat. I bought a can of 3M77 once, with the same type nozzle and it was useless. Something for someone to check out by buying a can and trying it.
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Old Oct 21, 2004, 04:05 PM
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Bay Area, Ca
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@rcmann - you are right that the 90 spray comes out more lace like, I think that was the term used in the 3m docs. I'm with you that the 77 is much more likely to lay down a light even coat which is just what we want for the film. The "stringy" texture is better for the more robust materials it is designed for such as sheets of foam.

If tdevil is getting the 90 for free, it's pretty hard to make the arguement to go spring nearly 10 bucks a can on the 77, unless they can ask and get it for free. :-)
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Old Oct 21, 2004, 06:20 PM
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Grand Rapids Kent Cty, Michigan, United States
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Yes we have followed the directions and applied the 90 to both surfaces. (We are building Tog's Bird Dogs) It is easier to control where it goes. It goes down in amost pencil like lines. As long as you spray lightly and sparingly it covers well and goes where you want it with very little overspray.

I may have to check and see if my partners wife has the old 77 available. Just so long as it is free as well. Free is good when you are a teacher in a school district that can't even supply you with copy paper for your classroom.
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Old Oct 21, 2004, 06:29 PM
Will fly for food
Maryland
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Actually 77 could be applied one surface or two. Two surface with some drying time was a more permanent bond.

I just used my can of 3M 90 today, and I found it comes out in a fan shaped pattern, but layed down a nice thin even coat. You will have to mask to lay down a narrow band for say taping.
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Old Oct 24, 2004, 11:51 AM
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Rochester, MN
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Quote:
Originally Posted by Pinecone
As you can see from the MSDSs posted, 3M 90 does NOT contain any acetone.
Well, the MSDS data I have

http://www.setonresourcecenter.com/m...1/wcd001a1.htm

shows that 3M 90 has 10-20% acetone. I believe that the last time I actually looked at a can of 3M 90 it listed acetone as an ingredient as well.

Perhaps 3M 90 has been reformulated just as 3M 77 was.

Mike
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Old Oct 24, 2004, 12:34 PM
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Rochester, MN
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I did some more research and, as Windtrader's data shows, the current formulation of 3M 90 does not have acetone. That data is direct from 3M's website and carries a date of Aug 2004. Earlier versions of 3M 90 did have 10-20% acetone (the data I originally found was from 2001).

The net is when you go to buy 3M 90 make sure that the can does not list acetone as an ingredient.

Mike
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Old Oct 24, 2004, 12:53 PM
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3m 77

I'm down to my last large can and haven't reordered. I e-mailed 3 M sometime back about the problem. Barb told me that they still make it under the label "Super 77 Original formula". Calif as usual screwed everthing up trying to protect our A**. One guess who those idiots are voting for?

Barb said 78 is a direct replacement for foam if you can find it.
www.uline.com has the old stuff. $8.65 for 17oz. Also check out www.dream-flight.com for their clearco. Looks good.
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