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Old Jun 10, 2002, 03:27 PM
David Cairns
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Orange, CA
Joined Apr 2002
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3M 77 Rumors

I have noticed in a few posts, people talking about hoarding 3M 77 spray adhesive, due to a change in the formula. I decided to check into this a bit, and called 3M. It is true, the formula has changed as of January 1 2002 due to EPA meddling. There was some small amount of acetone in the old formula, but there is a lot in the new formula and they no longer recommend it for foam (although some foams may tolerate it). They are aware this would be a problem for some people, so they have had a replacement product around for several years. 3M 78 spray adhesive is the replacement product. Here are some specs quoted to me :

Peel strength
3M 77 = 15 lbs/inch
3M 78 = 15-20 lbs/inch

Temperature max
3M 77 = 110 degrees
3M 78 = 147 degrees

Working Time
3M 77 = 30 min
3M 78 = 15 min

The temperature rating is most interesting, as I suspect more planes delaminate due to storage in a hot car, than anything else. The only bad news is that 3M 78 is not as easily available as 77. They gave me the name of a local Industrial distributor that will break cases and sell to individuals. (For you fellow SoCal folks it is R.S. Hughes www.rshughes.com) The cost per can is 10.70 and is 9.73 a can if you buy a case of 12. I seem to recall the 77 selling for $6-$8 a can at Home Depot so it is not too bad an increase and if we all start badgering Home Depot to carry it, perhaps it will be about the same as they sold the 77 for.

As an aside, I would like to compliment 3M on their call handling. I called their contact number from the 3M website (1-888-364-3577) and got an actual human! And he quickly transferred me to another human who answered my questions! Astonishing for a mega-corporation, no endless maze of computerized choices that don't match what I am looking for

-Dave
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Old Jun 10, 2002, 03:35 PM
Lifes 2 short, go sloping
colorado @ 5500feet
Joined Sep 2001
1,054 Posts
I did hear about this in Jan. and you can still get the remaining supplies for 77 at hardware stores, I got 3 cans and now use it wisely. I have heard that the 78 is much more clumpy and thicker coming out. It is very hard to get a fine mist on a wing as it splatters alot when it comes out.

The new 77 cans have brown on them and the old (Good) 77 is all black, go to smaller hardware store where they move less of it and you may find it. I found mine way in the back of the new stuff and there were 3 cans left.

GOOD Luck and if you try the 78 give us all a report of how it works.
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Old Jun 10, 2002, 03:43 PM
Señor Meember
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Joined Sep 2001
973 Posts
So you guys know, the new 3m 77 works fine on EPP and I actually prefer it over the old formula. It sprays on much finer and smells like acetone instead of toe funk like the old stuff did. So far I've bulit 5 planes using it without any problems.

Mario
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Old Jun 10, 2002, 04:00 PM
Ming's Avatar
Hong Kong
Joined Jun 2002
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New 3M 77

Please see the QFEI June issue, They have a very detail review about it.
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Old Jun 10, 2002, 04:06 PM
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Rialto, CA
Joined Jun 2002
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Quote:
Originally posted by Vinnya42
I have heard that the 78 is much more clumpy and thicker coming out. It is very hard to get a fine mist on a wing as it splatters alot when it comes out.
<snip>
GOOD Luck and if you try the 78 give us all a report of how it works.
I have also heard of the 78 being clumpy, but that using a spray tip from a can of 77 helps. you may want to try that also, if giving a can of 78 a try.
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Old Jun 10, 2002, 04:32 PM
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Las Vegas
Joined May 2002
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I bought some 77 this weekend and I also saw a 3M 90. I think it was 90. Was in a different color can. I read once that is may harm foam. Any word on 3M 90? ( I think this was the product number.)
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Old Jun 10, 2002, 04:46 PM
David Cairns
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Orange, CA
Joined Apr 2002
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Cmiller

3M's website has a "product finder" that recommends a product based on what you want to bond. When I put in "rigid foam" and "wood" it came back with these three:

3M Super 77 Spray Adhesive - High tack, high coverage and fast drying for permanently attaching foils, carpeting, lightweight foams, paper, cardboard, felt and, cloth to painted or unpainted metals, wood and hardboard.

3M Hi-Strength Spray Adhesive 90 - Drying in just one to two minutes, substrates that are to be bonded can be assembled faster for improved productivity. Bonds difficult substrates including: polyethylene, polypropylene, many other plastics.

3M Insulation Spray Adhesive 78 - Aerosol adhesive designed to bond foam board insulation to exterior walls, interior walls and roof applications. Will not attack expanded or extruded polystyrene making it the ideal choice for insulation applications.


The 3M representative that I spoke to said that the 3M 77 recommendation is out of date due to the change and was going to look into getting the website up to date.

-Dave
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Old Jun 10, 2002, 04:48 PM
That Freeking Laird Guy
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United States, CA, Riverside
Joined Feb 2002
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3M-78 is useless as a replacement for 3M-77. It comes out in stringy globs.

3M-99 is also not good. It comes out like silly string and it eats styrene foams.

3M-77 spray is still fine to use on EPP just don't use it on regular styrene based foams (blue foam, white expanded foam etc.) Like others have posted there are still places that have the old formula on the shelves. If you use it then buy a few cans. Use them only where required and use the newer formula stuff where you can. Your old formula 77 spray should last a long time that way.

TFLG
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Old Jun 11, 2002, 02:08 AM
Will work for planes
omega blood's Avatar
Fullerton, California, United States
Joined Jan 2002
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will it still work for foam board? I don't know what kind of foam foam board is.
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Old Jun 11, 2002, 10:03 AM
Lifes 2 short, go sloping
colorado @ 5500feet
Joined Sep 2001
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It will not work with foam board I believe to will only work with EPP foam.
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Old Jun 25, 2002, 07:13 PM
Crash Site Instigator
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Novato, CA USA
Joined Jan 2002
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I have a couple of projects that specify this stuff - found a hardware store that still had some black cans ("good stuff"). I'm pretty new at this, but foam ARF's seem to be my thing.

I bought 3 cans. Should I run back & get the 2 I left on the shelf ? Just don't know how much I'll use, or how far it goes...
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Old Jun 26, 2002, 10:14 AM
Certified Slopehead
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San Diego, CA.
Joined Jan 2001
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If you're going to stay in this hobby for ANY length of time, then yes, go grab it By the way, I bought some of the Elmers spray adhesive and it works great on EPP and BlueCor foam...
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Old Jun 29, 2002, 06:03 PM
Registered User
Heart of Texas
Joined Apr 2002
95 Posts
There have been several posts on this issue, but none that address the issue as well as this explanation I found on another site.

3M recently made a formula change to their Super 77 Spray Adhesive, to meet the new California Air Quality Management District Rule 1168. This required the solvent cyclohexane in the old 3M Super 77 formula to be replaced with acetone. If used inappropriately, acetone-based adhesives can dissolve the EPS and Styrofoam components of your foam model. The 3M corporation suggests the use of 3M Insulation 78 Spray Adhesive as a replacement adhesive for the bonding of Styrofoam. The formula change does not affect application onto EPP foam.

Remember to check behind the new formula cans to see if there are any old formula cans hidden away. To determine if you have the new or old formula, read the contents on the back of the can. Following the word “Contains”, the old formula lists “cyclohexane” as the first ingredient. The new formula lists “acetone” as the first ingredient. The old formula is packaged in the familiar, all black can. The new formula can is SUPPOSED TO BE dark orange fading to brown and finally to black. DON'T BUY STRICTLY BY THE COLOR OF THE CAN. I FOUND SOME SMALLER SIZE CANS THAT WERE SOLID BLACK, BUT HAVE ACETONE AS THE MAIN SOLVENT.

Follow these procedures when using the new Super 77 formula on foam. Practice on a piece of scrap foam to get the hang of it.

To apply Super 77 spray adhesive prior to taping or covering, hold the can 18 inches from the surface and apply a light coat. Allow15 minutes drying time between coats. Apply a second (and third, if needed) light coat.

To join foam pieces together (or to some other material), spray some adhesive into a disposable paper cup (remember what it does to foam?). Stir the glue for about 15 minutes to evaporate the acetone. With a small brush or a piece of scrap foam, apply thin coats of the glue to the surfaces to be joined. 5-minute epoxy is a more foam-friendly way to make these joints.
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Old Jul 12, 2002, 05:22 PM
Registered User
West Yorkshire,England
Joined Jul 2001
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Here in the UK I use 3M Photomount.

Comes in a red can and works a treat on all types of foam!

Bill
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