The 3M 8115 discussion

Belgian1979vette said:
Well as far as their explanation on only bonding goes : i bonded the round thingies that go under the hood to keep the insulation in place on my L88 hood and gues what, they are showing ghost lines too.

An informed man ...
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I find it difficult to believe the 8115 is at fault here. I wish I could see
this car in person, but you're just a wee bit too far away. I have used this
product for years in numerous applications and have not experienced the
problems your encountering. I think the problem is elsewhere.
 
Belgian1979vette said:
Could be. I don't mind being told that i'm somehow at fault, but i don't see how. I used the 3M gun (expensive) etc etc....
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If your painter has a legitimate shop, why don't you get him to have the 3m rep stop by and look at it? That's what there are there for.
Look at the warranty they give in the link I previously posted.
If it's as good as they say, you might get something out of it, or at least find the causes.
 
I used Evercoat adhesive filler and Fibertech. No problems so far.

You probably don't need to get rid of all of it, just grind it down a bit and fill with one of the above two.
 
I'm sure I have mentioned this..I have read somewhere in the 8219/8115 tech sheets that these products should not be top-coated. They are adhesives, not fillers. That is why I use products like Evercoat 870, which is a filler designed exclusively for filling fiberglass and SMC. It is a high-solids polyester based product. Other products we use in my shop are Evercoat Fiber-tech. Recently we have started using a product called Addtech, by Cass Polymers. A 'Vette shop in Dallas has been using it with good success. http://www.adtechplastics.com/pc-23-34-p-11-type-l-frp-bond-fill.aspx
 
big_G said:
I'm sure I have mentioned this..I have read somewhere in the 8219/8115 tech sheets that these products should not be top-coated. They are adhesives, not fillers. That is why I use products like Evercoat 870, which is a filler designed exclusively for filling fiberglass and SMC. It is a high-solids polyester based product. Other products we use in my shop are Evercoat Fiber-tech. Recently we have started using a product called Addtech, by Cass Polymers. A 'Vette shop in Dallas has been using it with good success. http://www.adtechplastics.com/pc-23-34-p-11-type-l-frp-bond-fill.aspx
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I have never seen the mentioning of this in its tech brochure. Nor did the rep of 3M say something about it.
 
Both are adhesives but only the 8116 is good for SMC - the screenshot below is from Summit's website, I'll see if I can find the same info on 3M's....

214c192bfbdabe0.jpg

I have not seen any info anywhere that says it can be used as filler and that it can be topcoated....
 
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MYBAD79 said:
That's what I mean when I say "topcoating" - primer or paint....

Do you have this tech sheet for the adhesive?

http://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSu7zK1fslxtUN8txm8_Bev7qe17zHvTSevTSeSSSSSS--

It does not say anything about using this stuff as filler. It does mention that it can be used for "bumper cover repairs". These bumpers are typically urethane which is more flexible than fiberglass. It's probably just like Big_G said, it's an adhesive, not a filler.
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The 3M website has this:
354c1a090f19dfc.jpg

And the Product Uses from your link Karsten, states:
3M said:
...Typical substrates include cold roll steel, aluminum, SMC, and FRP...
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I used 8115 in all my body mods and although I did use it as a filler, it was never very deep or a large area and ultimately ended up with body filler over the top of it anyway. I used it to fill all the razor blade nicks I put in it too and then the whole car was primed with epoxy then hi-build primer. I know the car's not top coated yet, but the temperature extremes out here make me think that the 8115 would show itself, if it was ever going to.
Some of the repairs/mods in a few spots have sunk a little bit but I think this is pretty normal as the solvents evaporate but those areas don't appear to look any different at midday than they do late at night and I certainly haven't seen anything swelling or standing proud :confused:
 
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saudivette said:
and ultimately ended up with body filler over the top of it anyway.
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I think that is what makes the difference.... I'm just guessing (not claiming to be a chemistry professor) but I think the solvents in the epoxy or 2k primer are not compatible with the adhesive, it appears that it needs a layer of body filler to separate the adhesive from the primer or paint.
 
MYBAD79 said:
saudivette said:
and ultimately ended up with body filler over the top of it anyway.
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I think that is what makes the difference.... I'm just guessing (not claiming to be a chemistry professor) but I think the solvents in the epoxy or 2k primer are not compatible with the adhesive, it appears that it needs a layer of body filler to separate the adhesive from the primer or paint.
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This certainly is a good point, since the spots that have filler over it don't show.

But it still leaves the issue of the sound deadner fasteners under the hood that show on the top ....

Saudi, i don't know about your car, but mine certainly does it every time it gets out in de sun and not even very high temps. Look at the pictures i put in the thread. This is the kind of swelling i mean.
 
Coming back to this.

My different pieces and body are being painted as you know. My painter is taking his time to do it (takes my car in between other work he has to do and when he has the time), but results are perfect. BUT we are having a mayor PITA with that 3M stuff and in addition to this also with the original bonding seams of my body.

Apparently when in the paint booth and when being baked, every part that has the 3M glue or any original seam seems to show/swell. The only parts that do not show up, are apparently the ones that have about 2-3mm of epoxy filler on it.
 
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