Hmm what did I do wrong

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Hmm what did I do wrong

Postby Outoforder » Mon Apr 06, 2020 8:22 am

So I primed the foam with kilz let it dry
Painted the foam with tite bond 2 1to1 with water placed the canvas on the foam and then painted the canvas with tite bond 2 with water

Four days later the canvas peels off

What did I do wrong?
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Re: Hmm what did I do wrong

Postby KennethW » Mon Apr 06, 2020 9:03 am

You don't paint the foam !!! You should have when over the foam with a wallpaper cutter(used to remove pall paper) then glued the canvas to the foam with lots of tite bond II. NO KILZ
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Re: Hmm what did I do wrong

Postby ghcoe » Mon Apr 06, 2020 10:24 am

Canvas will peel off of foam quite easily if you try. The idea is not to try. What seems to be a weak bond is actually all you need. The strength comes in shear not in lift.
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Re: Hmm what did I do wrong

Postby Outoforder » Mon Apr 06, 2020 11:35 am

ghcoe wrote:Canvas will peel off of foam quite easily if you try. The idea is not to try. What seems to be a weak bond is actually all you need. The strength comes in shear not in lift.
Ohhhh ok thanks!

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Re: Hmm what did I do wrong

Postby Outoforder » Mon Apr 06, 2020 11:37 am

KennethW wrote:You don't paint the foam !!! You should have when over the foam with a wallpaper cutter(used to remove pall paper) then glued the canvas to the foam with lots of tite bond II. NO KILZ
Hmm oh well everything I read and watched said to prime the foam...... could a saved $20

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Re: Hmm what did I do wrong

Postby ghcoe » Mon Apr 06, 2020 12:27 pm

Outoforder wrote:
KennethW wrote:You don't paint the foam !!! You should have when over the foam with a wallpaper cutter(used to remove pall paper) then glued the canvas to the foam with lots of tite bond II. NO KILZ
Hmm oh well everything I read and watched said to prime the foam...... could a saved $20

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I have applied with and without primer and I have never used a wallpaper cutter. I have had a slight delamination issue on the body that I did not use primer first. Although I can not really determine if that was the real issue or not at this point. I do feel you get a better bond with the primer. I have not used KILZ though.

Also, I do highly recommend wiping foam down with alcohol and/or sand before applying paint or adhesive.
George.

Gorrilla Glue, Great Stuff and Gripper. The three G's of foamie construction.

My build viewtopic.php?t=54099
Working with flashing for foamie construction viewtopic.php?f=55&t=60303
Making a hot wire http://tnttt.com/viewtopic.php?f=55&t=55323
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Re: Hmm what did I do wrong

Postby JazzVinyl » Mon Apr 06, 2020 6:35 pm

I think as George says...that you must sand using a sanding block and get the shiny surface off the foam (this is a very important step), He also says wipe off the surface twice, 2nd time use rubbing alcohol before gluing and this is also important, I think...

I did prime mine with Kilz2 and no problems thus far. Also very important (I think) is the roller. You must press the canvas down real good with the roller. The TB2 50/50 mix applied such that the weave is saturated. Use a spray bottle and wet the canvas some before pressing it in with the roller. I used lots of push pins to hold the canvas in place as it dries...

And in more humid areas, may take more then one day for the glue to fully dry?

The procedure I used is exactly what George specifies in his tutorial vid:

https://www.youtube.com/watch?v=NeR6WVAlenk

And I can tell you....it works!

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Re: Hmm what did I do wrong

Postby pchast » Mon Apr 06, 2020 8:37 pm

Depending on how much you coated your canvas it may take several days to dry thoroughly. Mine took 4 or 5 through a period of high humidity and rain.

There are several methods to prepare the foam. The problem stems from the method used to make it. A release may be used in the mold. Or if extruded in a long sheet the outer 'skin' may be harder and slippery. These things resist adhesion.

Variously: scoring, puncturing, sanding and or washing with solvent can be used to improve adhesion of the applied membrane.

The envelope is the strength more than the attachment to the foam as stated above.
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Re: Hmm what did I do wrong

Postby GPW » Tue Apr 07, 2020 4:06 am

We’ve tried many different ways and things to adhere canvas to foam and ALL seem to be fairly easy to tear off … But as George has said , The real Strength of the foam cabin is the unified “SOCK” that covers it … Just like a sock holds all your toes in , so it does to the Foam … So simple … Well proven by now ... :thumbsup:
There’s no place like Foam !
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