Heater box foam adhesive

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adam83

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I've prepped the metal flap doors for new foam in my 71 non ac heater box. I've got the foam kit from Detroit Muscle Technologies. Kit says to use 3m super 77 for adhering the foam, but I've read people saying to use 3M 90 spray adhesive, 3M yellow weatherstrip adhesive, and permatex black right stuff.

I have all these available to me, wanted to know your opinions on using one over the other.
 
I would NOT use silicone ANYWHERE on the body. Silicone is for engines. The other 3m products are just fine. I'd use the super 77 because it's easier.
 
If the kit specifies a certain chemical and you can easily get it why stray from success?
 
No problem with the super 77, Just looking for opinions and experiences people have had whove done this and what they used.
 
I have done 4 boxs with DMT kit, ive always used the 3M 77.... works great every time...Rich
 
mad dog said:
I have done 4 boxs with DMT kit, ive always used the 3M 77.... works great every time...Rich
Click to expand...

Do you use the adhesive on both the metal and the foam separately then stick them together?
 
i only spray the foam, i let it tack up for a minute and then apply to the metal doors..... be careful to only spray the backside of the foam, sometimes it gets confusing..hope this helps
 
I like to spray only the surface the foam is going on and apply the foam right away.
Any area that doesn’t stick down immediately will on the second press.
 
The only problem I had with it was getting my hand into some of the tight spaces to lay the foam down, especially after it was sprayed with the tacky stuff. I got my 8 year old grandson to fit his hand in where mine wouldn't go.
 
The 77 worked out great for the lighter foam on the doors and inner doors, and also the denser foam that goes between the boxes and cowl. I feel like you could peel up the foam if you really pulled hard, but the foam will never see that kind of force inside the heater box.

On the white foam strip that goes between the inner door and metal plate, i used 3M yellow weatherstrip and trim adhesive, it holds stronger and that white strip is in there tight.

I also used some 3M strip calk around the heater core where it meets the box. Probably unecessary but i went overboard on this project already.. cleaning and repainting all the doors, blower motor, rivets and the metal backing plate on the box.

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those white foam strips can be tricky, nice job, looks really good..Rich
 
Thanks. I followed your lead and sprayed only the foam for most of it, and glad I did because to evenly apply the adhesive on the doors or box you'd have to tape off a lot to avoid a huge mess
 
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