Primer before contact cement?

[Gerdo]

Is it best to primer the wood before you apply contact cement for the skin?

[ralaco]

Gerdo

Never seal where you are going to use any glue.



Raul

[IraRat]

Gerdo

Never seal where you are going to use any glue.



Raul

Well, I haven't been following THIS rule.

[madjack]

...neither have I, Ira. WE have prefinished/sealed almost all components of the Alligator Tear, however when we glue up something that has a finish/seal on it, we use a urethane based glue...so far I have seen no problems. Some adhesives do not work well on raw wood, some do not handle finishes well, it all depends on what you are gluing and what you are gluing with
madjack

[Gerdo]

So with contact cement is it best to seal the wood or leave it un-sealed?

[madjack]

...if using old fashioned contact cement(non water based) I would say leave it unsealed and use the contact cement as both seal and adhesive.

IMHO & YMMV(legal discalimers )

madjack

[IraRat]

On my exterior skins, which are bradded all along the perimeters anyway, I presealed with varnish and used a ton of Titebond II to secure. (It was cool watching that glue drip down onto the frame and tires.)

I guess if you're using a poly glue, usually requiring water prep to activate, and you had like 100% coverage with that glue, you wouldn't have to seal first.

But what are the chances that you're going to be able to adequately cover every square inch of the surface with that glue?

I figure the way i did it, the worst that could happen is I MAY have a tiny bulge somewhere that I can fix with a brad.

[madjack]

...Ira, some poly adhesives require water to activate them(gorilla glue) some use atmospheric moisture(humidity) to activate(Sikaflex) and some are 2 part adhesives requiring a primer
madjack

p.s. not all adhesives, even in the same category, work the same way...always read the instuctions(I know, I know) for proper uses and applications

[Mark]

What do you think about varnishing the wood prior to applying outdoor carpet adhesive to hold the aluminum? Do you think it's a waste of time?

[madjack]

...having no experience with the carpet adhesive I really can't advise one way or another. However, the sides of our tear have 3 coats of polyurethane on them and in the debate over carpet adhesive Vs. Sikaflex(or something similar) that has not even entered the conversation
madjack

[Ken A Hood]

Doesn't all glue/adhesive eventually break down? (The bond I mean between the wood and aluminum). My understanding (limited) is that the glue/adhesive will hold the aluminum side till all the corner trim/window/door etc. is installed to hold the edges.........floating the aluminum. Since wood and aluminum expand/contract at different rates, it's only a matter of time before contact cement (rigid adhesives) fail. I'm not sure about the flexible adhesives.

Sealing the sides (varnish) is done to protect the wood SHOULD any water get behind/underneath the aluminum sides/top/trim......or that's the way it was explained to me....


I will be starting soon..........need to get a new(er) vehicle 1st though.

[Chris C]

IraRat,

I really don't like being the bearer of bad news but..................wood glues (which, of course, includes Titebond II) soak into the fiber of the wood on both pieces and then bond the two together. If the wood is sealed first, it would be like trying to bond two pieces of non-porus materials together, like metal, and can't do it's job. Likely the only meaningful bond you'll have is the surface tension of the glue and your brads.

[Chris C]

IraRat, I think I misunderstood; your post. Did you mean you were attaching your aluminum with Titebond II?

[IraRat]

IraRat, I think I misunderstood; your post. Did you mean you were attaching your aluminum with Titebond II?

How did you bring aluminum into this? I'm not using that at all.

And don't worry about being the bearer of bad news:

Sealing my backsides on those skins, using Titebond to secure to the ply walls , and bradding all along the perimeter edges and around the door openings...where the heck is that that piece going to go?

Plus, it's not even STRUCTURAL. It's a skin.

[Chris C]

Okay. Sorry I brought it up.