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Flyin_Finn's avatar
Flyin_Finn
Explorer
Jun 17, 2015

Attaching fiberglass panel to plywood, usin contact cement

Hi,

I am replacing a 6x6 foot section of my outside wall on on my 5th wheel.
The plan is to first glue the thin fiberglass panel to the 1/8" plywood, and then attach the sandwiched panel to the aluminum frame.

I already purchased the glue, a red contact cement called Helmiprene 4570, made by Helmitin. I will spray the glue to the surfaces.
Once the glue dries, I will join the surfaces together.
This is where I am getting confused: I am supposed to apply pressure to the surface. Why? I thought it was an instant, strong bonding. Is the purpose of the pressure to strengthen the bonding? Is the pressure just momentary, for example using a j-roller?. Or is pressure supposed to be applied for a given curing time?
I do understand that I need to make sure there are no air bubbles trapped between the layers.

At the moment, I am experimenting with the gluing process on some scrap pieces, to make sure I do it right when I do glue the actual panel.
  • Flyin_Finn's avatar
    Flyin_Finn
    Explorer
    Jun 17, 2015
    Trackrig wrote:
    To achieve complete contact and avoid any air bubbles. Lay the top layer down from one side or edge, don't try to lay it down all at once - if that makes sense.

    Bill


    Yeah, that makes sense. I was thinking about starting from one of the corners. It will be tricky, but doable!
  • Trackrig's avatar
    Trackrig
    Explorer II
    Jun 17, 2015
    To achieve complete contact and avoid any air bubbles. Lay the top layer down from one side or edge, don't try to lay it down all at once - if that makes sense.

    Bill
  • Flyin_Finn's avatar
    Flyin_Finn
    Explorer
    Jun 17, 2015
    DrewE wrote:
    Typically the pressure is to ensure complete contact, as I understand it. A good rolling with a good J-roller should be sufficient. If the instructions don't specify some duration for the pressure, it seems to me it's pretty safe to assume momentary pressure is sufficient.


    Thanks for the quick reply. The retailer sold it in a generic can, with no written material or instructions, except for a MSDS printout. He did give some verbal instructions, such as spray it on rather than roll/brush.
    Just a moment ago, I found the mfg website, and sent them email, asking for the info.
  • DrewE's avatar
    DrewE
    Explorer II
    Jun 17, 2015
    Typically the pressure is to ensure complete contact, as I understand it. A good rolling with a good J-roller should be sufficient. If the instructions don't specify some duration for the pressure, it seems to me it's pretty safe to assume momentary pressure is sufficient.

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