Bonding sheet aluminum to composite Panels?

[Rusgo]

I'm in the middle of a flatbed camper build in the fullsize section and need a bit of expertise.

I have surplus 30mm honeycomb panels from a yacht builder with a fiberglass weave on both sides. They will be bonded to the outside of the aluminum camper frame, then 1/16 aluminum sheet will be bonded on the outer side of the panels as an exterior skin.

I'm thinking of using a fiberglass epoxy with good aluminum bonding characteristics. Might be asking a lot of it. A Sikaflex type product might work for the frame side of things, but the aluminum sheet side needs to be more spreadable.

Suggestions?

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[mrfoamy]

I think I would add wood flour to any boat building epoxy until you reach your desired consistency and spread with a 1/8" notched trowel. Research surface prep on the aluminum. Sand, clean, then possibly a primer.

 

[IdaSHO]

Plenty of adhesives out there that would work, but dont skimp on aluminum prep.
The aluminum will need to be sanded and primed with the appropriate primer.

 

[Alloy]

Try Henkle. The company own Loctite and many others.
We used a Methyl methacrylate (MMA) on new alum. that had an incredible bond strength. It did not require any mechanical (sanding/grinding) prep.

Products

www.henkel-adhesives.com

 

[Alloy]

One more thing......the thermal expansion of aluminum (in the sun) is several times greater than fiberglass. Bonding a fiberglass sheet to the panels might work better.

 

[IdaSHO]

We used a Methyl methacrylate (MMA) on new alum. that had an incredible bond strength. [/URL]

While MMAs are great, the volume needed for bonding full sheets might be prohibitive.

Epoxy might be a better alternative, and with the correct prep just as strong or stronger.

 

[VerMonsterRV]

Although a bit more labor intensive you could layer a couple/three layers of fiberglass on the panels then paint. Would take care of the thermal expansion difference. Then the build would become a bit like Everlanders on Youtube (which I think they did a great job on the build, minus the no windows thing).

 

[Rusgo]

Try Henkle. The company own Loctite and many others.
We used a Methyl methacrylate (MMA) on new alum. that had an incredible bond strength. It did not require any mechanical (sanding/grinding) prep.

Products

www.henkel-adhesives.com

I gave them a call and they pointed me toward this epoxy stuff. 9430.

Loctite 420338 - 9430 Hysol Adhesive, Impact Resistant, 1.2 Gal

<p>The Loctite 420338 is a Series 9430 epoxy adhesive with a mix ratio of 100:23.</p><b>The Loctite 420338 Features: </b><br><ul><li>High peel and high shear strength</li><li>Room temperature cure</li><li>Bonds variety of substrates</li><li>Long pot life</li><li>Excellent low temperature...

www.hisco.com

Seems pretty great. Big kit too.

They said that MMA cures very hard so might not handle thermal expansion of different materials well. What did you bond the aluminum to?

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[Rusgo]

While MMAs are great, the volume needed for bonding full sheets might be prohibitive.

Epoxy might be a better alternative, and with the correct prep just as strong or stronger.

Found this epoxy system. Company says it bonds very well to plastics and aluminum. Some commercial body/box builders use it for a panel adhesive. And it comes in a gallon kit.

100 minute cure time. Multiply purpose multi material system.

Araldite 2011

Araldite 2011 is a multipurpose, high strength, viscous, epoxy adhesive. This versatile paste has the capabilities to bond a wide variety of materials including metals, ceramics, plastics, glass, rubber and most other materials. It has good resistance to dynamic loading and it provides a long...

krayden.com

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[Rusgo]

One more thing......the thermal expansion of aluminum (in the sun) is several times greater than fiberglass. Bonding a fiberglass sheet to the panels might work better.

Yeah that's my main concern. I have the aluminum sheets and panels already so trying to find a super durable tough flexible long term options for what I'm using is high on my current list.

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[Alloy]

I gave them a call and they pointed me toward this epoxy stuff. 9430.

Loctite 420338 - 9430 Hysol Adhesive, Impact Resistant, 1.2 Gal

<p>The Loctite 420338 is a Series 9430 epoxy adhesive with a mix ratio of 100:23.</p><b>The Loctite 420338 Features: </b><br><ul><li>High peel and high shear strength</li><li>Room temperature cure</li><li>Bonds variety of substrates</li><li>Long pot life</li><li>Excellent low temperature...

www.hisco.com

Seems pretty great. Big kit too.

They said that MMA cures very hard so might not handle thermal expansion of different materials well. What did you bond the aluminum to?

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We were bonding a.188 alum hat sections to .188 alum sheet.
Our test will bond was 2pcs of .188 x 2"W x 10"L flatbar bonded together with a 2" overlap. We then bent the 18" long flatbar 90 degrees.

Get the name of the local rep and see if they can supply some product for testing.

Edit.....the spec sheet for the epoxy didn't mention aluminum

 

[Alloy]

Yeah that's my main concern. I have the aluminum sheets and panels already so trying to find a super durable tough flexible long term options for what I'm using is high on my current list.

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Sheets are new or like new? As aluminum ages the oxide builds which make bonding more difficult.

How big are the sheets? Will you have to seam the alum sheets? Some fiberglass is on rolls 8' wide .

 

[Rusgo]

We were bonding a.188 alum hat sections to .188 alum sheet.
Our test will bond was 2pcs of .188 x 2"W x 10"L flatbar bonded together with a 2" overlap. We then bent the 18" long flatbar 90 degrees.

Get the name of the local rep and see if they can supply some product for testing.

Edit.....the spec sheet for the epoxy didn't mention aluminum

I noticed on the TSD they did use it for aluminum. At the moment it's between loctite 9430 and Araldite 2011.

9430 does have better elongation at 6% vs 4% for the 2011. That might be a factor in expansion. But the fiberglass will allow for a thicker layer of adhesive, which will compensate for expansion some.

Leaning toward Alaldite. It seems like more of a universal product that could be used in other parts of the build.

Both are about $300 for a gallon kit. Yikes.

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[Rusgo]

Sheets are new or like new? As aluminum ages the oxide builds which make bonding more difficult.

How big are the sheets? Will you have to seam the alum sheets? Some fiberglass is on rolls 8' wide .

Sheets are new. Still going to clean and etch.

Panels are 4x7x1.25 aluminum is 4x10x.067. Will cut the aluminum to fit. Thinking about tig welding the aluminum panels to make it seamless. Would have to do that before the bonding.

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[Alloy]

Sheets are new. Still going to clean and etch.

Panels are 4x7x1.25 aluminum is 4x10x.067. Will cut the aluminum to fit. Thinking about tig welding the aluminum panels to make it seamless. Would have to do that before the bonding.

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Welds will shrink...distort the sheet...the seam will end up looking like it was pounded on with a hammer.