joining to a surface aluminum body panels

[dkm0038]

what are the best options for joining things to body panels?

I've got an aluminum body panel that i'd like to attach a few brackets to the b-side w/o any exposed fasteners or read thru to the a-side. it could be supporting up to ~10lb and would see some good vibration and wind load. first thought is somehow bonding or structural tape but don't have any experience and not sure if any concern running thru a paint oven.

thanks, look forward to any specific suggestions

 

[Dave K]

We've used Hysol adhesives on various race cars, I forget which number, but when properly prepped, it's got some serious holding strength.

-Dave

NX 11, Teamcenter 11

 

[MintJulep]

If you want specific suggestions you really need to provide some specific requirements first.

Good vibration
Wind load
paint oven

 

[TugboatEng]

Acrylic adhesives such as 3M DP805 or DP820 are the go to. See Click Bond for some examples. You'll probably want to etch or abrade the aluminum surface first. Depending on the thickness of the panel it may not be wise to simply attach a fastener in the center of a wide, unsupported portion of the panel.

 

[BrianPetersen]

In a normal application, structural attachments aren't made directly to outer skin panels, not even on the inside. Trim parts, and little parts, sure ... stuff that doesn't have much load on it.

If you find some way to attach something heavy to the inside of a skin panel and it isn't suitably reinforced, even if you make it stick, it's asking for distortion of the panel, which will be visible from the outside. That's why it's not done (except for light stuff).

Normal practice is for everything structural to be attached (by welding or riveting or bolting or whatever) to the structural panels under the skin (which also means the appearance doesn't matter so much) and the outer, cosmetic skin panels are either attached to the inner structural panel by a stripe of adhesive all the way around and then hemming (folding) the edge of the outer cosmetic panel around the edge of the inner structural one (open the door of your car and look at the inside of any of the edges around the perimeter, you can see the outcome), or bolting them on via flanges around the edges that end up being covered by other parts (front fenders are usually done that way). Doesn't matter much whether it is steel or aluminum construction.

Now, explain why you can't do it that way.

 

[gruntguru]

If this is a one off eg adding something to a custom car, you can get away with it by ensuring you bond to a large surface area and use an adhesive that will conform (highly thickness tolerant) and flexible. Possibilities include a number of Sikaflex products ([link file:///Users/test/Downloads/Dist.WallChart_Sika-Product-Range%20.pdf]Link[/url]) eg 255 Extra, silicone sealants, T-Rex or similar.

je suis charlie

 

[GregLocock]

I agree with Brian, but if you are in production, talk to 3M, they do lovely things with tape.

Cheers

Greg Locock


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