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O/T - Bonding thin aluminum sheet to composite board?

Terry Keeley

Terry Keeley

Titanium
Joined
Oct 18, 2005
Location
Toronto, Canada eh!
I need to bond some 0.025" 3003 aluminum to fiberglass composite board (Coosa board) for trailer doors.

Thought about contact cement but I hate that stuff, if it ain't perfectly aligned the parts are trashed.

Also thought about 3m polyurethane adhesive but it's not thin enough to roll or brush.

https://www.3mcanada.ca/3M/en_CA/p/d/b40066983/

Would like something I can move the aluminum a bit for alignment before it sets up. Parts are roughly 5' x 18" each.

Any suggestions?
 
There are a thousand formica mechanics building kitchen counter tops that are laughing at you for not being able to use a few dowels to place the top sheet accurately. ;-)
 
Put wax paper between the 2 and gently slide the paper out while you guide the 2 halves where you want them
Don


Sent from my iPhone using Tapatalk Pro
 
Terry Keeley said:
I need to bond some 0.025" 3003 aluminum to fiberglass composite board (Coosa board) for trailer doors.

Thought about contact cement but I hate that stuff, if it ain't perfectly aligned the parts are trashed.

Also thought about 3m polyurethane adhesive but it's not thin enough to roll or brush.

https://www.3mcanada.ca/3M/en_CA/p/d/b40066983/

Would like something I can move the aluminum a bit for alignment before it sets up. Parts are roughly 5' x 18" each.

Any suggestions?
Click to expand...

West system epoxy thickened to stay on the surface of the fiberglass board and not seep through
Vacuum bag to clsmp while it goes off.
 
3m makes some "tapes" (I forget the names) which are meant to be permanent - as in people put exterior panels onto RVs with it. I think "VHB" is the stuff of interest.

You'd still have the alignment/trim issue.

While I often read about the stuff, I've never actually used it - do your diligence.
 
Most fiberglass is made with polyester resin which is not really compatible with epoxy resin. It will hold, but the bond will degrade. There are some products used in the automotive industry for gluing body panels on such as “3M panel bond 38315”. Make sure you abrade the surfaces well to get a good mechanical bond
 
You will need to bond aluminum to both sides to have a balanced panel. There will be slight differences in dimensions with temperature changes and the panels will curl if not balanced. Bond also needs to be flexible for same reason. I would cut aluminum oversize and trim just like making a plam counter top. I have made thousands of plam counter tops. Contact cement is easy enough if you spray the stuff. Roll or brushing will leave lumps that will telegraph through and surface reflections will look like crap. 3M VHB films is an even better choice.
I have never used dowels or wax paper to help with aligning the laminate. I do have a big bundle of old aluminum window blind leaves that work better. Once aligned I slip the end leaf out and touch down the end. Then roll up the laminate, pull out blinds and smooth down the plam as I lay it down across the entire length.
 
The panel adhesive that body shops use to attach Ford box sides to trucks is pretty runny right out of the mixxer tube, and stays that way for awhile. I don't recall the name of it, tho...
 
Thanks for the suggestions.

I thought about using West Systems epoxy (it's on hand) but figured I'd us a whole quart or so and for the price it's kinda over-kill. The “3M panel bond 38315” would be similar.

Tapes would add too much thickness and the door sealing "J" channels wouldn't fit.

Was just gonna do the outside, hopefully things don't move too much as Scruff mentioned.

Think I'm gonna try 3m Super 77 with dowels and rolling it out from the middle to avoid bubbles. It says you can reposition pieces slightly for the first minute or so, anyone have experience with it?

https://www.alliedelec.com/m/d/910adcb514356ea101325ef78c982022.pdf
 
You can look for transfer adhesive. It is like tape without the tape. There is a peel off backing that leaves just the adhesive behind.
 
The 3M Super 77 worked well, I positioned the aluminum over the board with dowels and 1-2-3 blocks for alignment and worked it center out with a paint roller.

I don't know why they say it's "repositionable", once it's down it's down.

Thanks for all the help.
 
bryan_machine said:
3m makes some "tapes" (I forget the names) which are meant to be permanent - as in people put exterior panels onto RVs with it. I think "VHB" is the stuff of interest.

You'd still have the alignment/trim issue.

While I often read about the stuff, I've never actually used it - do your diligence.
Click to expand...

I’ve used it , very very good. built a conversion hauler on a class 8 truck frame.was square tube. Sanded the tube with 80 grit on a da sander to prep it, epoxi primered it , scuffed with scotch brit pad, cleaned with wax and grease remover ,applied the tape and stuck .047 alum sheets. Your right ,absolutely no repositioning. Had to cut one sheet off because of that but 10 years of winter time use in mn in salt and no delamination.
But, you must buy the commercial tape not the stuff for emblems. Oh ya not cheap either.


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thermite said:
Laminate trimmer, actually.

What's so wrong about you doing the same thing, exactly, to the coosa board OR the shiney-wood, AFTER bonding them together - with wotever sort of guides it takes to hit the spec dead-nuts?
Click to expand...


Guess I coulda left the aluminum big and used my router to trim it but I wasn't sure how it would cut.

As it turned out it wasn't as big a deal as I thought aligning the parts and pulling dowels as CalG mentioned in post #2.
 
Terry Keeley said:
Guess I coulda left the aluminum big and used my router to trim it but I wasn't sure how it would cut.

As it turned out it wasn't as big a deal as I thought aligning the parts and pulling dowels as CalG mentioned in post #2.
Click to expand...

We would typically TILT the sub with a simple rail brad-attached, "downhill" side and one end. The contact cement (Weldwood, IIRC?) had "dried" so UNcoated flat strips served to prevent attaching whilst the laminate was tilted - fair close to the vertical, on initial positioning - to pick up the fences, spacers retracted, dropped right into place.

Thin Shiney-wood, once adhered to a substrate, edge-trims more neatly that one can shear it. A Carbide-tooled router will even work Cast Iron rather well.

Chips are right hazardous, though!
 
Glad the contact cement worked. Your first thought of using polyurethane glue will also work and it is quite easy to spread with a custom roller.
I have not tried the 3M poly glue as I use a German brand. It is a bit thinner than the very common Gorilla glue.

I have glued large panels in my vacuum press and the one step process with fast cure time is an advantage over other glues. However you have to be able to spread it pretty fast! The roller I made quite easily from a piece of radiator hose that was the right size to slip over a regular (short) paint roller. The smooth surface of the rubber hose allowed easy rolling and spreading of the glue. A very constant film thickness was easily achievable.

And as you may know a little bit of poly glue goes a long way. It is really an excellent glue but don't get any on your hands as it will be with you for quite a few days. Cleaning off the glue is its only real problem and the roller I made is still being used, I roll off the excess glue on a piece of paper and then just let it dry, still going strong after a few years.

My supplier now stocks poly glues that have variable open times. This is a fantastic bit of progress over the one type fits all original product with quite a short open time. The range is something like 20,40 and 60 minutes. When I made the roller I had only one choice of poly glue open time, now with the longer open time I can do larger projects with multiple layers which is handy when doing veneer layups and curved work.
 
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