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Suggestions for gluing aluminum strip to pine

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Forum topic by wdm posted 07-28-2019 08:21 PM 457 views 0 times favorited 13 replies Add to Favorites Watch
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wdm

9 posts in 1881 days


07-28-2019 08:21 PM

Topic tags/keywords: glue wood metal

Anyone know what kind of glue to use to attach a 1/8” thick by 1.5” wide aluminum strip to the 1.5” edge of a pine 2×6. I have two 24” edges and two 48” edges that I need to attach the aluminum strips to. The 2×6’s are part of my brewery kegerator that the lid of a 15 cu ft freezer closes onto the aluminum, so it will be subjected to 38 degrees.

I have already used construction cement and that didn’t work. Construction cement stuck just fine to the pine but eventually did not stay adhered to the aluminum. Side note: it was a load of fun getting the cured construction cement off the pine without damaging the wood. Had to use the old nasty strypeeze and that took at least 3 applications. Anyway, appreciate some help here.


13 replies so far

View waho6o9's profile

waho6o9

8701 posts in 3024 days


#1 posted 07-28-2019 08:33 PM

View mnguy's profile

mnguy

277 posts in 3845 days


#2 posted 07-28-2019 08:38 PM

I don’t understand exactly where this pine + aluminum is going on your kegerator, but why can’t you attach it with countersunk #4 FH screws? Or at least use a few of these screws to help the epoxy or other adhesive? This would give you full adherence, the seal between wood and aluminum (assuming that is important here), and give you a flat aluminum surface.

Abrading the adhesive side of the aluminum with sandpaper will likely help, too.

View wdm's profile

wdm

9 posts in 1881 days


#3 posted 07-28-2019 09:31 PM


I don t understand exactly where this pine + aluminum is going on your kegerator, but why can t you attach it with countersunk #4 FH screws? Or at least use a few of these screws to help the epoxy or other adhesive? This would give you full adherence, the seal between wood and aluminum (assuming that is important here), and give you a flat aluminum surface.

Abrading the adhesive side of the aluminum with sandpaper will likely help, too.

- mnguy

mnguy, thanks for the suggestions.

fyi, you take a chest freezer, remove the lid, and attach a 2×6 to the freezer (vertically), then reattach the freezer lid so it closes on the 2×6. This increases the height of the freezer to make room for the kegs and provides a place to install the beer taps. The aluminum strips provide a better seal for the lid than just the wood. I suppose if I could find some plastic strips instead of aluminum they would be easier to attach and probably a better seal than the aluminum.

Anyway, I like your idea of some counter sunk screws if it can be done where the lid seal does not hit.

Also I did clean and abrade the adhesive side of the aluminum, spread a thin layer of construction cement and clamped well so I don’t think it the problem was in the gluing.

View CaptainKlutz's profile

CaptainKlutz

1613 posts in 1941 days


#4 posted 07-28-2019 09:53 PM

Best Luck, as Aluminum bonding is very tricky.
Your adhesion issue is because of the way aluminum reacts with air to create oxide layer – instantly.

Aluminum oxides have very poor adhesion to base metal, and are easily de-bonded with moisture or any polar solvent.

The professional way to bond aluminum is to have the surface stripped, chemically cleaned, and plated with chromate conversion coating that is removes the aluminum oxide issues. The amateur method of improving aluminum bonding is to use abrasion seconds before application of adhesive.
Reference: http://www.epotek.com/site/files/Techtips/pdfs/Tech_Tip_24_-_Bonding_to_AL.pdf

Once method recommended by amateur boat building community for bonding aluminum to wood/fiberglass; is to abrade the aluminum surface with 60-80 grit sand paper with the epoxy applied to surface at same time. This prevents oxygen from reaching the surface and allowing the oxides to weaken the bond to metal. It works, but it is very messy. The low viscosity lamination epoxies (as sold by West Systems, or System 3) used for this application will create a stable bond to aluminum. A thicker structural epoxy will work, but is total PIA during the sanding process.

Suggestions:

#1: Use steel strips and paint steel. Much easier to bond clean steel with epoxy.

#2: Use a slow cure laminating epoxy with clean aluminum strips. If the cure time is too fast and generates to much heat in aluminum; the wood and aluminum will expand at different rates, which will build in stress to the joint. A stresses joint will break if joint sees any serious impact event.

PS – Even professionals have random issues with aluminum bonding. Getting it right is almost a like accepting a religion. The key is using a consistent surface prep to avoid oxides or any contamination, and following the mfg recommendation for the chosen adhesive.

You have my condolences if you continue to chose aluminum and only adhesives for this job.

Cheers!

-- I'm an engineer not a woodworker, but I can randomly find useful tools and furniture inside a pile of lumber!

View bilyo's profile

bilyo

774 posts in 1549 days


#5 posted 07-28-2019 10:14 PM

Many refrigerators/freezers use magnetic gaskets. You might check to see if that is the case with your freezer. If so, you might be better off using a steel angle. You could let one leg of the angle hang over the outside edge of the 2×6 and screw it through that surface so that it would be secured in place without interfering with the seal. If the seal is not magnetic, you could also get an aluminum angle and mount it the same way. You would not even need glue. Just caulk it to have a good seal.

View John Smith's profile

John Smith

1912 posts in 610 days


#6 posted 07-28-2019 10:29 PM

I have had a heck of a time removing Weldwood Contact Cement from aluminum.
and almost impossible to remove 3M-5200 Marine Adhesive.

.

.

-- I am a painter. That's what I do. I paint things --

View squazo's profile

squazo

131 posts in 2092 days


#7 posted 07-28-2019 10:53 PM

regular old 100% silicone, i tell you i tried removing some of a piece of aluminum with a pressure washer once I ended up having to scrape it. I just used some the other week to glue a strip of aluminum to some other aluminum in an entry way, left it alone for 2 days and now I step on it daily, good to go.

Im sure any kind would work but to ease your mind I use the GE silicone 2+ the kind that says 10 yr mold free protection its 5 bucks a tube. glue it and leave it alone for at least 24 hours.

View AlaskaGuy's profile

AlaskaGuy

5332 posts in 2756 days


#8 posted 07-28-2019 11:32 PM



regular old 100% silicone, i tell you i tried removing some of a piece of aluminum with a pressure washer once I ended up having to scrape it. I just used some the other week to glue a strip of aluminum to some other aluminum in an entry way, left it alone for 2 days and now I step on it daily, good to go.

Im sure any kind would work but to ease your mind I use the GE silicone 2+ the kind that says 10 yr mold free protection its 5 bucks a tube. glue it and leave it alone for at least 24 hours.

- squazo


+1

-- Alaskan's for Global warming!

View therealSteveN's profile

therealSteveN

3351 posts in 1021 days


#9 posted 07-29-2019 02:26 AM

Use some sandpaper to rough up the back of each piece. The side where they will contact each other.

Wood must be dust, glue, and finish free, all of them will interfere with the bond.

The Aluminum must be cleaned with a degreaser. Heavy oils are used in the extrusion process. Some aluminum even feels slick, wash it even if it doesn’t. No matter which brand of cleaner it must say “cleaner and degreaser”

Use any good 2 part epoxy bonding agent, it will probably say bonding agent. I like the JB Weld products, they seem to have great bonds. The problem with them is reading the backs, and getting the epoxy which specifies wood, and aluminum. Probably any bonding epoxy will work though.

For the first few hours clamping the pieces together makes sure that while bonding there is no separation. This is important. If it is a thing that won’t allow a clamp, then the screws mentioned before are your clamp.

Done this way you can do chin ups after 1 day.

-- Think safe, be safe

View SMP's profile

SMP

1302 posts in 352 days


#10 posted 07-29-2019 03:58 AM

Yep I have had to scrape 100% silicone off of aluminum bar many times. Does not want to come off. Though usually metal to wood connections i try to use mechanical fasteners. Countersunk aluminum screws with some filler to make smooth.

View ocean's profile

ocean

172 posts in 1280 days


#11 posted 07-29-2019 01:41 PM

+1 on the 3M-5200. Also available in fast cure.

-- Bob, FL Keys

View theart's profile

theart

108 posts in 1001 days


#12 posted 07-29-2019 02:52 PM


Many refrigerators/freezers use magnetic gaskets. You might check to see if that is the case with your freezer. If so, you might be better off using a steel angle. You could let one leg of the angle hang over the outside edge of the 2×6 and screw it through that surface so that it would be secured in place without interfering with the seal. If the seal is not magnetic, you could also get an aluminum angle and mount it the same way. You would not even need glue. Just caulk it to have a good seal.

- bilyo

I would use an angle even with aluminum. The hanging leg could go on the inside if aesthetics are an issue. There are going to be all kinds of movement issues with the temperature and humidity swings this part is going to see. It might be too much shear stress for most adhesives even if the bond is good.

View wdm's profile

wdm

9 posts in 1881 days


#13 posted 07-30-2019 08:51 PM

Been out of pocket for a bit. Thanks for all the suggestions. The lid gasket is not magnetized so using steel is not necessary. If I don’t use the aluminum I already have cut, I will probably use some sort of plastic. I do have some left over “formica” that I used for the table tops for my routers. Been awhile since I did that but I think I used rubber cement. Not sure about the exposure to the cold.

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