Adhesive used for attaching plywood to steel plate..

[Joel Wesseling]

Hello All.

I need to sandwich 3/16 steel plate between 2 plywood layers.

I did this same project before and used construction adhesive. It
certainly works but the adhesive is thick and hard to spread evenly to a consistant thickness..
While clamping it wont dissipate well..

Maybe some of you have a recommended glue or 2 part expoxy..

Thanks in advance.

Joel

[Jerome Hanby]

Mr Sawdust instructs to use epoxy to attach the steel ribs between the two layers of his RAS table,,,

[John TenEyck]

Contact cement for non-structural applications, epoxy if it's structural.

John

[Ken Fitzgerald]

Here's a site I like to use: http://www.thistothat.com/

[Joel Wesseling]

Thanks,

I think the contact cement could work fine but forgot to mention gap filling is important.

I can do the gap filling before I glue in the second piece of plywood.
There's through holes in the metal and screws go through them and prefer the
holes get filled and cut srew threads well..

Does epoxy hold screws as well as plywood?

Thanks again, Joel

[Joel Wesseling]

Oh Yeh the Glue This To That site is cool, Thanks

[Chris Padilla]

Most epoxy dries hard enough that you could tap threads into it, Joel! :)

[Jim Heffner]

When I have a situation that requires odd things to be attached to one another, such as the one you mentioned, I generally use some of my Liquid Nails. That stuff really holds when other things WON"T! Give it a try....I'm surprised at what it does hold together!

[Mort Stevens]

While I'm not normally a big fan of it - this is an application where I would use polyurethane glue (ie "Gorilla Glue").

[Chris Parks]

Sikaflex, they glue cars together with it.

http://usa.sika.com/

[Joel Wesseling]

Thanks for all help..

I have some looking around experimenting to do before I pick..

Thanks again, Joel

[ian maybury]

On balance a liquid polyurethane like gorilla glue - because it's very easily spread, requires no mixing and is a structural/no creep adhesive. It is gap filling, but the foam that fills gaps isn't rigid (the adhesive film is) - use epoxy if the gap filling needs to be rigid.

Sikaflex is also a polyurethane, but those cartridge packed automotive structural adhesives are filled to increase the viscosity and awkward to spread.

Solvent washing with cellulose thinners or the like and roughening with sandpaper seems advisable.

Whatever the adhesive I'd be cautious about how long it might last and would want to check with a manufacturer's tech support (not a sales guy or a support line junior there because nobody else will do it - who will say whatever it takes to get a sale, but an applications engineering guy) - especially if the area is fairly large.

In that there is potentially even with ply quite a difference in rates of expansion and contraction with both heat and moisture, and the problem gets worse with size. Could be that even if it stays flat that either the adhesive or the ply will eventually fatigue and fail. Maybe expansion joints are a possibility?

ian

[Howard Acheson]

What will the panel be used for? My shop used solvent based contact adhesive to make something like you propose. Worked well. Of couse, epoxy will work fine also.

[Richard Dragin]

Epoxy. Wipe the metal down with acetone first.

[Myk Rian]

What are you making?

You could use a tile flooring trowel to spread adhesive.
Grout trowel?

[Joel Wesseling]

I'm making Speaker Cabinets. I have a CNC'd steel panel, shown in picture..
The wood will be machined slightly smaller than the openings in the steel..
The front panel will total about 18mm. The steel is 3/16"231274

Id like the adhesive to wrap around the two layers of wood at the inside cirlcle, hence the steel disapears A sheet goes in before the steel(not shown)

Thanks for all the responses. Joel

[Phil Thien]

Polyurethane glue.

[Alan Lightstone]

Here's a site I like to use: http://www.thistothat.com/

Cool site, Ken. Thanks.

[Joel Wesseling]

I like the look of this

[Joel Wesseling]

Polyurethane glue looks like a good possibilty

[Rich Engelhardt]

Here's what I'd do.

Prime the steel with red oxide metal primer (Rustoleum).
Use a mastic like Liquid Nails in the quart can.
Drill in from behind and runs some sheet metal screws through the back layer of ply and steel and into the front layer of ply.

[Stephen Cherry]

3m 5200, or epoxy with filler (west system sells several fillers for different purposes)

5200 sticks almost anything to almost anything, and it's a little flexible. Epoxy also sticks anything to anything, but it's hard. For structures, flexible adhesive is better in many situations because the flex allows a load to be distrubuted over a wider area.

[Greg Portland]

Hello All.

I need to sandwich 3/16 steel plate between 2 plywood layers.

I did this same project before and used construction adhesive. It
certainly works but the adhesive is thick and hard to spread evenly to a consistant thickness..
While clamping it wont dissipate well..

Maybe some of you have a recommended glue or 2 part expoxy..

Thanks in advance.

Joel
Would a disposable (plastic) notched trowel allow you to spread the construction adhesive evenly?

I would have some concern that the off-gassing of the adhesive solvents could harm the glue or surrounds of the speaker drivers.

[steve brownell]

I'd second what S. Cherry recommended: 3M 5200 is very tough, easy to apply and unfortunately, impossibly messy (wear gloves)
No need to paint the steel, just clean it. It may also have some marginal vibration damping effect too.
I've used it in this application while building boat bulkheads and installing metal backing plates and it's 100%.
But never plan on removing it.....that's a whole different story.

[ian maybury]

I've not used that 3M 5200 product (most 3M products are prohibitively expensive over here except for use in high value applications), but can also say that I've had good luck bonding metal (usually zinc plated duct fittings well sanded) to wood with bog standard polyurethane sealers and structural adhesives. There's very little that seems to prevent PU getting a good grip on lots of surfaces. I'd still be wary of the effects of movement over larger areas though.

I worked for a period in adhesive assembly systems R&D, and while I don't know much about polyurethanes ended up with the view that the performance of most adhesive systems is primarily a function of the basic polymer chemistry. (polyurethane, epoxy, methacrylate etc) As in the chemists play around with all sorts of additives (e.g. powder fillers to adjust viscosity, and plasticisers to adjust flexibility) to enable all sorts of claims and inflated selling prices, but in the end it doesn't make that much difference.

You'd be amazed how often the latest wonder product (especially if it's application specific) entails little more than a colour change and a shake more fumed silica powder to adjust the viscosity.

That's not to say that there aren't exceptions...

ian

[Patrick Grady]

Another vote for 3M 5200. Its holding and gap filling and flexibility and overall holding strength make it perfect for your application. But as said previously, it is notoriously nasty and permanent. I think the stuff was invented in the devils own workshop and years ago I banned it from my boat (4200 is slightly more workable). Much has been written about 5200. It is great strong permanent stuff but you must be careful about where you turn it loose.

[Joel Wesseling]

I'll Get 3m 5200 and test it out..

Thanks

[David Sharp]

What is the purpose of the steel? 3m also makes a 4000 series adhesive that is like a fast setting 5200. West epoxy thickened with cabosil would be quicker to spread and probably cheaper. 5200 doesn't spread that well and costs about $12.00-15.00 a tube.

[Joel Wesseling]

The steel gives better mechanical stability for the drivers..The audible difference is increased three dimensional focus..
The ultimate way is a 3/4 machined Aluminum front panel but the cost is to high..

I saw the West epoxy system over the weekend.. Going to have to make a choice..

Thanks, Joel