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Horst
09-17-2015, 03:39 PM
Im covering a thick steel vibrating table top (24x24) with 22ga. 304 #4 stainless.

I dont want anything protruding above the surface. Frequency ≈60 Hz and amplitude will be whatever the mounts allow (McMaster-Carr # 9378K22 - 0.20 max). The vibration unit (CVC-RES 1-2) has adjustable force from 0 220# and Im guessing Ill be operating in the 10%-20% range.

My initial thought is to rake on Liquid Nails, flip the table top over and let its 120# mass set the stainless, but prudence dictates I inquire of those who might actually know what they are doing.

bob_s
09-17-2015, 06:23 PM
Your shaker table looks to be able to generate approximately 5.4 G's at maximum settings.

I wouldn't trust any glued joint at that kind of loading.

But what the heck, build a small test pedestal with 304 sheet glued to the top, mechanically attach it to the table and test it out.

If it works wonderful! If it doesn't no big deal.

Kiwi
09-17-2015, 06:28 PM
Stitch weld around the edges with a tig welder ?

Mike Burch
09-17-2015, 06:42 PM
Epoxy.

10KPete
09-17-2015, 08:01 PM
There is an epoxy, I believe it's made by System Three, called 'G-Flex, that I've used successfully to bond sstl to epoxy/glass
composites, carbon steel, wood, etc. It's a 'toughened' material that stays a bit flexible and doesn't crack during temperature
cycles on materials with different coefficients of expansion. I've always sanded/bead blasted the metal and super cleaned.
Never used it for shocks like you're describing but with that amount of area available......

Pete

Horst
09-17-2015, 08:33 PM
I am now thinking what I will do is to restrain the edges of the SS sheet both laterally and vertically and let it go at that. The SS is flat enough that I think it will just lay there.

Glug
09-17-2015, 08:38 PM
I'm curious how well an adhesive would last in that application. Will it tend to fatigue or work harden due to the cyclic stress?

Will it be a problem if it suddenly separates?

CarlByrns
09-17-2015, 08:51 PM
There is an epoxy, I believe it's made by System Three, called 'G-Flex'

It's made by WEST System (Gougeon Brothers).
Their tech support (good and fast) can answer any questions about their products.

Wayne Sippola
09-18-2015, 07:47 AM
You've got 576 square inches of glue surface for a couple pounds of stainless sheet. Any glue that actually sticks to the stainless should hold! Epoxies are in the 10k PSI range - extreme overkill, but so what. I do think you will want to glue it down, or you're going to get a lot of movement between the steel plate and the stainless. The stainless won't be moving with the base plate, but will be getting hammered from below if it's not glued down. And I would expect you want the vibration transmitted through the stainless as best you can. A flexible glue may tend to dampen some of the vibration, though if it's kept to a thin layer it may not be significant. The liquid nails would probably work fine, the epoxy would be great too.

Willy
09-18-2015, 08:29 AM
Spray-on contact adhesive.
The layer of adhesive is thin enough so as not to impede the transfer of motion and it sticks like crazy. Its used for applying stainless back splashes very successfully on a wide verity of materials. Have use it for applying metal cladding numerous times. Not for your application however, although from personal experience I think it would work better than liquid nails construction adhesive.

Horst
09-18-2015, 11:11 AM
I want to thank you all for your help; this forum is an incredible resource. At the risk of waxing rhapsodic I must say I still find it amazing that I can type in a question at home and have it go out to the whole world for an answer. It was not that long ago that this would have involved perhaps hours of research which may or may not have yielded satisfactory results. I found the West System link particularly valuable.

I am going to go with my physical restraint idea with the addition of 3M spray glue, it being the cheapest, easiest, and most readily accessible method.

Rich Carlstedt
09-18-2015, 08:21 PM
Be careful of the 3 M spray contact adhesives
I love their "77" cement and it works like clockwork.
Then I saw their "New Hi Strength 90 " contact spray and bought a can ( not cheap !)
I had utter failure with the adhesive on metal and documented the issues and sent it to 3 M.
Well, I never got a response about my problem, or the data I sent , except for an acknowledgement of my original transmission.
I guess they had so many failures they didn't answer ?

I finished the job by stripping all the adhesive and reverted back to the 77

Rich

outlawspeeder
09-18-2015, 10:39 PM
+1 on the 77. I never had it fail, only me not clean the surface before hand.

Doozer
09-18-2015, 10:44 PM
You need real contact adhesive.
The kind for Fromica counter tops.
Not the spray on kind.
This stuff has some lacquer thinner
base solvent system, and has plenty
of VOCs, so that means it works.
Pilobond is one brand sold at HD.
Be sure and let both sides dry before
sticking them together.

--Doozer

bborr01
09-19-2015, 06:03 AM
I'd use contact cement. Coat both surfaces and let them dry. Then coat one surface and let it dry before putting it together. I found that the extra coat will make sure it sticks. Sometimes on counter tops one coat isn't enough.

Brian

Black_Moons
09-19-2015, 08:30 AM
I'd use contact cement. Coat both surfaces and let them dry. Then coat one surface and let it dry before putting it together. I found that the extra coat will make sure it sticks. Sometimes on counter tops one coat isn't enough.

Brian

You only need multiple coats when the material wicks the cement in, then the first coat seals the surface for the 2nd coat and keeps it on top.

I use contact cement to put foam air filters together. Amazingly its gasoline resistant.

Horst
09-19-2015, 12:01 PM
Well, this morning I thoroughly cleaned both surfaces and sprayed each one. The adhesive did not stick at all well to the semi-polished SS and was only marginally better on the mild steel table top.

I stopped before I tried to join the pieces. The glue peels off fairly easily so no harm done. This was with 3M Super 77. I will be talking to West Systems Monday morning. I understand they have a product specifically for this.

rallycat
09-20-2015, 01:21 PM
Scuff both the table and the ss sheet with red scotchbrite or 400 grit wet&dry paper using water or isopropyl alcohol. Clean up with isopropyl or acetone. This might be enough tooth for the super 77 to grip.

Epoxy will definitely hold better. Prep the glue faces as above. You'll need a good flat surface like tooling plate or a surface plate to set the glue-up on while it cures. Make sure that plate is covered with a plastic sheet for a release liner and make sure there are no wrinkles. Tape the top side of the stainless - glue will wick into this space and it's a pain to sand off later. Tape around the edge of the steel table so you don't get a big glue fillet there. From the epoxy data sheet figures out how much glue you will need to mix up to get a .005" glue layer on each face - this is a guess assuming the table is flat within ~.002". Make some blocks - uhmw, teflon, or something plastic wrapped to hold the table aligned with the stainless, because the table will try to slide off the sheet as the epoxy squeezes out. Mix your epoxy, dump the rough amount on each face, and roll it out in an even layer with a short nap paint roller. Set down the stainless sheet, flip the table over and set it on top, set up blocks around the edges, and then start putting sandbags, weights, or clamps to pull the assembly together. The weight of the table is less than a psi of clamping force, you will want more.

Didn't mean to go on this long, but all the details add up. If you ever heard painters say that 90% of painting is prep work - same for bonded assemblies.

hitnmiss
09-20-2015, 08:00 PM
I'd think about 3M pressure sensitive tape. I use it to hold parts in the mill.

Expensive though, not sure if it gets cheaper if you buy a lot.

Horst
09-22-2015, 08:46 AM
I talked to West Systems and read all their online literature and here is what I came up with.

I used a diamond face grinder to remove the scale and high points caused by the stitch welding underneath, so the top is relatively smooth but it is far from flat. Using a straight edge I get about .075” between the highs and lows so I will attach the stainless sheet in a two stage operation.

First I covered my surface plate with plastic wrap and will set the top, top down, on the plate and, after building a dam around its perimeter will pour their G/Flex bonding agent through the numerous holes in the top, which exist from prior fixtures. After the bonding agent cures I should then have a flat top.

For the second stage I will flip the top right side up, apply the G/Flex per directions, secure the edges to prevent slipping, and vacuum bag the whole thing. Since my roughing pump is capable of greater than 99.9% vacuum that should give me over 8,000 lbs. of clamping force.

I hope it works. Thanks again for your help.

Kiwi
09-22-2015, 05:41 PM
If the metals condensate epoxy won't hold for long