Test of Adhesives for Ply/Foam/GRP Sandwich

[nigelmercier]

I've recently bought a new Whale Watermaster FW1215 fresh water pump ... My plan is to ... glue a small plywood board to the front of the foam, and mount the pump on that. My question is: what adhesive should I use on the board/foam/panel?

Update on this. I discovered that I had some 15mm thick Neoprene foam (eBay 261338185781) so I would do some tests. I cut identical rectangles of the foam: 38mm x 24mm, then stuck them between a piece of wood I had coated with a layer of Polyester resin, and a piece of plywood (very dilute varnished), both cleaned with Acetone. They were clamped to this with a 1kg weight each for 48 hours. The adhesives were:

Generic SuperGlue Gel (difficult to get an even spread, as seen in results)
EvoStik "Sticks-Like" All Weather Adhesive: http://amzn.to/1pJBKRx
Everbuild Lumberjack PU Adhesive http://amzn.to/1tx5HTS
Generic Epoxy Adhesive (Slow Cure)

This is the test rig:

.

As can been seen, the SuperGlue didn't spread evenly, so lost grip early.

All of the foam samples tore before the adhesive lost grip.

The scores:
Generic SuperGlue Gel (see above) 8.9kg
EvoStik "Sticks-Like" 11.9kg
Everbuild Lumberjack PU 12.9kg
Generic Epoxy 13.5kg

So at over 1kg per cm², I think this demonstrates that any of these adhesives are adequate for these substrates, as the foam is the weakest link.

I shot a video of one of them letting go, can post if requested.

 

[LadyInBed]

You should get out more

 

[oldsaltoz]

Update on this. I discovered that I had some 15mm thick Neoprene foam (eBay 261338185781) so I would do some tests. I cut identical rectangles of the foam: 38mm x 24mm, then stuck them between a piece of wood I had coated with a layer of Polyester resin, and a piece of plywood (very dilute varnished), both cleaned with Acetone. They were clamped to this with a 1kg weight each for 48 hours. The adhesives were:

Generic SuperGlue Gel (difficult to get an even spread, as seen in results)
EvoStik "Sticks-Like" All Weather Adhesive: http://amzn.to/1pJBKRx
Everbuild Lumberjack PU Adhesive http://amzn.to/1tx5HTS
Generic Epoxy Adhesive (Slow Cure)


The scores:
Generic SuperGlue Gel (see above) 8.9kg
EvoStik "Sticks-Like" 11.9kg
Everbuild Lumberjack PU 12.9kg
Generic Epoxy 13.5kg

So at over 1kg per cm², I think this demonstrates that any of these adhesives are adequate for these substrates, as the foam is the weakest link.

Hi Nigel,

I would love to see the results you get with the epoxy resin with some Micro-fibres mixed in and a 3 mm gap between both materials. I'm tipping the timber will be the weak link.

Good luck and fair winds.

 

[dsw]

have you got shares in the pu glue company ?

 

[PuffTheMagicDragon]

Interesting experiment if somewhat inconclusive vis-a-vis the efficiency of adhesives.

Do you have any explanation for the failure loads that were 8.9, 11.9, 12.9 and 13.5? That is quite a spread for identical foam pieces.

 

[symondo]

glad to get some results from this however....

what im more interested in is how did the conversation with the mrs go when she came out n asked what you were doing?

 

[nigelmercier]

The SuperGlue failed early because it was difficult to spread evenly. I only included this as I'd had great success using it to bond a piece of solid rubber to ABS. This is the only time I have ever used it and it has worked.

I guess the foam wasn't identical, and any imperfection in the edge accelerated the tearing. My main reason for doing the test was to establish if much larger pieces bonded in this way would hold my water pump and the board it is mounted on.

Mrs Nigel is used to my "experiments", see my thread on removing chrome

Uploaded a video, just for fun: http://youtu.be/1RmrJQRNpHs and yes, the grips did end up in the water each time, but luckily my camera didn't