Sealing sponge

Hi fellas
I want to seal the surface on some bits of sponge. A couple of squares to fit on ply seat tops which will get upholstered with pvc fabric/sheet

And I want to make a soft gasket to go under the rear tailgate of my car which is an estate. The bloody rubber molding is buggered and the thing rattles like crazy

I cant anything else locally that I can use in both areas. Is there a way I can seal the surface so it doesnt readily absorb water? But remains cushiony

 

btw, only thing I can think off that might do the trick is to paint it with purbond and mist it coated stuff with water spray

 

the problem is than anything you use to seal an absorbent material that also has to flex will eventually develop leaks in the surface and it will eventually saturate the inner padding material. Having something bonded to the outside will act to hold the moisture inside it once there is seepage through the outer layer. Using some kind of closed-cell foam if you can get it would be best.

for the tailgate of the car I would think a hollow rubber tube or hose might work better, if it leaks to the inside it will at least be able to drain out.

As far as the seats tops go, you will eventually get water to seep in, so make it easy to remove the inner padding and be able to dry it out in the open air. the pvc fabric will mostly keep it dry but water will find a way in. So make it easy to be able to open it up and allow you to remove the padding so it can dry out.

Good luck.

 

spray on polyure.

 

You need to get some weatherstrip material that is a closed cell foam. If you try to seal an open cell foam it will leak and the sponge will soak up water and make a mess. Look for a proper weatherstrip material and do it right.