Is sanding sealer waterproof?

I have purchased some Wattyl Sanding Sealer to seal the edges of Melamine cabinet where it is in a laundry, and the edge of the cabinet sides, nearest the floor, are bare chipboard beween the Melamine surfaces and likely to absorb moisture.

Is this adequate, or do I have to coat with something else as well?

regards,
Jill

No its not waterproof, are you using HMR chipboard(moisture rated).
Give it a few coats of thick polyU after the sealer, this will help but ultimately will not stop water damage... you should get a number of years out of it tho.

Thanks Harry. No I am not using moisture rated Melamine, unfortunately

regards,

Jill

Here is advice received from Wattyl Tech Services Dept:

In our Retail range, we normally recommend sealing MDF & Chipboard type surfaces with a premium or ultra premium Water Based undercoat, such as our I.D Primer Sealer Undercoat.

It can then be overcoated with either a Water Based paint or an Oil Based paint, once it's dry.. For example either the I.D Gloss Acrylic ( Water Based ), or I.D High Gloss Enamel or I.D Satin Enamel ( both Oil Based )..

Neither system would be considered as a waterproof finish.


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The Wattyl Sanding Sealer product you mentioned is normally used to seal solid timber such as pine, where it raises the grain for easier sanding. It is then overcoated with one of our Oil Based Estapol products.. It is not suitable for use on MDF, and not normally recommended for use on chipboard. The solvents in Oil Based products can sometimes react with waxes and glues in manufactured boards. That's why we recommend sealing with a water based product first. Just need to make sure the edges and any other bare sections of chipboard or MDF are porous, i.e water can wet the surface or absorb into it, rather than bead off.


hope this helps someone else too. In the end, as advised in part by harry72 above, I put on the sanding sealer ( before the Wattyl advice arrived) , sanded and coated with Estapol, then sanded and glued a pine strip around the base using Bondcrete and screws


regards,
Jill

I'm about to replace an external door, the original having been ruined by water getting into the bottom. The bottom 6" or so of the door is now swollen and delaminating. Seems the cowboy builders didn't bother sealing it properly, and just slapped their usual (watered down) coat of paint.:((

When I fit the replacement, I am planning on 'painting' a thin coat of epoxy (Tech Glue or West System) around the entire edge which could be exposed to the weather, then painting over the top once this is cured.

A thin epoxy like West System might be a good thing to paint onto the bottom edge of your melamine to seal it. I have read somewhere about a furniture maker who paints a thin coat of epoxy onto the bottom of table legs etc. to seal then against moisture ingress.

Mr Bush, the only method that really works is to build a small (or large ) shelter over your door to keep the water and sun off your door. Failing that what you are suggesting is probably the next best thing...


Chipman

I have edited the Wattyl advice as shown previously- it did not cut and paste properly in my first attempt