# Sealing MDF



## tweeds (Jul 19, 2018)

Hello, just a quick question about sealing MDF.
All the fish safe pond sealers I’ve found are water based, but I’m hesitant to use a water based sealer on MDF. So is there a safe solvent based option or is it OK to use a water based sealer on MDF?


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## Bluetongue1 (Jul 19, 2018)

I am not that clued up on different sealers but I have a mate who sealed wooden floors for a living and was also a herp keeper, and his recommendation was 3 to 4 coats of polyurethane. I have also seen this recommended on a reputable herp site.


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## pythoninfinite (Jul 19, 2018)

You can use the water based polyurethanes, available from any hardware outlet, Bunnings etc. Most of the specialist timber-finish brands make a water based product - very low odour, recoat in 2-4 hours, and very hard and water resistant when fully cured. I've used it heaps of times on raw MDF - very little swelling following the first coat, a light sand, then another 2 or 3 coats with a very light sand in between, and you should get a great finish. I've mostly used the satin shine level.

Jamie


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## Bluetongue1 (Jul 20, 2018)

Thanks for expanding on that Jamie. It had slipped my mind that there are also solvent based polyurethane sealants. Even though they are more commonly used for sealing and protecting concrete finishes rather than wood, it is important to know about them so as not to utilise one.


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