Humidity proofing MDF

[eRiCdWoNg]

...OK this is for my car stereo, but I am using Madisound purchased Vifa tweeters and midrange drivers and 8" Silver Flute woofers. I made adaptor plates for my doors and used MDF. However I am concerned that over time the humidity will cause the MDF to swell. What is the best way to seal the MDF so it can tolerate being used in a humid enviroment? Im thinking perhaps some type of a paint. I don't care what it looks like, I want it to work. Anybody recommend a specific product?

PS I searched and found a thread about sealing the MDF, but it was very concerned of how it looked. I don't care how it looks one way or the other, as the plates are hidden, but I do care about how effective the treatment is. Suggestions?

[DcibeL]

I am told that a mixture of wood glue and water makes a good sealant. Perhaps someone else could confirm?

[chipco3434]

Perhaps someone else could confirm?

I would be happy to confirm that it would not....

Use varnish, 2-part epoxy, or 2-part urethanes.

[eRiCdWoNg]

What about Thompson's water treatment, or something similar that one would use to treat an outdoor deck? Im also thinking about using a polyurethane similar to that used to treat a hardwood floor.

[chipco3434]

Are you installing your speakers in an outdoor deck or a fence?

Then Thompson's would be perfect! Everybody knows that wax is the best preservative for wood. You need only reapply every two years.

Good luck on your experiment!

[Ron E]

Use plywood instead of MDF if you believe water contact is possible. Plywood is stronger and lighter than MDF and it does not disintegrate when it gets wet. Using some deck water seal seems silly to me, but it might work. It also might interfere with any further paint or finish treatment you try. A nice coat of a good oil-based hard paint should be all the waterproofing it needs.

[lolojr1]

use fiberglass resin thats how lots of car stereo boxes and such get built ive done it and it works really good

[Byrd]

eric - I am imaging you are worried about it ending up like ordinary chipboard does? If you are using MDF - It is highly unlikely it will swell or disintegrate from humidity.

A good sealant - if you still want to do it - is glue. I use this to fill cut edges before sanding and painting and it works pretty well.

If I were you I wouldn;t even worry about it.

[Volenti]

The doors of a car are considered a "wet" area, raw MDF panels/speaker rings will eventually get wet and swell (seen it happen many times)

Seal the mdf with PVA glue or better yet fibreglass resin.

[KBK]

Go to a artist shop,and pick up the TRI-ART brand of "topcoat'. It is a undiluted acrylic-urethane. It takes time to cure, but the MDF will practically be submersible after that.

It is the same acrylic urethane that is used to finish BMW cars, for example. You are highly unlikely to find it cheaper..or better. best in the business. PS..it makes a helluva coating for finishing speakers, before painting, as well.