Anyone ever try Minwax Wood Hardener to seal mdf?

[lunchmoney]

http://www.minwax.com/products/wood_..._hardener.html

[Froste]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

Dan, I think there was a thread on the HT form, that talked about this product.

[justame1213]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

I haven't seen this. I've been using deck stain/sealer. I think I'm gonna have to check this out.

[davepellegrene]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

http://www.minwax.com/products/wood_..._hardener.html

I tried it with my Nightmare speaker build. Both speakers took a fool can. I could have used another half can. At $10 a can. I think it was a waste of money. I still had seams show through and I used bin 123 and auto primer on top of that. Pic 13 and 14.
Dave
http://picasaweb.google.com/pelegrn/TheNightmares#

[BiggerRigger]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

Ditto to Dave's post. The cabs I built per Wolf's specs for the indy 2008 show did the same thing. Every staple and joint are visable with the sealer inside and out and 3 coats of high build primer and 4 coats of house of colors auto paint + 2 coats of top coat. $75 worth of auto paint f$%#*d up due to the sealer. Did I mention I sanded between all coats. Its like it never dries out and swells the surface of the substraight. Look at them one day and you cant see a seam come back the next day and there all swelled up. Only to dry out a little and swell up again like a bad x-girlfriend.
Aaron

[brianpowers27]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

The thread over at HTGUIDE had a great discussion over how to make your own hardener. For all that hate the swelling of mdf, I'm not sure hardener will fix it. I still stick to my guns on using undiluted wood glue across both the inside and outside surfaces.... After that, allow the material to marinate in a controlled humidity environment for a few weeks...

[lunchmoney]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

The thread over at HTGUIDE had a great discussion over how to make your own hardener. For all that hate the swelling of mdf, I'm not sure hardener will fix it. I still stick to my guns on using undiluted wood glue across both the inside and outside surfaces.... After that, allow the material to marinate in a controlled humidity environment for a few weeks...

I'm going to seal my poor man's today, will try less-diluted or undiluted wood glue (I've been using 60/40 glue/water in the past)... it all comes down to how well it spreads.

[lunchmoney]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

Brian, what kind of wood glue are you using undiluted?

Today I tried Elmer's wood glue undiluted to seal my "Poor Man's", and it was much too thick to spread into a nice thin, even coat... I ended up diluting it 2/1 (glue/water) and even that was just barely thin enough...

I'll go back to 60/40 on my next project... unless you know of a thinner wood glue.

[jonpike]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

The hardener seemed to make it harder... than Shellac or other things in that test. Not sure if the water penetration would be different, or something else would win out or not. Stuff is pretty expensive.

With all these folks "sealing" their boxes and still having dimensional shift, I wonder how many are actually sealing the inside as well as the outside? I imagine if you don't cover pretty much every square inch, you eventually might have problems.

Only problem with the thicker glue/water would be how uneven it may end up, and more sanding to level the surface. Well, that and the basic thing of when you use glue and water, you're adding WATER to your MDF, which then will need to distribute, and outgas over time. I still think shellac with it's ethyl alcohol base might impact less and evaporate faster. But, haven't done any comparisons that would be true experiments.

[brianpowers27]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

Brian, what kind of wood glue are you using undiluted?

Today I tried Elmer's wood glue undiluted to seal my "Poor Man's", and it was much too thick to spread into a nice thin, even coat... I ended up diluting it 2/1 (glue/water) and even that was just barely thin enough...

I'll go back to 60/40 on my next project... unless you know of a thinner wood glue.

I used Elmers... I sand afterward. Sanding is a long and tedious process after gluing in this way. I confess that I haven't used dewaxed shellac but it does sound like it has its benefits. I wonder how many coats it would require on end grain....

FWIW: I have pretty much stopped using MDF due to the laborious nature of the process.

[lunchmoney]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

FWIW: I have pretty much stopped using MDF due to the laborious nature of the process.

Yeah, the only thing that keeps me using it is the low cost.

[brianpowers27]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

Yeah, the only thing that keeps me using it is the low cost.

The more I think about it the more it seems like one could be successful using mdf by doing something like this.

0. Seal insides of box
1. Build box
2. Bring inside and let sit for 2 weeks in a controlled temp/humidity environment with air flow.
3. Flush trim
4. Seal box
5. Let sit 2 more weeks
6. Sand and finish

I am finding that Regular 3/4" birch plywood is not too much more expensive and is much less labor intensive. I probably pay $40 for the sheet vs $24 for the mdf. The finishing materials really aren't too much more expensive than paint. In fact, they may be cheaper.

[lunchmoney]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

I have a friend who has a big oven at his shop... he's going to be building mdf speakers soon, and intends to bake the panels prior to gluing up, and then bake again after gluing and sealing. If that doesn't work, I don't know what will.

I think the bigger question is: do you really care if the seams emerge a tiny fraction of a millimeter?

I was quite annoyed when I first noticed it, but I no longer care. The speakers still look fantastic, and you can only tell from less than a foot away.

[bobhowell]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

I would be careful putting watered down glue on MDF in large amounts. It is WATER, the nemise of MDF. Use something with a solvent based thinner, like shellac, woodhardner or the clear SANDING SEALER from Minwax; for sealing purposes.

I seal the edges of my baffles with PVA glue but this is a lot more water!!

[davepellegrene]

Re: Anyone ever try Minwax Wood Hardener to seal mdf?

I have a friend who has a big oven at his shop... he's going to be building mdf speakers soon, and intends to bake the panels prior to gluing up, and then bake again after gluing and sealing. If that doesn't work, I don't know what will.

I think the bigger question is: do you really care if the seams emerge a tiny fraction of a millimeter?

I was quite annoyed when I first noticed it, but I no longer care. The speakers still look fantastic, and you can only tell from less than a foot away.

I still think that there will be issues when they are moved to the house. Heating to cooling season there is a change in humidity that I think will allow enough expansion and contraction to show the seam. I wonder if coating the speaker with fiberglass resin, like you are doing with the glue would work better. This might bridge the movement enough. The only thing I could see happening with enough expansion it could crack the resin.
Has anyone used latex paint? I wonder if it has enough flexibility not to show through.