Small center using leftovers

[rpb]

[rpb]

Glued, now I wait. Bevel is 1.75".

[rpb]

Close up of the joints. There is some overlap.

[rpb]

Here it is after a few more passes on the saw. What would be good for sealing up the mdf?

[djg]

Call it Ft. Knox.

[DeZZar]

I use a sanding sealer like this one https://www.feastwatson.com.au/produ...anding-sealer/.

Or head straight into a couple coats of a high build primer.

You can also just water down some wood glue and paint that on.

[rpb]

I use a sanding sealer like this one https://www.feastwatson.com.au/produ...anding-sealer/.

Or head straight into a couple coats of a high build primer.

You can also just water down some wood glue and paint that on.

I suspect that a skim coat of body filler might be needed, but I'd prefer not to do that. I'm assuming that the porous surface needs to soak in something. I think I've used glue before, but don't recall for sure. Seems like with body filler, (or maybe it was the glue ), it's harder than the mdf, and when sanded, the sandpaper digs the mdf before the surface is level. What about maybe polyurethane, or latex wall paint? I have body filler, and rattle can primer. I guess I just want something easy. The final finish will likely be a flat black. This is for a HT system, and shinny is not ideal.

[Steve Lee]

What DeZZar said - go with a sanding sealer either water based or oil and sand between coats (120/220/320).

I did 5 coats of sanding sealer on my Sambas then a coat of Johnson's paste wax over that and they look fine.

[a4eaudio]

I was waiting for djg to reply but I'll jump in...Zinsser B-I-N Shellac based primer. This has been recommended a lot over the years but I always had other stuff on hand. I finally used it recently and it really is nice.

I read in one post to use a wood glue/water mixture first, let it dry and sand, and then the shellac based primer after that, but don't know if that is necessary.

[djg]

I'll just add that there are several BIN primers, some water based. The Shellac base works best for me. Read the label.

[DeZZar]

Even just a few coats of your rattle can primer will work fine.

- Sanding sealer will soak in and actually harden the MDF itself so that it can be sanded smooth. I've found you can get away with a single coat if you're then onto primer and paint.

- Glue water mix will just soak in and create a seal/barrier so that subsequent coats of whatever sit on top rather than soaking in. You do risk some swelling due to the water and you want to make sure it dries quickly.

- Primer, if it's the high build type, will sort of soak in a little with the first coat and then build layers with subsequent coats.

With the raw edge nature of what you're dealing with here it's important to remember that MDF has varying 'hardness'. The surface is the hardest with the middle of the board being the softest. This is why I recommend the sanding sealer because of how it will harden the exposed edge surface so that it all behaves the same way when sanding etc.

[rpb]

I'll work on the finish later. I was anxious to see how things measure. I have not picked a tweeter yet, but the woofer is mounted, so I took some sweeps. On axis, and 45 degrees off axis. I figured it would be smooth, but this is crazy.

[rpb]

I had to try this. Made a filter for some BSC, and a notch.

[DeZZar]

Nice! What's the notch targeting?

[rpb]

Nice! What's the notch targeting?

It was to eliminate the rise from 3.5k to 6k. I didn't spend a lot of time getting it fine tuned. I played some shows with 5.1 sound, and the dialog was very clear. and natural sounding.