With what do YOU cover seams in MDF?

bdp24 · « **on:** 31 Dec 2012, 01:38 am »

I'm starting on a build of a pair of W-frames, and would love to hear from those who have had good results with any product/technique for filling the seam between glued-together pieces of MDF, screw holes in same, and what is good for sealing the exposed MDF interior in end cuts. I have seen testimonials for Bondo, wood putty, and glazing putty for the seams and screw holes, and diluted wood glue for sealing the ends of MDF. I am going to paint the frames, so how about the primer for the faces of the MDF? Also, what type and grit of sandpaper is good for preparing MDF for paint? Thanks for any advice you can provide.

S Clark · « **Reply #1 on:** 31 Dec 2012, 01:52 am »

Bondo works very well.

stevenkelby · « **Reply #2 on:** 31 Dec 2012, 02:14 am »

I like glazing putty as it sands easy. Starting with 120 and finishing with 400 grit no-fill paper works for me.

I've also used this stuff with great results, sands easy:

http://www.feastwatson.com.au/SealerFillersSandingSealer.asp

PDR · « **Reply #3 on:** 31 Dec 2012, 02:19 am »

I'm a glazing putty guy for filling seams, its much easier to work with than bondo, less
fuss as you dont have to mix it. It sands easier as well.
The kind of sandpaper would depend on the type of paint finish.
When I did my Super V I started with 220 and worked my way up to 600.
The primer again would depend on the type of paint

Good luck, and now that you let us know, its required you post pics of your progress....

hdspeakerman · « **Reply #4 on:** 31 Dec 2012, 02:55 am »

Many of the guys over at Parts Express that build a lot of speakers from mdf use a mixture that is 50% glue and 50% water, I have not done it but Wolf is the person to talk with about this technique.
Howard

bdp24 · « **Reply #5 on:** 31 Dec 2012, 04:29 am »

Quote from: PDR on 31 Dec 2012, 02:19 am

I'm a glazing putty guy for filling seams, its much easier to work with than bondo, less
fuss as you dont have to mix it. It sands easier as well.
The kind of sandpaper would depend on the type of paint finish.
When I did my Super V I started with 220 and worked my way up to 600.
The primer again would depend on the type of paint

Good luck, and now that you let us know, its required you post pics of your progress....

Ha! Fair enough. But I gotta warn ya.....I work slow. It's taken me about six months just to get to this point! Thanks everybody, I'm getting all of my materials together, including the sand to fill the cavity I'm making in the side panels. Wonder where I got that idea?!

WireNut · « **Reply #6 on:** 31 Dec 2012, 04:54 am »

Quote from: S Clark on 31 Dec 2012, 01:52 am

Bondo works very well.

+1

I use Bondo also.

WireNut · « **Reply #7 on:** 31 Dec 2012, 04:58 am »

Captainhemo · « **Reply #8 on:** 31 Dec 2012, 06:01 am »

Quote from: hdspeakerman on 31 Dec 2012, 02:55 am

Many of the guys over at Parts Express that build a lot of speakers from mdf use a mixture that is 50% glue and 50% water, I have not done it but Wolf is the person to talk with about this technique.
Howard

I use the glue/water mix to seal up the MDF after using glazing uptty or wood putty on the seams. I just mix it up in samll paint tray and roll it on. Iusually do a coule coats sanding smooth between coats (240 & 400 grit)

-jay

PDR · « **Reply #9 on:** 31 Dec 2012, 06:31 am »

Used bondo when I built these....

They turned out really nice, but the labour was intensive.

Used glazing putty when I built these....

Also turned out nice, but the sanding time was way down...

WireNut · « **Reply #10 on:** 31 Dec 2012, 07:32 am »

PDR, Nice builds.

In the top two pics what brand, type of paint, and color is that?
You must have used a sprayer.

bdp24 · « **Reply #11 on:** 31 Dec 2012, 07:57 am »

PDR---Those 2-12 cabs are SO clean! I got to the GR party late, and by the time I got hip Danny had (has, actually) only two of the 8 ohm 12's left. If he had four I would have taken 'em. But him not having them did give me time to read more and realize that a pair of the 16 ohm in an OB frame would mate better with my ESL's anyway. I'm going to paint them in what Vintage Hot Rod guys call Eggshell. It's flatter than Semi-Gloss, but not as flat as Matte. And I'm going with Charcoal rather than black, with black grilles for contrast. I want the frames to look like Slate, and I found some cool Vintage looking grille cloth on the Acoustone website. So PDR, do you still have all of the cabs pictured? The 2-12? If you see what I'm getting at!

PDR · « **Reply #12 on:** 31 Dec 2012, 01:25 pm »

Quote from: WireNut on 31 Dec 2012, 07:32 am

PDR, Nice builds.

In the top two pics what brand, type of paint, and color is that?
You must have used a sprayer.

Cant remember the brand name.....but it came out of a can.....

Many coats, lightly sprayed and fine sanded in between.
They actually look better than the pics.
Takes a lot of patience, but can turn out very nice.

PDR · « **Reply #13 on:** 31 Dec 2012, 01:31 pm »

Quote from: bdp24 on 31 Dec 2012, 07:57 am

PDR---Those 2-12 cabs are SO clean! I got to the GR party late, and by the time I got hip Danny had (has, actually) only two of the 8 ohm 12's left.....
So PDR, do you still have all of the cabs pictured? The 2-12? If you see what I'm getting at!

Those were built before I discovered GR.
Theyre Dayton subs with a OAudio 500w Bash.
There are a pair of these, and yes I still have them.
I have a whole HT system, just not in use,
thats where the subs go....look in my gallery.
Right now the 2 subs are in the rear of my room
playing out of phase with the Super Vs

bdp24 · « **Reply #14 on:** 31 Dec 2012, 02:37 pm »

I thought the cone material looked smoother and shinier than the GR's. I put a "Wanted" notice for a pair of the 8 ohm 12's here on Audiocircle, but received a response from Danny only. I almost took them, but without another pair I can't do stereo subs. Anybody wanna let go of their's?!
I too am going to give a can of spray paint (Krylon) a shot, and if they don't turn out well enough, I'll take them to a pro. First I gotta get them together!

bdp24 · « **Reply #15 on:** 31 Dec 2012, 03:40 pm »

Personal note to the person who sent me a thoughtful email suggesting I wait for the new plate amps (which will allow a pair of 4 ohm drivers to be run off of the amp): I wrote back thanking you for your thoughfullness and the suggestion, but when I hit send.....I was informed that you had blocked me from being able to email you. I didn't know I was THAT big of a PITA!

rockdrummer · « **Reply #16 on:** 31 Dec 2012, 04:11 pm »

I built one pair of AV2's and tried wood glue and water. Then I brush-painted primer and sanded. Disappointed in the seal of the ends. The work I put into filling in tiny gaps in a couple butt joints were fine. But the multiple coats of glue and water kept soaking into the fiber edges. I'm going with an inexpensive elmer's sandable wood putty this time. I also have some stands that have lots of edges needing sealing. Will post pics when I get there.

Ben

MLS · « **Reply #17 on:** 31 Dec 2012, 05:53 pm »

I am about to start filling the seams on a pair of MTM floor standers and dreading mixing bondo and spreading it on two floor standers. The glazing putty idea is intriguing but I have a hard time believing it will get hard enough if I am thinking about the same type of glazing putty. The kind that you use to instal window glass into true divided light windows?

Thanks for any advice.

Scott

PDR · « **Reply #18 on:** 31 Dec 2012, 06:21 pm »

Quote from: MLS on 31 Dec 2012, 05:53 pm

I am about to start filling the seams on a pair of MTM floor standers and dreading mixing bondo and spreading it on two floor standers. The glazing putty idea is intriguing but I have a hard time believing it will get hard enough if I am thinking about the same type of glazing putty. The kind that you use to instal window glass into true divided light windows?

Thanks for any advice.

Scott

Nope, its automotive glazing putty.....right next to the bondo on the store shelf.
Its for finishing bondo work on cars, small scratches etc.

WireNut · « **Reply #19 on:** 31 Dec 2012, 07:14 pm »

Quote from: PDR on 31 Dec 2012, 06:21 pm

Nope, its automotive glazing putty.....right next to the bondo on the store shelf.
Its for finishing bondo work on cars, small scratches etc.

Must be something like this.
Do you use it all over the cabs or just the seams