bondo to smooth mdf surface?

Yeah...I'm sure it's MDF.  The suface of it is indeed smooth, but that's not the problem.  My problem is the cut edges of the MDF...maybe the problem is that I've used just primer in the past.  From what you're saying...sealer/primer would make the cut edges appear better, right?

What would be a good product to apply to the outside of the box if I want hide the seams from where all the boards meet???

Thanks!

if the edges are rough, then I would consider adjusting the height of the blade and the type of blade you are using. I found that with most blades, setting the blade to just 1-1.5 tooth above the top of the board will help minimize the tearing of the board as it is being cut.

Second, consider changing the blade of the saw too. If it is tearing the edges, then it's too rough or you are pushing too hard on the wood as it is cutting. Let the blade do the work, not the pressure. If you are not applying pressure on the wood and letting the blade do the work, then consider getting a blade for soft woods. That will take care of the problem to begin with.

As for what you have now and want to make it look better, yes and no. You will need to use a high-build primer/sealer. Depending on how bad the edges are, several light coats will be needed. Don't use a heavy coat because that will weaken it.

For the seams, I like to use one of several products. My personal favorite for blending seams is good old carpenter's glue. It will pull the seams closer and fill in the gaps. From there, I would use a flush trim bit on a router/trim router to make it as smooth as possible. Use a couple of coats of high-build primer/sealer and sand that down to make the seams disappear.

Ganbatte ne!

The edges aren't getting torn up due to the blade, I was just talking about how the cut edges aren't as smooth as the face of the MDF.  However, using a build up primer/sealer makes sense...that's exactly what I'll do.  I've already sanded all the edges so that they are smoothly blended into the surface...now I just want to work on making the seams disappear for when I paint it.

Thanks for the suggestions, I'll let you know how it turns out!!!

Mike

Oh, my mistake. I didn't quite understand what you were talking about exactly. Due to the construction of the MDF, you'll never get a perfectly smooth cut face. All that can be done to perfectly plane it is to seal it and go from there.

Please post pictures. Ganbatte ne!

Keiika

My bad for not making it clear...it's all good.  I'm using that Kilz2 primer and it seems to be doing the job.  I put it on heavy with a brush, so I'll sand it down with a fine grain paper to get rid of the brush strokes, prime it again with a roller and then hit it with the paint.  Once the edges have saturated enough, it'll smooth out with the sanding and then it'll take the glossy paint the way I want it.

Thanks for the input though.  I should have pictures soon as I get my friggin sub from Pioneer!!!  (of course they're draggin their feet on this as it's a replacment sub).

Mike

No problem. LOL sorry about your sub problem, but it seems to be pretty common there... What I find that frequently works is to call them repeatedly. Keep up the inquiries and they tend to respond faster.

Ganbatte ne!

Keiika