How do you...

[ShinOBIWAN]

How do you stop the joints from MDF reappearing after using a spray finish on cabinets?

Its driving me absolutely crazy, I've gone for a seam free look and yet they keep reappearing despite having around 5 coats of spray with sanding between.

Sure they look good for a couple of days and then the joints show again.

Thanks in advance

[phn]

I know nothing about making speaker cabinets. But I do have some first-hand experience when it comes to paint. And after painting my home I know pretty well what paint can and cannot do. In this case, paint is very poor at hiding stuff. You better make the foundation right from the start or you might end up having to redo everything.

So my guess would be some paste of sort. Of course, the latter is just a guess. But one thing remains, the seam won't go away with paint.

[AudioFreak]

a little wood putty applied to the area and sanded before painting probably would of done the job.

[ShinOBIWAN]

Originally posted by AudioFreak
a little wood putty applied to the area and sanded before painting probably would of done the job.

Thats the funny thing though, I did fill all joints with wood filler and then sanded back before priming and then spraying.

Any other suggestions.

[ShinOBIWAN]

I think I'm going to re-do the cabinets again.

But this time I want to get it right, I could veneer like in the past but its not the look I want this time.

[RobWells]

Hi Shinobiwan,

I usually seal my cabs with a few coats of watered down pva woodglue. Use a small 'radiator' foam roller, sand down between coats. Stops the topcoat soaking into the mdf. (the 'end grain' is more spongy than the rest)

Another option is to use 3mm mdf as a veneer over the thicker stuff. Makes the edges less trouble to start with.

Or make your life ~really~ difficult and do mitred corners.


What sub did you end up with btw ?

Cheers,

Rob

[stee-b]

Hi ShinOBIWAN, I'd try scraping a groove along the joint and refilling with car body filler rather than wood filler.
IME most wood fillers take a long time to stop shrinking, where as car body filler is much more stable. Seal as per Rob's recommendation. Patience is all I can recommend(but hey I bow down to your previous efforts).
Good luck!!
Steve

[ShinOBIWAN]

Originally posted by RobWells
Hi Shinobiwan,

I usually seal my cabs with a few coats of watered down pva woodglue. Use a small 'radiator' foam roller, sand down between coats. Stops the topcoat soaking into the mdf. (the 'end grain' is more spongy than the rest)

Another option is to use 3mm mdf as a veneer over the thicker stuff. Makes the edges less trouble to start with.

Or make your life ~really~ difficult and do mitred corners.


What sub did you end up with btw ?

Cheers,

Rob

Hello Rob,

Really don't know whats going on with this one, the floorstanding ribbons I did last had a ton of joints which were filled with the same stuff I'm using now and non reappeared.

This time I use 25mm MDF instead of 18mm and it all goes pear shaped.

Will knock up some test joints with the filler&PVA coat and then the spray. Hopefully the joints will stay invisible.

Re Sub: I'm using a Mackie HRS120 at the minute, its not a DIY job this time but I find it to be very accurate with good depth.

[ShinOBIWAN]

Originally posted by stee-b
Hi ShinOBIWAN, I'd try scraping a groove along the joint and refilling with car body filler rather than wood filler.
IME most wood fillers take a long time to stop shrinking, where as car body filler is much more stable. Seal as per Rob's recommendation. Patience is all I can recommend(but hey I bow down to your previous efforts).
Good luck!!
Steve

Good to hear from a familiar name, hope all is well.

Like Robs suggestion, I'll definitely give what you've suggested a try.

As for these cabinets, well I've got my eye on cloning some lovely looking monitors. So I think I'll leave them as is, the joints aren't really that bad, its just that because I know where to look I tend to think everyone else will see them. When in reality you can only see the join close up and in the right light.

[stee-b]

So I think I'll leave them as is, the joints aren't really that bad, its just that because I know where to look I tend to think everyone else will see them. When in reality you can only see the join close up and in the right light. [/B]

Firm case of perfection paranoira

Sit, listen to some tunes with a few beers and I'm sure you'll not see any of them joints
Good luck!!
Steve