Prefinish before vinyl application?

[acex008]

I just finished putting together my precut Tritrix TL enclosures and am ready to sand and prep for the Dayton Cherry vinyl application. Should I seal the MDF? Just rattle can primer? Both? If so, with what products? I'm concerned that I need to select the right products so that the vinyl's backing adhesive will stick to it securely... I've heard of several sealing methods for MDF but want the best possible adhesion for this thin vinyl finish... Thanks!

[biff]

I'd use a spray sealer, shellac, something quick drying, and get some tack cloths ready, Shoot, sand, TACK, repeat to at least 200 or finer. Once you get it glassy then roll on. I've only used vinyl a couple of times and never had a problem with adhesion, but little bits of who knows what print through like crazy! And a soft spreader like the ones for body putty helped squeegee things down. When you find a trapped bubble, I use a razor blade and make a tiny slice along the alleged grain and push the air out then rub it down. Some of this stuff lately looks darn realistic!

[jeffa]

I was told on another forum that no primer is necessary if you are using it over MDF. However to be safe I used rattle can primer. It was a year ago but I'm pretty sure it was Krylon. I used the Dayton black ash vinyl laminate. To date I've had no problems with bubbling or peeling.

[acex008]

I think I'm going to seal with a 60% wood glue to 40% water solution, then rattle can high build primer, sand, finish primer, sand some more working up to 220 grit (which I already have) and then vinyl. I'm actually painting the back of the cabinet flat black so I want to get a 'paintable' surface for the entire cabinet anyhow...

[benhinkle711]

Well sealing certainly won't hurt anything I feel it's unnecessary. I covered a set of bookshelf speakers and a sub, made from MDF, for my office in the birch vinyl (very realistic BTW) without sealing or primering and they turned out great. I will say that if you have any uneven joints they WILL show through the vinyl. I sanded mine smooth made sure that there was no dust etc. on the surface and wrapped 'em up. Also to ease things and to get one continuous wrap I used a 3/8 roundover on the corners. Two years later they still look great.

[jerryanderson]

Seal the end grain good with diluted woodglue. May take several coats, but seems to work the best. Tite Bond works the best, the Blue label sets up pretty quick. Would'nt hurt to put a couple of coats on the whole project. Let set for a couple of days, then seal with a coat or two of clear poly!. Light sand between coats, keeping things nice and smooth! Just my 2cents worth!

[ocool_15]

I have used the PE vinyl on 2 different sets. The better results were with a couple coats of shellac. On the other one the joints of the MDF showed up over time.

[acex008]

Yeah, the end grain showing thru over time is my main concern...

[lunchmoney]

Yeah, the end grain showing thru over time is my main concern...

It seems to me that seams will eventually emerge no matter what you do. (I've yet to hear anyone claiming absolute victory over this issue)

MDF expands and contracts. Sealing the top fraction of a millimeter does little to stop this... unless you could somehow bake the mdf to get all the moisture out prior to sealing.

I've used shellac and wood glue/water, in both cases seams emerged slightly... definitely prefer wood glue/water, sands much better.

The vinyl will help hide it of course.

[acex008]

Alright, thanks for the suggestions guys. I think I am going to use the glue/water to 'seal' and then sand, prime, and apply vinyl/paint.

[lunchmoney]

Alright, thanks for the suggestions guys. I think I am going to use the glue/water to 'seal' and then sand, prime, and apply vinyl/paint.

Sounds good... although I wouldn't bother priming... sanding the glue/water seal will give you a plenty smooth enough surface.