MDF Prime before Vinyl artwork application...Water/Oil or other based primer?

[stigzler]

Like anything on the interweb, no definitive answer. What are people using to prime? I see lots of recommendations for Kilz oil based, but that's like £40 here in the UK! also seen Zinsser Bulls Eye 1-2-3 Primer & Sealer recommended -but that's water-based and thinking of using the "water+washing up liquid in a bottle" application methods + you're not meant to use water based if doing this?

Any advice appreciated.

[MartyKong]

Hey stigzler,
I used the Zinsser bulls eye which was water based. I went with this cause it said sandable on the can and I wanted it smooth for the application. My worry would be water-based over MDF. Mine was ply so not an issue and it worked well.

[JS94]

I am using 3/4" mdf and I bought a quart of Zinsser interior/exterior oil based primer sealer from Lowes.  I did 2 coats, sanded, then another coat and it turned out great.  I am using a rustoleum oil based paint to finish.  I have read some woodworkers sites where they say not to use water based.  Other than not having many oil based color options, it works fine.

[stigzler]

Thanks both. JS94 - your steer led me to decide on using the oil based as this should keep all options open and reduce the possibility of problems (i.e. mainly the using of water based on porous wood products + also if using spray washing up liquid method).

I finally found a UK product that should fit the bill:

https://www.amazon.co.uk/gp/product/B00A497ATG/ref=ox_sc_act_title_2?smid=A3P5ROKL5A1OLE&psc=1

I'll try and 'member to check back in and update, but if you find this and I haven't, just PM me to query outcomes.

[shaolindrunkard]

Water based paint and primer work fine on MDF. It doesn't soak in or swell the mdf like you might think, oil based works fine too. Just never put oil over latex.

[stigzler]

Just to make double double sure, oil primer will be safe with vinyl? When do people use latex on their cabs?

[shaolindrunkard]

I would not put Vinyl over primer of any kind. Primer is usually very flat and porous. I would prime and then do at least one coat of paint. Oil based or Water based makes no difference. Once the paint is dry its dry, water is not going to make it come off. So if your talking about what I think you are meaning using some dish soap and water so you can slide your side art around until its in place it really doesn't matter as along as you have a top coat of paint and its fully dry.

But if you are worried about it just go with oil.

[stigzler]

Ah OK - think this is the peril of this topic - I've also seen a large number of posts saying don't paint - just use primer. Where's Myth Busters when you need them?

[shaolindrunkard]

Maybe they know something I don't.

[JS94]

One more thing.  There is also a debate on whether to use a paint roller or spray paint.  I tried both and prefer to roll on the paint.  I have kids so anything I can do to protect the wood and everything inside I will do it.  Good luck and let us know what you decide and how it went.

[shaolindrunkard]

One more thing.  There is also a debate on whether to use a paint roller or spray paint.  I tried both and prefer to roll on the paint.  I have kids so anything I can do to protect the wood and everything inside I will do it.  Good luck and let us know what you decide and how it went.

Spray paint is not thick enough to hide the small pores and imperfections on MDF. You have to use a thick primer then paint or simply a thick paint with a brush or roller (roller is better). This is necessary in order for it to fill the small pores that are invisible to the naked eye on mdf until you start painting. One technique is to brush or roll on a think primer or paint and then do a light sanding to get rid of all brush or roller marks and then finish with spray paint once you have a good base coat...

If you try to just spray paint MDF you will be severely disappointing. You need about 50 coats of spray paint to equal 1 coat of a good traditional paint.

[jennifer]

  It depends on what kind of finish you want and what you are trying to hide,  I normally don't use primer at all, (unless its a work area), but use a clear sealer .... Oil is just a bad idea, that belongs a a garden shed or something.

[MartyKong]

Just for my own clarification shaolindrunkard. When you say
"just never put oil over latex" do you mean even primer? I thought it didn't matter what type of paint over good primer was applied.

[shaolindrunkard]

Just for my own clarification shaolindrunkard. When you say
"just never put oil over latex" do you mean even primer? I thought it didn't matter what type of paint over good primer was applied.

You should never put oil over latex no matter what type. The reason is that oil is a hard film forming medium. Meaning that it seals completely without porousness. Latex or water based paint is slightly porous even when dry and actually "breaths" or lets air pass through it. If you put oil on top of latex, the latex underneath can't let the air through and it will lift the finish off eventually. You will get paint peeling and chipping ect.

[shaolindrunkard]

I generally use a good quality water based paint without primer. Rustoleum Ultra cover brush on works great...

[Drnick]

If you try to just spray paint MDF you will be severely disappointing. You need about 50 coats of spray paint to equal 1 coat of a good traditional paint.

Quoted for truth,  Having had experience of  both spraying mdf and rolling paint on.  If you want to do the job quicker than about 2 weeks then roll away

[MartyKong]

Wow, great explanation. Learned something new

[jennifer]

Just for my own clarification shaolindrunkard. When you say
"just never put oil over latex" do you mean even primer? I thought it didn't matter what type of paint over good primer was applied.

You should never put oil over latex no matter what type. The reason is that oil is a hard film forming medium. Meaning that it seals completely without porousness. Latex or water based paint is slightly porous even when dry and actually "breaths" or lets air pass through it. If you put oil on top of latex, the latex underneath can't let the air through and it will lift the finish off eventually. You will get paint peeling and chipping ect.

?....Once its dry air is not passing through it, at best the oil would soak into the pores and increase the adhesion bond, compatibility would be more of an issue.... Oil however takes too long to dry to be practical as far as color sanding or reworking goes and really offers no upside benefits over waterborne, enamels or even lacquer.

[shaolindrunkard]

Just for my own clarification shaolindrunkard. When you say
"just never put oil over latex" do you mean even primer? I thought it didn't matter what type of paint over good primer was applied.

You should never put oil over latex no matter what type. The reason is that oil is a hard film forming medium. Meaning that it seals completely without porousness. Latex or water based paint is slightly porous even when dry and actually "breaths" or lets air pass through it. If you put oil on top of latex, the latex underneath can't let the air through and it will lift the finish off eventually. You will get paint peeling and chipping ect.

?....Once its dry air is not passing through it, at best the oil would soak into the pores and increase the adhesion bond, compatibility would be more of an issue.... Oil however takes too long to dry to be practical as far as color sanding or reworking goes and really offers no upside benefits over waterborne, enamels or even lacquer.

https://www.todayshomeowner.com/video/how-to-paint-over-oil-based-paint-with-latex/

"Now, you never want to paint oil over latex. It just won’t stick. But you can paint latex over oil-based paint, if you prepare the surface properly."

Not saying this guy is an expert but I worked at a hardware store for over 12 years and this was always a known issue. Modern paints may have resolved this issue for all I know, but I cant speak to that. I agree that oil based paints are largely useless. That's why I don't use them.

http://colerepair.com/Latex%20paint%20vs%20oil%20based%20paint

"Latex paint is also porous and allows moisture to escape from the paint surface."

[shaolindrunkard]

Really you should probably avoid mixing oil or latex in any configuration I've heard it can go bad both ways. And really there is no reason to do it. I say stick with water based.

[stigzler]

So. I'm OK using oil based primer before applying my vinyl....? 

[Drnick]

Oil based primer, let it dry thoroughly, sand, clean,  coat with 1 or 2 layers of top coat, sand, clean and pop that vinyl on

[stigzler]

Ah. The topcoat recommendation again. Is there any evidence to support this over  the primer alone? Or is it all inductive reasoning without empirical evidence? 

[MartyKong]

Stigzler, In my earlier post I should've mentioned I applied a finish coat of paint before vinyl install. It sticks best to a smooth semi or gloss finish. Also, I want to mention I waited 2 weeks before applying my vinyl. With high humidity at the time, I wanted to let the paint dry/cure before applying.

[jennifer]

So to answer your question, Why yes you can put vinyl over cured and dry oil primer.... But you got to ask yourself why is everyone else in this thread doing something different? Perhaps its because we like wasting time and money? Perhaps its the culmination of experience of been there done that all the members are drawing upon, Maybe we simply all saw the same u/tubes video and we don't know any better, or is it something else?...Good luck with that friend.

[stigzler]

leave sarcasm to the British, Jennifer, darling. Your argument is full of holes and I have the feeling trying to debate with you about that would be like trying to push water uphill.

To others thanks for your views. I still remain curious about measured comparisons between different methods. I'll report back with the outcomes of my method of choice.

[jennifer]

I would have no reason to argue with you, Jenn is simply agreeing with everyone else in this thread....Prime/seal, sand, paint.

[stigzler]

Update on outcomes:

OK - these are the results of this process:

MDF > Sand > Oil based primer > Sand > Oil based primer > Light sand @ 400 (de-nib)
Left the primer 24 hours between coats/sand.

Outcomes attached. Happy with the results. What is clear is that:

• Even the slightest relief will transfer through onto your vinyl - e.g. the 'orange peel' of the paint (although I quite like the slight textured quality)
• Didn't have to use the 'soapy water' technique. I could lift the vinyl on finding a nib and re-apply - paint securely in place.
• 1 Ltr primer is plenty for both sides.

I used a Matt finish vinyl laminate. Not sure how it would look with a gloss laminate finish. Guess if you're looking for a "piano finish" then a coat of gloss on top of the primer would produce this.

Materials used:
Zinsser ZINCSP1L 1 Litre Cover Stain Primer/Finish Paint (https://www.amazon.co.uk/gp/product/B00A497ATG/ref=oh_aui_detailpage_o02_s01?ie=UTF8&psc=1)
Vinyl: Pixart Printing: Flat Surface Stickers: https://www.pixartprinting.co.uk/wide-format/printing-self-adhesive-pvc/flat-surface-adhesive/
Foam roller
Vinyl sqeedgee
craft/exacto knife
'soft' rubber mallet
Stapler (for bottom fold-over)

See attached pics. The 'orange peel' effect looks a lot more pronounced in the photos than it does in real life (lighting emphasises it). The first photo if the primer texture.

Also made a vid showing the process and outcomes:

(p.s. why is it so difficult to embed youtube videos?)

[shaolindrunkard]

Well done. You actually wrapped the cab. I've never done that before, usually just trim it to the edge. Only time will tell if it starts to bubble... Also that subwoofer may blow a hole through your floor.

[jennifer]

   Well., In the end You did that right, congrats,  I would have let that dry longer between coats, (or used infrared chicken lights) Because that much product tends to shrink and cure especially with subsequent coats like that. But I get why you that, it, that's what the can says.... Sega did that black matte thing, with screened vinyl  stuck over the top of that. but don't believe they used any primer or sealer, (fast clean out the door) and like discussed earlier peeling was a problem, and when it did let go there was no color underneath.

[stigzler]

If anyone's revisiting this in a year and want to know how it's holding up, just message me and I'll report back..