Matt Over Silk

[mrsparks]

I'm in the process of painting walls - some are newly plastered, some have vinyl silk on them. On the new plaster, I'm going to use Optiva Primer and Optiva 5. On the walls that have vinyl silk, I'll be using the same but I'm seeing conflicting advice on prep. Some say don't sand, just apply the matt - it's the sanding that causes problems. Others say sand. Tikkurila customer support say sand, then Primer then top coat. I must confess to sanding some areas of the silk already - to the point of trying to remove all the sheen. It's hard work - mainly because of the roller texture in silk.

So, I have a couple of questions.

I have a whole room of silk to cover, which I haven't started yet, and with it being such hard work to sand, I'm wondering whether to bite the bullet and apply Zinsser Gardz (got to be easier than sanding), before Optiva Primer. Or just try OP over the silk - no sanding.

On the hallway I'm currently working on, I'm wondering whether the silk I've heavily sanded is going to cause problems, and whether on the remaining areas of silk I should just lightly sand - or not sand at all - prior to OP and topcoat.

What say you?

[dewaltdisney]

On the silk covered walls we had a recent thread on here about painting over. The poster managed to do it straight over but you can experience roller skid. It is a good idea to rub over with a used scotch pad to degrease and key the surface. Just a light rub over usually is enough.

DWD

[mrsparks]

On the silk covered walls we had a recent thread on here about painting over. The poster managed to do it straight over but you can experience roller skid. It is a good idea to rub over with a used scotch pad to degrease and key the surface. Just a light rub over usually is enough.

DWD

So I might have gone a bit far by giving it a hard rub with 80 grit?

My concern was adhesion of the primer to any shiny surface. When lightly sanding vinyl silk that's been applied with a roller, you're only actually roughing up the high spots and there's still a lot of shiny bits in the low spots (if you know what I mean).

Seems a lot of varying advice out there for what to do before top coats - no sanding, light sand, sugar soap, Zinsser 123, Zinsser Guardz, and others I expect.

[dynamod]

So I might have gone a bit far by giving it a hard rub with 80 grit?

80 grit is a bit OTT, and might actually risk shredding the surface paint.

FWIW, for the better part of 30 years, all we ever gave silk was a once over with P120 or P180 depending on texture. Not once did it disperse or cause any problems. All this talk of Gardz and 123 is just wasting money, and a belt and braces approach is all that's needed. Provided the surface is clear of contaminants and has been lightly abraded to give the top coat a key, there will be no issues.

This 'adhesion primer over silk' has gained traction on forums for some bizarre reason, and has almost turned into a meme. Yes, it'll work, but given basic preparation, it's wholly unnecessary.

Seems a lot of varying advice out there for what to do before top coats - no sanding, light sand, sugar soap, Zinsser 123, Zinsser Gardz, and others I expect.

Forums will give varying answers and results by their very nature, I'm afraid. In reality, all of the above, in the right circumstances will give acceptable results, but my contention with the Gardz/123 thing is that in either a DIY or a paying client context, this approach adds time and materials into a situation that simply doesn't require this level of attention. Gloss, OK, but silk just doesn't need primed with anything if it's been sanded and cleaned. I've been saying this for years, and I will continue to say it.

As an aside, Zinsser problem-solving primers are often viewed as a substitute for preparation, and there has been (IMO at least) far too much of a reliance on them, by both trade and public alike. They have their place, and all work well, to varying degrees, given the right situation....but thorough and correct preparation is still as necessary now as it ever was.

[dynamod]

BTW, as an exercise in pure hair-splitting, you could conceivably use Gardz, Peelstop, Coverstain, BIN, acrylic primer or even mid-sheen emulsion as a bridge from silk to matt. Over the years I've heard of all of the above being used, and a few others besides. They all worked in as far as they prevented dispersion and adhesion issues, but none of them were necessary. That's kind of the point here.

[mrsparks]

So I might have gone a bit far by giving it a hard rub with 80 grit?

80 grit is a bit OTT, and might actually risk shredding the surface paint.

FWIW, for the better part of 30 years, all we ever gave silk was a once over with P120 or P180 depending on texture. Not once did it disperse or cause any problems. All this talk of Gardz and 123 is just wasting money, and a belt and braces approach is all that's needed. Provided the surface is clear of contaminants and has been lightly abraded to give the top coat a key, there will be no issues.

This 'adhesion primer over silk' has gained traction on forums for some bizarre reason, and has almost turned into a meme. Yes, it'll work, but given basic preparation, it's wholly unnecessary.

Seems a lot of varying advice out there for what to do before top coats - no sanding, light sand, sugar soap, Zinsser 123, Zinsser Gardz, and others I expect.

Forums will give varying answers and results by their very nature, I'm afraid. In reality, all of the above, in the right circumstances will give acceptable results, but my contention with the Gardz/123 thing is that in either a DIY or a paying client context, this approach adds time and materials into a situation that simply doesn't require this level of attention. Gloss, OK, but silk just doesn't need primed with anything if it's been sanded and cleaned. I've been saying this for years, and I will continue to say it.

As an aside, Zinsser problem-solving primers are often viewed as a substitute for preparation, and there has been (IMO at least) far too much of a reliance on them, by both trade and public alike. They have their place, and all work well, to varying degrees, given the right situation....but thorough and correct preparation is still as necessary now as it ever was.

Oh dear. I certainly have been very robust with the 80 grit on a small area - definitely shred the surface. What would you do on that area to rescue it? If it needs sealing I have some 123 and also Optiva Primer.

I have 3 walls of silk untouched so I'll be more careful with them.

Thanks for all the advice.

BTW, what would you clean the surface with after a light sanding?

[dewaltdisney]

If you use wet and dry paper (or a scotch pad) with a splash of washing up liquid in the bucket it will degrease, clean, and lubricate at the same time.

DWD

[dynamod]

Pretty much all that's needed. I always think there's a bit of confusion over what constitutes sanding in this context. It's not a case of creating a dust apocalypse, or sanding the coating utterly flat; it's just to knock the sheen off and create a key.

The 80 grit section should be OK if you go over it's edges with something finer. 180 would be my choice

[mrsparks]

OK - an update. The hallway, which had a mixture of new plaster and vinyl silk is sorted.

Now I have a living room to paint completely. Newly plastered ceiling, 1 wall of new plaster, 3 walls vinyl silk - again.

This is what I'm going to do. On the new plastered parts (ceiling and walls) - Optiva Primer. Then on the ceiling Tikkurila Anti Reflex 2. The topcoat on the walls will be Optiva 5.

On the vinyl silk walls ... did I mention I'm really really fed up of sanding? I've done a ton recently and I'm not up to doing any more. So, the good folk on the internet say that Zinsser 123 can be applied directly to vinyl silk, with no prep (except I might give it a wipe with a damp cloth) - and I have some 123, so that's what I'm going to put on it. (I have the energy to roller paint onto walls, but no enthusiasm for sanding anyore - plus it's more fun applying paint than removing it). The only decision I have to make is whether to bung some Optiva Primer on top of the 123, so that the Optiva 5 topcoat is going onto the same base coat on all walls. I have no idea whether Optiva 5 on top of 123 is a good idea (123 is only a primer after all? and very similar in consistency to Optiva Primer) - and Tikkurila customer support won't give any advice on products which aren't theirs.

Incidentally, Optiva Primer onto bare plaster is a bit of a b*gg*r. It dries almost immediately - barely any working time. If you're not careful when rollering you end up with some ugly overlapped edges.

[dynamod]

Optiva over 123 shouldn't cause any issues.

As much as you don't enjoy the sanding process (understandable I daresay) part of the reasoning in the method I described, is not to introduce any other potential coatings into the mix.

A sanding pole with P180 should take no more than 30 minutes to do a normal sized room. At the very least, make sure to de-nib the surface first. Going mad with hand sanding isn't what's needed anyway, as a good once over is all you need.

This thread shows me how utterly warped this matt over silk issue has become. It wasn't, and isn't the problem it often gets made out to be. We painted hundreds of rooms with matt over silk back in the day, with no problems at all. It didn't disperse, it didn't peel and there were never any issues down the line. Provided the matt emulsion is of 'Trade' quality, with decent levels of pigment, binder and resins, it'll ahdere perfectly well over lightly sanded and cleaned walls.

Nobody had access to Gardz, 123 or anything else, and silk was much shinier back then. It was also used far more, so we encountered it regularly. Until this 'issue' started being talked about on some of these forums, a huge portion of the trade was unaware a problem even existed.

I'm quite happy to help folks with their decorating problems, but I have to confess to being utterly baffled by this Matt/Silk thing. It's never been an issue, and minimal prep has always sufficed. It's a proper case of emperor's new clothes and should have been put to bed years ago, as a search of this forum (and other forums) return all manner of conflicting advice, which has only served to confuse people.

Sand, dust and clean. Trust me, it's all that's needed.

[dewaltdisney]

I think a lot of this overfocus is related to advances in car spraying. Adhesion promoters came into use spraying bumpers and plastics. I am sure someone grabbed this notion for preparing 'slippy' surfaces and it grew into the myth it is today. I am not a pro painter like Dyno but over the years I have done my fair share of painting on a variety of jobs. My experience was that my roller skidded going over silk and to fix this I gently washed and keyed using wet and dry. I have also used a scotch pad which worked as well. It really is not hard to go over a wall and it works. But that dies not mean that going over with 123 would not work, it would just add to cost.

DWD

[dynamod]

But that dies not mean that going over with 123 would not work, it would just add to cost.

It does work, (as do many other coatings, as I previously said) and I suppose for anyone who wanted to be absolutely sure, it's fair enough. I advocated the belt and braces approach, as it's 100% effective. Why fix what wasn't broken?

DIY-er doesn't want to spend any more money than necessary, paying customer wants value, and professional decorators want to be competitive. In each case, the answer isn't adding more materials and time, when such simple and basic prep works.

This has been the point of all my responses on this and other related threads. Many coatings and primers will work as a bridge to promote adhesion, and in certain cases it may be argued they could help, but they're not essential. I personally maintain none of them are even necessary, given how often we worked without them.

With most things in life, I find the best solutions are the most straightforward, and when they are also the cheapest, why look to reinvent the wheel.

[mrsparks]

Thanks everyone for your input. I wouldn't have given this a second thought until I saw some random post about it a while ago.

Clearly, it is an issue for some people because there are plenty of horror stories out there. Whether that's the result of poor prep or whatever ... who knows. My concern as a DIYer is that if it did go wrong, I'm into a world of pain.

In view of your comments, I may reconsider the light sand followed by Optiva Primer. To be decided ...

[dynamod]

Clearly, it is an issue for some people because there are plenty of horror stories out there. Whether that's the result of poor prep or whatever ... who knows. My concern as a DIYer is that if it did go wrong, I'm into a world of pain.

Stay with trade paint. Don't, I repeat don't go near retail paint if you're at all worried about adhesion. Retail emulsion is like night and day to trade emulsion.

Lack of preparation, cheap rollers and brushes, contaminants not cleaned, poor technique all affect end results. It's not a black and white issue of whether a bridge coat was used or not.

If you feel that using 123 or similar gives you peace of mind, by all means go that way. It won't hurt.

[mrsparks]

Clearly, it is an issue for some people because there are plenty of horror stories out there. Whether that's the result of poor prep or whatever ... who knows. My concern as a DIYer is that if it did go wrong, I'm into a world of pain.

Stay with trade paint. Don't, I repeat don't go near retail paint if you're at all worried about adhesion. Retail emulsion is like night and day to trade emulsion.

Lack of preparation, cheap rollers and brushes, contaminants not cleaned, poor technique all affect end results. It's not a black and white issue of whether a bridge coat was used or not.

If you feel that using 123 or similar gives you peace of mind, by all means go that way. It won't hurt.

Does Optiva 5 count as trade paint?