planiprep sc

[SpaceCadet]

Does anyone have experience with mapei's planiprep sc?

I've been trying to get it to work on some scrap plywood. It mixes and spreads fine but does not seem to set. It's hard, smooth, and flexible once it dries but if it gets wet it turns mushy again. I can wet a finger and rub the dried planiprep off the plywood a few days after applying it. Bag is a few months old and was opened less than a week ago. I've been mixing small batches but I poured the whole bag out into a bucket and mixed it up with a paddle in a low speed drill so it's not dry ingredient separation. Is this just how this stuff is? Don't see what I could be doing wrong.

[Kman]

Odd that there's no mention of a primer in the instructions. Every other SLC I'm familiar with requires a primer. Anyway....

On your test board, how thick are you pouring the material? Does it spread out to a thin layer before setting? Have you tried removing a piece of it from the plywood and see what a cross-section looks like?

[SpaceCadet]

Planiprep SC is not self-leveling. It's a cement-based patch like planipatch but you don't have to mix in planipatch plus for the latex reinforcement/flexibility and it gives you a little more working time. I've been doing mostly skim coats but maybe up to 1/8" in places and there's globs here and there. I did at least half a dozen test smears and I wasn't very neat about it.

[cx]

I don't recall that product from any of our MAPEI training seminars, Paul, and I've never used it.

The TDS does indicate it's perhaps a bit moisture sensitive, but not to the extent that it can be rubbed away with a wet finger, I wouldn't think. It is restricted to interior use, but still.........

No mention of a primer over plywood, Kevin.

You indicate the bag is only "a few months old," but I presume that's how long you've had it, rather than from the manufacturer date. Would that be correct?

I'll see if I can get a MAPEI rep to comment.

[SpaceCadet]

Age of bags is from date of manufacture going by the timestamp on the bag. I can go get the exact date if anyone is curious (it's out of reach at the moment) but the newer bag is something like middle of last fall. Well within the specified shelf life. The older bag that I was playing with is from august 2020. They seem to behave the same.

I have been PM'ing with Holden from Mapei tech support and he has done his best to help. I did not want to post this on the forum because it feels like bad press for what I consider a good company but this is a last ditch effort to figure this out before the weekend is out. Holden's suggestion was to mix up the powder in the bag but that didn't seem to change anything.

[Tool Guy - Kg]

Nothing stands out as a problem or issue on your end from what you've described, so far. If you're in a time crunch, I'd go to a different store to purchase a new bag and use that.

You can figure out the problem after the weekend. Very, very, very infrequently, there is an issue with manufacturing. I think most manufacturers routinely pull batch samples during manufacturing for testing at a later date, if needed.

[SpaceCadet]

I used 2 bags bought months apart from different place. One 16 mo old, one ~3 mo old. Same thing happens with both of them. It's very unlikely that I got a defective batch.

[MAPEI - Technical Service]

Paul, if you don't mind shooting me the batch codes when you get a moment, I will check them out on my end to see exactly how old those bags are, and if we have any complaints against them.

Otherwise, just to sum up we have chatted about over PM for everyone stopping by this thread:

Planiprep SC is a bit softer and more flexible than Planipatch, so Planiprep SC just is not going to look or act the same as Planipatch.

Temperature does factor in to set time, early strength development, and other working properties. 50F is the minimum ambient and substrate temperature for the application of this product. If it is below 50F where you are doing the test batches, or in the final install area, you can have some workability and setting troubles.

We talked a bit about dry mixing product, and from what you have sent me and posted here, I don't believe that to be the issue. We want all the dry components blended well before you mix any water in, that way there isn't an imbalance of raw materials in the mix.

Expired product concerns were where we started in the conversation, but with a new bag doing the same thing, it's possible what you are seeing is due to environmental conditions.

[cx]

Thanks, Holden.

Is that Planiprep a relatively new product? I don't recall it from any of our (TYW) training sessions with MAPEI.

[SpaceCadet]

Bag info:


The new bag is older than I thought but still well within the 1 year shelf life.

I am doing the test batches in my basement. It's unfinished but heated and I run a dehumidifier so it's always around 63 degrees and 35% relative humidity. Should never be anywhere near 50. The patch is applied to very old 1/4 in plywood scrap. 2 layers of cardboard between the plywood and a concrete floor. The leftover material in the mixing containers seem to have the same properties. I'm in new england so the temperature is all over the place. Thin it was in the 20s when I did these.

A picture of the test smear. The dark bit on the right is me just having rubbed off the planiprep with a wet finger just now. The lighter feature to the left is where I did the same days ago. This was applied at least 2 days ago.

[cx]

Originally Posted by Paul

The patch is applied to very old 1/4 in plywood scrap. 2 layers of cardboard between the plywood and a concrete floor.

You're fixin' to tile over that, Paul?

[SpaceCadet]

Originally Posted by CX

You're fixin' to tile over that, Paul?

No, it's just a test application.

[cx]

I feel better already.

[SpaceCadet]

Originally Posted by CX

I feel better already.

The 2 layers of cardboard under the plywood are actually a stomped flat storm window box. Sounds like a legit substrate scheme to me.

[cx]

Oh, no question about it! I'm sure I just missed it somewhere in the A108/A118 book.