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Stucto-lite Questions

Posted by julienola (My Page) on
Mon, May 15, 06 at 10:25

Is Structo-lite supposed to be brittle once it dries? And is it supposed to feel like sand? I used the substance to plaster a portion of my ceiling and noticed that the end result is hard and grainy--not powdery and smooth like the old horse hair plaster that covers the rest of the ceiling and walls in the room. Am I going to be able to nail wood trim onto the ceiling or will it crack?

Also, how do I know for certain that keys are being formed? I mixed the structo-lite with water until the texture was a little runnier than peanut-butter, wet the lathe with a spray bottle, then pressed the mixture onto the wood lathe until I achieved a desired thickness.

Finally, can anyone tell me what to use for the second/final coat? Can I use structo-lite again, or can I use a premixed plaster patch that comes in a white, plastic container?

Any help will be much appreciated.


Follow-Up Postings:

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RE: Stucto-lite Questions

Hi,
Where to begin?
Was the lath old or new? sawn or riven?
You pressed the structolite onto the lath. Most people prefer a trowel for that job. The action of troweling evenly forces the mixture between the openings, where it slumps over to form keys.
Smooth plaster is done in three coats. A scratch coat directly on the lath forming the keys. A brown coat on top of that that is grounded/screeded to 1/16 to 1/8 inch less than finished thickness. Finally a white coat consisting of "lime putty" mixed with a small amount of guaging plaster, and retarder, plus enough water to make it workable. Not plaster of paris or patching plaster. Those materials have no working time, being pure gypsum.
It sounds like you needed to do a bit more preparatory research before you ended up where you are at.
Properly cured structolite is steel gray, and not powdery. If it can be scraped off with your fingernail, it dried out before it cured, and may be worthless as a substrate for further work.
I really like to use a bonding agent (Link or Plaster Weld) for any old lath. Lath was originally immersed in water before being put up. I have been taught about plaster by a semi-retired pro, but I'm still reticent about doing white coat.
Casey


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RE: Stucto-lite Questions

Thanks for the information. The structo-lite has dried to a steel gray color, so maybe I'm doing something right. And I did use a trowel to apply the plaster onto the the wood lath. The lath is old, original to the 150 year old house--I sprayed it with water before applying the plaster. Since I live in New Orleans, I thought that I would be able to find plastering products easily, but haven't thus far. Can I use structo-lite for the second or third coats? If not, can you provide me with the name of a specific product so that I can order it online?

Thanks again for your help.


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RE: Stucto-lite Questions

Structolite can be used for a second coat, provided it's at least 1/4inch thick. It won't go on smoothly any thinner.
White coat is made of autoclaved finish lime slaked in water at the very least 24 hrs before use. Since it never hardens or goes bad, you can store it forever in a 5 gallon drywall mud bucket with the lid on tight. The slaked lime is called lime putty.
Using a mixing board (piece of 3/4 inch plywood about 30 inches square) trowel out a ring of lime putty about 15 inches diameter and 3 inches tall. Put two cups of water in this ring. Gradually sprinkle in enough guaging plaster to result in a creamy consistency. The more guaging you use, the faster the plaster will set. To have strong plaster but still have good working time, retarder is mixed in, usually about 1 tsp is adequate for a batch. Retarder is very difficult to come across; if you find a place that sells that, they will have all the other needed supplies. Scoop the plaster up onto your hawk with you trowel, and apply no more than an eighth of an inch thick. You will know when the plaster starts to "go off" or set. It quickly becomes stiff and unworkable. At this point, you can start to work the plaster smooth with the trowel; previously you have just been applying it. Wetting an area with water flung on from a brush, work the wall with sweeping motions of the trowel until high and low spots are worked out. For a very formal look, the walls are hard troweled to a glass finish, but for most of us, a sponged finish is more practical, and in keeping with the skills we are likely to develop. Using a wet but not soaking drywall sponge, finish out any ridges that you failed to remove with the trowel, eventually minimizing the sponge tracks. Do not over work the plaster by rewetting too often, as this will make it prone to drying cracks.
Good luck.
Casey


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RE: Stucto-lite Questions

Thank you Casey for these instructions. I have it in mind to try some bigger (meaning more than just small divot patching) plaster jobs this summer. I was planning to post asking for help and instructions when I can describe my projects better, but you've given me a head start to begin thinking about.

Julie, I hope your project is progressing and I would love to read your reports of how it goes. Since you're in NO, I guess it's a good thing you didn't have "soaked" lathe, or maybe you did and just now it is dried enough to repair. I grieved for the human tragedy and for the lost and bewildered pets after the hurricane, but I also worried about the old buildings and gardens. I hope you and your neighborhood are getting back to normal, soon.

Molly~


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RE: Stucto-lite Questions

Thanks again, Casey. I think I am in over my head, but I'm going to keep trying.

Molly, I'll let you know how things go. Luckily, I live in area that received little flooding. A portion of the ceiling fell due to old age or leaky plumbing--we never did see signs of water damage, but there's a bathroom overhead. My goal is to have the ceiling repaired before the start of the next hurricane season.


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RE: Stucto-lite Questions

I wanted to follow up on this topic since someone else might have questions about Structolite.

A representative of Structolite told me that they do not recommend any of their products for wood lath, and that I should have added wire/metal to the wood. I had already finished the first coat, though, when I spoke to this guy, so I wasn't about to start over.

The second coat wasn't thick enough; it dried before it had a chance to cure properly, so I scraped it off and reapplied. The final coat (I used Master of Plaster)looks really bumpy where the new plaster joins with the old.

I'm disappointed in my own work, but I figure if the ceiling falls down again, maybe I can do a better job. I underestimated how strenuous working on 14 ft. ceilings can be.


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RE: Stucto-lite Questions

If you want to learn how do plastering get a copy of "Plastering Skills".


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RE: Stucto-lite Questions

Structo-lite over interior brick: I want to repair an interior brick wall. I've removed the old plaster (an area of about three feet high by four five feet wide) and scraped the old brick pretty clean. I need to put it on about an inch thick. Then I was going to put a layer of Durobond and then Easy-Sand as a finish coat. I've purchased some bonding agent which I was going to brush on the wall. Does this sound okay. Any 'heads up' advice?


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RE: Stucto-lite Questions

Keep the coats of structolite less than half an inch and it will be fine. IOW, two coats. I like the first coat to cure before the next, so I'd wait a week, esp. with cold weather which is going to slow the escape of the water. If you don't you'll have to wait even longer to paint.
Casey


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RE: Stucto-lite Questions

What about the bonding agent. I usually wet brick down before putting any kind of cement, mortar, plaster, stucco-like material on it. But how do I use the bonding agent. Do I spread it on dry brick and then put the structo-lite over it without using any water?


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RE: Stucto-lite Questions

The bonding agent is a water-based product that seems like thinned-out elmers glue. It is brushed or rolled on. It seals porous surfaces so the structolite sticks better. But, since the sealed surface is no longer porous, all of the water can only move out of the wet plaster into the room. So the drying time is going to be longer than if the brick hadn't been treated.
There is no reason to wet down the sealed brick, in fact it would be bad; the structolite would probably want to slide off.
If you feel confident in you skills you can wet down the bare brick and forego the bonding agent, and enjoy a shorter cure time.
Casey


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RE: Stucto-lite Questions

Thank you, Casey. I kind of like the older, and more simple methods. I think that is what I'll do (dampen the brick with water). In you first answer you said you thought I should not apply the first layer more than 1/2 inch and then wait between coats.
Could I go 3/4 or an inch ?
Should I damped the first coat as it dries, like mortar or leave it alone?
If I do two coats how do I know when the first is ready to be topcoated?
And how do I know when I can go over the last coat with my durobond or easy sand?
And most of all -- Thanks for taking your time to help another guy out --

Jim


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RE: Stucto-lite Questions

Can this product be used in a basement? I have a rental house - in the past I've painted the cement block walls and the cement basement. It seriously needs another paint job or something else - there's some humidity when it rains a lot tho I have a dehumidifier running and that helps a lot. Thanks much for your help. Diana


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RE: Stucto-lite Questions

Diana, You would be much better off covering the walls with Drylok...Here's a link so you can read about it.

Here is a link that might be useful: Drylok


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RE: Stucto-lite Questions

I think stucto-lite may be the material needed to build my free standing sculpture. The structure will be about 6' x 4' x3', hollow to keep it light, painted/ colored and & stand on its own base. I intend to make a wire armature for the most part to hold the chicken wire structure that will keep together the stucto-lite. Several questions pop up since it will be outdoors 1) Will this hold up in the weather conditions of the midwest? 2) Is there a way to seal it better? 3) should I use a bonding agent w/ wire frame/armature? 4) how much can I very the thickness of the piece w/out cracking or degrading the materials.


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RE: Stucto-lite Questions

I think you'd be happier with a lightweight portland,sand and vermiculite concrete. Structolite is gypsum-based and it's not frost-proof and would dissolve after about 2 winters.
Casey


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RE: Stucto-lite Questions

In the early 1970’s hydronic radiant heat was installed in the ceilings of my antique cape. The pipes are copper and filled with antifreeze. I was told to only use Struct Lite plaster on the ceilings. Three rooms have a rough, swirled finish but all other rooms are smooth. One of the smooth ceilings was damaged by a water leak from a gutter. The painter repaired it but not with Structo Lite After a year and a half the entire repair area is peeling. There is no evidence of another leak. Can you tell me how Structo Lite is beneficial for use in radiant heat ceilings and if this area should be repaired with it?


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