Saturday, April 21, 2007

More Plaster Confusion

The place I buy my plaster from is essentially a brickyard. They sell other things besides bricks, but most everything is brick or masonry related. Most of their business goes to trades people and they aren’t really set up to handle a brisk retail business.

When I go to buy the plaster I pull up to a small cinder block office building, and go in and tell a woman I need some plaster. She gets on an intercom and calls out to the yard that a customer is coming for plaster. She then tells me to drive to the second warehouse and someone will meet me there.

I drive through the gate and back to the second warehouse where two bored looking young men are leaning against pallets of different masonry products. There are a dozen different products in 50 and 80 pound bags on all of the different pallets. I tell them I want 3 Structo-Lite and 3 Diamond Finish plaster. There are no prices and none of the pallets are marked. They load up my truck and write up a tag. I then drive back to the cinderblock warehouse where the woman fills in the prices and totals, and I pay her.

I don’t remember what I got three years ago when I did my first plaster work in the upstairs bathroom. That room came out great and I had few problems. Then 2 years ago I did the kitchen and it didn’t go as smoothly. Some of the problems, which I won’t go in to, were unrelated to the plaster, but in general, it just didn’t go as smooth.

When I did the kitchen I bought the product in the picture above. It is the same as in the Worley PFD file. It is Structo-Lite Pre-Mixed Perlited Gypsum Plaster. Perlite is a volcanic mineral that has the interesting property that when it’s heated to 1600 degrees it pops like popcorn. It expands to 20 times it’s original size and is a common filler in masonry products. I still had most of one bag left over from the kitchen, and I was planning on using it up this time.

When I went to get more plaster this time I went through the same routine at the brickyard only this time they gave me a different product, or at least I think they might have. Below is what I got this time. It’s called Structo-Lite Base Coat. The ingredients are the same (Plaster of Paris and Expanded Perlite), but it seems to be a slightly different product.

Maybe it’s just my imagination, but this Base Coat Structo-Lite seems to be easier to mix and does not set up as quickly. After I finished my first bag of the of the Base Coat I got the old bag of pre-mixed perlited plaster and started mixing it in with the other type. I used 1/3 of the old and 1/3 of the new and 1/3 of the diamond finish plaster for the brown coat. Immediately I began to have the same problems I had in the kitchen. It’s just harder to work with.

After a few batches with the old Sturcto-Lite I decided it wasn’t worth it and I would just throw it away rather than deal with the problems it caused. The trouble is, I now don’t have enough plaster to finish the room. Also, the brickyard is only open Monday through Friday. My choices are to wait until Monday to finish, or muddle through with the old plaster I don’t like.

I’ve decided to use it anyway so I can finish up this weekend. I got about 4/5th of the way around the room when I realized I would need to use the old Structo-Lite. I had been at it for several hours today, and I decided to wait and finish up tomorrow. There is nothing worse than running in to problems at the end of the day. I’ll just start in fresh tomorrow and finish the room. I have a half of bag of the old and a half of bag of the new, so I'll just mix them together and hope for the best. I should be able to get the brown coat finished and start the finish coat tomorrow.

Tomorrow I’ll post lots of pictures and more tips & tricks I’ve discovered.


Gary said...

I say stop everything and go have a few beers. Get plastered (pun absolutely intended). Everything looks better after a few beers. It will turn a dog into a fox!

Greg said...

Well, a few beers is always a good idea after a days work, but actually, the bathroom is turning out good. So far, this plastering job is on par with the other bathroom.

Anonymous said...

Structo lite is for building up in a 3 coat system from lath. Basecoat is for veneer plastering that is done over blue board, or on existitng walls that have plaster weld on them. I have never seen those two products switched and have no idea what the result would be. keep us updated.

Greg said...


According to the bags, that is not correct. I'm not sure what you use as a veneer plaster over blue board. I assumed it was the Diamond Finish Plaster. The instructions for both bags say that both products are for lath and used in a 3-coat plastering system. Perhaps there is another product called "Basecoat" that you are referring to. USG makes lots of products.

I will be writing more about this today.