how to make thinset bond to a plastic sheet material [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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04-19-2010, 02:43 AM
My company makes shower doors but wants to expand into shower bases and other products related in consumption.
I stumbled onto your site by reading a thread where everyone warned against using mastic in a shower environment. Well, I long ago lost count of how many times I have seen people make that mistake. Anyway, I concluded that the contributors know their stuff and might be kind enough to help me with a bit of R&D by steering me in the right direction.
What I want to make is a line of premanufactured shower pans that will accept thinset that are also designed to work with my shower doors.
Somehow I doubt that I will find a vacuum formable sheet material (such as acrylic) that will bond with thinset, but maybe someone knows of one...
The other main idea I have is to impregnate another material into the sheet material after heating it to a state where that is possible.
I am looking for ideas as to what material I could use for this. I have considered such things as fiberglass batting, a loosely woven thin rayon material, or even just plain sand.
One underlying question is how does thinset actually bond to anything? I look at some tile that seems fairly smooth on the underside and am mildly impressed that thinset actually works, though I know that some tiles require modified thinsets. Is the bond a microscopic mechanical bond? Would simply roughing up just about any material provide a mechanical bond? Or is it a chemical bond?
Thanks in advance to anyone who can offer some pointers.

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04-19-2010, 05:08 AM
Jules- tough market to compete in. Lots of company';s specialize in that for many years. Besides, as a door manufacturer, I'll bet you have never had a customer complaint that their shower door leaked.

Thinset can be bonded to lots of things, (some by mechanical means, some by chemistry) just go buy a lot of products already available and start testing them.

Also, might be better to team up with another manufacturer that makes waterproofing and has already done the work, and figure out how to pair your shower door with their stuff.


04-19-2010, 06:46 AM
hi Jules and welcome,
Epoxy mortars can be used to bond to certain prepared resin-cast and plasticized fixtures. The cost and head-ache involved with epoxy mortars may not suit your target market though? What is unique about your shower door design that begs for a proprietary pan-and-curb design? I agree with Gueuze that finding a current product that your own product can integrate well with might be a better partnership than assuming the entire burden onto your own company.

John Bridge
04-19-2010, 07:51 AM
Welcome aboard, Jules. Geuezman mentioned to the two ways thin set can bond. Generally, cement products bond mechanically. When latex or polymers are added the products also provide a chemical bond. But I don't know of any cement product that will really do the job on plastic unless the surface is very rough.

Also, you might have a look at the Ditra tiling membrane made by Schluter Systems ( It depends entirely on a mechanical bond.

04-19-2010, 09:09 PM
Thank you so much for your input.
The question was asked "What is unique about your shower door design that begs for a proprietary pan-and-curb design?" and it deserves an answer.
I have been in this industry a long time and two things have become obvious to me. First, shower doors are generally designed by people who have never installed them and, while their designs look great on paper they often suffer in the real world where walls are rarely plumb and curbs are frequently out of level from side to side. Lack of sufficient adjustability is a frequent critique of shower doors. Secondly, the people who design curbs are not the same people who design shower doors. I do not wish to go too far down this road as it might sound like criticism when in fact I have learned and adopted much from those who have gone before me. Suffice it to say that by thinking of the two as a matched pair it does lead to fertile ground for design improvements. If I ever get my ideas to market I will be sure to ask you to check them out and you will see what I mean.
As for the Schluter systems I certainly was thinking of the Kerdi system which I have strongly recommended since first being exposed to it (they should pay me for all the times I have convinced people to use it), but I had forgotten about the Ditra system. Great suggestion.
In the end I know I have a lot of testing to do before deciding on a direction to go in.
For anyone interested, I have been effectively forced by our government (Canada) to move production to China (or pay a HUGE import duty on my principal raw material that would quickly bankrupt me). This has disadvantages, such as trying to find modified thinset when tiles are applied here using portland cement, dirty sand and water;) I have also learned the hard way that one does not give design ideas to a Chinese supplier or he will soon become a competitor. On the other hand R&D will be relatively inexpensive and if I find something that works with the locals' thinset then it will work with anything that North America has.
Thanks for your answers and do please wish me good luck.

04-20-2010, 09:21 AM
This has disadvantages, such as trying to find modified thinset when tiles are applied here using portland cement, dirty sand and water

Modified thinset is hard to find in Canada? Hard to believe. China, on the other hand, I could understand.

However, I believe that Laticrete did supply all the setting materials for the Beijing olympic pool cube.

Must be available somewhere.


Bill Vincent
04-20-2010, 02:32 PM
Jules, the problem isn't so much the bonding. It's the STAYING bonded. Most plastics will expand and contract at a much greater rate than thinset, and as a result, even the highest latex content thinsets won't be able to hang on. That's assuming that the base is engineered in such a way that it will have zero flex to it.

There's one company that makes a "ready to tile" shower pan called Tile-Redi, and in addition to my own experience with it, I've heard nothing but problems from it, mainly because of the flex of the pan causing tile to break loose. That would be problem number one to solve. The second would be rate of expansion and contraction.

As far as thinset in China is concerned, Laticrete does have a manufacturing plant in country. YOu want to get in touch with a member by the name of hbrothberg. His first name is Henry, and he knows some of the "higher ups" at Laticrete. :D

04-20-2010, 06:29 PM
he knows some of the "higher ups" at Laticrete.

LOL, Bill. Oh, I guess that Ed Metcalf guy, maybe.


Bill Vincent
04-20-2010, 07:14 PM
Yeah, and I think he might have a passing aquaintence with the CEO, too. :D :D :D

04-25-2010, 07:38 PM
There is of course no problem finding a myriad of tile adhesives in Canada. In Kaifeng, Henan, China (where I now live and where my manufacturing will take place) there may be a problem.
It is actually quite an interesting challange finding things here. For example, I would like to buy a table saw, a band saw, a box stapler and a biscuit cutter. These things are all made in China and I know I can find manufacturers easily enough and I should be able to get them to sell me just the one that I need. But I have not been able to find any of these items in the stores and showing pictures to the factories that would normally have such items and the universally common reaction is that they have never heard of these tools which are all so readily available in Canada. For a table saw they just screw a circular saw to the underside of a sheet of plywood on some saw horses. With the guard thus inactivated it can hardly be considered safe! The office I am in is tiled, and a toilet plunger would easily remove any one of the tiles. The jobs are not all that bad of course, but even 5-star hotels frequently do not have P-traps in the sinks and thus sewer gases in the suites. This was the first problem on my list in the place I am living and the lack of adequate venting still causes the traps to drain due to the vacuum caused when the toilet is flushed. On the other hand the cell phone networks put North America's networks to shame with such things as caller id or redial etc being standard features that they charge a ton of money for in Canada and I suspect the USA.
I have heard a from others that they do not like the redi-tile and I do not want to have a pan where the tile setter needs to use my special adhesive. If I can find something that accepts unmodified thinset then I think the tile setters will embrace it, especially if the cost is reasonable.
That information about the different rates of expansion and contraction is priceless. I had not considered it before and yet, now that you mention it, it seems pretty obvious. Whats more, it would not have manifest itself on the small samples I was going to do my initial testing on. I owe a special debt of gratitude to you, Bill Vincent, for that tidbit of information and will be sure to address and later test for that problem extensively.

SP100 beta tester
04-25-2010, 08:59 PM
Why don't you consider making a precast pan similar to a FIAT shower pan to your own dimensions.

Less expansion and contraction than a plastic base, tile-able and you can create the curb to your own specs.


Bill Vincent
04-25-2010, 09:21 PM
Jules-- Re the tile adhesives problem, we joked about Henry Rothberg before. Seriously, get in touch with him. When we said he "knew" some of the higher ups in the company, his father is the founder, his brother is the CEO, and he's the corporate vice president of Laticrete International, and I know for a fact they just opened up a plant (and retail business) in China. In fact, I'm surprised he hasn't popped in here yet. I'm going to give him a shout and have him check this thread out. I have a feeling that a business relationship between the two of you will be extremely valuable to the both of you.