Judy, I'm just learning myself, but wanted to welcome you. I know you'll get some great answers here from these wonderful friends. I'm working on my first real mosaic myself and am getting a lot of help from the people here.

Also, I've learned that if you go to the search box here and type in a word or two about the information you need, often your questions have been answered for someone else earlier and are available here.

Good luck on your project! I'll be checking here for WIP updates and photos!

Greetings, Judy! Glad to have you pop in! There are many here with more experience than me, but I think you are letting yourself in for a major problem using particle board as your substrate. It can really expand and contract ALOT which, along with cracking your grout, will lead to the tile popping off. If this is for an outside table (even in a protected area) I would definitely use something more stable, like cement board or hardibacker. The last thing you want is to see all your work fall apart. Sorry to 'dampen' your idea, but disappointments can be devastating! I'll let someone else who knows more than I do jump in here about the indoor possibilities.

Pat

WELCOME JM. Good advice from CURB. Don't use wood for outside projects. After saying that I'll tell you I've mosaiced a pedestal for my garden, but it is made of cedar. As CURB said - get the hardibacker for your base, then yes, you can butter each piece of tile w/thinset b/f you apply it to your base. Spritz the cement board b/f you put the tile down, cuz it's very pourous, and w/suck the moisture from your thinset. My favorite thinset is the Mapei Ultra Flex II - a polymer modified mortar. I also use it for the grouting. You can color it, if you don't like the white or gray that it comes in. Lowes carries the Mapei and the colorant in several colors. If you want to leave an area in the middle of your table, I wouldn't put grout. Just grout around your tiles in a circle or whatever pattern you intend to leave vacant, smoothing it as it drys to be beveled w/your table, and perhaps put a platter, or just a sheet of colored glass behind your flowers. Don't understand about the flowers - you mean you're making them out of tiles or glass or ??? 'splain, please. Grout isn't for that purpose and won't hold up.

Sorry to be confusing about what I'm trying to do. The rocks I'm using are different shapes and I'm using a round one as a center of flower then making petals from other stones. I have the flowers sort of interlocking, but there are some areas where the grout will be about 1 inch square area between. If I add more rocks I lose the flower shape. Thanks for the advice about particle board...I was afraid of that. How do you get a perfectly round piece of cement board? We have a hand held jigsaw, but I'm certain I couldn't make it right. I have laid out the tiles in the design I'm considering. Here is a picture to get feedback about the design and grout issue. OK-that won't work on this laptop...I'll post a pic from the real computer.
Judy

Re cutting the cement board, FLAG just bought blades for cutting masonry I think. When I was trying to make an egg-shaped piece for a gift, I just broke the pieces off by hand. It crumbles pretty easily, I realize you need a perfectly cut base. I'd suggest you get a masonry blade for your jigsaw. BE SURE AND WEAR A MASK. This is cement you're working with, and you don't want to inhale the dust. Don't know what size your table is, but the hardibacker comes in 4'X 8', so you may have to put two pieces together to make your circle. You CAN use a utility knife, but it would take awhile to cut a circle. It CAN be done, though, it just takes several passes for each cut. One inch of grout is too much, so I'll bet you'll figure out a way to make your center w/o so much grout.

I have some of those beautiful stones and have done a couple things with them. Can't wait to see the progress of this table.

You've already gotten good advice from those who know so i won't add more,what they've told you is the thing to do!

Here is the picture of my table top. Please comment freely especially about the "empty spaces" and how to maintain the flowers in the center if you think that works. I was thinking of maybe really tiny stones for between that area...just pressed into the grout. Ideas?
Thanks,
Judy

Tiny stones would work, as would stained glass pieces, aquarium gravel, keys....you get the idea...just about anything that **isn't** the same size and shape as your pretty pattern. Definitely too much surface area for blank grout. Even on the hardibacker or cement board the grout would crack. Cute idea! Looking forward to seeing it both in progress and finished!

Pat

I am a newbie to, but wanted to tell you that this is so cool looking. I was thinking the same as Pat with the stained glass pieces. I can't wait to see this finished.

Allyson

VERY NICE project!!! And how about those little round copper BBs that everybody is using, it's a better way to use ammo and it is a nice feature! lol!

Love your design,as someone said the grout will crack with nothing else in your spaces,I have a pedestal that fell apart after a couple of years because I left to big spaces in the grout.fill in with some black glass cut random pieces or tiny rocks like someone suggested also.

Oooo, that design is nice! And I really like the copper bb idea or the aqaurium gravel idea as it does need something to fill all those gaps. Looking forward to seeing this as you go...

Your design and the stones are wonderful. Wow. It's great you're taking your time and learning all there is to know before you start. You won't want to lose this beautiful piece! We can hardly wait to see how it develops!

Thanks so much for all the helpful comments and compliments! I like the bb idea...or maybe an iridescent glass tile. I'd like to keep things in the same tone, if that makes sense...not too much contrast. Next hurdles are trying to cut a cement board circle and finding the right filler. Will post more pics when I make some progress.
Judy

OOOOOOOOOOOOHHHHHHHHHHHHHHHhhhhhooooooooohhhhh! Now I see what you mean. I thought you were just leaving a round space in the center to use for table-scaping w/a vase of flowers or whatever when in use. Since you want to keep it very organic, the aquarium gravel is a great suggestion, as well as the BBs. Also, try putting a couple more petals in each flower - make them touch each other. That's gonna really be a neat table.

I was lookin at this again and had a thought. If you wanted to keep it the way it is without adding anything else, instead of grouting, just pour envirotex lite over it all. I did that with the wine lady tray .
I ordered it online but can't remember where, but I've since seen it at big box home improvement stores.