What type of solid surface are you referring to?

It's Staron by Samsung (like Corian). I'm not sure how to post a pic, but here is a link to a picture of one of the seams.

Here is a link that might be useful:

One of the benefits of going solid surface is the invisible seams. The only time you should see them is if your finish has a pattern to it that gets interrupted. Yours does have just enough of a pattern to be noticeable but in my opinion the seam itself isn't as good as it should be.

NO solid surface manufacturer will tell you that their seams are invisible. It's just not so in some colors, especially those with lots of aggregate content or directional flow. What they will tell you is that their seams are inconspicuous. The color you chose has larger particulates which can mean the seams are more noticeable than those with small particulates. If it is smooth to the touch with no indentation, then it's not a bad seam even though it may be a touch more visible than you would like.

I don't know that doesn't seem right to me. But I've had Corian and not the type that you have. I've never seen a seam on my Corian or anyone elses either. Oh well, it will be interesting to see what they say about why the one onsite is invisible and the ones done in the shop are not. Seems almost like it would be the other way around.

The owner/fabricator said that the seam done on-site "just came out better".

The seam done on-site was done by the installer, who has been doing it for over 10 years. The seams done in the shop were glued up by the young guy in the shop, who is just learning (ours was the first top he put together, as told to us by the installer).

Yes, it's true that not all seams in solid surface are undetectable, but I think the closeup nature of the pic is making the particulates look larger than they actually are. In a color with 1/4" color chunks, that seam would be great. I don't think this is one of those larger particle colors, even though it may appear to be from the pic.

I think the issue here is that when you are seaming the material, you use an epoxy color matched to the background color and then use suction cups and clamps to pull the two parts together. The more visible seams weren't pulled tightly enough together.

The simple fix would be to saw the counter apart at the seam and allow the more experienced fabricator to reseam it. You might lose 1/4" on the overall length of the counter, but that should be fine.

I have had solid surface (through Home Depot) and it was flawless. No seams. I just got solid surface in my new house (through Lowes) and it's been a train wreck. Seams so bad they are jagged white lines on grey countertops. They had to take my island back to shop, cut it in half and re-do the seam. Came out perfect. Yet there are other visible seams that look sort of clear. One was actually cut out and re-seamed. Now I can feel it. Like a knife cut so they are coming back out to fix it AGAIN.. Lowes has been AWFUL about this. Terrible customer service. I now refuse to deal with them at all. The fabricator, though completely inept, has been great to deal with. Moral of this story, DO NOT GET SOLID SURFACE FROM LOWES! They use poor fabricators and refuse to take any responsibility. Not so much as an apology.

If you can feel a solid surface seam, there is a lack of adhesive in the joint. Sometimes a little super glue does the trick, other times it's a do-over. Post some pictures, please.