Poor honing job or damaged temper?

The razor: FW Engels Argo Steel full hollow made in Solingen Germany purchased on Ebay. It was inexpensive, so I figured why not.

The bevel was set using a Norton 1K, then I went through and honed it up using Norton 4K/8K stones. Thumbpad and thumbnail tests both seemed to indicate a nice shave ready blade.

A short time into the initial shave, the blade began to pull really heavily and now, thumbnail and thumbpad tests both reflect a dulled blade.

This is my first effort at honing my own, so I'm trying to work out what happened here. I can see one small spot out at the end of the blade that might be heat damage, but I can't be sure of it. Is it possible that the blade's temper was damaged by a previous owner or is it more likely that I messed up honing the edge?

First off, welcome to the wonderful world of honing. You are doing the correct thing in that you are working on a razor that doesn't seem to be all that good.
You said that the razor passed the TNT and the TPT. You should never do the TNT after the 1k stone. You may have inadvertently dulled the razor doing it.
Start all over again and work on the 1k stone until you can pop hairs on your arm at their base. Check on 4 or 5 points along the blade. If any one, especially the heel and toe, do not pop hair, keep going. When you can do that, move on to the 4/8k stone.
Then do a pyramid and when you are finished, strop the blade and do the HHT. If it passes at least 6 points along the blade, shave with it. If not, do another pyramid set.
This takes a lot of patience, so hang in there.

Enjoy!

Ray

Pretty much what Rayman said dont do the thumbnail after the bevel is set. Try again and let us know how it goes.

Highly unlikely the previous owner destroyed the temper unless they tried to hone or polish it using an electric sharpening or polishing tool.

If you find your razor is doing well for a while and then suddenly stats too pull you're nearly but not quite there or the cutting edge is not uniformly sharp.

This is what I would do: give it 20 laps on the 8K, strop it and see what happens. If this improves your edge you can repeat as often as needed. If the result is as bad as it was you have to go one step downwards on the grit ladder and work your way up and see what happens. Etc. till your edge is satisfactory.

You can mark the bevel with a felt tip to see it there are parts that do not touch the hone. If so you certainly need to go down on the grit ladder.
Good luck!