Preparing to graft Ariocarpus

Greetings folks,
As the title suggests I will be attempting to graft some Ariocarpus in the next few weeks.
The seedlings are all healthy and several weeks old (manageable size) the Peres stock will be ready in a few weeks time and as such I have begun to slowly harden off the seedlings.
I have been quietly grafting some other species over the past few months with mixed results.
Have had good success with seedlings taking but have encountered problems where the join will develop a brown/orange colour and eventually eats the seedling.
Some however appear to have taken and are beginning to grow.
Will try and post some photos soon but it's difficult to get a clean image.

Any tips or hints that anyone has to share would love to hear your thoughts?
I do have one question, the seedlings seem quiet long (compared to other cacti seedlings) how far up should I cut?

I think the grafting from now is a bit late, not optimun timing but you can try.
I started the seedling grafting in September and completed in January.
Scions need time to grow before winter coming.
Around 200 seedlings mainly Ariocarpus were grafted.


Around 40 days old seedling is the vest for grafting.
You should cut 1/3 of seedling bottom off and graft top.
Turning color of grafting joint should be a evidence of "not good enough sterilization of knife".

The attached photo is some of grafted Ariocarpus in this season.

Wow! Just a couple of plants there
Top work.

Thank you for the advice hanazono.
Might just try a couple and see how they go, the rest of the seedlings I will grow on own roots.
Your grafts look amazing and your peres are all so straight! Some of mine grow with a bend in them.

It is alight to graft Ariocarpus seedlings now.
When you grafted small type of Ariocarpus such as agavoides, kotschoubeyanus in September, you can see some flowers in April.
A bit late means you can not see flowers in coming autumn.
I also keep almost all Ariocarpus seedlings as own-roots.

I use Pereskiopsis off-shoots grown in this season for grafting stocks.
All off-shoots are very straight.
7 days rooting and 10 days grafting process is my grafting method.
As shown on the attached photo, off-shoots are straight.
When off-shoots reached to 15 cm length, I cut them and root.

Update: I grated 2 ario's last night onto peres.
They're under a bucket at the moment to keep up the humidity and protect from bright light.
Will check on them in a few days and let you guys know how they are going.
Also grafted a bunch of random seedlings to opuntia, have had the least success with opuntia grafts but still gave it a go as some previous attempts have taken.

I know its a bit late to add to this post, but I use clear plastic wrap from the kitchen with clothes pins to hold the small pieces over the scion. It eliminates the need for the humid environment and keeps the seedling firmly held to the stock. I typically have a 90-100% success rate doing this. Occasional contamination happens, but if you have any bigger problems than "on occasion" you need to clean your instruments better. I usually wipe the pereskiopsis stalk with an alcohol wipe before I make the cut.

It was not perfect but 196 attempted and 192 taken, 98% in this season.
Several Ariocarpus are now in flower, 8 months old.
I use a different grafting method.