Grafting to Acer Rubrum

Can you graft Japanese maple foliage onto Acer Rubrum trunks?

You can only graft an acer species onto another of the same series.

See:
http://webpages.charter.net/wbshell/garden/FAQ.htm

And:
https://en.wikipedia.org/wiki/List_of_Acer_species

Alain K is correct.

Scion and understock need to be "compatible" for a graft to be stable for the time periods we want our bonsai to last. If you want a bonsai to last 50 to 100 years or more, the understock and the scion have to be so compatible that the two fuse completely. While the mechanisms are entirely different, it is analogous to matching a human kidney donor with a kidney recipient. The more traits matched (in humans, immune system traits) the better the match. If the match is poor in humans you have rejection.

The further apart the relationship between the scion and the understock, the probability of graft union becoming stable and well fused for the 50 to 100 year life cycle we are looking for goes down rapidly. Often the grafts will not take at all if you put JM on understock from a species that is not in the Palmatum section of the maple genus. Or if it does take, it won't be a stable graft, it will fail in time.

The goal is to have the graft fuse completely and become invisible to the casual observer, hopefully within 5 to 10 years. The only way to get smooth grafts is to use closely related species. Generally it is best if the growth rates of the understock and the scion are fairly equal. If not perfectly equal, the scion should be just a little slower growing than the understock. IF the reverse is the case, you will end up with reverse taper below the graft union. If the understock is too vigorous,there will always be an abrupt size change at the graft with the understock being fat, thicker in diameter, you will never get the graft union to disappear visually. So not only do the species have to be closely related, they should be matched for growth characteristics if one is going for "the perfect, invisible graft". Therefore, in JM, palmatum is usually only grafted to palmatum.

In bonsai, the evidence of the artist's techniques should not be visible.

You can graft anything to anything, and if it lives, the resulting "Frankentree" will always show the hand of man. I did see a photo of a hinoki cypress scion grafted on to a branch of a plum tree. Photo was about 3 months after the graft was made. Never did see the follow up. But it did look weird. Doubtful that it survive past a winter.

Leo's explanations are very clear.

It's true that some grafts can be, or rather seem to be successful for a limited period of time, even if some "frankengrafts" are possible. For instance, a professional told me once that you can graft lilac on privet (two totally different species). The interest is that the grafted lilac tree doesnt produce the many suckers like non-grafted lilacs do. but these possibilities are very rare.