Improving relationship between two boars

Question
My sister had just brought home a new guinea pig who is about 6-8 months old just about a few days ago. We tried introducing them in an area that was not familiar to our guinea pig, seaweed. At first, seaweed showed some signs of dominance towards the small one who did not react much. However a few minutes after seaweed stop showing dominance and started ignoring the small one, the small one started to chatter,show his teeth and push seaweed around. We only separated them when the small one attack seaweed in a very aggressive way. We thus decided to place a partition between the cage we bought for them which has grids in them to allow them to see and communicate with each other but prevent either one of them from injuring the other.The small one has being biting the grid obsessively but only when something frightens him. Both of them would try to put their head through the grids as if they are trying to bite the other.We however still continues the "meet ups" for them to allow them to get to know each other without a barrier between them. But it seems that seaweed is quite annoyed by this and sometimes starts "vibrating" (I am not sure of the technical terms) and does not seem to want to do anything except to go home. I am worried that we will never be able to remove the partition forever and seaweed would never experience having a partner again. Seaweed actually when through his grandma, brother,aunt ,mother and father death so we really hope that the small one would be his new companion till he pass on.

Answer
Well, the simplest idea would have been to purchase a female!  Yes and No!  Your boar would happily accept a female friend, but that only if you want more guinea pigs.  Imprudent breeding is not a good idea.  The boar that was purchased is just to old and I'm sure your pig is territorial.  Your boar might have like a baby to care for.  I don't know how much time you have to put into this unification.  I have 4 boars that have know each other for over a year and none of them can be placed together without a fight.  So you must determine your path.  Perhaps you'll end up with two cages and two separate animals.  That's the best I can tell you from my experiences.  Cindy