Jon Peterson makes bum shelters -- that's bum shelter, not bomb.

His hotels for hobos, his igloos for vagrants, are handmade abstract sculptures -- waterproof and windproof and big enough to sleep in. He puts them out in cities in the scuzziest of places: in alleys, under bridges or on those filth-strewn vacant lots where winos congregate and bums bed down.

Today he will begin installing three of them in Washington. He will not say just where. "I want them to be used; I don't want people gawking." They are part of his exhibit, if exhibit is the word, for the International Sculpture Conference, which opens here on June 4.

Peterson, an artist who lives in Los Angeles, fabricates his shelters of plywood covered with masonite and fiberglass. He does not try to sell them. Once they are installed, he just leaves them there.

Their colors are the brightest yellow, orange, red and blue. Their profiles are elegant, their surfaces smooth. Because the sites are grim, they look as if they have somehow been put in place by a flying saucer.

"I often think," he says, "of some stumbler, dead drunk, passing out in one of them -- and then waking up to find himself in a shelter made especially for him."

Compassion is, however, not Peterson's only motive. "Not many people see them, not many people use them." He does not see his shelters as a practical solution to the problems of skid row.

"They come," the sculptor says, "out of the realm of art. I was trying to put some subject matter, some content into my work. The question was how to create an abstract object that had a reason for existing other than just being art."

As the sculpture conference's citywide exhibit no doubt will make clear, there is something empty and hugely self-indulgent about abstract public art. Unlike triumphal arches (which celebrate victories) or equestrian statues (which, at least, honor heroes), many modern outdoor works seem to say, "The only reason I am here is that he who made me likes the way I look."

Much art that is abstract and minimalist in spirit carries with it the smell of white-walled galleries, some aura of the privileged, the costly and the clean. The bum shelters of Peterson manage to escape that trap because of their locations and the way they're used.

"Think about them. You have to love them," says Al Nodal, director of the Washington Project for the Arts. Nodal is helping put in place outdoor works by Nade Haley, Sam Gilliam, Rockne Krebs, Leonard Cave, Ed Zerne, Rod McCurdy, Patrick Mohr, Uzikee Nelson, David Staton, Jim Sanborn and other local sculptors that will be on view here while the four-day conference runs. And it was Al Nodal who took Peterson through Washington on the search for bums.

Peterson, who's placed three shelters in Los Angeles and three in Manhattan, says that he was "totally mystified by Washington. I couldn't find the 'Bowery.' The guys said they sleep anywhere. Your transients are transients -- there is no skid row here." He nonetheless has chosen three sites that he likes.

A man of serious mien, he does not brag or gossip. A Minnesota native, now 35, he used to design helicopters for a living. "It was a horrible job, believe me. I looked at numbers all day long." He turned to art.

"One of the strangenesses about being an artist is that if you look at something long enough it starts to become beautiful. I have come to prefer the worst parts of town.

"The site alters the art. Put it in a gallery, and it looks expensive -- like a work of art. Put it on skid row, and it becomes a throwaway -- yet it is only there that the work is truly useful.

"Once I put them out, I leave them till they disappear. The more abstract they are, the less likely they are to be stolen. That is interesting," said Peterson. "Some of them are free-standing. Some I fix to walls or bridge abutments.

"One day I went out to take some photographs of my orange shelter. The bum that I found sleeping there told me he had made it. He said he'd sell it for $2 -- a special price for me. The next day it was gone. Maybe he sold it to someone else."

Peterson does sell photographs and drawings of the shelters he installs. A set of nine color photographs goes for $500. The Sculpture Conference, which is partially supported by grants totaling $82,000 from the National Endowment for the Arts, has given Jon Peterson $2,000 with which to buy his plane tickets, purchase his materials, and install his works.