how do i fix a small crack in my lexan body for 2 wd slash.

My buddy used zip-ties to hold his body together.
Clean the cracked area really well and use duck tape.

Drill a small hole in the end of the crack so it doesnt travel farther and zip tie stitch it together. It should look pretty cool when done. I've done it on full size car bumpers and it has a nice effect. Just make sure you use the smallest width zip ties possible.

shoe goo! and maybe some duct tape.

the drill it and zip tie method is really good too. just doesnt look as clean.

I use drywall tape and shoo goo.

Shoo Goo. You can also add sheet rock fiberglass seeming tape. The fiberglass tape has a sticky side to make it even easier to apply.

Also, they make adhesive clear plastic (like a typical sticker). This clear sticker can be placed over the crack on the outside. It's great to have the plastic already on where the major rub zones are on the truck and to proactively Goo the shell at what looks like the weakest areas.

agreed shoo goo is what I have been using

+ 7 Drill both ends of crack, or where ever the crack appears to be traveling next. Drywall tape, and shoe goo.

I use Amazing Goop which supposedly sets up quicker than Shoe Goo and has the same amount of flexibility. I started backing the Goop with Gorilla brand Duct Tape instead of Drywall Tape. I find it helps align and repair nasty cracks better for me.

When first painting a new body, it's a good idea to reinforce known weak areas as well as backing your paint job with Goop to prevent any chipped paint flakes etc.

I recently found a can of rubber spray from Rustoleum I plan to experiment with on my next body. It is designed to repair leaky gutters, but I think it may work nicely to reinforce the paint on a body as a preventative for the final backing.

A buddy of mine lines his bodies with spray on bed liner to protect the paint. Seems to do decent and makes the body a little heavier and it sounds a little different when it rolls.