I have pushed alot of pins into a bunch of balsa in my lifetime and I am here to tell ya, using lead or steel ingots is much safer for your airplane and your fingers. I know for a fact that a structure that must be pinned down then taken up, then pinned down again any number of times is ultimately going to get weaker every time a new pin hole is added. Like I said, use the weights (match the proper weight for the structure you are holding down) to immobilize a structure dry....move things around as needed under the weights....and when everything is lined up to your satisfaction....glue her! can't be easier. Also, Dave Platt (in his vidios) likes to glue structures right to the glass and work on them. I have done this as well and it works great. When you want to take it up, a slight twist and she is in your hands. Then just scrape the CA off the glass with a scraper. This is great for things that must be sheeted. The pin and board method always gave me fits when it was time to sheet something because you had to reposition a hundred pins so that you could get at them after the structure was sheeted. Anyway, If you can not afford a large chunk of glass for a building table, get a small piece to build small structures (tail Feathers and such???) on. Once you see how nice it works, you may start saving for the bigger chunk of glass. Razorback11