I'm making a white pine picnic table. Around here, (unfinished) they seem to last ~10 years before they're too rotten to use. Is there something, hopefully inexpensive, that I can put n it to extend that by at least a few years? Would things like Thompson's Waterseal or linseed oil do anything? I think Cetol would help, but it is rather pricey, and it does turn thing orange. What about a dilute varnish? I'm hoping to hear of a traditional something used for extending lifetime of outdoor white pine. Thanks in advance.