A Typo Mistake?
Our typo corner focused on someone talking about building canapés when, from the context, it appeared he or she meant canopies. However, an astute reader from Quebec pointed out that canapés are not only foods, but furniture as well. – Editor
“The word canapé does mean hors d’oeuvres, but it also means a piece of furniture; in particular a sofa that seats three. Perhaps the writer was building canapés.” – Serge Sansregret
Perhaps he was, Serge. – Editor
George Washington’s Teeth
Our last issue had a bit about whether or not Washington was a Shaker, and we picked up the motif in the introduction to the free plans by saying “Whether the spirit of George Washington is or isn’t a Shaker, we suspect he would find this little table a handy place to set his wooden teeth.” Of course, our readers could not let that popular gaffe go unchallenged. – Editor
“The old story about George having wooden teeth is actually the consequence of someone misunderstanding what he was looking at. The February 2006 issue of Scientific American had an article about attempts to recreate figures of our first president at various ages for a museum display. One of the items mentioned was that his teeth were actually made of ivory, possibly from hippopotamus. The teeth developed fine cracks that held stains from food, beverages and tobacco so that they looked somewhat like wood. One of the reasons given about the need for dentures was that old George liked walnuts, but got in the habit of cracking the shells by jaw-muscle power, which had somewhat disastrous consequences to the teeth that were between the jaw and the nutshells. Sorry, but those dentures weren’t one of the most important woodworking projects of the early years of the U.S.A. Of course, he certainly could have put his ivory ones on that table.” – Milford Brown
Kreg Jig
“Yep, it’s a great tool. I love it. There is a problem, though. Finding the pocket screws is quite a challenge here in Columbus, Ohio. Lowe’s® usually stocks only one size: one inch.” – Ron Capanir
Have others of you found this to be a problem and, perhaps just as important, where do most of you Kreg Jig users buy your pocket screws? We’re listening, and we’ll post your comments in the next issue. Perhaps your answers will help Ron. – Editor
PVC Pipe
There was a lively discussion after one of our questions asked about copper pipe and several readers wrote in to say they use PVC. The last letter we printed on the subject contained a warning about the dangers of using PVC. Nevertheless, we got a flood of responses about it. These first few contain OSHA warnings, but you will soon see that some folks shared personal experiences. – Editor
“When discussing the use of PVC piping for compressed air, it should be noted that many states and OSHA prohibit its use for compressed air lines. The problem is that, when it fails, it explodes with considerable force and sends plastic shards in all directions. This is a serious safety issue. Additionally, if you check with the manufacturers of the PVC piping, they will not recommend it for compressed air. Some of your readers correctly identified the rust issue with iron piping as well. There is an alternative: several manufactures now offer aluminum piping that is designed for compressed air service. They address the corrosion issue as well as reducing condensates from the air stream and improving tool life.” – Brad D. Wolford
“When PVC shatters, it will blow pieces everywhere, and these pieces will be sharp. OSHA will shut down a shop when PVC is found to be used for this application.” – Glenn MacRill
“Please be aware that OSHA does not recognize PVC as an acceptable means to contain high pressure air in a commercial shop. OSHA will shut down a shop the day they walk in if the shop has a PVC distribution system for high pressure air.” – Larry Lyons
Just in case you are now curious to see for yourself what OSHA has to say about this, here is a section of the OSHA web site that deals with the issue. Of course, hobby shops do not come under the aegis of OSHA, so let’s hear from some people with personal experience in the matter. – Editor
“I had the unpleasant experience of standing within 20 feet of a PVC air line that exploded in an auto repair shop. Fragments, both large and small, were blown as far as 75 feet away, accompanied by an explosion that left everyone in the shop with their ears ringing and their nerves shattered. Fortunately, no one was injured, but that was only due to the fact that no one was struck by the many pieces of shattered pipe. I would highly recommend that PVC not be used for air lines.” – John Sheffield
“I had installed PVC airlines in my shop in Wisconsin, used it for four years, then, BLAMMO! A small seeping air leak around one of the fittings erupted one night. The whole pipe system for about four feet exploded and just splintered into what resembled glass shards. Little pieces were stuck into the drywall and were blown all over the room. If I had been in the shop, I might have enjoyed picking PVC splinters out of my you-know-what!” – Tim B. Inman
OK, we now know that PVC air lines are both illegal and dangerous, but that does not mean there is no possibility of using plastic pipe. Read on, and you will see what we mean. – Editor
“Up until a few months ago, I worked for a thermoplastic pipe manufacturer here in the [United Kingdom]. We actually had a dedicated airline system designed with a 30-year life at 12.5bar. The base material was ABS, but it had an additive to slightly alter the properties. This product has been sold to many major manufacturers as an alternative to traditional galvanized steel pipe systems or copper, all of which will corrode. Whilst the plastic is more expensive, the installation speed is a lot quicker, and the no maintenance and long life made the added value worth considering. However, it was always very much part of all our sales presentations and technical training to stress to people that PVC must never be used on compressed air systems. The reason ABS is used is that it is ductile and can operate from -40deg to + 70deg. If there is any damage, the pipe ruptures rather than shatters. There are several manufacturers around the world that now produce dedicated airline systems from plastic bases, even with push fit fittings.” – Simon Merckel
We here at the magazine have long known the difference between PVC, which does indeed explode when stressed, and ABS, which tends to rip, but it is nice to hear that there are companies making modified ABS specifically for compressed air systems. Just in case your acronym generator is on the blink, PVC stands for polyvinyl chloride, while ABS is acrylonitrile butadiene styrene. – Editor
Typo Corner
Our last effort notwithstanding, we vow not to be fazed, and continue with the ever popular typo corner. – Editor
“I am planning to use Douglas Firm”
We’re almost certain he meant to write Douglas fir, but we’re braced for another astute writer to point out that it is simply a harder subspecies of the popular softwood. – Editor
Waterlox
“It was refreshing to read something about Waterlox. Twenty years ago when I started to take up serious woodworking as a hobby, Waterlox was one of the first and easiest finishes I discovered. It still is. The really strange thing is that when I mentioned using it to several of my woodworking buddies, they didn’t know what I was talking about.” – Walter Morgan
