Capping and sealing parts

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I just made a plow frame for the FEL on my tractor.  I capped off the tube stock that I used to prevent rusting.  I'm wondering if I should also run a small bead around all other parts that are put together to prevent water and moisture from getting inbetween them and rusting them out too.  Most likely this will be outside most of its life.  Seems that most people don't bother as it probably isn't cost effective, but cost isn't and issue here.  I see rust spots showing on paint where other stuff hasn't been welded and moisture is getting in.  Just curious, thanks, Nick.
Reply:if your existing welds are enough then just feel in the gaps with a paintable chaulk, let it dry then paint to match.PL polyutherthane is the best as it will expand & contact with the metal so water can't get in. regular cheap chaulk srink over time and let water in the sunken gap. You find the PL brand at Lowe's, Home Depot, Ace Hardward, and boat shops.Last edited by specter; 01-25-2009 at 08:37 PM.Co-Own CNC shop:Miller :1251 plasma cutter, MaxStar 700 TIG/Stick, & XMT 456 Multiprocess Welder.&  2 Hypertherm HPR260's Plasma CutterSorry I had a bad stroke but now I am back.
Reply:I build stainless steel tables at work. A little different but we use caulk and spray paint on the undersides where people aren't going to be looking a lot. Sometimes if I'm in a good mood I will put in more welds than are strictly necessary though. It's your plow weld em up if you want but caulk will work too.Edit: BTW my employer has had a lot more trouble with people sending out work with way too few welds than to many and I guarantee they won't complain.Last edited by blkfirsprk; 01-25-2009 at 09:04 PM.
Reply:Another vote for caulk, I have seen farm machinery, mining equipment etc. all get the caulk treatment at the factory.I don't know how your FEL is built, and this may not be the case with it but just because certain things aren't welded does not mean they should be. Some things on heavy equipment, buildings and so on have places where it looks like a weld is missing, when in fact it was intentionally done that way for a specific reason.2 centsYup
Reply:All I'm trying to do is prevent rust.  I wasn't going to weld it for strength purposes.  Just to seal it up.  I've been working on this thing long enough...  I am kind of leaning towards the caulk method.
Reply:It is a good idea to cap and seal tube stock.  I repaired the rear most beam on a horse trailer last year.  A 2x4 inch tube had a hole rusted through about the size of a quarter.  After repairing it, I wanted to rust proof by spraying Krown Rust proofing inside the tube. I drilled ½ inch holes in the end caps and two other holes along its length.  I was surprise to find it was full of sand and small stones.  They entered the tube through ½ inch holes used to pass wiring for tail lights.  To clear the debris, I removed one end cap and connected a 3/8 inch length of copper tube to my garden hole and forced out the crap.  It filled a 4 litre ice cream pale.  Prevention is always best.
Reply:Just a little bit of a different slant on the problemI think it's a good idea to cap tubing, if you know the welds are good.  Any question, put a weep hole at the lowest point.Let's say you have a piece of plate welded onto the equipment somewhere.  It really didn't need to be welded all the way around.  And you're worried about the rust that seems to seep out of the joint every time it rains.Maybe closing off the plate by welding it all the way around will cause unacceptable distortion where you don't want it.OK, so now we're thinkin' about caulk.  Caulk can get you into trouble.  It can crack with age and let water in, and worse of all, the caulk, or the weld, on the lower side of the piece can maybe hold water.  You gotta real problem.Sometimes the rust stains you see aren't all that bad.  It means water is DRAINING thru the thing.  And if it's draining, it also has 02 flowing thru it to dry it out once the wet weather passes.I deal with tillage and hay equipment that gets all sorts of stuff caught in nooks and crannies.  If you don't clean the crud out of these places every season, it provides a place for water to collect and sit for a while.  It needs to dry out.  I clean all the crap off, and have alleviated about 90% of my problems by allowing air to the area instead of sitting damp for long periods.I think that if you're building things that might sit on a lot for a while before they're sold, it's a good idea.  Makes it look better without all those ugly stains on it.But if it's your own equipment, I'm not so sure.A lot of hidden water damage can occur.Just a thought."Any day above ground is a good day"http://www.farmersamm.com/
Reply:As you seal up tubes, you may find the weld blowing back as you near the end of the job.You are in fact forming a sealed vessel, and as the end of the welding nears, the air inside, now pressurized, is trying to escape. If you have encountered  "blow -out", just stop, grind out the affected area, wait for the piece to cool completely, then close the last little bit. I too have been quite amazed at how much sand and other road "stuff" ends up inside tubing, with the resulting rust damage.Bgbkwndo.
Reply:Originally Posted by BgbkwndoAs you seal up tubes, you may find the weld blowing back as you near the end of the job.You are in fact forming a sealed vessel, and as the end of the welding nears, the air inside, now pressurized, is trying to escape. If you have encountered  "blow -out", just stop, grind out the affected area, wait for the piece to cool completely, then close the last little bit. I too have been quite amazed at how much sand and other road "stuff" ends up inside tubing, with the resulting rust damage.Bgbkwndo.
Reply:Good morning farmersamm,                                        I would say that the smaller volumes tend to be the most troublesome. During my welding career, I did a lot of tube frame fabrication for race cars and street rods. To prevent this "blow-out" problem, I would drill holes where one tube intersected another, thus forming a larger vessel. By skip-welding around the frame, the problem was eliminated, and the holes were hidden inside the joint.Bgbkwndo.