View Full Version : portland cement for screw bung holes?
05-23-2005, 07:00 PM
I was wondering if portland cement has been used to fill bung holes on the bottom planks? Anyone done this? Seems cheap, I dont know if it would stay in a 1/2 inch hole upside down as you were trying to fill the hole. Other alternative is the cheap 35 year acrlic latex caulk from HD at 1.50 per tube all the way to more expensive polurethane caulk. I am still going to coat the bottom with sanitred permaflex, and I am still putting together the port bottom side of the boat so nowhere near finished yet.
I will have about 4 thousand holes to fill and I have been thinking thru various materials that could be used for this besides wood plugs which would be quite tedious and onerous to make.
I hear cement bungs are just the thing for cement hulls. Sorry, couldn't resist. I don't have an answer to your question.
05-23-2005, 07:27 PM
Turn da bot downsideup...
sheesh... datz da eazy answer
05-23-2005, 07:40 PM
Well...this may be stating the obvious to you Sdowney, but 4000 Phil Mahog or such bungs, of the size typically needed for say, 1-1/2" screws, can probably be had for a couple hundred buck or so with bulk pricing.
I should think wielding a sharp chisel or slick would be more fun (and quicker) than trying to stuff sagging goop in overhead holes..and hoping it doesn't shrink below hull level as it dries, necessitating round 2..
The benefits over goop can be legion....
05-23-2005, 07:53 PM
...stone boats sink....
Don't use cement, I can almost guarantee it will fail using it as screw plugs.
Use famowood, about $4. a pint and a pint ought to do at least a few hundred.
When you have to dig it out, will you think that cement was a good choice? we have a tendency to look for a short-cut going in and end up wishing somebody had delivered a good swift kick when we needed it. You want cheep? use painter's putty.
05-23-2005, 08:57 PM
I would hate to hit that cement with my chisel...why not marine grade "bondo"
05-23-2005, 10:08 PM
If you must, try epxoy with micorbaloons, which will sand about as well as wood. You don't want a harder material like cement because when you fair the bottom over time, it will have bumps where the cement was harder than the wood. DUMB IDEA. If epoxy isn't your cup of tea, then use good old fashioned white lead putty. Or, buy a plug cutter and hire an idiot boy to turn out however many bungs you need on the drill press out of scrap offcuts. Buying bungs is really crazy. The first hundred or so will pay for the ten buck cutter and after that, they're all free. If the day comes that you ever have to pull a fastening or three, you'll be glad you used the bungs and not epoxy, putty or, God forbid, cement.
[ 05-23-2005, 11:09 PM: Message edited by: Bob Cleek ]
05-23-2005, 10:18 PM
He's coating the hull with Sanitred. Does it really matter what he fills the screw holes with? smile.gif
At the last WoodenBoat show they had a demonstration of filling screw holes with a mixture of rosin and beeswax. They melted them together in an old pan. Dried hard and was paintable. Anyone else try this?
05-24-2005, 12:25 AM
Dry Portland cement powder mixed with bottom paint is an old formula for long lasting and virtually indistructable below water seam and bung hole fillling, especiallly in wet problem seams and fastening holes. It worked a hundred years ago and it still works today! Been there done that many many times. Trust me it does work, and work wery well!
05-24-2005, 05:37 AM
I like wooden plugs, I have made tons of them for plugging the frame holes gluing them into the frames for the screws and really am not looking forward to making any more. I have been making them out of white oak.
The famowood is also a good idea I think. Where can you buy it?
yes, mixing the cement with paint sounds better than just the water. I suppose if you mixed it with oil based bottom paint, it would stay softer? I will have to try this, mix some with latex paint, water, oil paint and bottom paint and do a test to see which is best. as far as getting cement out of holes I was thinking you could use an air impact hammer and fracture it out of there if the cement was mixed with water.
But if it is mixed with an oil paint it may stay softer.
Really all I need is an easy to use filler that is not very expensive.
I cant turn the boat, it is 37 feet and weighs 15 tons. But I wish I could.
05-24-2005, 06:08 AM
Steve Bauer pretty much nailed it, he's coating the bottom with Sanitred, he might as well fill the holes with drywall compound, it's cheap its easy to use it drys fast, it's sandable....
05-24-2005, 06:12 AM
Below waterline best practice is some sort of filler, cement and bottom paint (bottom paint!) being common. Often the hole is dabbed with a bit of red lead before the screw is set.
Though it's work, I like dabbing the hole with CPES before setting the screw.
There's a huge range of commercial and home made glops for filler. Again, this is modern times and I personally like thickened epoxy best.
Above the waterline, use bungs. Even though you'll likely paint over, they really do look better if the grain runs with the planking grain and if you cut them from planking stock ends.
05-24-2005, 07:18 AM
15 TONS, 35 FEET, and you want sanitred and HD caulk or cement bungs... huh?
Portland Cement (not to be confused with Portland cement concrete, FYI is highly acidic and corrosive... I'd not want it on my boat, but maybe I'm picky.
05-24-2005, 07:26 AM
The above 'stormpetral' comment is actually mine - I was not paying attention to the log-on.
05-24-2005, 07:43 AM
You have scraps of wood from planking material, making plugs is a good project for rainy days or instead of sitting in front of the TV. A 35 foot boat is a long project, some days desire to do other things just isn't there, so set down and glue in a hundred or so plugs, a hundred or so at a time and by the time the hull is planked all the plugs will be in. By the way when making plugs keep them attached to a thin strip of the wood for holding them during glueing, don't break them off and toss 'em into a bag like the store bought things.
Famo-wood is sold by glen-l. I think it works great, might have to hit it a second time on deep holes.
The comments on mixing pure cement with bottom paint, is very interesting.
It is always amazing on subjects like this, how some will say, it is crazy to do it, and then others will say it works great and has worked great for the last hundred years.
I am always open to trying something new, or better yet something that is old and tried and true, if so be it.A little experimenting might be in order.
I do not believe the cement is caustic at all, that has been proven by the cement in the bilge, but as a plain plug, I would think that it would need to be mixed with something.
05-24-2005, 11:39 AM
Wood bungs will be the easiest and best solution.
Trimming the bungs, if you use the right tool, will be a lot, and I mean A LOT faster than sanding any kind of putty. The best tool is an offset chisel.
If I had to use a putty, I'd go with epoxy thickened with microballoons.
05-24-2005, 11:47 AM
Cement is caustic / basic (not acidic as I said earlier). If you don't beleive me, go pour a large concrete structure, walk around in it for a few work days and don't wear the standard rubber boots... I worked at a concrete lab, and we kept photos of severe portland cement concrete burns on the wall as reminders to us an our guests to be reasonable with handling.
A quick Google search turned up:
C&CI site (http://cnci.org.za/inf/leaflets_html/guide_safe.html)
and short story version (http://experts.about.com/q/1357/3965995.htm)
Wich is why I don't like concrete in bilges either. But, I am a novice with boats and such, and I've been wrong enough to know better than to be too stubborn. OTOH, I'd wonder why basic/caustic concrete would be placed on acidic oak and other structural wood timbers.
05-24-2005, 12:50 PM
I once partialy replanked the bottom of a Columbia River gill netter that had been damaged in a grounding. The boat was about 90 years old and had cement filled bilges. The galvanised boat nail holes on the bottom were filled with the mixture of soft bottom paint known as "Tripple C" (Cape Cod Copper Compound) and Portland dry cement powder. the wood under the cement bilge filler was still in good shape. The fastenings, though rusted at the clinches were still good under the cement bungs.
The holes had been red leaded prior to the filling with the cement and bottom paint.
05-24-2005, 01:59 PM
Have to agree with Jay, based both on personal experience and discussions with folks far more knowledgeable than I. It wasn't uncommon to have fish boat folks use it as patching material on their planked boats. It is available as hydraulic cement and comes as a powder in quart or 1 gallon cans. Can't recall the brand name right now...
Thad Van Gilder
05-24-2005, 04:25 PM
You know what guys,
It's an Egg Harbor...
If it was a Herreshoff or a Hilyard, It would rightfully deserve respectable repairs.
I give in... I suppose cement bungs painted with sanitred is par for the course :rolleyes:
In fact, you could probably staple chicken wire to the hull and plaster it with cement. I have heard of it being done on tugboats!!!
Sir, good luck on your mission.
05-24-2005, 04:35 PM
, it is 37 feet and weighs 15 tons. Well... any 37 Egg that weighs THAT much allready probably has 4 or 5 tons of Cment in it's bilge so a few thousand pebble size rocks wont add much and the Sanitred may just keep it inplace..
Sheesh... this is nutz
Thad Van Gilder
05-24-2005, 05:04 PM
That's what I figure...
If you put 2 tons on a boat that already displaces 15 tons, you're still ok.
05-24-2005, 10:10 PM
Cement is caustic / basic (not acidic as I said earlier). If you don't beleive me, go pour a large concrete structure, walk around in it for a few work days and don't wear the standard rubber boots... And don't I know it. I copped it about 15 years ago. I was excavating a basement under the house and had dug a trench for the footings. The concrete truck didn't have enough chutes so just dumped all the concrete in one spot. I had rubber boots - but only short ones. I got concrete in the boots, but kept working until I'd spread the concrete out.
I got caustic burns and lost about 30 square inches of skin - it just peeled off, hair and all. Absolute bloody agony - couldn't walk. Still got the scars, but they have faded a bit.
I've learnt to have less task orientation and balanced it with more process orientation over the years :D
05-25-2005, 08:15 AM
yes, cement will burn you
So some of you think 4000 bung holes filled with concrete add up to 2 tons???
I am guessing more like 100 lbs or less.
And from what I have read seen and heard, concrete does not destroy wood but seems to preserve it, perhaps due to its caustic nature creating an environment that wood fungus does not like. It can affect the PH balance of dirt and hurt acid loving plants and shrubs.
05-25-2005, 12:48 PM
The gentleman plainly asked a simple question and some of you pompous asses want to scathe him. I realize things may be different up north or out west, but manners in the south require folks to converse with each other in a civilized way. To put it bluntly, my wife is beautiful, my dog doesn't bark or bite, my kids don't sass, my boat is great- and for you to publicly state otherwise will get you a good whippin !!! This forum is a tremendous source of info. But just because your boat is the best thing that ever floated does not make anyone elses less. I've had more fun in a 16 ft. john boat with a paddle than most of you guys that own display queens will ever have, sldowney likes messin with his boat and has his own ideas about things that you may not share. Wouldn't the world suck if we were all the same ?
Working a few yards in England, I learned many good basic methods. One was the making of Swedish tar. But here I can tell you that a little cement mixed with some linseed oil, all to the right consistancy does a good job at filling gashes or holes in the planks. no problem! QMBob
Mr.Vaitsis has often suggested that with leaks that couldn't otherwise be stopped that fast plug cement was a good choice. I think that that expressions of horror here have been with regard to the need in the future to remove those cement bungs to get at the fasteners. I think that we are dealing with workboat economics here and not to be confused with fine wood boat building. I guess if it works it is a good job.
05-26-2005, 01:34 AM
Well said Kulas 44.
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