i have to build 10 fancy newelposts for a patio. each post is 42″ high and 10″ square with one recessed panel on each side. i thought making a simple box out of marine plywood or mdf and then adding more wood to to each corner like a stile and rail or frame and panel look with a panelmoulding. this hollow post will sit over a 4×4 treated post. all newelposts will be painted, my question is: which material is better for the exterior and should i use a mahogany moulding for the recessed panel? thanks for any help and advice.
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Have you thought about Spainish Cedar for the whole thing? I Have used marine plywood with no problems but it is pricey. I have also soaked a piece of Medex exterior mdf in a buckect of water for a month and no change in thickness. So it is probably your choice.
Chuck S
thanks for your info. i dont mind spending the extra bucks for the marine plywood. that medexply has paper on one or two sides, can you glue wood onto that. what is your experience with titebond #3 waterproof glue? if you have fhb #84 nov 1993 on the cover it shows the newel post i want to built. it's amazing how my old magazines are still helpful even some stuff is outdated. if you have time let me know what you think of that newel post.
I have FHB back to about #40. Large format. I like the Index issues better than the new on-line method. No computer in the shop. Tite Bond III seems to have a longer open time than I or II. Medex has no paper, it is MDF. MDO has a paper. MDO is used by signmakers. You can probably attach all the trim blind, screws from behind, then assemble.
Chuck S live, work, build, ...better with wood
I am not sure of this, but I am under the impression that marine plywood has no better weather resistance than exterior plywood.The marine rating is for structural usage and does not have any voids in any plies..
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Bill
I have always been told the same thing about exterior ply and marine ply, just as you have it...
Doug
You are mixing terms. There is no medexply. Medex is the designation for a supposedly watrer resistant MDF ( Medium Density Fibreboard) MDO is a fir plywood with an A surface coated with hard paper in resin. It is used extensively for those green signs along the interstae and is often called Signboard. Yes you can glue to it just like wood. MDO stands for medium density overlay
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Edited 6/23/2007 8:06 am ET by Piffin
another choice might be MDO, an exterior ply with a paper outside layer.
Paints up very well, think road signs. You wont have any grain show through on your paint job with MDO.
If you want the panel to be stain grade then of course I'd use something like the Mahogany that you suggested but if its going to be painted then either the MDO or Med-ite(exterior MDF).
Doug
The MEDEX would be more stable in that it is less likely tomove from moisture gains so long term I think it would hold paint better.
The down side is that I assume you will be attaching railings to this and that could be a weak point, depending how they attach.
Have you looked into Fypon to see if they have a pattern to meet your needs? Their post attachment system is pretty nice.
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Taunton University of Knowledge FHB Campus at Breaktime.
where ...
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All good suggestions. Since this will be painted and is cosmetic, I'd look into white plastic products like Celotex(sp) or other. Should give the longest maintenance free lifespan.
Expert since 10 am.
OK, I am confused....Are you also woodpecker47?how did celotex come into this?
I mentioned Fypon and it is not plastic. It is a high density polyurethene
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Paul,It sounds like the panels will face the deck and the flat sides are for the railing. He could put some solid blocking behind the Medex, Medite or ply. If I were doing it I would not use the 4X4 posts and do 4- 5/4 raised panels with blind rabbeted corners and keep the top rail wide enough for the railing. I would make sure any joinery would shed water and have copper caps fabricated.Chuck Slive, work, build, ...better with wood
"how did celotex come into this?"Yes, that is very confusing.The ORGINAL Celotex was a pressed fiber board (sugar cane stalks if IIRC, if it might be a different one).But then Celotex made a bunch of other products under the Celotex name including Polyiso insulation and FG shingles.Then they went bankrupt so there are no any products under the Celotex name."I mentioned Fypon and it is not plastic. It is a high density polyurethene"????????????What is polyureathene."Main Entry: 2plastic
Function: noun
1 : a plastic substance; specifically : any of numerous organic synthetic or processed materials that are mostly thermoplastic or thermosetting polymers of high molecular weight and that can be made into objects, films, or filaments".
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A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.
Yeah, OK, concrete is a plastic according to strict definition too....
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mdo
Maybe I got a bad lot, but I used Medex for an exterior application and it failed badly. Made some columns over PT 4x4's with lap joints at corners, the columns under a covered porch are OK, with only a little swelling. The columns that are exposed fulltime are destroyed. I'm in CT, the joints failed within one year.
Regading construction, Gorilla Glue and biscuited all joints, sealed inside and out with SW oil based paint and primer.
I'd try MDO or real wood.
David
Wow, I heard something had changed in the MEDEX formulae....MDO is great stuff too but I would have to carefully mill a lock joint for the corner. Wouldn't want a bare edge splintering.Just a few days ago, I was cleaning up out near the shop and pulled a sheet of MDO off the ground. Don't know how long it had been laying down growing green stuff and soaking uip water, but it was still sound.
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I've had MDO as the exterior for my trailer for over 5 years and the things been beaten, bruised and battered - still holding up great.Let's not confuse the issue with facts!
OK all show you my work, it's really sad, I put alot of time into the fence. Picture one is the fence I built, about 4 years old. Notice one of the pickets is broken, just broke off, inside the picket was wet. Picture 2 shows the top cap of one of the exposed posts. I think the 3/4" thickness is more like 1" now.Picture 3 shows the joints completely ripped apart. After the first year, I tried to recaulk and repaint everything (thats why it looks so bad). I was hoping to get an extra couple of years.Picture 4 shows a joint on a column under the porch.FYI this is the north side of the house.I took extra pains to help drain water, the horizontal surfaces are all sloped, kerfs underneath to shed water etc.
I wasn't doubting you at all. Like I said, I'd heard that something had changed. I had done some back in about 1995 that like your porch columns are partially protected, but the caretaker places flowerpots there and sprinkles them regularly. I was by there two day ago and they seem just fine.
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I think I'm going to rebuid the fence this year. What would you use for Mat'l? I'm thinking MDO. (with locking mitered corners)David
I wonder how that locking miter will work on plywood(MDO).
I've built some things outside with MDO and I just mitered the corners, using bisquets along with a good exterior glue - several years later everyting still looks good, tight joints and all that jazz.
Doug
For A FENCE LIKE THAT i WOULD USE cvg FIR OR RED CEDAR
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WD,
Check with the manufacturer. You supplier may have sold/substituted (yard monkeys) something that was not what you ordered, unless they changed the product, as Piffen stated.
Chuck Slive, work, build, ...better with wood
No, I'm 99% sure it had Medex written on the edge. I remember paying $60 a sheet and thinking this stuff better be good!! Oh well, it'll give me something to do this summer. David
David
I just went to their web site and they no loger claim it to be an exterior product.
http://www.sierrapine.com/products/mdf.htm
Class Action? I do not think it would be worth it. Try a solid wood with good exterior properties.
BTW, nice work. It will be easier this time around.
Chuck Slive, work, build, ...better with wood
I would consider Azek or their competitors for this app.
MDEX is NOT rated for exterior use. Talked to a rep about it, They say it should not even be used in a bathroom. Makes you wonder what the point of the stuff is.
woodpecker,
MDO.
I have concrete forms I have had for 5 yrs. made from it, some have sat uncovered for half that time and with water dripping on them 6 months out of the year.
No edge treatment at all , some cut down from the original 4 x 8 and Still in good shape.