M.D.O. & H.D.O. UPDATE....

[RonW]

We have had some info reguarding using mdo & hdo for boat hulls. Someone posted recently that harbor sales, are now selling signal mdo, and 1/2 in. is approx. $52. and 3/4 is approx. $67.
I just spent some time talking to olympic about this, and spelled it out, BOAT HULL.

They tell me that signal mdo is excellent for hull material, and the absolute best would be highway hdo. Stay away from concrete panels, they are too slick to hold paint with a plastic type resin overlay.Highway hdo should cost about $10, a sheet more then signal mdo. Both of these panels will take and hold paint well, but you do have certain paints to use.For xtra you can also get these in pre primed.
Both of these panels are marine quality ply with a hardwood overlay, the overlay is african mahogany. Not occummee.Then the resin overlay over this. They tell me there should be no problem at all and did say it is a good deal when you drill for your fasteners to put a little something in the hole before your fastener to help seal, like a polyurethane caulk.

I was also told that harbor sales have just recently paid them a visit, and should very shortly being carrying the highway hdo as well.

http://www.simpson-plywood.com/sign_making/highway_hdo.php

Occummee may be short lived all but for the smallest and lightest.

[Venchka]

Way to go. I spent most of yesterday exchanging emails and phone calls with one of their salesman and didn't get anywhere near that much information. The person I spoke to wouldn't come close to telling what there "hardwood" was. Nor would he say that the Signal MDO interior was marine grade. Thanks!

So, they actually said Highway HDO was the answer for building hulls? Sealing and protecting the edges of course. Great news.

Stop. Time out. If I'm reading the web page correctly, The Highway HDO doesn't have the "mystery hardwood" face veneers. Signal MDO is the only panel with that feature.

Did you also see the 4'x10' Signal MDO at Harbor Sales for very little extra over the 4'x8' size. 4'x10'x3/8"=$70.20, 4'x10'x1/2"=$76.10, 4'x10'x3/4"=$81.50. 4'x10'x1/2" A/A marine fir=$96.94.

Wayne
In the Swamp. :D

[RonW]

Nope the highway hdo does have the hardwood overlay as well. The hardwood overlay is one of 9 species, that they use. It is of the mohagony family and very much like merantti. Both of these panles are also very tight cores, just like marine. Actually there are voids and core gaps allowed in the concrete panels that are not allowed in these. With the emphasis being put on the thick plastic overlays that are slick and hard for concrete panels. He said harbor sales spent quite a bit of time with them, and will be carrying the highway hdo also. I did not see that harbor is also carrying 4x10's that is good. Also olympic says they can make bigger panels by special order, harbor might want to look into 5x10's.

And you do want to buy both sides finished, I questioned him as to the inside bottom of the hull where water will sit from time to time as to it softening the overlay, he says no worry. Again the highway is the same as siganl mdo but the resin overlay is a higher quality and thicker.

He also tells me they use to make marine, but quit, it is just too hard to find clean veneers, and he described my last batch of marine to the tee. Lucky if the b side has less then 30 plugs.
So with this they can plug as needed, hardwood veneers, and resin overlay and have a better product that is easier and cheaper to make as well as selling for less.Better product to boot, and no more grain showing or having to coat the hull with epoxy and cloth.

This is a hell of a product.

And for the guys in cincy, Remeir's lumber carry some, but olympic tells me they only charge $50. for a break down unit, like 5 or 10 sheets, and it can just be delivered with the next load to remier's in ciny.You can do the same, just find out from olympic the closet lumber yard to you and have it special ordered.

Sorry Wayne, but I hasve 30 years experience in dealing with lumber yards, and you have to push your way to the top and ask the hard core questions. When the salesman stutters,or has to look it up in the book, I am done and up the ladder to the next one.

[JimD]

Good info to have, thanks, Ron.

[Venchka]

...and I did catch the only guy in the office on a holiday. :D

This throws a whole new light on my future boatbuilding plans. Wee Seal II is looming larger on the horizon. Seal the plank edges with cypress set in epoxy. Probably come in 30%-35% heavier than Iain thinks. Hmmmm..... :cool:

Wayne
In the Swamp. :D

[ 05-31-2005, 08:26 PM: Message edited by: Venchka ]

[shoal_draft_fantasies]

Canadian source for MDO /HDO
http://www.white-wood.com/wwf_sign_panel.htm

Winnipeg, and Calgary.

I'm going to have to give them a visit just to see what this stuff looks like.

[Venchka]

Question?

I see the advantage of having the MDO or HDO on both sides. I assume, since the faces will end up in glued joints, that the primed and painted MDO/HDO should be avoided?

Wayne
In the Swamp.

[shoal_draft_fantasies]

good question re the primed/painted finish.

I have questions about:

1) flexibility of the material ( if 2 sided ) how well does the stuff stand up to compression, tension when curved into place. Is it the same as ply? or does the outer coating have "issues" like cracking? How much bend before it is being tortured?

2) what is the outer coating chemically - can it be epoxied to succesfully? or does every joint need to be ground down to original plywood?

..sdf

3) I suppose I need to see some sort of engineering spec sheet on the stuff.

[Paulyboy]

Hey, RonW, I used to buy MDO from Reimers lumber for use as a sign board substrate. They used to stock it in several ticknesses and also in single or double overlay. I still cruise by signs I painted going on 12 to 15 years ago and the surface as well as the signs look great. If they can stand up to 24/7/365 exposure to all the weather and UV , wouldn't that tell something of their durability?

[RonW]

Paul, think your post might rattle a few cages.
Might give the occummee and epoxy crowd something to think about. Good solid info.Thanks.

I would think a boat hull with reasonable care should last 3 times as long, at least.

Check out the link above to simpson or olympic panels and read the paint schedule. I would think 3 thin coats of a oil base paint. But you tell us, what would be the best way to paint these mdo and hdo panels?

I would see no reason to bother with the pre-primed panels, and absolutely no need to bother grinding off the resin for a glue joint.If anything the resin overlay would give you a better glue joint, especially with epoxy.

[WoodenBNut]

You guys in Cincinnati: Where is Reimers Lumber?? I need to be picking up some MDO for some deck repair in the near future. Thanks

[RonW]

Tennessee avenue, just off the norwood lateral.
They are in the yellow pages as well.

[sand some more]

I have never seen this stuff what does it look like and can you varnish it and if you do how will it look

[Venchka]

Originally posted by sand some more:
...can you varnish it...Nope. It has a tough "phenolic resin" coating on 1 or both sides. No wood (no checks, no grain, no patches) shows except around the edges. You paint it. That's all.

From Olympic Panel:

Signal® MDO panels are made of high quality, exterior-grade plywood with the same adhesives used in marine plywood. The Medium Density Overlay is a fiber sheet which has been treated with a resin formula for optimal paint adhesion.

I would add that except for exposed edges you don't have to coat it with epoxy prior to painting. That saves time and $$$s over raw wood plywood.

Wayne
In the Swamp. :D

[ 06-02-2005, 04:44 PM: Message edited by: Venchka ]

[Dave Gray]

Must be great on hand tools!